tag:theconversation.com,2011:/uk/topics/caffeine-4969/articlesCaffeine – The Conversation2024-01-24T00:16:27Ztag:theconversation.com,2011:article/2215912024-01-24T00:16:27Z2024-01-24T00:16:27ZSome Australian Open matches run extremely late. How would that impact player sleep and recovery?<p>For many Australians, January is synonymous with late nights spent watching the Australian Open tennis tournament. These night matches are a great spectacle, and many players consider the prime time slot on centre court as a privilege and reward for their hard work.</p>
<p>An early highlight of this year’s tournament was the men’s third seed Daniil Medvedev playing out <a href="https://www.tennis.com/news/articles/daniil-medvedev-emil-ruusuvuori-australian-open-339-am">a five-set thriller</a> against unseeded Emil Ruusuvuori, with the match finishing at nearly 4am. Less than 48 hours later, Medvedev followed this up <a href="https://ausopen.com/articles/news/medvedev-eases-past-auger-aliassime-sets-borges-clash">by winning his next round match</a>. </p>
<p>In Medvedev’s <a href="https://apnews.com/article/medvedev-late-australian-open-tennis-708e79d5b03b1d8f042e4b23f183cc88">post-match interview</a>, he discussed recovery and preparation strategies after the previous late-night finish. This included ice baths, medical treatment and physio work before finally going to bed at around 7am, managing to get five hours of sleep.</p>
<p>Similarly, the first round match for women’s number two seed, Aryna Sabalenka, didn’t start <a href="https://womensagenda.com.au/life/sport/defending-womens-champion-plays-just-before-midnight-at-australian-open-raising-scheduling-questions/">until almost midnight</a>.</p>
<p>As sleep scientists, we know limited and disrupted sleep opportunities can impact the body. So what do these late nights and lack of sleep mean for players’ recovery and performance?</p>
<h2>Why a lack of sleep is bad for your muscles</h2>
<p>The function of sleep is still not well understood, despite us spending close to a third of our life asleep. While we do know that sleeping less than six hours a night is linked to the increased risk of several <a href="https://doi.org/10.2337/dc09-1124">chronic diseases</a>, there is still much to investigate.</p>
<p>Several recent studies we’ve worked on have demonstrated the importance of sleep for optimal muscle function. For example, one night of <a href="https://doi.org/10.14814/phy2.14660">sleep deprivation</a> (pulling an “all-nighter”) or <a href="https://doi.org/10.1113/JP278828">repeated nights of short sleep</a> actually impair the muscles’ ability to make new proteins, which is essential for repair and recovery.</p>
<p>Furthermore, other recent research suggests that a period of sleep loss (five nights, with four hours of sleep each night) can <a href="https://doi.org/10.1016/j.molmet.2020.101110">reduce mitochondrial function</a> within your muscles. Mitochondria are known as the “powerhouses of the cell” and are responsible for producing the energy needed to exercise – and win a tennis match.</p>
<p>Therefore, the lack of sleep tennis players experience after such late-night finishes may well impact their recovery and subsequent performance.</p>
<h2>Sleep loss directly affects athletic performance</h2>
<p>It is well accepted that sleep loss negatively impacts cognitive function and decision making. While the data is not definitive, there are also several studies that show sleep loss <a href="https://doi.org/10.1016/j.jsams.2018.01.012">impacts athletic performance</a>.</p>
<p><a href="https://doi.org/10.1249/mss.0000000000003000">A recent study</a> in healthy young women accustomed to resistance exercise found that when they performed their weights session after several nights of restricted sleep, the quality and volume of their performance was reduced. The effort it took to complete the session increased, too.</p>
<p>Losing sleep is also detrimental to anaerobic power and skill execution – both of which are critical for Australian Open hopefuls. One study <a href="https://doi.org/10.1016/j.physbeh.2013.07.002">found a decline in tennis serving accuracy</a> with only five hours of sleep, while another found a <a href="https://doi.org/10.1080/07420520802551568">decline in maximal power output</a>. </p>
<h2>Exercise can help you sleep – but it depends</h2>
<p>It is a widely held belief <a href="https://www.hopkinsmedicine.org/health/wellness-and-prevention/exercising-for-better-sleep">that exercise improves sleep</a>. However, falling asleep shortly after completing an adrenaline-fuelled, high-intensity tennis match is not always easy.</p>
<p>Indeed, a recent study investigated the impact of <a href="https://doi.org/10.1093/sleep/zsad099">high-intensity exercise on sleep quality</a>. When the high-intensity exercise was performed in the early afternoon, deep sleep was improved. But when participants exercised shortly before bed, their sleep quality diminished.</p>
<p>However, this effect also depended on whether the person was a morning lark or evening owl (scientists call this a chronotype). The sleep quality of evening types was unaffected by exercise in the evening.</p>
<p>When it comes to tennis stars, a late-night finish can also affect their circadian rhythm. By the time Medvedev or Sabalenka would have got to bed, their natural, tightly regulated internal clock would have been readying them to wake up. Such a misalignment between the body’s circadian rhythm and the body’s drive for sleep tend to result in disrupted, insufficient sleep. </p>
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<h2>Can players prepare to handle late-night matches?</h2>
<p>Some players have <a href="https://apnews.com/article/australian-open-late-matches-explainer-509cb3dab84762ae346a1c7fc7b3dfe4">voiced their concerns</a> regarding <a href="https://www.abc.net.au/news/2023-10-03/australian-open-extended-late-night-finishes-thing-of-past/102927520">late-night matches</a>. But other players suggest it’s just <a href="https://www.theage.com.au/sport/tennis/it-s-the-nature-of-the-beast-why-the-australian-open-can-t-avoid-late-nights-20240115-p5excn.html">part of the game</a>. So what can a player do to prepare for the sleep disruption?</p>
<p>Professional athletes have a number of strategies available. For example, <a href="https://doi.org/10.3390/ijerph17134650">napping has myriad benefits</a> for both cognitive function and physical performance.</p>
<p>A popular supplement, caffeine, has consistently been shown to improve physical performance and alertness. While endurance exercise has shown the largest performance benefits from caffeine, small to moderate improvements have been shown in muscle strength, sprinting, jumping and throwing performance.</p>
<p>However, caffeine can be detrimental to subsequent sleep. While athletes preparing for late matches might have an evening caffeine hit, the average Australian should avoid drinking coffee after 3pm.</p>
<p>Increasing sleep duration in the week leading up to late-night matches can also help. Studies have shown that sleep extension <a href="https://doi.org/10.1016/j.physbeh.2015.08.035">increases tennis serving</a> and <a href="https://doi.org/10.5665/sleep.1132">basketball free throw</a> accuracy almost 10%. Increasing sleep duration could really be the difference between hitting a winner or an unforced error. </p>
<p>It remains to be seen if athletes like Medvedev and Sabalenka will overcome their disrupted sleep and prevail at this year’s Australian Open. But there’s certainly an advantage to having a good night’s shut eye.</p><img src="https://counter.theconversation.com/content/221591/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nicholas Saner receives funding from the Victorian Medical Research Acceleration Fund. </span></em></p><p class="fine-print"><em><span>Olivia Knowles does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Night matches at the Australian Open are a great spectacle, but sleep disruption is likely to wreak havoc even on professional athletes.Nicholas Saner, Post-doctoral researcher in sleep science, Victoria UniversityOlivia Knowles, High Performance Manager, Hawthorn FC, and Researcher, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2199552024-01-17T13:37:48Z2024-01-17T13:37:48ZWhat’s the best diet for healthy sleep? A nutritional epidemiologist explains what food choices will help you get more restful z’s<figure><img src="https://images.theconversation.com/files/569476/original/file-20240116-23-j8753f.jpg?ixlib=rb-1.1.0&rect=12%2C0%2C2105%2C1409&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A balanced diet is one key factor in getting a restful night's sleep. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/freshly-woken-up-young-woman-enjoying-the-morning-royalty-free-image/1413633179?phrase=person+sleeping&searchscope=image%2Cfilm&adppopup=true">SimpleImages/Moment via Getty Images</a></span></figcaption></figure><p>You probably already know that how you eat before bed affects your sleep. Maybe you’ve found yourself still lying awake at 2 a.m. after enjoying a cup of coffee with dessert. But did you know that your eating choices throughout the day may also affect your sleep at night? </p>
<p>In fact, more and more evidence shows that <a href="https://doi.org/10.3390/nu12092830">overall dietary patterns</a> can <a href="https://doi.org/10.3390/nu14142998">affect sleep quality and contribute to insomnia</a>.</p>
<p>I am a <a href="https://sph.umich.edu/faculty-profiles/jansen-erica.html">nutritional epidemiologist</a>, and I’m <a href="https://scholar.google.com/citations?user=NwgRhPYAAAAJ&hl=en">trained to look at diets at the population level</a> and how they affect health. </p>
<p>In the U.S., a large percentage of the population suffers from <a href="https://www.gallup.com/analytics/390536/sleep-in-america-2022.aspx">poor sleep quality</a> and sleep disorders like <a href="https://www.nhlbi.nih.gov/health/insomnia#">insomnia</a> and <a href="https://www.ncbi.nlm.nih.gov/books/NBK459252/#">obstructive sleep apnea</a>, a condition in which the upper airway becomes blocked and breathing stops during sleep. At the same time, most Americans eat far too much <a href="https://fns-prod.azureedge.us/sites/default/files/media/file/AverageHealthyEatingIndex-2020ScoresfortheUSPopulation.pdf">fatty and processed food, too little fiber and too few fruits and vegetables</a>. </p>
<p>Although it is difficult to determine whether these two trends are causally linked to one another, more and more <a href="https://doi.org/10.1146%2Fannurev-nutr-120420-021719">research points to linkages between sleep and diet</a> and offers hints at the biological underpinnings of these relationships.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/569475/original/file-20240116-23-bh5k9m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Overhead view of colorful foods with high dietary fiber content arranged side by side on a countertop." src="https://images.theconversation.com/files/569475/original/file-20240116-23-bh5k9m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/569475/original/file-20240116-23-bh5k9m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/569475/original/file-20240116-23-bh5k9m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/569475/original/file-20240116-23-bh5k9m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/569475/original/file-20240116-23-bh5k9m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/569475/original/file-20240116-23-bh5k9m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/569475/original/file-20240116-23-bh5k9m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Most Americans consume far too little fiber and too few fresh fruits and vegetables.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/group-of-food-with-high-content-of-dietary-fiber-royalty-free-image/1457889029?phrase=high+fiber+diet&searchscope=image%2Cfilm&adppopup=true">fcafotodigital/E+ via Getty Images</a></span>
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<h2>How diet and sleep quality can be intertwined</h2>
<p>My colleagues and I wanted to get a deeper understanding of the possible link between sleep and diet in Americans who are 18 and older. So we analyzed whether people who follow <a href="https://health.gov/our-work/nutrition-physical-activity/dietary-guidelines">the government’s Dietary Guidelines for Americans</a> get more hours of sleep.</p>
<p>Using a nationally representative dataset of surveys collected from 2011 to 2016, we found that people who did not adhere to dietary recommendations such as consuming enough servings of fruits, vegetables, legumes and whole grains <a href="https://doi.org/10.1016/j.appet.2020.104748">had shorter sleep duration</a>.</p>
<p>In a separate study, we followed more than 1,000 young adults ages 21 to 30 who were enrolled in a web-based dietary intervention study designed to help them increase their daily servings of fruits and vegetables. We found that those who increased their fruit and vegetable consumption over a three-month period reported better sleep quality and <a href="https://doi.org/10.1016/j.sleh.2021.02.005">reductions in insomnia symptoms</a>. </p>
<p>Research conducted outside the U.S. by my group and others also shows that healthier overall dietary patterns are associated with better sleep quality and fewer insomnia symptoms. These include the <a href="https://doi.org/10.3390/nu12092830">Mediterranean diet</a> – a diet rich in plant foods, olive oil and seafood, and low in red meat and added sugar – and <a href="https://doi.org/10.3390/nu15020419">anti-inflammatory diets</a>. These are <a href="https://doi.org/10.1016/j.appet.2021.105881">similar to the Mediterranean diet</a> but include additional emphasis on <a href="https://doi.org/10.1093/sleep/zsy158">certain components in the diet</a> like <a href="https://doi.org/10.3390%2Fmolecules25225243">flavonoids</a>, a group of compounds found in plants, which are shown to lower inflammatory biomakers in the blood.</p>
<h2>Parsing the foods and nutrients</h2>
<p>Within overall healthy diet patterns, there are numerous individual foods and nutrients that may be linked to quality of sleep, with varying degrees of evidence. </p>
<p>For example, studies have linked consumption of <a href="https://doi.org/10.5664/jcsm.3714">fatty fish</a>, <a href="https://doi.org/10.1016/j.advnut.2023.01.004">dairy</a>, <a href="https://doi.org/10.3389/fnut.2023.1079609">kiwi fruit</a>, <a href="https://doi.org/10.1097/mjt.0000000000000584">tart cherries</a> and <a href="https://doi.org/10.3390/nu15245115">other berries</a> such as strawberries and blueberries with better sleep. One of the common pathways through which these foods may affect sleep is by <a href="https://www.nccih.nih.gov/health/melatonin-what-you-need-to-know">providing melatonin</a>, an important modulator of sleep and wake cycles in the brain.</p>
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<figcaption><span class="caption">Walnuts and almonds, as well as fruits like kiwis and bananas, provide natural sources of melatonin.</span></figcaption>
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<p><a href="https://theconversation.com/fiber-is-your-bodys-natural-guide-to-weight-management-rather-than-cutting-carbs-out-of-your-diet-eat-them-in-their-original-fiber-packaging-instead-205159">Fiber-rich foods</a> like beans and oatmeal and certain protein sources – especially those that are high in the amino acid tryptophan, such as poultry – are also associated with <a href="https://doi.org/10.1016/j.jand.2022.01.007">higher-quality sleep</a>. Individual nutrients that may be beneficial include <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3703169/">magnesium</a>, <a href="https://doi.org/10.1016/j.tjnut.2023.11.030">vitamin D</a>, <a href="https://doi.org/10.1016/j.tjnut.2023.11.030">iron</a>, <a href="https://doi.org/10.1093/jn/nxz286">omega-3 fatty acids</a> and <a href="https://doi.org/10.1016/j.tjnut.2023.11.012">manganese</a>. Some foods like salmon are sources of multiple nutrients. </p>
<h2>Untangling the complexity</h2>
<p>One important caveat with a lot of the research on individual foods, as well as diet patterns, is that most studies cannot easily disentangle the direction of the relationships.</p>
<p>In other words, it’s hard to know whether the association is a result of diet affecting sleep, or sleep affecting diet. The reality is that it is likely a cyclical relationship, where a healthy diet promotes good sleep quality, which in turn helps to <a href="https://doi.org/10.1146/annurev-nutr-120420-021719">reinforce good dietary habits</a>. </p>
<p>With observational studies, there are also possible confounding factors, such as age and economic status, that may have important correlations with both sleep and diet.</p>
<h2>Foods to avoid for sleep health</h2>
<p>Aiming for higher intake of sleep-promoting foods isn’t necessarily enough to get better sleep. It’s also important to avoid certain foods that could be bad for sleep. Here are some of the main culprits:</p>
<ul>
<li><p>Saturated fats, such as that in burgers and fries and processed foods, could <a href="https://doi.org/10.5664/jcsm.5384">lead to less slow-wave sleep</a>, which is <a href="https://pubmed.ncbi.nlm.nih.gov/19998869/">considered the most restorative sleep</a>. </p></li>
<li><p>Refined carbohydrates, such as those in white bread and pasta, are metabolized quickly. If you eat these foods for dinner, they can result in <a href="https://doi.org/10.3389/fpubh.2022.931781">waking up from hunger</a>. </p></li>
<li><p><a href="https://doi.org/10.1016/j.alcohol.2014.07.019">Alcohol disrupts sleep quality</a>. Although the sedative effects of alcohol can initially make it easier to fall asleep, it disrupts sleep patterns by shortening the amount of <a href="https://www.webmd.com/sleep-disorders/sleep-101">REM, or rapid eye movement</a>, sleep in the first part of the night and leads to more night awakenings.</p></li>
<li><p>Caffeine consumed even six hours before bed can <a href="https://doi.org/10.5664/jcsm.3170">make it difficult to fall asleep</a> because it blocks the hormone adenosine, which promotes sleepiness. </p></li>
<li><p>The consistent overconsumption of calories can lead to weight gain, one of the <a href="https://doi.org/10.1016/j.smrv.2023.101838">strongest predictors of obstructive sleep apnea</a>. Having excess weight is a factor because it can put additional pressure on the diaphragm and lungs, and can also lead to a narrower airway if fat accumulates around the neck and throat.</p></li>
</ul>
<p>Interestingly, our group has recently shown that toxicants in food or food packaging, <a href="https://doi.org/10.1186/s12889-021-12014-x">like pesticides</a>, <a href="https://doi.org/10.1016/j.envres.2020.110216">mercury</a> and <a href="https://doi.org/10.1007/s11356-023-26833-5">phthalates</a> – chemicals used to manufacture plastics – can affect sleep. Since toxicants can be found in both healthy and unhealthy foods, this research suggests that some foods can contain a mix of components that are both beneficial and harmful for sleep.</p>
<h2>Timing of meals and gender considerations</h2>
<p>The timing and consistency of eating, known as “chrononutrition” in the sleep research field, also very likely help to explain associations between healthy diets and good sleep. </p>
<p>In the U.S., eating at conventional meal times as opposed to random snacking <a href="https://doi.org/10.1017/S136898001000296X">has been associated with better sleep</a>. In addition, late-night eating is typically associated with unhealthier food intake – such as processed snacks – and could <a href="https://doi.org/10.1017/s0007114521003597">cause more fragmented sleep</a>.</p>
<p>A final and very interesting piece of this puzzle is that associations between diet and sleep often differ by gender. For example, it appears that the associations between healthy diet patterns and insomnia symptoms <a href="https://doi.org/10.1016/j.sleh.2021.02.005">could be stronger among women</a>. One reason for this could be gender differences in sleep. In particular, <a href="https://doi.org/10.3389%2Ffpsyt.2020.577429">women are more likely than men to suffer from insomnia</a>.</p>
<h2>Keys to a good night’s sleep</h2>
<p>Overall, there is not one magic food or drink that will improve your sleep. It’s better to focus on overall healthy dietary patterns throughout the day, with a higher proportion of calories consumed earlier in the day. </p>
<p>And, in addition to avoiding caffeine, alcohol and heavy meals in the two to three hours before bed, the last few hours of the day should include other <a href="https://sleepeducation.org/healthy-sleep/healthy-sleep-habits/">good sleep hygiene practices</a>. </p>
<p>These include disengaging from technology, reducing light exposure and creating a comfortable and relaxing environment for sleep. Moreover, allowing enough time to sleep and maintaining a consistent bedtime and wake time is essential.</p><img src="https://counter.theconversation.com/content/219955/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Erica Jansen receives funding from the National Heart Lung Blood Institute (NHBLI) through a K01 award (K01HL151673). </span></em></p>A growing body of research is finding a robust link between diet and sleep quality. But it’s not just the usual suspects like caffeine and alcohol that can get in the way of restful sleep.Erica Jansen, Assistant Professor of Nutritional Sciences, University of MichiganLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2207462024-01-17T13:06:03Z2024-01-17T13:06:03ZCaffeine: here’s how quitting can benefit your health<figure><img src="https://images.theconversation.com/files/569554/original/file-20240116-15-cnvn6w.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3122%2C2070&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Because caffeine is water and fat soluble, it's able to exert its affects on many parts of the body.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/unhappy-coffee-409558066">andrew crotty/ Shutterstock</a></span></figcaption></figure><p>Caffeine is the <a href="https://pubmed.ncbi.nlm.nih.gov/19769434/">most consumed psychoactive compound</a> in the world. Even if you don’t drink coffee or tea, you probably still regularly consume caffeine since it’s found in everything from <a href="https://pubmed.ncbi.nlm.nih.gov/17995675/">fizzy drinks</a> and <a href="https://www.medicines.org.uk/emc/ingredient/731#gref">cold remedies</a> to <a href="https://pubmed.ncbi.nlm.nih.gov/17132260/">decaf coffee</a> and <a href="https://www.yahoo.com/lifestyle/does-chocolate-caffeine-yes-higher-140325414.html?">chocolate</a>.</p>
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<p>When caffeine is consumed, it’s rapidly absorbed by the body – reaching peak effects <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4898153/">within two hours</a> (though it may take up to <a href="https://www.ncbi.nlm.nih.gov/books/NBK223808/">nine hours</a> to leave your body). It’s also water and fat soluble, so it gets into all <a href="https://www.sciencedirect.com/science/article/abs/pii/S0002822321032405">body tissues</a>, which explains why caffeine can affect many different parts of the body.</p>
<p>It’s recommended that adults consume no more than <a href="https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much">400mg of caffeine a day</a> (approximately four cups of coffee). More than this may lead to muscle tremors, nausea, headaches, pounding heart and even <a href="https://www.bbc.co.uk/news/uk-wales-60570470">death</a> (in extreme cases). </p>
<p>But even people who only consume a couple cups of coffee or tea daily may feel it still has <a href="https://www.thetimes.co.uk/article/how-stop-drinking-coffee-caffeine-addiction-c9cfptdbx">adverse effects</a> – such as irritability, difficulty falling asleep and feeling jittery. This is why a growing number of people are deciding to give up caffeine. </p>
<p>If you’re thinking about giving up caffeine and are wondering what benefits it may have, here’s what the research says:</p>
<h2>Brain function</h2>
<p>Caffeine withdrawal can cause headaches, fatigue and tiredness. This is because the body develops a tolerance to caffeine. </p>
<p>Caffeine binds to a receptor in the brain used by <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8160517/">adenosine</a>. The binding of caffeine to these receptors causes the body to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3153505/">delay the onset of fatigue</a>. But over time the brain cells produce <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9541543/">more adenosine receptors</a> to enable normal adenosine binding to happen. </p>
<p>So, when you stop consuming caffeine, there are excess adenosine receptors to bind to. This allows fatigue and tiredness to kick in as normal, with the person feeling more tired than before.</p>
<p>Headaches happens as a result of the absence of caffeine. In the head and neck, caffeine causes the blood vessels to narrow, reducing blood flow to the brain. When you stop drinking caffeine, after approximately 24 hours it causes the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2738587/">blood vessels to return to normal</a>, causing an <a href="https://pubmed.ncbi.nlm.nih.gov/10672630/">increase in blood flow</a> to the brain and triggering headaches. They may last up to <a href="https://jpet.aspetjournals.org/content/255/3/1123.long">9 days</a> on average.</p>
<p>And because caffeine binds to adenosine receptors (which also modulate pain) quitting caffeine may temporarily <a href="https://www.sciencedirect.com/science/article/pii/S2452073X22000046">increase your perception and sensitivity</a> to pain because there’s more receptors available.</p>
<p>Caffeine really only affects sleep when consumed in the late afternoon and evenings. This is because caffeine delays the release of <a href="https://www.nhs.uk/medicines/melatonin/">melatonin</a> (a hormone which makes us tired) by <a href="https://www.science.org/doi/10.1126/scitranslmed.aac5125">40 minutes</a>. Caffeine also reduces the overall <a href="https://www.science.org/doi/10.1126/scitranslmed.aac5125">time you sleep</a> and shortens the period of <a href="https://pubmed.ncbi.nlm.nih.gov/24235903/">deep sleep</a>. </p>
<p>This can increase your tiredness the next day, leading to cycle of using caffeine to wake you up but having trouble sleeping later on as a result. When you stop caffeine, you may find your sleep improves. Some evidence suggests improvements are seen in as little as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7907384/">12 hours</a>. </p>
<figure class="align-center ">
<img alt="A tired woman looks at her laptop with multiple finished cups of coffee." src="https://images.theconversation.com/files/569558/original/file-20240116-17-7vakxl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/569558/original/file-20240116-17-7vakxl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=395&fit=crop&dpr=1 600w, https://images.theconversation.com/files/569558/original/file-20240116-17-7vakxl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=395&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/569558/original/file-20240116-17-7vakxl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=395&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/569558/original/file-20240116-17-7vakxl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=497&fit=crop&dpr=1 754w, https://images.theconversation.com/files/569558/original/file-20240116-17-7vakxl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=497&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/569558/original/file-20240116-17-7vakxl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=497&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The effect caffeine has on sleep may create a cycle of needing more caffeine to stay awake.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/caffeine-addicted-bad-lifestyle-concept-young-1920296081">SrideeStudio/ Shutterstock</a></span>
</figcaption>
</figure>
<p>Caffeine has also been linked to increased <a href="https://pubmed.ncbi.nlm.nih.gov/34871964/">anxiety and panic attacks</a> – and not just in those with a pre-disposition to mental health issues. Reducing or eliminating caffeine may improve your mood. This may partly be because it improves sleep. Sleep deprivation can <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2862829/">exacerbate anxiety</a> and other <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6122651/">mood disorders</a>.</p>
<p>But the adenosine receptors that caffeine bind to are also involved in the modulation of other neurotransmitters that have a role in <a href="https://www.nature.com/articles/1395332">stress</a>, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3008658/">happiness</a> and <a href="https://www.ncbi.nlm.nih.gov/books/NBK526124/">fear</a>.</p>
<h2>Cardiovascular health</h2>
<p>Reducing or eliminating caffeine might also cure heartburn and indigestion. Caffeine <a href="https://pubmed.ncbi.nlm.nih.gov/28696284/">induces acid secretion</a> in the stomach and weakens the oesophageal sphincter, which controls reflux of stomach contents up the oesophagus – triggering heartburn and indigestion.</p>
<p>Quitting caffeine may also lower your <a href="https://pubmed.ncbi.nlm.nih.gov/9402612/">blood pressure</a> and reduce your <a href="https://link.springer.com/article/10.1007/BF01857602">heart rate</a> – although other studies have shown <a href="https://www.nature.com/articles/s41598-017-08678-4">little change</a>.</p>
<p>This is because if someone consumes caffeine daily for many years, their body adapts to the exposure – and it becomes the new norm with its stimulant effects on the nervous system, bowels and heart. </p>
<p>There also appears to be <a href="https://www.nature.com/articles/s41598-017-08678-4">genetic component</a> to caffeine tolerance and metabolism. This could mean some people are more affected by caffeine over others – though more research is needed on this link. </p>
<h2>A brighter smile</h2>
<p>Cutting out caffeine may improve the whiteness of your teeth – not because of caffeine directly, but because <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10266434/">tea</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/1629514/">coffee</a> contain compounds including tannins that <a href="https://www.nature.com/articles/4800959">stain teeth</a>. </p>
<p>Sugar in <a href="https://pubmed.ncbi.nlm.nih.gov/28438229/">energy drinks</a> can also cause damage to your teeth. Quitting may help protect them. Evidence also suggests caffeinated drinks may <a href="https://onlinelibrary.wiley.com/doi/full/10.1034/j.1601-0825.2003.03967.x">reduce the amount of saliva</a> you produce, which normally protects our teeth from damage.</p>
<p>You may also find that you have an increased sensitivity to the taste of sweet food and drinks after quitting, as caffeine interferes with the <a href="https://pubmed.ncbi.nlm.nih.gov/28833098/">tasting of sweet substances</a>.</p>
<h2>Going to the toilet less</h2>
<p>Caffeine acts on the smooth muscle of the intestines, particularly in the colon, causing them to contract and trigger <a href="https://pubmed.ncbi.nlm.nih.gov/9581985/">the urge to poo</a>. Caffeine can also change the consistency of your poo – especially if you drink too much, as caffeine affects <a href="https://www.ncbi.nlm.nih.gov/books/NBK507857/">water absorption</a>. </p>
<p>Reducing caffeine intake may cause a less frequent urge to poo – and the consistency of your stools may change. </p>
<p>Caffeine also acts as a mild diuretic, causing an <a href="https://bpspubs.onlinelibrary.wiley.com/doi/full/10.1111/bcp.14856">increase in urine production</a>. This is because caffeine binds the adenosine receptors in the kidney, which alters how sodium is exchanged, affecting water retention. There’s also evidence caffeine is a <a href="https://nafc.org/bhealth-blog/the-big-four-bladder-irritants/">bladder irritant</a>, which can cause a more <a href="https://pubmed.ncbi.nlm.nih.gov/32441853/">frequent urge</a> to urinate. Quitting caffeine may decrease your daily toilet visits.</p>
<h2>Moderate consumption</h2>
<p>As with many things, it’s about moderation. </p>
<p>But if you’re seriously considering removing caffeine from your diet, the best way to do so is gradually. Going “cold turkey” will bring on side effects such as headaches and tiredness which can last <a href="https://jpet.aspetjournals.org/content/255/3/1123.long">two</a> to <a href="https://www.sciencedirect.com/science/article/pii/009130579500029V?via%3Dihub">three</a> weeks. </p>
<p>How severe and long-lasting these are depends on how much caffeine you’ve consumed per day and how long your habit has been going.</p><img src="https://counter.theconversation.com/content/220746/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adam Taylor does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Caffeine is the most consumed psychoactive substance globally.Adam Taylor, Professor and Director of the Clinical Anatomy Learning Centre, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2183442023-12-21T23:19:57Z2023-12-21T23:19:57ZGot period pain or cramps? What to eat and avoid, according to science<figure><img src="https://images.theconversation.com/files/566750/original/file-20231219-27-7x7oaq.jpg?ixlib=rb-1.1.0&rect=1%2C1%2C1276%2C848&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.pexels.com/photo/woman-suffering-from-a-stomach-pain-5938362/">Sora Shimazaki/Pexels</a></span></figcaption></figure><p>Painful periods are common. More than half of people who menstruate have some pain for up to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8943241/">three days a month</a>, typically throbbing or cramping in the lower abdomen. </p>
<p>Digestive changes – such as vomiting, gas, bloating, diarrhoea and a “bubbling gut” – are also <a href="https://bmcwomenshealth.biomedcentral.com/articles/10.1186/s12905-018-0538-8">common</a> around the time of menstruation. </p>
<p>There are many <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8943241/">treatments</a> for period pain (known medically as dysmenorrhoea). Not all these treatments are well-tolerated or work for everyone.</p>
<p>We’re learning more about food’s role in influencing <a href="https://theconversation.com/9-signs-you-have-inflammation-in-your-body-could-an-anti-inflammatory-diet-help-210468">inflammation</a> in our body. So, could eating or avoiding certain foods <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5963185/">help</a> with painful periods? Here’s what we know based on high-quality research.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/from-sharp-butt-pains-to-period-poos-5-lesser-known-menstrual-cycle-symptoms-191352">From sharp butt pains to period poos: 5 lesser-known menstrual cycle symptoms</a>
</strong>
</em>
</p>
<hr>
<h2>Foods that may relieve period pain or cramps</h2>
<p><strong>Foods containing omega-3 fatty acids</strong></p>
<p>Foods rich in omega-3 fatty acids include chia seeds, walnuts, flaxseeds, salmon, herring, sardines, mackerel, oysters and edamame beans. Omega-3 fatty acids are naturally present in oils including fish, cod liver, algal, krill, flaxseed (linseed), soybean and canola oils.</p>
<p>Omega-3 fatty acids <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3257651/">affect</a> how our cells function and the signalling pathways associated with inflammation and pain. </p>
<p>Earlier this year, researchers published a <a href="https://pubmed.ncbi.nlm.nih.gov/37545015/#:%7E:text=Meta%2Danalysis%20(n%20%3D%208,0.51)%20at%20reducing%20dysmenorrhoea%20pain.">meta-analysis</a> where they combined and analysed all data available on the impact of omega-3 fatty acids on period pain. They found diets high in omega-3 fatty acids (including supplements of 300-1,800 milligrams a day) over two to three months may reduce pain, and pain medication use, in people with painful periods.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/566754/original/file-20231219-15-vu9xne.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Open sardine can, parsley, cut lemon on wooden table." src="https://images.theconversation.com/files/566754/original/file-20231219-15-vu9xne.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566754/original/file-20231219-15-vu9xne.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566754/original/file-20231219-15-vu9xne.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566754/original/file-20231219-15-vu9xne.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566754/original/file-20231219-15-vu9xne.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566754/original/file-20231219-15-vu9xne.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566754/original/file-20231219-15-vu9xne.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sardines and other oily fish are rich in omega-3 fatty acids.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/open-can-sardines-preserves-oil-on-1636046179">BearFotos/Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/are-fish-oil-supplements-as-healthy-as-we-think-and-is-eating-fish-better-212250">Are fish oil supplements as healthy as we think? And is eating fish better?</a>
</strong>
</em>
</p>
<hr>
<p><strong>Foods high in vitamin D</strong></p>
<p>Foods high in vitamin D include trout, salmon, tuna and mackerel, as well as fish liver oils. Small amounts are also found in beef liver, egg yolk and cheese. Mushrooms contain varying levels of vitamin D, and you can <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6213178/">boost</a> this by exposing them to direct midday sunlight for 15-120 minutes. </p>
<p>The body can make vitamin D when it gets sunlight exposure and you can also get vitamin D from supplements.</p>
<p>Vitamin D <a href="https://pubmed.ncbi.nlm.nih.gov/24262718/">may help</a> reduce the factors that cause inflammation in the uterus. This includes levels of hormone-like molecules called prostaglandins. </p>
<p>A 2023 <a href="https://www.mdpi.com/2072-6643/15/13/2830#B11-nutrients-15-02830">meta-analysis</a> showed women who received weekly doses of vitamin D greater than 50,000 IU (or international units) had relief from period pain, regardless of how long and how often women took the vitamin.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/should-i-be-getting-my-vitamin-d-levels-checked-211268">Should I be getting my vitamin D levels checked?</a>
</strong>
</em>
</p>
<hr>
<p><strong>Foods high in vitamin E</strong></p>
<p>Foods rich in vitamin E include seeds (particularly sunflower seeds), nuts (particularly almonds, hazelnuts and peanuts) and spinach, broccoli, kiwifruit, mango and tomato. </p>
<p>There is some evidence vitamin E supplements reduce period pain. In a well-conducted <a href="https://pubmed.ncbi.nlm.nih.gov/15777446/">trial</a> run over the course of four periods, women took vitamin E supplements (90 milligrams, twice a day) for five days, beginning two days before the expected start of the period. This significantly reduced the severity and duration of period pain. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/566756/original/file-20231220-17-d2da5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Woman tipping out nut mix into palm of hand" src="https://images.theconversation.com/files/566756/original/file-20231220-17-d2da5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566756/original/file-20231220-17-d2da5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566756/original/file-20231220-17-d2da5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566756/original/file-20231220-17-d2da5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566756/original/file-20231220-17-d2da5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566756/original/file-20231220-17-d2da5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566756/original/file-20231220-17-d2da5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Seeds and nuts are rich in vitamin E.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/hands-holding-jar-nuts-dried-fruits-1112521214">NazarBazar/Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/i-have-painful-periods-could-it-be-endometriosis-101026">I have painful periods, could it be endometriosis?</a>
</strong>
</em>
</p>
<hr>
<h2>Foods that may worsen period pain or cramps</h2>
<p><strong>Highly processed foods</strong></p>
<p>Highly processed foods include energy-dense, nutrient-poor foods such as takeaways, chips, biscuits, doughnuts, processed meats and soft drinks. </p>
<p>Research findings on the impact of a diet high in processed foods on period pain vary. A 2019 <a href="https://karger.com/goi/article/84/3/209/153726/Nutrition-as-a-Potential-Factor-of-Primary">review</a> found sugar consumption had little association with painful periods. </p>
<p>However, some observational studies (which do not involve an intervention) suggest women who eat more processed foods may have more intense period pain. For example, a <a href="https://pubmed.ncbi.nlm.nih.gov/19468949/">2009 study</a> found adolescent females who ate fast or processed foods for two days or more a week reported more period pain compared with those who did not. Therefore, eating less processed food may be something to consider. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/8-everyday-foods-you-might-not-realise-are-ultra-processed-and-how-to-spot-them-197993">8 everyday foods you might not realise are ultra processed – and how to spot them</a>
</strong>
</em>
</p>
<hr>
<p><strong>Caffeine</strong></p>
<p>Foods high in caffeine include coffee, energy drinks and some processed energy bars. Caffeine intake is <a href="https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwij7LmPxfSCAxV5d_UHHRnyDyUQFnoECBIQAQ&url=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC4222008%2F&usg=AOvVaw2mEjyMadOB1D6geQgAwckc&opi=89978449">associated with</a> menstrual pain. </p>
<p>Although we don’t know the precise underlying mechanism, researchers think caffeine may narrow blood vessels, which limits blood flow, leading to stronger cramps.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/566757/original/file-20231220-23-u1d2j2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Tired woman staring at bowl of breakfast, cereal and cup on kitchen table" src="https://images.theconversation.com/files/566757/original/file-20231220-23-u1d2j2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566757/original/file-20231220-23-u1d2j2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566757/original/file-20231220-23-u1d2j2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566757/original/file-20231220-23-u1d2j2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566757/original/file-20231220-23-u1d2j2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566757/original/file-20231220-23-u1d2j2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566757/original/file-20231220-23-u1d2j2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Avoiding coffee may help your period pain.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/woman-does-not-want-eat-her-151886987">Lolostock/Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/nope-coffee-wont-give-you-extra-energy-itll-just-borrow-a-bit-that-youll-pay-for-later-197897">Nope, coffee won't give you extra energy. It'll just borrow a bit that you'll pay for later</a>
</strong>
</em>
</p>
<hr>
<p><strong>Alcohol</strong></p>
<p>Drinking alcohol is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4859868/">not</a> a recognised risk factor for painful periods. However, chronic heavy alcohol use reduces levels of <a href="https://academic.oup.com/alcalc/article/55/2/164/5734241">magnesium</a> in the blood. Magnesium is an important factor in relaxing muscles and supporting blood flow.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/adele-called-herself-a-borderline-alcoholic-but-is-that-a-real-thing-215987">Adele called herself a 'borderline alcoholic'. But is that a real thing?</a>
</strong>
</em>
</p>
<hr>
<h2>A healthy, balanced diet is your best best</h2>
<p>Having a healthy, balanced diet is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7071223/">one of the best ways</a> we can support our own health and prevent future chronic conditions. This can help reduce inflammation in our bodies, thought to be the main way diet can help people with painful periods.</p>
<p>If you are looking for tailored dietary advice or a menstrual health meal plan, speak with an <a href="https://member.dietitiansaustralia.org.au/Portal/Portal/Search-Directories/Find-a-Dietitian.aspx">accredited practising dietitian</a>.</p>
<p>It’s important to stress, however, that diet alone cannot treat all forms of menstrual pain. So if you are concerned about your painful periods, check in with your GP who can discuss your options.</p>
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Read more:
<a href="https://theconversation.com/9-signs-you-have-inflammation-in-your-body-could-an-anti-inflammatory-diet-help-210468">9 signs you have inflammation in your body. Could an anti-inflammatory diet help?</a>
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<p><em>This article has been updated to reflect the correct date of a review that found sugar consumption had little association with painful periods.</em></p><img src="https://counter.theconversation.com/content/218344/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lauren Ball works for The University of Queensland and receives funding from the National Health and Medical Research Council, Queensland Health and Mater Misericordia. She is a Director of Dietitians Australia, a Director of the Darling Downs and West Moreton Primary Health Network and an Associate Member of the Australian Academy of Health and Medical Sciences.</span></em></p><p class="fine-print"><em><span>Emily Burch is an Accredited Practising Dietitian and member of Dietitians Australia. She works for Southern Cross University. </span></em></p><p class="fine-print"><em><span>Pui Ting Wong is a PhD Candidate at The University Queensland (UQ) Centre for Community Health and Wellbeing, and receives the UQ Tuition Fee Offset and Stipend Scholarship. She is also an Accredited Practising Dietitian and a member of Dietitians Australia.</span></em></p>A cup of coffee might help you kick-start your day, but it may actually make painful periods worse. Here’s what else to avoid (and eat) if you have period pain.Lauren Ball, Professor of Community Health and Wellbeing, The University of QueenslandEmily Burch, Lecturer, Southern Cross UniversityPui Ting Wong, PhD Candidate, culinary education and adolescent mental health, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2155462023-10-31T19:17:51Z2023-10-31T19:17:51ZHow is decaf coffee made? And is it really caffeine-free?<figure><img src="https://images.theconversation.com/files/556740/original/file-20231030-21-uurqzu.jpg?ixlib=rb-1.1.0&rect=133%2C47%2C6059%2C3540&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/gray-metal-tool-aaHwnxgBmHs">Volodymyr Proskurovskyi/Unsplash</a></span></figcaption></figure><p>Coffee is one of the most popular drinks in the world, and its high levels of caffeine are among the main reasons why. It’s a natural stimulant that provides an energy buzz, and we just can’t get enough.</p>
<p>However, some people prefer to limit their caffeine intake <a href="https://pubmed.ncbi.nlm.nih.gov/12684194/">for health</a> or other reasons. Decaffeinated or “decaf” coffee is widely available, and its consumption is reported to be <a href="https://www.coffeebeanshop.com.au/coffee-blog/decaf-coffee-market-worth-2145-billion-by-2025-at-69">on the rise</a>.</p>
<p>Here’s what you need to know about decaf coffee: how it’s made, the flavour, the benefits – and whether it’s actually caffeine-free.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-four-reasons-to-have-another-cup-of-coffee-40390">Health Check: four reasons to have another cup of coffee</a>
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</em>
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<h2>How is decaf made?</h2>
<p>Removing caffeine while keeping a coffee bean’s aroma and flavour intact isn’t a simple task. Decaf coffee is made by stripping green, unroasted coffee beans of their caffeine content and relies on the fact that <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6318762/#:%7E:text=Caffeine%20(Figure%201a)%20being,(15%20g%2FL).">caffeine dissolves</a> in water.</p>
<p>Three main methods are used for removing caffeine: chemical solvents, liquid carbon dioxide (CO₂), or plain water with special filters. </p>
<p>The additional steps required in all of these processing methods are why decaf coffee is often more expensive. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/556561/original/file-20231030-27-ab4y1v.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A close-up of a small branch with bright green berries on it" src="https://images.theconversation.com/files/556561/original/file-20231030-27-ab4y1v.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556561/original/file-20231030-27-ab4y1v.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556561/original/file-20231030-27-ab4y1v.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556561/original/file-20231030-27-ab4y1v.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556561/original/file-20231030-27-ab4y1v.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556561/original/file-20231030-27-ab4y1v.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556561/original/file-20231030-27-ab4y1v.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Coffee beans are not actually beans – they are the hard seeds nestled inside the fruit of the coffee plant.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/green-leaf-budded-during-daytime-VMJtKiREtMc">Marc Babin/Unsplash</a></span>
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<h2>Solvent-based methods</h2>
<p>Most decaf coffee is made using <a href="https://www.tandfonline.com/doi/epdf/10.1080/10408699991279231?needAccess=true">solvent-based</a> methods as it’s the cheapest process. This method breaks down into two further types: <a href="https://www.sciencedirect.com/science/article/abs/pii/B9780123849472001835">direct and indirect</a>.</p>
<p>The <strong>direct method</strong> involves steaming the coffee beans and then repeatedly soaking them in a chemical solvent (usually methylene chloride or ethyl acetate) which binds to the caffeine and extracts it from the beans.</p>
<p>After a pre-determined time, the caffeine has been extracted and the coffee beans are steamed once more to remove any residual chemical solvent. </p>
<p>The <strong>indirect method</strong> still uses a chemical solvent, but it doesn’t come into direct contact with the coffee beans. Instead, the beans are soaked in hot water, then the water is separated from the beans and treated with the chemical solvent. </p>
<p>The caffeine bonds to the solvent in the water and is evaporated. The caffeine-free water is then returned to the beans to reabsorb the coffee flavours and aromas. </p>
<p>The solvent chemicals (particularly methylene chloride) used in these processes are a source of controversy around decaf coffee. This is because <a href="https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/dichloromethane">methylene chloride</a> is suggested to be mildly carcinogenic in high doses. Methylene chloride and ethyl acetate are commonly used in paint stripper, nail polish removers and degreaser.</p>
<p>However, both the <a href="https://www.foodstandards.gov.au/code/pages/default.aspx">Australian New Zealand Food Standards Code</a> and <a href="https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm?fr=173.255">the United States Food and Drug Administration</a> permit the use of these solvents to process decaf. They also have strict limits on the amount of the chemicals that can still be present on the beans, and in reality <a href="https://www.chemicals.co.uk/blog/how-dangerous-is-methylene-chloride">practically no solvent</a> is left behind.</p>
<h2>Non-solvent-based methods</h2>
<p>Non-solvent-based methods that use liquid carbon dioxide or water are becoming increasingly popular as they don’t involve chemical solvents.</p>
<p>In the <a href="https://www.tandfonline.com/doi/pdf/10.1080/10408699991279231"><strong>CO₂ method</strong></a>, liquid carbon dioxide is pumped into a high-pressure chamber with the beans, where it binds to the caffeine and is then removed through high pressure, leaving behind decaffeinated beans.</p>
<p>The <strong>water method</strong> (also known as the Swiss water process) is exactly what it sounds like – it <a href="http://publication.eiar.gov.et:8080/xmlui/bitstream/handle/123456789/3234/ECSS%20Proceeding%20Final.pdf?sequence=1#page=294">involves extracting caffeine</a> from coffee beans using water. There are variations on this method, but the basic steps are as follows. </p>
<p>For an initial batch, green coffee beans are soaked in hot water, creating an extract rich in caffeine and flavour compounds (the flavourless beans are then discarded). This green coffee extract is passed through activated charcoal filters, which trap the caffeine molecules while allowing the flavours to pass through.</p>
<p>Once created in this way, the caffeine-free extract can be used to soak a new batch of green coffee beans – since the flavours are already saturating the extract, the only thing that will be dissolved from the beans is the caffeine. </p>
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<h2>Is caffeine fully removed from decaf?</h2>
<p>Switching to decaf may not be as caffeine free as you think. </p>
<p>It is unlikely that 100% of the caffeine will be successfully <a href="https://pubmed.ncbi.nlm.nih.gov/8603790/">stripped from the coffee beans</a>. Just like the caffeine content of coffee can vary, some <a href="https://pubmed.ncbi.nlm.nih.gov/17132260/">small amounts</a> of caffeine are still present in decaf. </p>
<p>However, the amount is quite modest. You would need to drink more than ten cups of decaf to reach the caffeine level typically present in <a href="https://academic.oup.com/jat/article/30/8/611/714415">one cup of caffeinated coffee</a>.</p>
<p>Australia <a href="https://www.foodstandards.gov.au/code/Documents/1.1.2%20Definitions%20v157.pdf">does not require</a> coffee roasters or producers to detail the process used to create their decaf coffee. However, you might find this information on some producers’ websites if they have chosen to advertise it.</p>
<h2>Does decaf coffee taste different?</h2>
<p>Some people say decaf tastes different. Depending on how the beans are decaffeinated, some aromatic elements may be co-extracted with the caffeine <a href="https://pubmed.ncbi.nlm.nih.gov/23745606/">during the process</a>.</p>
<p>Caffeine also contributes to the bitterness of coffee, so when the caffeine is removed, so is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8948847/">some of the bitterness</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/556739/original/file-20231030-23-t3sdwn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A tub of partially roasted coffee beans in a pale tan colour" src="https://images.theconversation.com/files/556739/original/file-20231030-23-t3sdwn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556739/original/file-20231030-23-t3sdwn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556739/original/file-20231030-23-t3sdwn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556739/original/file-20231030-23-t3sdwn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556739/original/file-20231030-23-t3sdwn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556739/original/file-20231030-23-t3sdwn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556739/original/file-20231030-23-t3sdwn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Caffeine contributes some of the bitterness of coffee, but there are also plenty of flavour compounds that develop in green beans as they are roasted to a rich, dark brown.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/person-holding-brown-seed-XpyD7z6AP4g">Joshua Newton/Unsplash</a></span>
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<h2>Do caffeinated and decaf coffee have the same health benefits?</h2>
<p>The health benefits found for drinking decaf coffee are similar to that of caffeinated coffee, including a lower risk of type 2 diabetes, some cancers and overall <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5696634/">mortality</a>.
More recently, coffee has been linked with improved weight management over time.</p>
<p>Most of the health benefits have been shown by drinking <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5696634/">three cups</a> of decaf per day. </p>
<p>Moderation is key, and remember that the greatest health benefits will come from having a <a href="https://theconversation.com/what-is-a-balanced-diet-anyway-72432">balanced diet</a>.</p>
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<strong>
Read more:
<a href="https://theconversation.com/can-coffee-help-you-avoid-weight-gain-heres-what-the-science-says-214954">Can coffee help you avoid weight gain? Here's what the science says</a>
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<img src="https://counter.theconversation.com/content/215546/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lauren Ball works for The University of Queensland and receives funding from the National Health and Medical Research Council, Queensland Health and Mater Misericordia. She is a Director of Dietitians Australia, a Director of the Darling Downs and West Moreton Primary Health Network and an Associate Member of the Australian Academy of Health and Medical Sciences.</span></em></p><p class="fine-print"><em><span>Emily Burch works for Southern Cross University.</span></em></p>Some coffee lovers can’t do without their hit of caffeine. But if you prefer decaf, here’s the intriguing science of how it’s made, why it costs more – and how much caffeine makes it to your cup.Lauren Ball, Professor of Community Health and Wellbeing, The University of QueenslandEmily Burch, Dietitian, Researcher & Lecturer, Southern Cross UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2104492023-08-28T12:01:46Z2023-08-28T12:01:46ZShort naps can improve memory, increase productivity, reduce stress and promote a healthier heart<figure><img src="https://images.theconversation.com/files/542889/original/file-20230815-21-42kbnn.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5190%2C3457&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Short naps at the right time of day can benefit alertness and overall health in myriad ways.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/young-man-asleep-royalty-free-image/1352026356?phrase=Nap&adppopup=true">Tara Moore/Digital Vision via Getty Images</a></span></figcaption></figure><p>Napping during the day is an ancient custom that is practiced worldwide. </p>
<p>While some people view napping as a luxurious indulgence, others see it as a way to maintain alertness and well-being. But napping can come with drawbacks as well as benefits. </p>
<p>As an <a href="https://health.tamu.edu/experts/steven-bender.html">orofacial pain specialist</a>, I have extensive education in sleep medicine and how sleep impacts wellness, due mostly to the relationship between sleep and painful conditions such as headaches and facial pain. My training involved all aspects of sleep, especially sleep breathing disorders, insomnia and sleep-related movement disorders. </p>
<p>As such, I’m aware of the complex nature of napping, and why a short nap – that is, a nap during the daytime that lasts from 20 to 30 minutes – may be beneficial in myriad ways. </p>
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<figcaption><span class="caption">While napping is generally a good habit for many people, there are some caveats to consider.</span></figcaption>
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<h2>An abundance of health benefits</h2>
<p>Research shows that there are many benefits to napping. Short naps can <a href="https://doi.org/10.1016/j.smrv.2022.101666">boost mental functioning and memory</a>, as well as <a href="https://www.apa.org/monitor/2016/07-08/naps">improve alertness, attention and reaction time</a>. </p>
<p>Short naps are also linked to <a href="https://www.media.mit.edu/articles/that-moment-when-you-re-nodding-off-is-a-sweet-spot-for-creativity/">increased productivity and creativity</a>. Because napping seems to improve creative thinking, some companies have attempted to harness this by introducing <a href="https://www.yahoo.com/now/nap-job-10-companies-100300632.html">napping rooms into the workplace</a>. </p>
<p>What’s more, it appears the brain uses nap time to process information gathered throughout the day, which appears to <a href="https://doi.org/10.1111/jsr.12728">enhance problem-solving abilities</a>. One small study revealed that people who took short naps were less frustrated and impulsive, which <a href="http://dx.doi.org/10.1016/j.paid.2015.06.013">resulted in better focus and efficiency</a> when performing work-related tasks. Napping may even lead to an improved ability <a href="https://doi.org/10.1007%2Fs40675-020-00193-9">to learn new motor skills</a>, such as a golf swing or the playing of a musical instrument. This is because these memories or skills become consolidated in the brain during sleep, whether at night or while napping.</p>
<p>Napping can also reduce stress. One study found that naps of approximately 20 minutes <a href="https://doi.org/10.5114/biolsport.2021.103569">improved the overall mood of participants</a>. However, longer naps lasting more than 30 minutes are not typically associated with improved mood and <a href="https://vitalrecord.tamhsc.edu/asked-grumpy-nap/">increased feelings of well-being</a>. </p>
<p>Short naps may also be associated with a <a href="http://dx.doi.org/10.1016/j.smrv.2016.09.002">reduced risk of cardiovascular diseases</a>. If we are awake more than we should be, we tend to have a buildup of the “fight or flight” chemicals in our bodies. Studies show that more consistent sleep <a href="https://doi.org/10.1007/s11906-018-0874-y">will help lower these chemicals</a>, resulting in a normalization of blood pressure and heart rates. Napping <a href="https://doi.org/10.1007/s11906-018-0874-y">appears to help this process</a> for some people. </p>
<p>But just as in nighttime sleep, some people may have trouble drifting off for a nap, especially when they have limited time. Progressive muscle relaxation techniques have been shown to be <a href="https://doi.org/10.1111/jsr.13574">beneficial for both nighttime sleep and napping</a>. Other nonspecific relaxation techniques, like listening to relaxing music, appear to also be beneficial for falling asleep. Interestingly, many people overestimate their time awake when trying to sleep and underestimate <a href="https://psycnet.apa.org/doi/10.1037/a0025730">the time they actually spent sleeping</a>. </p>
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<figcaption><span class="caption">Make sure the nap is short.</span></figcaption>
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<h2>Napping can have drawbacks</h2>
<p>One condition associated with napping longer than 30 minutes is <a href="https://www.sleepfoundation.org/how-sleep-works/sleep-inertia">sleep inertia</a> – the grogginess and disorientation that people sometime experience after waking from a longer nap. </p>
<p>Usually, the longer the nap, the more sleep inertia there is to overcome. This can impair cognitive function from several minutes up to half an hour. In many cases, these effects can be <a href="https://doi.org/10.2147/NSS.S188911">minimized by consuming caffeine</a> directly after the nap. </p>
<p>But it is important to note that <a href="https://theconversation.com/can-coffee-or-a-nap-make-up-for-sleep-deprivation-a-psychologist-explains-why-theres-no-substitute-for-shut-eye-206847">caffeine is not a substitute for sleep</a>. Caffeine acts to temporarily block the action of a chemical known as adenosine, a sleep-promoting agent that builds up during waking hours. If you are habitually dependent on caffeine consumption to keep you awake and alert, it may suggest that there is an underlying sleep disorder such as <a href="https://www.nhlbi.nih.gov/health/insomnia#">insomnia</a> or <a href="https://www.mayoclinic.org/diseases-conditions/sleep-apnea/symptoms-causes/syc-20377631#">sleep apnea</a>, in which a person temporarily stops breathing during sleep. </p>
<p>Long or late afternoon naps can also interfere with nighttime sleep, either by leading to difficulties falling asleep or staying asleep during the night. This disruption of the regular <a href="https://www.sciencedirect.com/topics/neuroscience/sleep-waking-cycle#">sleep-wake cycle</a> can result in <a href="https://my.clevelandclinic.org/health/diseases/23970-sleep-deprivation">overall sleep deprivation</a>, which <a href="http://dx.doi.org/10.1016/j.smrv.2016.09.002">can have numerous negative health effects</a>. </p>
<p>What’s more, for those age 60 and up, longer naps – beyond 30 minutes – <a href="https://doi.org/10.1016/j.smrv.2022.101682">may increase the risk for cardiovascular problems</a>. Researchers found that older adults taking naps for more than one hour per day have a higher incidence of increased blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol or triglyceride levels, sometimes known as metabolic syndrome. </p>
<p>The reason for this phenomenon is mostly unknown. Older individuals tend to nap more frequently than younger adults partly due to <a href="http://dx.doi.org/10.1016/j.smrv.2016.09.002">more disturbed sleep during the night</a>. This could be related to more pain or other health factors that will interfere with sleep, sleep altering medications and altered sleep rhythms seen with aging. </p>
<h2>Best practices</h2>
<p>So, to maximize benefits while reducing risks, here are some tips: Keep naps short to avoid sleep inertia and nighttime sleep disruptions. Nap in the early afternoon, as that aligns with a decrease in energy levels after lunch and with <a href="https://www.health.harvard.edu/staying-healthy/is-your-daily-nap-doing-more-harm-than-good#">the body’s natural circadian dip</a>, which is an increase in sleepiness similar to what occurs at dusk. Avoid late afternoon naps, finish naps at least four to six hours before bedtime, and create the right environment by napping in a quiet, comfortable and dimly lit space. </p>
<p>If you’re struggling with daytime sleepiness, it’s best to address the root cause rather than relying solely on napping. Reducing caffeine consumption, maintaining a regular sleep schedule and getting adequate nighttime sleep are essential steps to reduce daytime sleepiness. </p>
<p>Ultimately, napping should complement a healthy sleep routine, not serve as a <a href="https://theconversation.com/can-coffee-or-a-nap-make-up-for-sleep-deprivation-a-psychologist-explains-why-theres-no-substitute-for-shut-eye-206847">substitute for sufficient nighttime rest</a>. A balanced approach to napping can contribute to a more energized, focused and resilient life.</p><img src="https://counter.theconversation.com/content/210449/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Steven Bender does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Naps can be rejuvenating and beneficial to attentiveness and overall health, but the length of naps and the time of day are key.Steven Bender, Clinical Associate Professor, Texas A&M UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2068472023-08-17T12:35:47Z2023-08-17T12:35:47ZCan coffee or a nap make up for sleep deprivation? A psychologist explains why there’s no substitute for shut-eye<figure><img src="https://images.theconversation.com/files/542680/original/file-20230814-9571-esc8z7.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2121%2C1412&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A cup of coffee might provide you some pep, but it won't fully make up for lost sleep. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/woman-showing-arm-raised-up-holding-coffee-cup-on-royalty-free-image/1147318074">nopponpat/iStock via Getty Images Plus</a></span></figcaption></figure><p>There is no denying the importance of sleep. Everyone feels better after a good night of sleep, and lack of sleep can have <a href="https://theconversation.com/health-care-workers-are-frazzled-and-poor-sleep-may-turn-stress-into-poor-mental-health-199944">profoundly negative effects</a> on both the body and the brain. So what can be done to substitute for a lack of sleep? Put another way, how can you get less sleep and still perform at your peak?</p>
<p><a href="https://scholar.google.com/citations?user=g35Ez50AAAAJ&hl=en">As a psychologist</a> who studies the ways in which sleep benefits memory, I’m also interested in how sleep deprivation harms memory and cognition. After some initial research on <a href="https://theconversation.com/feeling-sleepy-you-might-be-at-risk-of-falsely-confessing-to-a-crime-you-did-not-commit-54229">sleep deprivation and false confessions</a>, my students at Michigan State University’s <a href="http://psychology.psy.msu.edu/sleeplab/">Sleep and Learning Lab</a> and I wanted to see what interventions could reverse the negative effects of sleep deprivation. </p>
<p>We found a simple answer: There is no substitute for sleep. </p>
<h2>Sleep deprivation impairs cognition</h2>
<p>For many years, scientists have known that sleep deprivation reduces the ability to <a href="https://doi.org/10.1038%2Fs41386-019-0432-6">maintain attention</a>. When asked to monitor a computer screen and press a button whenever a red dot appears – a pretty simple task – participants who are sleep deprived are much more likely to have lapses in attention. They don’t notice a bright red dot and fail to respond within a half-second. These lapses in attention are due to a <a href="https://www.cdc.gov/niosh/emres/longhourstraining/pressure.html">buildup in pressure to sleep</a> and are more common at points in the 24-hour circadian cycle when the body expects to be sleeping.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/dqONk48l5vY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Sleep deprivation can seriously damage your body.</span></figcaption>
</figure>
<p>Research investigating the effect of sleep derivation on more complex types of thinking has shown somewhat mixed results. So my team and I sought to determine how keeping people awake for one night affected different types of thinking. We had participants perform various cognitive tasks in the evening before we randomly assigned them to either go home and sleep or stay awake all night in the laboratory. The participants who were permitted to sleep returned in the morning, and everyone completed the cognitive tasks again. </p>
<p>Along with impairments in attention, we also found that sleep deprivation led to <a href="http://dx.doi.org/10.1037/xge0000495">more placekeeping errors</a>. Placekeeping is a <a href="https://doi.org/10.1037/a0030986">complex ability</a> that involves following a series of steps in order without skipping or repeating any of them. This would be similar to following a recipe to bake a cake from memory. You wouldn’t want to forget to add eggs or accidentally add the salt twice.</p>
<h2>Can caffeine replace sleep?</h2>
<p>Next, we set out to test different ways to potentially make up for a lack of sleep. What would you do if you did not sleep enough last night? Many people would reach for a cup of coffee or an energy drink. One 2022 survey found that <a href="https://foodinsight.org/caffeine-consumer-consumption-habits-and-safety-perceptions/">over 90% of the American adults sampled</a> consume some form of caffeine daily. We wanted to see whether caffeine would help maintain attention and avoid placekeeping errors after sleep deprivation. </p>
<p>Interestingly, we found that caffeine improved the ability to pay attention in sleep-deprived participants so well that their performance was <a href="https://doi.org/10.1037/xlm0001023">similar to people who slept all night</a>. Giving caffeine to people who had a full night of sleep also boosted their performance. So caffeine helped everyone maintain attention, not just those who did not sleep. This result was not surprising, as other studies have had <a href="https://doi.org/10.1016/j.nbscr.2020.100051">similar findings</a>. </p>
<p>However, we found that caffeine <a href="https://doi.org/10.1037/xlm0001023">did not reduce placekeeping errors</a> in either the sleep-deprived group or the group that slept. This means that if you are sleep deprived, caffeine may help you stay awake and play Candy Crush, but it likely will not help you ace your algebra exam.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/542687/original/file-20230814-26-ht98cu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Person with glasses sleeping on a stack of thick files, surrounded by coffee cups and paperwork" src="https://images.theconversation.com/files/542687/original/file-20230814-26-ht98cu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/542687/original/file-20230814-26-ht98cu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/542687/original/file-20230814-26-ht98cu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/542687/original/file-20230814-26-ht98cu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/542687/original/file-20230814-26-ht98cu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/542687/original/file-20230814-26-ht98cu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/542687/original/file-20230814-26-ht98cu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Your body turns up the pressure to sleep the longer it goes without it.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/exhausted-businesswoman-lying-down-on-the-desk-and-royalty-free-image/1199872302">cyano66/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<h2>Can naps make up for lost sleep?</h2>
<p>Of course, caffeine is an artificial way to replace sleep. We also reasoned that perhaps the best way to replace sleep would be with sleep. You have likely heard that <a href="https://theconversation.com/guilty-about-that-afternoon-nap-dont-be-its-good-for-you-89023">naps during the day</a> can boost energy and performance, so it is logical to think that a nap during the night should have a similar effect. </p>
<p>We gave some of our participants the opportunity to nap for either 30 or 60 minutes during an overnight deprivation period between 4 a.m. and 6 a.m. This time period roughly coincides with the lowest point of alertness in the circadian cycle. Importantly, we found that participants who napped <a href="https://doi.org/10.1093/sleep/zsab152">did no better</a> on either the simple attention task or the more complex placekeeping task than those who stayed up all night. </p>
<p>Thus, a nap in the middle of the night had no discernible benefits to cognitive performance during the morning after a night of overall sleep deprivation. </p>
<h2>Get your z’s</h2>
<p>While caffeine may help you stay awake and feel more alert, it likely won’t help you with tasks that require complex thought. And while a short nap may make you feel better on nights that you need to stay awake, it probably won’t help your performance. </p>
<p>In short, sufficient sleep is essential to your mind and brain, and there is simply no substitute for sleep.</p><img src="https://counter.theconversation.com/content/206847/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kimberly Fenn receives funding from the Office of Naval Research. </span></em></p>While a cup of joe or a brief nap during an all-nighter might help you feel a little more alert, it won’t offset cognitive impairments from sleep deprivation when you’re performing complex tasks.Kimberly Fenn, Professor of Psychology, Michigan State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2028292023-04-04T20:20:45Z2023-04-04T20:20:45ZPrime drinks aren’t suitable for children and pregnant women. Here’s why<figure><img src="https://images.theconversation.com/files/519151/original/file-20230403-14-8ognt5.jpg?ixlib=rb-1.1.0&rect=48%2C796%2C8003%2C4357&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/los-angeles-california-united-states-02012023-2275143831">Shutterstock</a></span></figcaption></figure><p>Prime drinks have been heavily promoted in Australia, leading to <a href="https://au.news.yahoo.com/woolworths-shoppers-in-frenzy-to-get-hands-on-cult-drink-prime-062849789.html">frenzied sales</a> in supermarkets, as well <a href="https://www.abc.net.au/news/2023-03-29/prime-logan-paul-ksi-drink-australian-schools-ban/102154550">bans in schools</a>. </p>
<p>Prime offers two products: one is marketed as a “hydration” drink, the other as an “energy” drink. The latter comes with a <a href="https://drinkprime.com/pages/faq">warning</a> it’s not suitable for people under 18 years of age, or pregnant or lactating women and isn’t legally sold in stores in Australia.</p>
<p>But both drinks may pose problems to under-18s and women who are pregnant or lactating. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1637195918595313665"}"></div></p>
<h2>What’s in Prime Energy?</h2>
<p>Prime Energy contains <a href="https://drinkprime.com/pages/faq">200 milligrams</a> of caffeine per can, which is equivalent to about two to three instant coffees. This caffeine content is roughly double what is <a href="https://www.foodstandards.gov.au/consumer/generalissues/pages/caffeine.aspx">legally allowed</a> for products sold in Australia. </p>
<p>Despite its name, Prime Energy drink contains only about 40 kilojoules from carbohydrates, which is one of our body’s key sources of energy. The “energy” in Prime Energy refers to the caffeine, which makes you feel more alert and lessens the perceived effort involved in any work you do. </p>
<p>Caffeine <a href="https://www.ais.gov.au/__data/assets/pdf_file/0003/1001379/Caffeine-Infographic-final.pdf">does provide performance benefits</a> for athletes aged over 18. However, given the high quantities in the drinks, there may be better ways to get caffeine in more appropriate doses. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/can-coffee-improve-your-workout-the-science-of-caffeine-and-exercise-92366">Can coffee improve your workout? The science of caffeine and exercise</a>
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</em>
</p>
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<h2>Caffeine is a concern during pregnancy</h2>
<p>Health guidelines recommend <a href="https://www.foodstandards.gov.au/consumer/generalissues/Pages/Caffeine.aspx">limiting</a> caffeine intake during pregnancy and while breastfeeding to below 200mg a day. </p>
<p>Theoretically, this drink alone, with 200mg of caffeine per can, should be fine. But practically, diets include many other sources of caffeine including coffee, tea, chocolate and cola drinks. Consumption of these alongside the energy drinks would increase the intake for pregnant women above this safety threshold. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/518988/original/file-20230403-14-14bsg4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/518988/original/file-20230403-14-14bsg4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/518988/original/file-20230403-14-14bsg4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=840&fit=crop&dpr=1 600w, https://images.theconversation.com/files/518988/original/file-20230403-14-14bsg4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=840&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/518988/original/file-20230403-14-14bsg4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=840&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/518988/original/file-20230403-14-14bsg4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1056&fit=crop&dpr=1 754w, https://images.theconversation.com/files/518988/original/file-20230403-14-14bsg4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1056&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/518988/original/file-20230403-14-14bsg4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1056&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="source" href="https://www.foodstandards.gov.au/consumer/generalissues/Pages/Caffeine.aspx">FSANZ</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Why is caffeine a problem for fetuses and babies?</h2>
<p>Caffeine can cross the placenta into the growing fetus’s bloodstream. Fetuses can’t break down the caffeine, so it remains in their circulation. </p>
<p>As the pregnancy proceeds, the mother becomes <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5872737/">slower at clearing caffeine</a> from her metabolism. This potentially exposes the fetus to caffeine for longer. </p>
<p>Studies have shown a high intake of caffeine is associated with <a href="https://link.springer.com/article/10.1007/s10654-014-9944-x">growth restriction</a>, <a href="https://pubmed.ncbi.nlm.nih.gov/26026343/">reduced birth weight, preterm birth and stillbirth</a>. Some experts argue there is <a href="https://ebm.bmj.com/content/26/3/114">no safe limit of caffeine intake</a> during pregnancy. </p>
<p>With breastfeeding, <a href="https://adc.bmj.com/content/54/10/787.short">caffeine passes into the breast milk</a>. It remains in the baby’s circulation, as they’re unable to metabolise it. <a href="https://pubmed.ncbi.nlm.nih.gov/9849117/">Evidence shows</a> that caffeine may make babies more colicky, irritable and less likely to sleep.</p>
<h2>What about in kids?</h2>
<p>Children also have a limited ability to break down caffeine. Combined with their lighter body mass, a caffeine-based drink will have a more pronounced effect. </p>
<p>As such, safe caffeine levels are determined on a weight basis: <a href="https://www.foodstandards.gov.au/code/proposals/Documents/P1056%20SD1%201st%20CFS%20Safety%20Assessment.pdf">3mg per kg of body weight per day</a>. For example, children aged 9 to 13 years, who weigh no more than 40kg, should have no more than 120mg of caffeine per day. Those aged between 14 to 17 years who weigh less than 60kg should have no more than 180mg per day.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1640853762519728129"}"></div></p>
<p><a href="https://www.internationaljournalofcardiology.com/article/S0167-5273(15)30918-9/fulltext">Studies have shown</a> higher intakes increase the risk of heart problems, such as heart palpitations, chest pain, shortness of breath and fainting. This may reflect underlying heart rhythm problems, which have in some case ended up with <a href="https://www.internationaljournalofcardiology.com/article/S0167-5273(15)30918-9/fulltext">children and teenagers</a> presenting to hospital emergency departments.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/should-teens-taking-adhd-anxiety-and-depression-drugs-consume-energy-drinks-and-coffee-166864">Should teens taking ADHD, anxiety and depression drugs consume energy drinks and coffee?</a>
</strong>
</em>
</p>
<hr>
<h2>What about Prime Hydrate, which doesn’t contain caffeine?</h2>
<p>This drink contains branch chain amino acids, or BCAA, which the supplements industry promotes as helping gain muscle bulk. There are three BCAA: valine, leucine and isoleucine.</p>
<p>However, there is no evidence they provide any benefit. As such, the <a href="https://www.ais.gov.au/nutrition/supplements/group_c">Australian Institute of Sport</a> has concluded they are not an effective supplement for athletes. </p>
<p>Supplements in general are not recommended in <a href="https://www.nccih.nih.gov/health/dietary-and-herbal-supplements">children or pregnant women</a> as they have not been tested in these groups. </p>
<p>There is also concern about the impact of BCAA and how they may impact the growth of the fetus. A <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7178017/">scientific animal study</a> has shown altered patterns of growth with fetal mice. </p>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7551332/">No human studies</a> have examined BCAA and fetal growth, so that research needs to be done before recommendations can be given to pregnant women. They should avoid these ingredients in the absence of evidence.</p>
<p>Similarly, there has been no testing of these supplements in children under 18 years, so there is no guarantee of their safety. </p>
<p>Performance-enhancing sport supplements are <a href="https://journals.humankinetics.com/view/journals/ijsnem/24/5/article-p570.xml">not recommended</a> for children and adolescents, as they are still developing physically as well as refining and improving their sporting skills. </p>
<figure class="align-center ">
<img alt="Children running" src="https://images.theconversation.com/files/519150/original/file-20230403-28-nwlh6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519150/original/file-20230403-28-nwlh6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519150/original/file-20230403-28-nwlh6e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519150/original/file-20230403-28-nwlh6e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519150/original/file-20230403-28-nwlh6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519150/original/file-20230403-28-nwlh6e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519150/original/file-20230403-28-nwlh6e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Children shouldn’t use performance-enhacing supplements.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>What does the science say about BCAA?</h2>
<p>Scientists have been investigating how BCAA affect adults. Circulating BCAA can affect carbohydrate metabolism in the muscle and therefore can <a href="https://www.mdpi.com/2072-6643/14/7/1454">change insulin sensitivity</a>. BCAA are elevated in adults with diet-induced obesity and are associated with <a href="https://www.mdpi.com/2072-6643/14/7/1454">increased future risk of type 2 diabetes</a>, even when scientists account for other baseline risk factors.</p>
<p>Adults with obesity and insulin resistance have been found to have higher levels of BCAA. <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.2047-6310.2012.00087.x">Emerging evidence suggests</a> children and adolescents with obesity also have higher levels of BCAA, which may predict future insulin resistance, a risk factor for diabetes. </p>
<p>However we don’t yet know if these elevated levels of BCAA in the blood are because people are overweight or obese, or if it plays a role in them becoming overweight or obese.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/do-athletes-really-need-protein-supplements-92773">Do athletes really need protein supplements?</a>
</strong>
</em>
</p>
<hr>
<p>The bottom line is we have clear evidence that caffeine is problematic for children and women who are pregnant and lactating. And there is emerging evidence BCAA may be also problematic.</p><img src="https://counter.theconversation.com/content/202829/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Evangeline Mantzioris is affiliated with Alliance for Research in Nutrition, Exercise and Activity (ARENA) at the University of South Australia. Evangeline Mantzioris has received funding from the National Health and Medical Research Council, and has been appointed to the National Health and Medical Research Council Dietary Guideline Expert Committee.</span></em></p>Prime has two offerings: one is marketed as a ‘hydration’ drink, the other as an ‘energy’ drink. But what’s actually in them?Evangeline Mantzioris, Program Director of Nutrition and Food Sciences, Accredited Practising Dietitian, University of South AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1978972023-01-29T19:09:07Z2023-01-29T19:09:07ZNope, coffee won’t give you extra energy. It’ll just borrow a bit that you’ll pay for later<figure><img src="https://images.theconversation.com/files/505804/original/file-20230123-15-2ygfk7.jpg?ixlib=rb-1.1.0&rect=34%2C34%2C7715%2C5135&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://images.pexels.com/photos/459270/pexels-photo-459270.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=2">Pexels</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Many of us want (or should I say <em>need</em>?) our morning coffee to give us our “get up and go”. Altogether, the people of the world drink more than <a href="https://link.springer.com/article/10.1007/s11906-021-01156-3">two billion cups of coffee each day</a>. </p>
<p>You might think coffee gives you the energy to get through the morning or the day – but coffee might not be giving you as much as you think.</p>
<p>The main stimulant in coffee is the caffeine. And the main way caffeine works is by changing the way the cells in our brain interact with a compound called <a href="https://www.sciencedirect.com/science/article/abs/pii/S1087079207000937">adenosine</a>. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/plunger-espresso-filter-just-because-your-coffee-is-bitter-doesnt-mean-its-stronger-188905">Plunger, espresso, filter? Just because your coffee is bitter, doesn't mean it's 'stronger'</a>
</strong>
</em>
</p>
<hr>
<h2>Getting busy, getting tired</h2>
<p>Adenosine is <a href="https://www.sciencedirect.com/science/article/abs/pii/S1087079201902011">part of the system</a> that regulates our sleep and wake cycle and part of why high levels of activity lead to tiredness. As we go about our days and do things, <a href="https://www.ingentaconnect.com/content/ben/ctmc/2011/00000011/00000008/art00008">levels of adenosine rise</a> because it is released as a by-product as energy is used in our cells. </p>
<p>Eventually <a href="https://www.sciencedirect.com/science/article/abs/pii/S1087079201902011">adenosine binds to its receptor</a> (parts of cells that receive signals) which tells the cells to slow down, making us feel drowsy and sleepy. This is why you feel tired after a big day of activity. While we are sleeping, <a href="https://www.ingentaconnect.com/content/ben/cn/2009/00000007/00000003/art00008">energy use drops</a> lowering adenosine levels as it gets shuffled back into other forms. You wake up in the morning feeling refreshed. Well, if you get enough sleep that is. </p>
<p>If you are still feeling drowsy when you wake up caffeine can help, for a while. It works by binding to the <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-0773.1995.Tb00111.X">adenosine receptor</a>, which it can do because it is a similar shape. But it is not so similar that it triggers the drowsy slow-down signal like adenosine does. Instead it just fills the spots and stops the adenosine from binding there. This is what staves off the drowsy feeling. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1617237578930954243"}"></div></p>
<h2>No free ride</h2>
<p>But there is a catch. While it feels energising, this little caffeine intervention is more a loan of the awake feeling, rather than a creation of any new energy. </p>
<p>This is because the <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1471-4159.2007.05196.x">caffeine won’t bind forever</a>, and the adenosine that it blocks doesn’t go away. So eventually the caffeine breaks down, lets go of the receptors and all that adenosine that has been waiting and building up latches on and the drowsy feeling comes back – sometimes all at once. </p>
<p>So, the debt you owe the caffeine always eventually needs to be repaid, and the only real way to repay it is to sleep. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/505803/original/file-20230123-17-uku54t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="cups of coffee on table in mug that reads life begins with coffee" src="https://images.theconversation.com/files/505803/original/file-20230123-17-uku54t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505803/original/file-20230123-17-uku54t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505803/original/file-20230123-17-uku54t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505803/original/file-20230123-17-uku54t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505803/original/file-20230123-17-uku54t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505803/original/file-20230123-17-uku54t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505803/original/file-20230123-17-uku54t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">But first, coffee.</span>
<span class="attribution"><a class="source" href="https://images.unsplash.com/photo-1504888527749-e68244b4d3d7?ixlib=rb-4.0.3&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=2070&q=80">Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Timing is everything</h2>
<p>How much free adenosine is in your system, that hasn’t attached to receptors yet, and how drowsy you are as a consequence will impact how much the caffeine you drink wakes you up. So, the coffee you drink <a href="https://journals.sagepub.com/doi/abs/10.1177/026988119100500205">later in the day</a>, when you have more drowsy signals your system may feel more powerful. </p>
<p>If it’s too late in the day, caffeine can make it hard to fall asleep at bedtime. The “half life” of caffeine (how long it takes to break down half of it) is about <a href="https://www.ncbi.nlm.nih.gov/books/NBK223808/#:%7E:text=The%20mean%20half%2Dlife%20of,et%20al.%2C%201989">five hours</a>). That said, we all <a href="https://pubmed.ncbi.nlm.nih.gov/29514871/#:%7E:text=The%20pharmacokinetics%20of%20caffeine%20are,enzyme%2C%20N%2Dacetyltransferase%202.">metabolise caffeine</a> differently, so for some of us the effects wear off more quickly. Regular coffee drinkers might feel less of a caffeine “punch”, with <a href="https://pubmed.ncbi.nlm.nih.gov/1888264/">tolerance</a> to the stimulant building up over time.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/505805/original/file-20230123-16-egstvh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="cup of coffee next to laptop" src="https://images.theconversation.com/files/505805/original/file-20230123-16-egstvh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505805/original/file-20230123-16-egstvh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505805/original/file-20230123-16-egstvh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505805/original/file-20230123-16-egstvh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505805/original/file-20230123-16-egstvh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505805/original/file-20230123-16-egstvh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505805/original/file-20230123-16-egstvh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Coffee drunk late in the day can hit differently.</span>
<span class="attribution"><a class="source" href="https://images.pexels.com/photos/414630/pexels-photo-414630.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=2">Pexels</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Caffeine can also <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2257922/">raise levels of cortisol</a>, a stress hormone that can make you feel more alert. This might mean caffeine feels more effective later in the morning, because you already have a natural rise in cortisol when you wake up. The impact of a coffee right out of bed might not seem as powerful for this reason. </p>
<p>If your caffeinated beverage of choice is also a sugary one, this can exacerbate the peak and crash feeling. Because while sugar does create actual energy in the body, the free sugars in your drink can cause a spike in blood sugar, which can then make you feel tired when the <a href="https://www.mayoclinic.org/diseases-conditions/diabetes/expert-answers/reactive-hypoglycemia/faq-20057778">dip comes afterwards</a>. </p>
<p>While there is no proven harm of drinking coffee on an empty stomach, <a href="https://www.hsph.harvard.edu/nutritionsource/caffeine/#:%7E:text=Food%20or%20food%20components%2C%20such,drank%20it%20while%20eating%20breakfast.">coffee with or after a meal</a> might hit you more slowly. This is because the food might slow down the rate at which the caffeine is absorbed. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/does-coffee-burn-more-fat-during-exercise-what-the-evidence-tells-us-157739">Does coffee burn more fat during exercise? What the evidence tells us</a>
</strong>
</em>
</p>
<hr>
<h2>What about a strong tea or fizzy cola?</h2>
<p>Coffee, of course, isn’t the only caffeinated beverage that can loan you some energy. </p>
<p>The caffeine in tea, energy drinks and other beverages still impacts the body in the same way. But, since the ingredients mostly come from plants, each caffeinated beverage has its own profile of additional compounds which can have their <a href="https://www.sciencedirect.com/science/article/abs/pii/S0195666312000335">own stimulant effect</a>, or can interact with caffeine to change its impacts.</p>
<p>Caffeine can be useful, but it isn’t magic. To create energy and re-energise our bodies we need enough food, water and sleep. </p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CnnSc1lvLgC","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p><img src="https://counter.theconversation.com/content/197897/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Emma Beckett has received funding for research or consulting from Mars Foods, Nutrition Research Australia, NHMRC, ARC, AMP Foundation, Kellogg, and the University of Newcastle. She is a member of committees/working groups related to nutrition or the Australian Academy of Science, the National Health and Medical Research Council and the Nutrition Society of Australia.</span></em></p>Feeling tired and groggy in the morning may well lead you to crave a coffee boost. But is it a gift or just a loan in terms of energy?Emma Beckett, Senior Lecturer (Food Science and Human Nutrition), School of Environmental and Life Sciences, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1889052022-08-26T01:42:15Z2022-08-26T01:42:15ZPlunger, espresso, filter? Just because your coffee is bitter, doesn’t mean it’s ‘stronger’<figure><img src="https://images.theconversation.com/files/480984/original/file-20220825-26-9rqpig.jpg?ixlib=rb-1.1.0&rect=840%2C9%2C4829%2C3848&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/rwwMB7kTNes">Devin Avery/Unsplash</a></span></figcaption></figure><p>Coffee – one bean with many possibilities. A big choice is how to brew it: espresso, filter, plunger, percolator, instant and more. Each method has unique equipment, timing, temperature, pressure, and coffee grind and water needs.</p>
<p>Our choices of brewing method can be <a href="https://www.tandfonline.com/doi/full/10.1080/13507486.2013.833717">cultural</a>, <a href="https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/food-choice-and-intake-the-human-factor/346D4AA3CECC6EFCCF5824435953122E">social</a> or practical. But how much do they really impact what’s in your cup?</p>
<h2>Which is the strongest brew?</h2>
<p>It depends. If we focus on <a href="https://theconversation.com/whats-the-buzz-on-caffeine-12669">caffeine</a> <em>concentration</em>, on a milligram per millilitre (mg/ml) basis espresso methods are <a href="https://www.sciencedirect.com/science/article/pii/S0963996918308093">typically the most concentrated</a>, able to deliver up to 4.2 mg/ml. This is about three times higher than other methods like <a href="https://www.atlasobscura.com/articles/make-coffee-moka-pot">Moka pot</a> (a type of boiling percolator) and cold brewing at about 1.25 mg/ml. Drip and plunger methods (including French and Aero-press) are about half that again. </p>
<p>Espresso methods extract the most caffeine for a few reasons. Using the finest grind means there is more contact between the coffee and water. Espresso also uses pressure, pushing more compounds out into the water. While other methods brew for longer, this doesn’t impact caffeine. This is because caffeine is water soluble and easy to extract, so it’s released early in brewing.</p>
<p>But these comparisons are made based on typical <em>extraction</em> situations, not typical <em>consumption</em> situations.</p>
<p>So, while espresso gives you the most concentrated product, this is delivered in a smaller volume (just 18–30ml), compared to much larger volumes for most other methods. These volumes of course vary depending on the maker, but a recent <a href="https://www.sciencedirect.com/science/article/pii/S0963996918308093">Italian study</a> defined a typical final serve of filter, percolator and cold brews as 120ml.</p>
<hr>
<p><iframe id="m6tf9" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/m6tf9/1/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<hr>
<p>Based on this maths, cold brew actually comes out as the highest dose of caffeine per serve with almost <a href="https://www.sciencedirect.com/science/article/pii/S0963996918308093">150mg</a> – even higher than the 42–122mg totals found in finished espresso. Although cold brew uses cold water, and a larger grind size, it is brewed with a high coffee to water ratio, with extra beans needed in the brew. Of course, “standard serves” are a concept not a reality – you can multiply serves and supersize any coffee beverage!</p>
<p>With the rising price of coffee, you might also be interested in extraction efficiency – how much caffeine you get for each gram of coffee input. </p>
<p>Interestingly, <a href="https://www.sciencedirect.com/science/article/pii/S0963996918308093">most methods are actually pretty similar</a>. Espresso methods vary but give an average of 10.5 milligrams per gram (mg/g), compared to 9.7–10.2mg/g for most other methods. The only outlier is the French press, with just 6.9mg/g of caffeine.</p>
<figure class="align-center ">
<img alt="A glass beaker in a dark plastic frame with coffee steeping inside, the plunger laid next to it" src="https://images.theconversation.com/files/481003/original/file-20220825-14-g2scbc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/481003/original/file-20220825-14-g2scbc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/481003/original/file-20220825-14-g2scbc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/481003/original/file-20220825-14-g2scbc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/481003/original/file-20220825-14-g2scbc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/481003/original/file-20220825-14-g2scbc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/481003/original/file-20220825-14-g2scbc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The French press or coffee plunger was actually invented in Italy, despite its modern name.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/A1wzMskhU_c">Rachel Brenner/Unsplash</a></span>
</figcaption>
</figure>
<h2>‘Strength’ is more than just caffeine</h2>
<p>Caffeine content only explains <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5488350/#:%7E:text=Although%20coffee%20contains%20multiple%20bitter,especially%20important%20for%20caffeine%20taste">a small part of the strength</a> of coffee. Thousands of compounds are extracted, contributing to aroma, flavour and function. Each has their own pattern of extraction, and they can <a href="https://pubs.acs.org/doi/10.1021/acs.jafc.0c01373">interact with each other to inhibit or enhance effects</a>. </p>
<p>The oils responsible for the crema – the rich brown ‘foam’ on top of the brew – are also <a href="https://www.sciencedirect.com/science/article/pii/B9780128035207000177">extracted more easily with high temperatures</a>, pressures, and fine grinds (another potential win for espresso and Moka). These methods also give <a href="https://www.sciencedirect.com/science/article/pii/S0963996918308093">higher levels of dissolved solids</a>, meaning a less watery consistency – but, again, this all depends on how the final product is served and diluted. </p>
<p>To further complicate matters – the receptors that detect caffeine and the other bitter compounds are highly variable between individuals due to <a href="https://www.cambridge.org/core/journals/twin-research-and-human-genetics/article/genetic-analysis-of-coffee-consumption-in-a-sample-of-dutch-twins/A0E54A955F4C207D83797E2183E51AFB">genetics and training from our usual exposures</a>. This means the same coffee samples could invoke diverse perceptions of their bitterness and strength in different people.</p>
<p>There are also differences in <a href="https://www.healthline.com/health/caffeine-sensitivity#:%7E:text=People%20with%20caffeine%20sensitivity%20experience,may%20last%20for%20several%20hours">how sensitive we are</a> to the stimulant effects of caffeine. So what we are looking for in a cup, and getting from it, is dependent on our own unique biology.</p>
<figure class="align-center ">
<img alt="A multifaceted aluminium pot with a black handle, with steam coming from the spout" src="https://images.theconversation.com/files/481002/original/file-20220825-19-adzw5q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/481002/original/file-20220825-19-adzw5q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/481002/original/file-20220825-19-adzw5q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/481002/original/file-20220825-19-adzw5q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/481002/original/file-20220825-19-adzw5q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/481002/original/file-20220825-19-adzw5q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/481002/original/file-20220825-19-adzw5q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Moka pot, another iconic Italian invention, brews coffee at high temperatures on a stovetop.</span>
<span class="attribution"><span class="source">Ccu.bat/Shutterstock</span></span>
</figcaption>
</figure>
<h2>Is there a healthier brew?</h2>
<p>Depending on the headline or the day, <a href="https://theconversation.com/mixed-messages-is-coffee-good-or-bad-for-us-it-might-help-but-it-doesnt-enhance-health-187343">coffee might be presented as a healthy choice, or an unhealthy one</a>. This is partly explained by our optimism bias (of course we want coffee to be good for us!) but may also be due to the difficulty of studying products like coffee, where it is difficult to capture the complexity of brewing methods and other variables. </p>
<p>Some studies have suggested that coffee’s health impacts are brew type specific. For example, filter coffee has been <a href="https://journals.sagepub.com/doi/abs/10.1177/2047487320914443">linked to more positive cardiovascular outcomes in the elderly</a>.</p>
<p>This link might be a coincidence, based on other habits that coexist, but there is some evidence that filter coffee is healthier because more diterpenes (a chemical found in coffee which might be <a href="https://pubmed.ncbi.nlm.nih.gov/9242972/">linked to raising levels of bad cholesterol</a>) are <a href="https://pubmed.ncbi.nlm.nih.gov/28873752/">left in the coffee and the filter</a>, meaning less make it to the cup. </p>
<h2>The bottom line?</h2>
<p>Each brewing method has its own features and inputs. This gives each one a unique profile of flavour, texture, appearance and bioactive compounds. While the complexity is real and interesting, ultimately, how to brew is a personal choice.</p>
<p>Different information and situations will drive different choices in different people and on different days. Not every food and drink choice needs to be optimised!</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-dark-brew-coffee-covid-and-colonialism-have-left-millions-struggling-to-make-a-living-143274">A dark brew: coffee, COVID and colonialism have left millions struggling to make a living</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/188905/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Emma Beckett does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>From espresso to plunger, our choice of coffee brewing method depends on many factors. But how much does it impact what’s actually in your cup?Emma Beckett, Senior Lecturer (Food Science and Human Nutrition), School of Environmental and Life Sciences, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1873432022-07-26T13:23:41Z2022-07-26T13:23:41ZMixed messages: Is coffee good or bad for us? It might help, but it doesn’t enhance health<figure><img src="https://images.theconversation.com/files/475002/original/file-20220720-26-x38x1u.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6468%2C3234&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The chemical properties of coffee are what produce its waking-up effects.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Coffee is good for you. Or it’s not. Maybe it is, then it isn’t, then it is again. If you drink coffee, and follow the news, then perhaps you’ve noticed this pattern. </p>
<p>A recent study showed that coffee, even sweetened, <a href="https://www.theglobeandmail.com/life/health-and-fitness/article-beck-coffee-delivers-health-perks-even-with-some-sugar-new-study/">was associated with health benefits</a>. But other studies <a href="https://www.hsph.harvard.edu/news/hsph-in-the-news/is-coffee-good-or-bad-for-your-health/">have come to more mixed conclusions</a>.</p>
<p>What’s driving these pendulum swings in the health status of coffee? Like a good cup of coffee, the answer is complex, but seems to boil down to human nature and scientific practice.</p>
<h2>Wishful optimism</h2>
<p>Globally, we consume about <a href="https://britishcoffeeassociation.org/coffee-consumption/">two billion cups of coffee each day</a>. That’s a lot of coffee, and many of those who imbibe want to know what that coffee is doing to us, in addition to waking us up. </p>
<p>As a species, we are often <a href="https://grist.org/article/80-percent-of-humans-are-delusionally-optimistic-says-science/">delusionally optimistic</a>. We want the world to be better, maybe simpler, than it is. We squint at our morning cup through those same rosy glasses: We really want coffee to bring us health, not just a sunny disposition.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/tnjjZR-59Wg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">CBC News reports on the World Health Organization’s announcement that drinking coffee does not cause bladder cancer.</span></figcaption>
</figure>
<p>But is that likely? In drinking coffee, we’re ingesting a complex brew that includes literally thousands of chemicals, including one that evolved to dissuade herbivores from munching on the coffee plant: caffeine.</p>
<h2>Coffee for the caffeine</h2>
<p>Our morning kickstart comes from a plant toxin. The possible health benefits of coffee are generally attributed to other molecules in the brew, often antioxidants including polyphenols, <a href="https://doi.org/10.1007/s00217-019-03388-9">a group that are found in substantial concentrations in coffee</a>. But they, and other antioxidants, are also found <a href="https://www.hsph.harvard.edu/nutritionsource/antioxidants/">in many plants like broccoli or blueberries, and in higher concentrations</a>. </p>
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Read more:
<a href="https://theconversation.com/the-biology-of-coffee-one-of-the-worlds-most-popular-drinks-129179">The biology of coffee, one of the world’s most popular drinks</a>
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<p>We drink coffee for the caffeine, not the antioxidants. The best we can realistically hope for is that we aren’t harming ourselves by drinking coffee. With any luck, coffee isn’t killing us nearly as quickly as other things that we’re doing to our bodies. I’m looking at you <a href="https://health.clevelandclinic.org/sluggish-start-the-5-worst-breakfast-foods/">doughnuts</a>, <a href="https://www.verywellhealth.com/microwave-popcorn-and-cancer-5085309">microwave popcorn</a> and <a href="https://www.mayoclinic.org/healthy-lifestyle/quit-smoking/expert-answers/cigar-smoking/faq-20057787">celebratory cigars</a>. </p>
<p>The dynamic nature of science also drives our on-again, off-again medical love affair with coffee. Scientists like to study coffee almost as much as we like to drink it; there are almost three and a half million scientific articles focused on coffee (thanks Google Scholar). Even the number of cups we consume is surprisingly contentious, with many aspects <a href="http://dx.doi.org/10.1136/bmjnph-2018-000013">being subject to scrutiny, study and debate</a>.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CVnyCfKNHhq","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>Changing research findings</h2>
<p>The dizzying swings in coffee’s health status highlight a fundamental challenge in modern science. Research is an ongoing process, and our understanding of the world around us changes as we explore and learn. We question, examine and make decisions based on the best information we have. Those decisions can, and should, change as we get new information.</p>
<p>In 1981, a high profile <em>New York Times</em> opinion piece loudly proclaimed that <a href="https://www.nytimes.com/1981/03/14/opinion/coffee-and-cancer.html">our morning cup was driving us to an early grave</a>. The writers wrung their hands as they swore off coffee and faced the grey reality of their post-coffee world. Their passionate convictions were driven by a then-recent study in which researchers clearly linked even moderate coffee consumption with a substantial rise in premature death.</p>
<p>Three years later the study was refuted by some of <a href="https://doi.org/10.1056/NEJM198608283150918">the same scientists</a>, and the editors were, presumably, back in their coffee cups – if they had ever actually stepped away.</p>
<p>The initial study was well done, included more than 1,000 patients from almost a dozen hospitals and five reputable scientists. The results were clear and the conclusions seemed justified. But a follow-up study failed to replicate the, admittedly shocking, conclusions: the authors found no link between drinking coffee and premature death.</p>
<p>What went wrong? One thing may have been the researchers’ reliance on a common measure of statistical significance, the <em>p</em> value. The value was developed as a way to explore data, but is often treated as a magic bullet that identifies significant results. </p>
<p>But there simply isn’t a foolproof, objective or irrefutable way to identify or quantify the significance of a result. We can reach reasonable conclusions in which we have some kind of confidence, but that is about as good as it is going to get.</p>
<p>We need to question conclusions that seem to be too good to be true, like the idea that consuming a plant toxin could make us live longer, that <a href="https://theconversation.com/hoping-to-get-in-shape-for-summer-ditch-the-fads-in-favour-of-a-diet-more-likely-to-stick-122648">only eating a fictional caveman diet will make us healthier</a>, <a href="https://www.theglobeandmail.com/canada/article-covid-19-pandemic-not-over/">acting as though the COVID-19 pandemic is over</a>, even in the face of daily evidence that it isn’t, will make it go away, or that <a href="https://www.forbes.com/sites/nilsrokke/2022/04/07/why-we-cant-ignore-the-latest-un-climate-change-report/">simply ignoring massive fluctuations in weather will make global climate change disappear</a>. Common sense can go a long way.</p>
<h2>Health benefits</h2>
<p>Is coffee good for you? Yes, in the sense that it will wake you up, brighten your mood, maybe even give you an excuse to get out of the house and chat with friends at a local coffee house. </p>
<p>Will drinking coffee make you healthier or help you live longer? Probably not. Sure, the antioxidants in our morning cup could actually be helping our bodies, but there are far better ways to boost your antioxidant intake.</p>
<p>So, wake up with a strong cup of coffee, <a href="https://theconversation.com/food-variety-is-important-for-our-health-but-the-definition-of-a-balanced-diet-is-often-murky-149126">but stay healthy with a complex and varied diet</a>.</p><img src="https://counter.theconversation.com/content/187343/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Thomas Merritt receives funding from the Natural Sciences Engineering and Research Council of Canada. </span></em></p>Drinking a cup of coffee means ingesting a complex mixture of chemicals. Research has given us mixed messaging about whether coffee is beneficial or harmful.Thomas Merritt, Professor, Chemistry and Biochemistry, Laurentian UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1729072021-12-16T14:23:10Z2021-12-16T14:23:10ZCoffee’s health benefits aren’t as straightforward as they seem – here’s why<figure><img src="https://images.theconversation.com/files/437989/original/file-20211216-17-4fznuz.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5760%2C3828&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Every cup of coffee is different.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/different-types-coffee-cups-on-dark-413980987">Africa Studio/ Shutterstock</a></span></figcaption></figure><p>You’ve probably heard it before: drinking coffee is good for your health. Studies have shown that drinking a moderate amount of coffee is associated with many health benefits, including a lower risk of developing <a href="https://www.acpjournals.org/doi/pdf/10.7326/0003-4819-140-1-200401060-00005">type 2 diabetes</a> and <a href="https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.113.005925?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed">cardiovascular disease</a>. But while these associations have been demonstrated many times, they don’t actually prove that coffee reduces disease risk. In fact, proving that coffee is good for your health is complicated.</p>
<p>While it’s suggested that consuming three to five cups of coffee a day will provide <a href="https://www.sciencedirect.com/science/article/pii/S0939475321002374#tbl3">optimal health benefits</a>, it’s not quite that straightforward. Coffee is chemically complex, containing many components that can affect your health in different ways. </p>
<p>While caffeine is the most well-known compound in coffee, there is more to coffee than caffeine. Here are a few of the other compounds found in coffee that might affect your health.</p>
<p><strong>Alkaloids.</strong> Aside from caffeine, trigonelline is another important alkaloid found in coffee. Trigonelline is less researched than caffeine, but research suggests that it may have health benefits, such as reducing the risk of <a href="https://care.diabetesjournals.org/content/diacare/32/6/1023.full.pdf">type 2 diabetes</a>. </p>
<p><strong>Polyphenols.</strong> Some research shows that these compounds, which are found in many plants, including cocoa and blueberries, are good for your <a href="https://pdfs.semanticscholar.org/8c23/2f7a7744309e370e8ac25bafe01909c08a3d.pdf">heart and blood vessels</a>, and may help to prevent neurodegenerative diseases such as <a href="https://www.sciencedirect.com/science/article/pii/S0891584911005764?casa_token=IOJ2NHQy-vkAAAAA:LCRWlOmiFFzQvbNiq3g2bPjQIQv4sSlfiDp7-qNW7jzQdis4zwCufAgbdRfHzm9h1mYQwcBcU6U">Alzheimer’s</a>. Coffee predominantly contains a class of polyphenols called chlorogenic acids. </p>
<p><strong>Diterpenes.</strong> Coffee contains two types of diterpenes – cafestol and kahweol – that make up coffee oil, the natural fatty substance released from coffee during brewing. Diterpenes may increase the risk of <a href="https://onlinelibrary.wiley.com/doi/epdf/10.1002/mnfr.200400109">cardiovascular disease</a>.</p>
<p><strong>Melanoidins.</strong> These compounds, which are produced at high temperatures during the roasting process, give roasted coffee its colour and provide the characteristic flavour and aroma of coffee. They may also have a prebiotic effect, meaning they increase the amount of <a href="https://onlinelibrary.wiley.com/doi/10.1002/mnfr.200500011">beneficial bacteria in your gut</a>, which is important for overall health.</p>
<p>The way your coffee is grown, brewed and served can all affect the compounds your coffee contains and hence the health benefits you might see.</p>
<p>First, growing conditions can affect the levels of caffeine and chlorogenic acids the coffee contains. For example, coffee grown at <a href="https://www.sciencedirect.com/science/article/abs/pii/S0963996917307858">high altitudes</a> will have both lower caffeine and chlorogenic acid content. The two types of coffee beans, <a href="https://www.sciencedirect.com/science/article/pii/S2212429221004983?via%3Dihub#bib2">arabica and robusta</a>, have also been shown to have different caffeine, chlorogenic acid and trigonelline levels. Although neither type has been shown to be more beneficial to health. </p>
<figure class="align-center ">
<img alt="A picture of a coffee plant on a farm." src="https://images.theconversation.com/files/437990/original/file-20211216-25-9hn8p9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/437990/original/file-20211216-25-9hn8p9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/437990/original/file-20211216-25-9hn8p9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/437990/original/file-20211216-25-9hn8p9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/437990/original/file-20211216-25-9hn8p9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/437990/original/file-20211216-25-9hn8p9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/437990/original/file-20211216-25-9hn8p9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">It isn’t just how you brew it – even where coffee is grown affects what compounds it contains.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/fresh-organic-coffee-arabica-beans-1702130041">alexan888/ Shutterstock</a></span>
</figcaption>
</figure>
<p>Processing will also affect the coffee’s <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8620865/">chemical composition</a>. For example, some coffee is decaffeinated. This is typically done before roasting, and depending on the decaffeination method, it may further affect other compounds. For example, <a href="https://pubmed.ncbi.nlm.nih.gov/16417293/">small levels of chlorogenic</a> acids are lost during the decaffeination process. </p>
<p>The extent that coffee is roasted is also key. The more severe the roasting, the more <a href="https://pubs.acs.org/doi/pdf/10.1021/jf800999a">melanoidins formed</a> (and the more intense the flavour). But this lowers <a href="https://pubmed.ncbi.nlm.nih.gov/23993490/">chlorogenic acids</a> and <a href="https://www.sciencedirect.com/science/article/abs/pii/S030881460500614X">trigonelline</a> content. </p>
<p>In the UK, instant coffee is the most commonly consumed type of coffee. This is typically freeze-dried. Research shows that instant coffee contains <a href="https://pubs.rsc.org/en/content/articlelanding/2011/FO/c0fo00156b">higher levels of melanoidins</a> per serving compared with filter coffee and espresso.</p>
<p>How you <a href="https://www.nature.com/articles/s41598-017-18247-4">prepare your coffee</a> will also affect its chemical composition. For example, <a href="https://www.sciencedirect.com/science/article/pii/S0278691596001238">boiled coffee</a> contains a higher level of diterpenes compared with filter coffee. Other factors – such as the amount of coffee used, how <a href="https://pubmed.ncbi.nlm.nih.gov/29230816/">finely it was ground</a>, water temperature and cup size – will also affect the coffee’s chemical composition.</p>
<h2>Health effects</h2>
<p>Every compound has different effects on your health, which is why the way coffee is produced and brewed can be important.</p>
<p>Chlorogenic acids, for example, are thought to reduce the risk of cardiovascular disease by improving the <a href="https://pubmed.ncbi.nlm.nih.gov/28012692/">function of your arteries</a>. There’s also evidence they may reduce the <a href="https://care.diabetesjournals.org/content/diacare/32/6/1023.full.pdf">risk of type 2 diabetes</a> by controlling blood sugar spikes after eating. </p>
<p>On the other hand, diterpenes have been shown to increase levels of low-density lipoprotein, a type of cholesterol associated with <a href="https://pubmed.ncbi.nlm.nih.gov/22713771/">cardiovascular disease</a>. While less research has focused on <a href="https://care.diabetesjournals.org/content/diacare/32/6/1023.full.pdf">trigonelline</a> and <a href="https://onlinelibrary.wiley.com/doi/10.1002/mnfr.200500011">melanoidins</a>, some evidence suggests both may be good for your health.</p>
<p>Adding cream, <a href="https://www.nhs.uk/live-well/eat-well/how-does-sugar-in-our-diet-affect-our-health">sugar</a> and syrup will change the nutritional content of your cup. Not only will they increase the calorie content, they may also increase your intake of saturated fats and sugars. Both of these are associated with increased risk of type 2 diabetes and cardiovascular disease and may counter the beneficial effects of the other compounds your cup of coffee contains.</p>
<p>There’s also evidence that people may respond differently to some of these compounds. Regularly drinking three to four cups of coffee daily has been shown to <a href="https://pubmed.ncbi.nlm.nih.gov/31900579/">build tolerance</a> to the blood pressure raising effects of caffeine. <a href="https://pubmed.ncbi.nlm.nih.gov/29569539/">Genetics</a> may also play a role in how your body handles caffeine and other compounds.</p>
<p>Increasing evidence also points to the gut microbiome as an important factor in determining what health effects coffee may have. For example, some research suggests the gut microbes play an important role in <a href="https://academic.oup.com/jn/article/133/6/1853/4688142">chlorogenic acid metabolism</a>, and hence may determine if they will benefit your health or not.</p>
<p>Researchers need to conduct large studies to confirm the findings of these smaller studies, which seem to show that coffee is good for your health. But in the meantime, minimise the sugar and cream you use in your coffee. And if you’re in good health and aren’t pregnant, continue to take a moderate approach to coffee consumption, choosing filter coffee where possible.</p><img src="https://counter.theconversation.com/content/172907/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Charlotte Mills is currently in receipt of a BBSRC DTP award to support a PhD student to investigate the impact of coffee on cardiometabolic health. She has previously worked on a BBSRC DRINC funded project on coffee processing and health which was also supported by Nestec Ltd, a subsidiary of Nestlé Ltd via BBSRC DRINC.
</span></em></p><p class="fine-print"><em><span>Ashley Hookings is currently completing a BBSRC DTP funded PhD, investigating the impact of coffee on cardiometabolic health.</span></em></p>Everything from where your coffee is grown right down to how it’s brewed can affect what health benefits it might have.Charlotte Mills, Lecturer in Human Nutrition, University of ReadingAshley Hookings, PhD Candidate, Coffee Intake and Cardiometabolic Health, University of ReadingLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1690002021-09-30T14:30:23Z2021-09-30T14:30:23ZCoffee bean prices have doubled in the past year and may double again – what’s going on?<figure><img src="https://images.theconversation.com/files/423995/original/file-20210930-12-18pvll8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Beans are booming. </span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/OmOvMdiaZZ0">Robert Shunev/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>International Coffee Day feels very different this year. Introduced by the <a href="https://www.ico.org/">International Coffee Organization</a> (ICO) on October 1 2015 to raise awareness of the product and the challenges faced by producers, the day has usually focused on how low prices paid for unroasted beans barely cover farmers’ costs – let alone support their families. </p>
<p>Not this year, though. In the past 12 months, the C price – the benchmark price for commodity-grade Arabica coffee on the New York International Commodity Exchange – has risen from US$1.07 (£0.80) per pound (454g) to around US$1.95. Back in July, <a href="https://www.macrotrends.net/2535/coffee-prices-historical-chart-data">it touched US$2.08</a>. </p>
<p><strong>Arabica bean prices (US$/lb)</strong></p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/423998/original/file-20210930-18-1hbqr1t.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Long-term price chart for Arabica coffee" src="https://images.theconversation.com/files/423998/original/file-20210930-18-1hbqr1t.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/423998/original/file-20210930-18-1hbqr1t.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=308&fit=crop&dpr=1 600w, https://images.theconversation.com/files/423998/original/file-20210930-18-1hbqr1t.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=308&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/423998/original/file-20210930-18-1hbqr1t.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=308&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/423998/original/file-20210930-18-1hbqr1t.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=387&fit=crop&dpr=1 754w, https://images.theconversation.com/files/423998/original/file-20210930-18-1hbqr1t.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=387&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/423998/original/file-20210930-18-1hbqr1t.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=387&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption"></span>
<span class="attribution"><a class="source" href="https://tradingeconomics.com/commodity/coffee">Trading Economics</a></span>
</figcaption>
</figure>
<p>Nearly all contracts for coffee delivery are benchmarked against the C price, with the result that prices for green Arabica (unroasted beans) have risen by over 80% during the past year. Those for Robusta coffee – a cheaper, less palatable alternative – have <a href="https://ycharts.com/indicators/world_coffee_robusta_price">risen over 30%</a>. And there is every chance that these prices will rise higher in the coming months. We may be on the verge of a major price correction that shifts the market upwards for years to come.</p>
<h2>Why coffee got expensive</h2>
<p>The principal reason for surging prices is a series of environmental events in Brazil. By far the world’s leading coffee producer, Brazil accounts for <a href="https://www.ico.org/historical/1990%20onwards/PDF/1a-total-production.pdf">around 35%</a> of global harvest. The volume of production regularly fluctuates between “on” and “off” years, and usually this is not sufficient to greatly affect prices because producers mitigate their risks through stock management and hedging prices using the <a href="https://perfectdailygrind.com/2019/01/what-is-coffee-hedging-how-does-it-impact-producers/">coffee futures market</a>. </p>
<p>However, yields in 2021 are likely to be dramatically lower. This is due to <a href="https://www.npr.org/2021/09/22/1039800090/how-brazils-severe-drought-affects-the-entire-worlds-coffee-supply-chain">a combination</a> of a severe drought earlier in the season, which reduced the numbers of coffee cherries, and recent intense frosts that might further damage the fruit and even the trees. The Brazilian authorities <a href="https://www.comunicaffe.com/brazil-conab-cut-its-official-estimate-for-the-2021-22-coffee-crop-to-46-9-million-bags/">are projecting</a> the lowest Arabica harvest for 12 years.</p>
<p>The big question is how this affects future production. Coffee trees can take up to five years to mature, so it will take a few seasons before the scale of the damage is clear. If, as <a href="http://www.spilling-the-beans.net/">some respected reporters</a> are suggesting, the frost causes maximum damage – potentially <a href="https://stir-tea-coffee.com/tea-coffee-news/brazil-frost-damage-worsens-global-coffee-supply-challenges-/">hitting two-thirds</a> of trees – there may be a long-lasting drop in world supplies. This could see prices breaking through the US$3.00 and even US$4.00 barrier.</p>
<h2>The long coffee cycle</h2>
<p><a href="https://www.amazon.co.uk/Coffee-Global-History-Jonathan-Morris/dp/1789140021/ref=tmm_hrd_swatch_0?_encoding=UTF8&qid=&sr=">The history</a> of coffee has been characterised by extreme price volatility. Periods of excessive supplies have progressively driven down prices until a catastrophic event – either environmental or political – results in a correction. </p>
<p>During the 1930s, a combination of bumper harvests and weak consumer demand in the depression era led to a massive supply glut. To reduce excess stock, Brazil resorted to dumping coffee at sea and also converting it into locomotive fuel. At the other extreme, many coffee trees were killed in 1975 when Brazil was struck by a series of “black” frosts. This led to a 60% fall in output in the following harvest, and prices trebling between 1975 and 1977. </p>
<p>In 1962, the ICO introduced producer quotas to try and keep prices buoyant in the face of such highs and lows. This was supported by the United States to avoid communism spreading from Cuba to mainland Latin America, but it was abandoned on American insistence after 1989. This led to an over-supply and ultimately a coffee crisis at the end of the century in which the C price remained under US$1.00 for four straight years. It had tended to trade between about US$1.00 and US$2.00 per pound, and the price crash saw many producers <a href="http://www.ico.org/documents/globalcrisise.pdf">going hungry</a>. </p>
<p>The price only recovered when a <a href="https://www.britannica.com/science/coffee-rust">coffee leaf rust</a> infected a significant portion of Central American and Colombian production. The bitter irony of the coffee market is that prices for producers only improve when many of them suffer unsustainable losses.</p>
<h2>The Robusta problem</h2>
<p>Coffee prices fell in the latter part of the 2010s primarily as a result of the expansion of global production. Most notable <a href="https://farrerscoffee.co.uk/blogs/blog/top-10-coffee-producing-countries-around-the-world">was Vietnam</a>, which is now the world’s second largest coffee producer and accounts for around 18% of total global production. As much as 95% of Vietnamese output is Robusta.</p>
<p><a href="https://www.amazon.co.uk/Coffee-Not-Forever-History-Ecology-ebook/dp/B07ZH85TNK/ref=sr_1_1?dchild=1&keywords=coffee+is+not+forever&qid=1632757826&qsid=257-4439212-9979455&s=books&sr=1-1&sres=0821423878%2CB09FSCKT9B%2C1398703427%2C1529105102%2CB086Y7D5S2%2C1785945149%2C178452087X%2C0008366276%2C0008375526%2C0008422982%2CB092PCTWBG%2C139870167X%2C1648450660%2CB09DTHQHQ7%2CB00VT94WXW%2C1640309470">Robusta was actually</a> first used for coffee cultivation because of an environmental catastrophe, when east Asia’s coffee production was virtually wiped out by coffee leaf rust during the late 19th century. In more recent times, procedures for “cleaning” Robusta to reduce off-flavours have improved to the point that <a href="https://www.thecoffeeguide.org/coffee-guide/coffee-quality/steam-cleaning/">roasters increasingly</a> resort to raising its proportion within a blend. This is particularly done when targeting markets which are primarily driven by price, such as instant coffee.</p>
<p>If prices keep spiking now, using more Robusta in blends could prevent coffee from becoming too expensive for consumers. But this will be difficult to do, at least short-term, because of severe COVID restrictions in Vietnam. This has caused <a href="https://www.comunicaffe.com/supply-concerns-in-vietnam-push-robusta-futures-prices-to-their-highest-levels-since-2017/">considerable disruptions</a> both to transporting coffee from the central highlands to the export hub of Ho Chi Minh city, and then managing the onward shipping logistics. The same issues have arisen in many coffee-producing nations. </p>
<p><a href="https://www.spillerandtait.co.uk/blogs/news/coffee-price-rises-for-small-roasters-imminent">Consequently we have</a> brokers battling to secure sufficient stocks, roasters contemplating how to pass on price rises to their business customers, and consumers facing the prospect of paying higher prices for household coffee products. </p>
<p>But will producers be the winners in this latest price surge? Those Brazilian agribusinesses that survive the immediate impact of the frosts surely will, as too the well-capitalised, medium-sized farms of Latin America. </p>
<p>What, though, of the smallholders and subsistence farmers who make up 95% of coffee farmers? For years, the ICO and its member states have presented these farmers as the victims of global market forces; now we will find out if these players are capable of delivering back to farmers the increased value their coffee is generating. If so, then International Coffee Day will indeed be something to celebrate.</p><img src="https://counter.theconversation.com/content/169000/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jonathan Morris does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The black stuff is suddenly much more expensive – the question is whether smallhold farmers will see any of the proceeds.Jonathan Morris, Professor of History, University of HertfordshireLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1668642021-09-27T12:55:25Z2021-09-27T12:55:25ZShould teens taking ADHD, anxiety and depression drugs consume energy drinks and coffee?<figure><img src="https://images.theconversation.com/files/421941/original/file-20210917-17-ye29c2.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5308%2C3112&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The American Academy of Pediatrics says teens should never consume energy drinks.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/teenage-girl-drinking-caffeine-energy-drink-gaming-royalty-free-image/1190647906?adppopup=true">monkeybusinessimages/istock via Getty Images</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>.</em></p>
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<blockquote>
<p><strong>Should teens taking ADHD, anxiety or depression drugs consume energy drinks or coffee? – Angela S.</strong></p>
</blockquote>
<hr>
<p>About <a href="https://www.cdc.gov/ncbddd/adhd/data.html">6.1 million children in the U.S.</a>, more than 9% of all kids and teens, have been <a href="https://www.psychiatry.org/patients-families/adhd/what-is-adhd">diagnosed at some point in their lives with attention deficit hyperactivity disorder</a>. Known as ADHD, it causes inattention, hyperactivity and impulsivity.</p>
<p>Many kids and teens diagnosed with ADHD take <a href="https://drugfree.org/drugs/prescription-stimulants/">prescription stimulants</a>, such as Adderall and Ritalin. These drugs increase brain activity to counteract a lack of focus and poor concentration.</p>
<p>In addition, 6 in 10 children diagnosed with ADHD have <a href="https://www.mayoclinic.org/diseases-conditions/adhd/diagnosis-treatment/drc-20350895">at least one other mental, emotional or behavioral disorder</a>, such as anxiety or depression. As a result, many of them take other kinds of prescription drugs too.</p>
<p>Meanwhile, Monster, Red Bull and other <a href="https://www.nccih.nih.gov/health/energy-drinks">energy drinks are commonly marketed to teens</a> as a way to boost stamina, physical performance and alertness. This is troubling because of the <a href="https://theconversation.com/is-it-ok-for-teens-to-drink-coffee-129133">high levels of caffeine</a> those drinks contain.</p>
<p>Ingesting large amounts of caffeine <a href="https://www.healthline.com/health/caffeine-effects-on-body#Central-nervous-system">overstimulates the nervous system</a>, which interferes with sleep and can increase stress as well as anxiety.</p>
<p>According to recommendations from the American Academy of Pediatrics, teenagers can consume <a href="https://www.aacap.org/AACAP/Families_and_Youth/Facts_for_Families/FFF-Guide/Caffeine_and_Children-131.aspx">up to 100 milligrams of caffeine a day</a>, the <a href="https://www.aacap.org/AACAP/Families_and_Youth/Facts_for_Families/FFF-Guide/Caffeine_and_Children-131.aspx">equivalent of two 12-ounce cans of soda</a>, without any trouble. </p>
<p>However, <a href="https://cspinet.org/eating-healthy/ingredients-of-concern/caffeine-chart">just one energy drink</a>, and some specialty coffee beverages, can have more than triple this amount of caffeine. In addition, the large amount of sugar in many of these drinks can <a href="https://sph.umich.edu/pursuit/2019posts/mood-blood-sugar-kujawski.html">disrupt blood sugar</a> levels, causing changes in brain chemistry and consequently contributing to mental health problems.</p>
<p>The <a href="https://pediatrics.aappublications.org/content/127/6/1182">academy also states teens should never consume energy drinks</a>, regardless of prescription drug intake. And yet about <a href="https://www.nccih.nih.gov/health/energy-drinks">one-third of Americans from 12 to 17 years old</a> drink these beverages on a regular basis.</p>
<p>I believe that consuming energy drinks is even more dangerous for teens taking prescription drugs for ADHD, anxiety or depression because of the additional stimulants they are getting. They should also curb their <a href="https://theconversation.com/is-it-ok-for-teens-to-drink-coffee-129133">coffee consumption</a>.</p>
<p><iframe id="qwlNR" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/qwlNR/4/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>The situation is even more complicated, though, because there are signs that <a href="https://www.tctmd.com/news/adhd-drug-overprescribing-raises-concerns-over-future-cv-events">not all of the young people taking those drugs need them</a>. </p>
<p>There is evidence that quite often, several ADHD symptoms could be caused by other conditions, such as <a href="https://www.healthline.com/health/brain-fog">stress, certain medications, insomnia and poor nutrition</a>. Among the drugs that may trigger these symptoms are those prescribed to treat <a href="https://www.medicalnewstoday.com/articles/323666">anxiety and depression</a>.</p>
<p>As a <a href="https://scholar.google.com/citations?hl=en&user=sOMbzQ0AAAAJ">nutritional neuroscientist</a> who studies the connections between what people eat and their lifestyle, stress and mental health, I believe that many teens diagnosed with ADHD, anxiety and depression may benefit from changing what they eat before they begin to take any prescription drugs.</p>
<p>One reason for this is that the <a href="https://raisingchildren.net.au/pre-teens/development/understanding-your-pre-teen/brain-development-teens">brain has a growth spurt</a> during the teen years. This growth requires essential nutrients, such as <a href="https://theconversation.com/want-to-eat-fish-thats-truly-good-for-you-here-are-some-guidelines-to-reeling-one-in-72933">omega-3 fatty acids</a> – typically found in high amounts in fish – that not all teens get enough of through their <a href="https://nutritionj.biomedcentral.com/articles/10.1186/s12937-018-0328-z">usual diet</a>. A poor-quality diet can interfere with this growth and development, contributing to poor concentration and even mental distress.</p>
<p>Perhaps even more troubling, many teens and college students without any symptoms of attention deficit hyperactivity disorder <a href="https://www.binghamton.edu/news/story/2892/binghamton-university-student-research-group-examines-adderall-abuse">take ADHD drugs for non-medical reasons</a>. They often do this because of a <a href="https://www.urmc.rochester.edu/encyclopedia/content.aspx?ContentTypeID=1&ContentID=23617">mistaken belief</a> that the drugs will help them do better at school.</p>
<p>In summary, whether or not a young person has a prescription for ADHD drugs, taking them makes avoiding energy drinks essential. </p>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/166864/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lina Begdache does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Energy drinks and coffee both contain lots of caffeine. That’s a problem for teens, especially those who take prescription stimulants.Lina Begdache, Assistant Professor of Nutrition, Binghamton University, State University of New YorkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1651812021-08-04T03:53:57Z2021-08-04T03:53:57ZCould drinking 6 cups of coffee a day shrink your brain and increase dementia risk?<figure><img src="https://images.theconversation.com/files/414250/original/file-20210803-17-1gd5jvu.jpg?ixlib=rb-1.1.0&rect=24%2C8%2C5338%2C3561&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/womans-hands-sweater-hold-cup-strong-327074582">Shutterstock</a></span></figcaption></figure><p><em><a href="https://theconversation.com/au/topics/research-check-25155">Research Checks</a> interrogate newly published studies and how they’re reported in the media. The analysis is undertaken by one or more academics not involved with the study, and reviewed by another, to make sure it’s accurate.</em></p>
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<p>Coffee is one of the most popular beverages worldwide. Many of us enjoy a cup in the morning to prime us for the day ahead, or reach for a cup later in the day to avert that mid-afternoon slump.</p>
<p>But you may have seen reports about a <a href="https://www.tandfonline.com/doi/full/10.1080/1028415X.2021.1945858">new study</a> finding that drinking more than six cups of coffee a day could shrink brain volume and increase dementia risk. So if you’re constantly seeking your next caffeine fix, should you be worried?</p>
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<p>Researchers from Australia and the United Kingdom found this level of coffee consumption is <em>associated</em> with smaller total brain volume and a 53% increased risk of dementia. But they didn’t show high caffeine intake <em>causes</em> dementia, and they note this study cannot confirm the underlying reason for the association.</p>
<h2>How was the study conducted?</h2>
<p>The paper, published in the journal <a href="https://www.tandfonline.com/doi/full/10.1080/1028415X.2021.1945858">Nutritional Neuroscience</a>, examined whether habitual coffee consumption was associated with differences in brain volume, and changed odds of developing dementia or stroke.</p>
<p>The researchers looked at 398,646 participants aged between 37 and 73, taken from the research database UK Biobank. </p>
<p>To measure disease outcomes, the researchers looked at the number of these people who developed dementia or had a stroke over time, and analysed this data alongside coffee intake.</p>
<p>For the association between coffee consumption and brain volume, the researchers compared brain imaging against the amount of coffee participants drank daily. This aspect of the study looked at 17,702 people out of the 398,646.</p>
<p>The study was observational, so researchers didn’t make any changes to the participants’ diets or lifestyles. Instead, they looked back at the individual’s coffee intake and correlated the amount of coffee consumed daily to their brain size, and the odds of developing dementia or having a stroke.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-why-do-i-get-a-headache-when-i-havent-had-my-coffee-100163">Health Check: why do I get a headache when I haven't had my coffee?</a>
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<h2>What did the researchers find?</h2>
<p>Overall, they found the more coffee participants consumed daily, the smaller their total brain volume. </p>
<p>Dementia risk was less straightforward. People who didn’t drink coffee, or drank decaf, showed slightly higher odds of developing dementia than people who drank a moderate amount of coffee. The odds of dementia were significantly higher for those who drank more than six cups daily. The results suggest people who drink one to two cups of coffee a day are at no increased risk of dementia.</p>
<p>After adjusting the data for variables such as underlying health conditions, age, sex and body-mass index, the researchers concluded consumption of more than six cups of coffee daily was associated with smaller brain volume, and 53% higher odds of dementia compared with one to two cups daily. </p>
<p>The evidence for any association between the amount of coffee consumed and stroke risk wasn’t significant. </p>
<figure class="align-center ">
<img alt="A barista puts a lid on a cup of takeaway coffee." src="https://images.theconversation.com/files/414249/original/file-20210803-27-4zjvql.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/414249/original/file-20210803-27-4zjvql.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/414249/original/file-20210803-27-4zjvql.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/414249/original/file-20210803-27-4zjvql.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/414249/original/file-20210803-27-4zjvql.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/414249/original/file-20210803-27-4zjvql.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/414249/original/file-20210803-27-4zjvql.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Is it good for us? Is it bad for us? Coffee is regularly making headlines.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/barista-apron-holding-hands-hot-cappuccino-1022383486">Shutterstock</a></span>
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<h2>How should we interpret these results?</h2>
<p>The consequences of smaller brain volume are unclear, and this study doesn’t address this question. However, brain shrinkage does happen naturally as we age, and <a href="https://www.nature.com/articles/s41598-017-10074-x">studies</a> suggest there is a connection between brain volume and dementia.</p>
<p>But does brain size really matter? There are plenty of animals with larger brains than humans, and the association between <a href="https://www.pnas.org/content/97/9/4932.short">brain size and intelligence</a> is weak. This is a growing area of research, so stay tuned.</p>
<p>Notably, the study doesn’t actually address whether the brain shrunk over time — brain volume measurements were conducted at one time point. So while <a href="https://fox40.com/morning/science/too-much-coffee-can-cause-your-brain-to-shrink-raise-risk-of-dementia-by-53-percent-study-finds/">some reports</a> have claimed the study found too much coffee can cause the brain to “shrink”, the researchers didn’t actually measure this. </p>
<p>One issue with this study is that full information on diet was only available for a portion of participants. This is a problem as <a href="https://bmjopen.bmj.com/content/9/1/e022846.abstract">poor diet is a major risk</a> for cognitive decline and dementia. On the flip side, <a href="https://www.cambridge.org/core/journals/proceedings-of-the-nutrition-society/article/nutrition-and-healthy-ageing-the-key-ingredients/AA02C12F48A3C1CFA00C5AE06AD2D226">healthy dietary patterns</a> have consistently been associated with longevity and better cognitive health. So dietary factors could be confounding the results.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/going-to-ground-how-used-coffee-beans-can-help-your-garden-and-your-health-88645">Going to ground: how used coffee beans can help your garden and your health</a>
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<p>Observational studies like these can only tell us whether certain things are linked, not whether there’s a causal relationship. </p>
<p>A potential explanation for the increased dementia risk could be related to the cardiovascular effects of caffeine. For instance, there’s evidence consuming <a href="https://www.nature.com/articles/1601668">unfiltered coffee increases cholesterol</a>, with high cholesterol being a leading risk factor for atherosclerosis (the buildup of fats on the artery walls), which is associated with vascular dementia. </p>
<p>However, other lifestyle factors, such as <a href="https://www.sciencedirect.com/science/article/pii/S0140673610615140">diet and inactivity</a>, appear to play a bigger role in cholesterol levels. </p>
<p>Ultimately, we don’t know the reasons behind the links observed in this study.</p>
<figure class="align-center ">
<img alt="A man sits on the floor on his laptop, with a cup of coffee in hand." src="https://images.theconversation.com/files/414274/original/file-20210803-15-1epct58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/414274/original/file-20210803-15-1epct58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/414274/original/file-20210803-15-1epct58.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/414274/original/file-20210803-15-1epct58.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/414274/original/file-20210803-15-1epct58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/414274/original/file-20210803-15-1epct58.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/414274/original/file-20210803-15-1epct58.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">This study finds correlation, but doesn’t prove causation.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/attractive-happy-smart-young-man-sitting-1674151531">Shutterstock</a></span>
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<h2>So what’s the take-home message?</h2>
<p>The results of this study shouldn’t be ignored, and help us form questions for future research. There’s plenty more research to be done into how caffeine interacts with our bodies.</p>
<p>This new study follows <a href="https://pubmed.ncbi.nlm.nih.gov/19158424/">previous research</a> that found drinking coffee in moderation <em>decreases</em> dementia risk by 65%. There’s a body of evidence suggesting drinking coffee is beneficial for health, reducing the risk of <a href="https://pubmed.ncbi.nlm.nih.gov/20008687/">diabetes</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/24201300/">heart disease</a>, and improving <a href="https://www.sciencedirect.com/science/article/pii/S0306456521001686">metabolism</a> and <a href="https://www.sciencedirect.com/science/article/pii/S0166432821003259">cognition</a>. </p>
<p>As with most things in life, the amount matters. So while the findings here aren’t cause for alarm, if you’re drinking six cups of coffee or more a day, you might want to think about drinking a little less. Perhaps one to three cups daily. </p>
<p>This will reduce your risk of any negative health outcomes, like those reported in this study, and may in fact increase the chances of ageing well. <strong>– Lachlan Van Schaik</strong></p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/phytonutrients-can-boost-your-health-here-are-4-and-where-to-find-them-including-in-your-next-cup-of-coffee-132100">Phytonutrients can boost your health. Here are 4 and where to find them (including in your next cup of coffee)</a>
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<h2>Blind peer review</h2>
<p>This article is a fair and rational analysis of the study. In this study the researchers did find high intake of coffee was associated with smaller brain volumes and higher dementia risk.</p>
<p>It’s also important to point out that this study did not look at other sources of caffeine (such as energy drinks), nor the types or strengths of coffee or tea people consume. This means it did not make any conclusions about brain size or dementia risk in relation to caffeine, just coffee itself.</p>
<p>The author is correct in pointing out this study was purely observational and did not find high coffee intake “caused” the brain to shrink. While the findings are interesting, this is a classic case of correlation not equalling causation. High coffee consumption <em>may</em> cause brain shrinkage, or even increase risk of dementia, but at this stage we just don’t know. </p>
<p>It does, however, hint this may be another health risk associated with high levels of coffee drinking. Perhaps erring on the side of moderation would be wise until we know more. <strong>– Greg Kennedy</strong></p><img src="https://counter.theconversation.com/content/165181/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lachlan Van Schaik is affiliated with La Trobe University and The University of Melbourne. </span></em></p><p class="fine-print"><em><span>Greg Kennedy does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>It seems as though every other week there’s a study telling us coffee is good for us, or it’s bad for us. Here’s what to make of this new piece of research.Lachlan Van Schaik, PhD candidate, School of Pharmacy and Biomedical Sciences, La Trobe UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1577392021-03-30T15:02:40Z2021-03-30T15:02:40ZDoes coffee burn more fat during exercise? What the evidence tells us<figure><img src="https://images.theconversation.com/files/392564/original/file-20210330-17-34iol3.jpg?ixlib=rb-1.1.0&rect=17%2C0%2C3817%2C2160&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Participants consumed the equivalent of a tall brewed filter coffee 30 minutes before exercise.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/two-dumbbells-cup-coffee-3d-rendering-1135349036">Pavel3d/ Shutterstock</a></span></figcaption></figure><p>Coffee, green tea and other caffeinated drinks are a popular way to start the morning. Not only does it give many people a much-needed boost, but caffeine can also help when it comes to fitness. <a href="https://bjsm.bmj.com/content/bjsports/54/11/681.full.pdf">Studies</a> show it can help people exercise harder and for longer, and even perform better. And recently, a study conducted at the University of Granada reported that consuming caffeine half an hour before aerobic exercise can actually help people burn fat.</p>
<p>In the <a href="https://jissn.biomedcentral.com/articles/10.1186/s12970-020-00400-6">study</a>, 15 men (aged around 32) ingested caffeine powder (about 3mg per kilogram of body mass – the equivalent of a tall brewed filter coffee) or a placebo 30 minutes before exercising. The participants then completed a total of four trials. They alternated between exercising at either 8am or 5pm on separate days. The study used a “triple-blind” experimental design – meaning that the participants, researchers and statistician did not know who had consumed caffeine or not during each trial.</p>
<p>To ensure the participants were exposed to the same conditions as each other, the researchers made sure it had been at least three hours since their last meal before the caffeine or placebo was ingested. No exercise had been performed for 24 hours before the trial. Each participant consumed the same diet the day of each trial.</p>
<p>During the trials, the participants cycled at increasingly higher intensities to determine peak fat oxidation (the process of breaking down fat to produce energy – “fat burning”). The researchers found that compared with the placebo group, consuming caffeine led to more fat being burned during exercise. </p>
<p>Fat burning after caffeine was up to 11% more in the morning, and 29% more in the afternoon. The greater fat burning in the afternoon could be explained by the higher concentration of adrenaline in our bodies which happens as a response to <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0137567">afternoon exercise</a>. But before you get too excited, even with the higher afternoon rate of 0.4 grams of fat burned per minute, in order to lose 1kg of body fat, one would have to exercise for nearly 42 hours. </p>
<p>The study’s findings confirm what other research has previously shown. A recent meta-analysis of 19 studies concluded that a pre-exercise intake of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7760526/pdf/nutrients-12-03603.pdf">caffeine may increase fat burning</a> during aerobic exercise, especially after a fasting period of at least five hours. Research has also shown <a href="https://link.springer.com/article/10.1007/s00394-020-02393-z">caffeine increased fat oxidation</a> from 19g an hour with the placebo group, to 25g with caffeine while cycling at maximum fat burning capacity. These results are comparable to the amount of fat burned in the afternoon in the new study. </p>
<h2>Caffeine and fat burning</h2>
<p>Burning more fat after ingesting caffeine may be explained by the interaction between caffeine and our body’s fatty acids. Fatty acids are the building blocks of fat and can supply the body with energy.</p>
<figure class="align-center ">
<img alt="A young man and woman wearing their activewear pause after a workout to drink water and coffee." src="https://images.theconversation.com/files/392522/original/file-20210330-17-1rcptjv.jpg?ixlib=rb-1.1.0&rect=10%2C0%2C6699%2C4476&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/392522/original/file-20210330-17-1rcptjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/392522/original/file-20210330-17-1rcptjv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/392522/original/file-20210330-17-1rcptjv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/392522/original/file-20210330-17-1rcptjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/392522/original/file-20210330-17-1rcptjv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/392522/original/file-20210330-17-1rcptjv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Caffeine interacts with our body’s fatty acids.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/fit-black-couple-taking-rest-after-1798732675">Prostock-studio/ Shutterstock</a></span>
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<p><a href="https://japsonline.com/admin/php/uploads/2318_pdf.pdf">Caffeine promotes lipolysis</a> (the process by which fats are broken down), due to a greater release of adrenaline. Lipolysis then causes fatty acids to be produced as a result. These fatty acids are then released into the blood and transported to muscle to be used as energy.</p>
<p>Caffeine’s fat-burning abilities are also related to increased energy expenditure. The <a href="https://jissn.biomedcentral.com/articles/10.1186/1550-2783-7-5">compound adenosine</a> under normal conditions, promotes sleep and suppresses arousal. However, caffeine and adenosine compete for the same receptors in the brain. So when caffeine is available, adenosine is less able to bind, causing greater stimulation of the central nervous system. During exercise this means more muscle fibres are being used during movement. </p>
<p>In addition, people feel exercise <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1600-0838.2005.00445.x?casa_token=7DH3XTRzDDIAAAAA%3AWM-dMLvLCjHK6Cw6frDPXIywVj31jaW0Co5JY2P_23brphmMIUaTLE-xpH7vMjFJZ1CItD4uGvc6mw">requires less effort</a> after consuming caffeine. Having caffeine before exercise has also been shown to make <a href="https://pdfs.semanticscholar.org/152b/3659c2308b3d83892f4683ff0523d1812d99.pdf">exercise more enjoyable</a>. These factors combined may subsequently make us work harder while exercising – which in turn may cause us to burn more fat during exercise.</p>
<p>Numerous studies have shown ingesting caffeine improves exercise performance, including <a href="https://link.springer.com/article/10.1007%2Fs40279-018-0939-8">endurance performance</a>, <a href="https://pubmed.ncbi.nlm.nih.gov/29140142/">short-term high-intensity performance</a> and <a href="https://link.springer.com/article/10.1007%2Fs40279-018-0997-y">resistance exercise</a> performance. Sports that require greater concentration and skill – such as <a href="https://pubmed.ncbi.nlm.nih.gov/30518253/">team sports</a>, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6886616/pdf/ijes-12-6-1290.pdf">tennis</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/26285020/">golf</a> – also benefit from caffeine ingestion.</p>
<p>But it’s important to note that the effects in this most recent study may have been increased due to this exercise being performed in a fasted state. When exercising without eating before, <a href="https://pubmed.ncbi.nlm.nih.gov/27609363/">fat oxidation is naturally higher</a>. Furthermore, the authors acknowledge that the present study used only a small cohort, and was only performed in active men who typically consumed only a small amount of caffeine. This study will need to be tested on a wider cohort that includes women, people who are less active, and those who regularly consume caffeine to see whether caffeine had a similar fat-burning effect.</p>
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Read more:
<a href="https://theconversation.com/can-coffee-improve-your-workout-the-science-of-caffeine-and-exercise-92366">Can coffee improve your workout? The science of caffeine and exercise</a>
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<p>However, studies have reported that <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6893638/pdf/nutrients-11-02575.pdf">men and women respond similarly to caffeine</a>, and that the <a href="https://journals.humankinetics.com/view/journals/ijsnem/31/1/article-p13.xml">amount of caffeine</a> people regularly consume doesn’t affect the performance benefits of caffeine. </p>
<p>The placebo effect – in which people expected to feel the effects of the caffeine – may also have affected the study’s results. For example, one study showed the placebo effect had <a href="https://www.mdpi.com/2072-6643/13/3/782">similar outcomes for fat oxidation</a> during exercise as actually receiving caffeine. </p>
<p>The increase in fat burning after consuming caffeine shown in this study may be relatively small. However, over time it could be important for weight maintenance or weight loss. But it’s important to state that weight loss will only occur when there is a negative energy balance. A negative energy balance means that you burn more calories than you take in.</p><img src="https://counter.theconversation.com/content/157739/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Neil Clarke has previously received research funding from The Institute for Scientific Information on Coffee (ISIC).</span></em></p>Participants who ingested caffeine powder burned up to 29% more fat.Neil Clarke, Assistant Professor in Sport and Exercise Science, Coventry UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1530322021-01-24T14:08:55Z2021-01-24T14:08:55ZThe quest for delicious decaf coffee could change the appetite for GMOs<figure><img src="https://images.theconversation.com/files/379625/original/file-20210119-23-dqr0h3.jpg?ixlib=rb-1.1.0&rect=47%2C0%2C5282%2C3556&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The quest for a tasty decaf may change the way we think about GMOs.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Coffee is one of the world’s most popular drinks, but that cup can come with a price of jitters or sleeplessness. The stimulant in coffee — the thing that gives it its kick and can lead to those jitters — is caffeine and it can be addictive. </p>
<p>Decaffeinated coffee is coffee with almost all of the caffeine removed; decaf coffee drinkers report <a href="https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/caffeine/art-20045678">less anxiety and improved sleep</a>. But decaf is comparatively unpopular, <a href="https://www.ncausa.org/Decaffeinated-Coffee">representing only 10 per cent of the global coffee market</a>.</p>
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Read more:
<a href="https://theconversation.com/the-biology-of-coffee-one-of-the-worlds-most-popular-drinks-129179">The biology of coffee, one of the world’s most popular drinks</a>
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<p>This lack of popularity is in part due to the <a href="https://www.vox.com/the-goods/2019/3/7/18253668/decaf-coffee-caffeine-stigma">“Death Before Decaf” mentality of some coffee drinkers</a>; for the more rational, the issue is taste. Commercial decaf coffee has been around for 100 years, but has tasted terrible, possibly due to the benzene, <a href="https://www.scientificamerican.com/article/how-is-caffeine-removed-t/">the powerful solvent that was used in extraction</a>.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CHBg5evBhUC","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<p>Our global population is growing and our planet is changing. Although we can feed today’s population, current agricultural techniques won’t keep pace and simply expanding existing agriculture could actually make things worse. Here’s where decaf coffee — <a href="http://doi.org/10.1038/483264a">or the science behind it</a> — comes in.</p>
<h2>Decaffeinating coffee</h2>
<p>Some of the approaches being explored to create a better cup of decaf are the changes that could create a secure food future. Historically, <a href="https://www.scientificamerican.com/article/why-people-oppose-gmos-even-though-science-says-they-are-safe/">there has been opposition to the widespread adoption of genetically modified organisms (GMOs)</a>, but maybe the turning point will come through better-tasting decaf.</p>
<p>All commercially grown coffee contains caffeine. To produce decaf, between 97 and 99.9 per cent of the caffeine is removed. There are several ways to do this, but they all depend on <a href="https://www.coffeeassoc.com/coffee-101/decaffeination/">the caffeine being dissolved out of the coffee beans before they are roasted</a>. Natural solvents include CO2, coffee oil or water, but other chemicals are also used, including methyl acetate and ethylene chloride. </p>
<p>These processes not only decaffeinate coffee, but also extract or alter the other chemicals that give coffee its <a href="https://doi.org/10.1021/jf0518305">fantastically complex taste and health benefits</a>.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/QYOpJKVdB5g?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The Swiss Water process is the gold standard of decaffeination processes, and produces a decent cup of coffee.</span></figcaption>
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<p>But, could a better cup of decaf raise that 10 per cent of the global market? Probably.</p>
<p>Right now, there are two main routes to naturally decaffeinated — actually caffeine-free — coffee: <a href="https://www.independent.co.uk/news/science/caffeine-free-coffee-tree-discovered-5355645.html">find genetic variation in the wild</a> or create it in the laboratory. In either case, the coffee grows without producing caffeine, eliminating the need for a decaffeination process and preserving the natural taste, and chemistry, of the bean.</p>
<h2>Natural variations</h2>
<p>There are over 130 species in the genus <em>Coffea</em>, but two species make up over 95 per cent of the global commercial coffee market, Arabica (<em>C. arabica</em>) and Robusta (<em>C. canefora</em>). Not all species of coffee produce caffeine, which begs the question of why most do. It is likely a defence against insects, but it also <a href="https://doi.org/10.1016/j.cub.2015.08.052">stimulates pollinators</a>. </p>
<p><a href="https://doi.org/10.1007/s10681-008-9674-9">Cross-breeding caffeine-free species with Arabica or Robusta</a> hasn’t, yet, yielded any coffee to market. There are also strains of the Arabica coffee that <a href="https://doi.org/10.1038/429826a">have a naturally occurring mutation that makes them caffeine-free</a>, and work is ongoing to breed these with commercial varieties of Arabica. </p>
<p>Interestingly, while these plants don’t produce caffeine, <a href="https://oureverydaylife.com/67188-stimulants-chocolate-not-caffeine.html">they do produce theobromine</a>, a close relative of caffeine and the stimulant more commonly found in chocolate. Coffee from these beans may still perk you up, although less than your typical cup, but these beans have also not yet made it to market.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/379628/original/file-20210119-21-1cw8x97.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Arabica coffee beans growing on a tree" src="https://images.theconversation.com/files/379628/original/file-20210119-21-1cw8x97.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/379628/original/file-20210119-21-1cw8x97.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/379628/original/file-20210119-21-1cw8x97.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/379628/original/file-20210119-21-1cw8x97.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/379628/original/file-20210119-21-1cw8x97.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/379628/original/file-20210119-21-1cw8x97.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/379628/original/file-20210119-21-1cw8x97.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">A genetic mutation in Arabica coffee plants can mean that the beans are naturally decaffeinated.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
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<h2>Editing genes</h2>
<p>Genetic engineering could allow us to turn off the entire caffeine synthesis pathway, avoiding the complication of theobromine. By editing the relevant genes, we could create beans that would grow caffeine-free and theobromine-free.</p>
<p>Low-caffeine Robusta has been created in the laboratory using a process called RNA inhibition (RNAi) to turn down activity of one of the genes involved in caffeine production by <a href="https://doi.org/10.1038/423823a">70 per cent</a>. This technique is promising, but almost 20 years after initial success, a coffee has not yet come to market.</p>
<p>It is also possible to create caffeine-free coffee in the laboratory by using <a href="https://doi.org/10.1007/s11240-018-1429-2">the gene-editing technique known as CRISPR-Cas9</a>. This approach has been used to <a href="https://doi.org/10.1007/s10584-019-02538-y">create hardy coffee plants that could withstand global climate change</a> and could be adapted to create decaf.</p>
<p>One advantage of both laboratory techniques is that they could be done directly in a variety of coffee beans that already yield high quality coffee. Because the techniques don’t require creating hybrids, the entire process could be done in as little as six years.</p>
<p>So why haven’t decaf beans made it to market? Although there is almost universal support for engineering across the scientific community, <a href="https://www.nytimes.com/2019/07/22/upshot/health-facts-importance-persuasion.html">there is a broad public mistrust of genetically modified foods</a>.</p>
<h2>Popularizing GMOs</h2>
<p>Could a better cup of decaf tip the scale in favour of genetically engineered agriculture?</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-we-wont-be-able-to-feed-the-world-without-gm-54442">Why we won't be able to feed the world without GM</a>
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<p>Modern agriculture must continue to evolve. Our warming planet and expanding population put the global food supply in jeopardy. Wheat, rice and soybean, for example, combine to provide two-thirds of human calories, but <a href="https://doi.org/10.1073/pnas.1701762114">crop yields from all three are in decline as global temperatures increase</a>. Modern, laboratory-driven agriculture has the potential to combat this threat by <a href="https://www.nytimes.com/2019/06/17/science/food-agriculture-genetics.html">drastically increasing yields</a>. </p>
<p>Similarly, globally, bananas are a dietary staple for 400 million people, but <a href="https://theconversation.com/the-quest-to-save-the-banana-from-extinction-112256">a fungus threatens to destroy commercial agriculture of this crucial crop</a>. A genetically engineered banana could <a href="https://www.wired.co.uk/article/cavendish-banana-extinction-gene-editing">avert this disaster</a>. </p>
<p>In these cases, the hurdle is <a href="https://www.nytimes.com/2019/01/15/well/eat/gmo-foods-genetically-modified-knowledge.html">public opinion and hesitancy related to consuming genetically engineered foods</a>. Having conversations about the value of modern technology in <a href="https://doi.org/10.1073/pnas.1212740110">supporting things that people need or hold dear</a> — like a better cup of decaf coffee — can help us find common ground. </p>
<p>It is, in fact, really hard to overestimate the value of a good cup of coffee.</p><img src="https://counter.theconversation.com/content/153032/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Thomas Merritt does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Genetically modified organisms can help address current agricultural challenges, but public opinion is against them. Maybe the search for delicious decaf coffee could lead to widespread acceptance.Thomas Merritt, Professor, Chemistry and Biochemistry, Laurentian UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1321622020-05-26T17:07:40Z2020-05-26T17:07:40ZCoffee versus cardio: Can exercise offer the same mental boost as caffeine?<figure><img src="https://images.theconversation.com/files/337138/original/file-20200522-124851-6i4ph7.jpg?ixlib=rb-1.1.0&rect=5%2C158%2C1988%2C1380&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A brisk 20-minute walk can increase energy level, alertness and mood, and improve working memory — with no caffeine side-effects.</span> <span class="attribution"><span class="source">(Pixabay)</span></span></figcaption></figure><p>Your alarm goes off and it’s time to start another day. What’s your first step? Perhaps making a cup of coffee? You may want to consider a brisk walk instead.</p>
<p>In Canada, <a href="https://www.doi.org/10.25318/82-003-x201900700003-eng">coffee is second only to water as the beverage most commonly consumed by adults</a>. Although caffeine — the psychoactive ingredient present in coffee — is associated with several positive effects such as increased alertness, energy and mood, caffeine is not all good news for everyone. Some individuals experience negative effects from caffeine consumption, such as <a href="https://doi.org/10.1038/sj.npp.1300232">increased anxiety symptoms</a> and <a href="https://doi.org/10.1089/jcr.2014.0020">muscle tremors</a>. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/336965/original/file-20200522-153894-gbmdhw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/336965/original/file-20200522-153894-gbmdhw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/336965/original/file-20200522-153894-gbmdhw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/336965/original/file-20200522-153894-gbmdhw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/336965/original/file-20200522-153894-gbmdhw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/336965/original/file-20200522-153894-gbmdhw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/336965/original/file-20200522-153894-gbmdhw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Caffeine can provide a boost in mood, energy and alertness, but it can also cause side-effects, including anxiety and tremors.</span>
<span class="attribution"><span class="source">(Pixabay)</span></span>
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<p>Concerns about caffeine consumption have also been raised for both <a href="https://healthycanadians.gc.ca/recall-alert-rappel-avis/hc-sc/2017/63362a-eng.php">children and pregnant women</a>, prompting reduced consumption guidelines for these groups. At some point, the majority of caffeine consumers have experienced the adverse effects of withdrawal symptoms. These can feel like a <a href="http://www.doi.org/10.1007/s00213-004-2000-x">headache, tiredness and grouchiness</a>. </p>
<p>The question then remains: what could provide similar benefits to caffeine without the side-effects? The answer may lie in aerobic exercise. </p>
<h2>Caffeine versus exercise</h2>
<p><a href="https://www.ehpl.uwo.ca/">Our lab</a> examines how exercise can improve various health outcomes, one being cognition. In a <a href="https://doi.org/10.1038/s41598-019-56251-y">recent study</a>, we put aerobic exercise and caffeine head to head, to look at their ability to provide a “boost” to a measure of cognition called working memory. </p>
<p><a href="https://doi.org/10.1038/nrn1201">Working memory</a> refers to our ability to temporarily store and manipulate information to complete a task. Working memory is what you are using when you are at the grocery store trying to quickly recall the items on your list, while updating that information with the price tags you are seeing in front of you. It is used in our everyday life and is associated with <a href="https://doi.org/10.1016/j.nlm.2004.06.010">how well we perform at school and work</a>. </p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/337134/original/file-20200522-124826-5d51iw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/337134/original/file-20200522-124826-5d51iw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/337134/original/file-20200522-124826-5d51iw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/337134/original/file-20200522-124826-5d51iw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/337134/original/file-20200522-124826-5d51iw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/337134/original/file-20200522-124826-5d51iw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/337134/original/file-20200522-124826-5d51iw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Twenty minutes on a treadmill had the same benefits as the amount of caffeine in a cup of coffee.</span>
<span class="attribution"><span class="source">(Piqsels)</span></span>
</figcaption>
</figure>
<p>In our study, we examined what would happen to working memory when we got healthy adults to complete a brisk, 20-minute walk on a treadmill versus when we gave them a dose of caffeine equivalent to what people consume in a small cup of coffee. </p>
<p>Our results indicated that a dose of moderate intensity exercise was essentially equivalent to a dose of caffeine in improving working memory in both adults who regularly consume caffeine and those who do not. This result would suggest that replacing coffee with a single bout of aerobic exercise could not only provide a cognitive boost similar to coffee but may also provide other health benefits that come along with exercise. </p>
<h2>Walk to reduce withdrawal symptoms</h2>
<p>To dig a little deeper into the issues surrounding caffeine, exercise and cognition, our team wanted to examine what would happen during caffeine withdrawal. </p>
<p>This time, we asked our caffeine consumers to undergo a 12-hour caffeine deprivation period. Then they had to come into the lab so we could assess their caffeine withdrawal symptoms, including fatigue, difficulty concentrating, grouchy mood, lack of motivation and headache. We also assessed their working memory, and found that it was not affected by caffeine withdrawal. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/336888/original/file-20200521-102637-xh0p9.jpg?ixlib=rb-1.1.0&rect=296%2C197%2C5694%2C3799&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/336888/original/file-20200521-102637-xh0p9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/336888/original/file-20200521-102637-xh0p9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/336888/original/file-20200521-102637-xh0p9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/336888/original/file-20200521-102637-xh0p9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/336888/original/file-20200521-102637-xh0p9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/336888/original/file-20200521-102637-xh0p9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">A brisk 20-minute walk provided a boost in energy and alertness.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
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</figure>
<p>Then we tested whether a brisk walk or caffeine consumption could reduce their withdrawal symptoms and improve their working memory. Interestingly, our results showed that the brisk 20-minute walk was able to reduce their withdrawal symptoms, particularly fatigue and depressed mood. However, working memory, which had not been affected by withdrawal, remained the same. </p>
<p>So how exactly does aerobic exercise provide this cognitive boost and reduce caffeine withdrawal symptoms? Although there is still a lot of debate, and investigations are underway, previous research has suggested improved <a href="https://doi.org/10.1016/j.mehy.2017.06.024">blood flow in the brain, the release of neurotrophic factors</a> (which are like food for brain cells) and the release of hormones, such as dopamine and epinephrine that are associated with <a href="http://www.doi.org/10.3233/BPL-160040">mood and energy</a>, may all be in some part responsible for these effects. </p>
<p>These findings are encouraging as they suggest something as simple as taking a brisk walk during your lunch break may help fight off the afternoon energy slump. Furthermore, for individuals who may want to avoid coffee, engaging in short bouts of aerobic exercise may be a compelling alternative for improving several health outcomes.</p><img src="https://counter.theconversation.com/content/132162/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anisa Morava receives funding from the Ontario Graduate Scholarship. </span></em></p><p class="fine-print"><em><span>Matthew Fagan receives funding from a CIHR Doctoral Studentship.</span></em></p>If you want to boost your energy and mood and feel more alert, get moving instead of getting coffee.Anisa Morava, PhD Student, Psychological Basis of Kinesiology, Western UniversityMatthew James Fagan, Ph.D. Student, Kinesiology, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1291332020-01-23T13:51:51Z2020-01-23T13:51:51ZIs it OK for teens to drink coffee?<figure><img src="https://images.theconversation.com/files/309310/original/file-20200109-80111-j91cm7.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C7688%2C3118&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Too much caffeine interferes with sleep.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/teenager-girl-dressing-gown-over-pink-1450721138">Luis Molinero/Shutterstock.com</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>Is it OK for teens to drink coffee? – Lucy G., Arlington, Virginia</strong></p>
</blockquote>
<hr>
<p>When my daughter was around 14 years old, she began to ask if she could have a <a href="https://theconversation.com/the-biology-of-coffee-129179">cup of coffee</a> in the morning like Mom and Dad. As a scientist who studies the <a href="http://sphhp.buffalo.edu/nutrition-and-health-research.html">effects of caffeine</a> – the ingredient in coffee that helps wake you up – on kids, I had more information available to me to inform my answer than most parents would.</p>
<p>Many kids and teens consume caffeine. The main source of this chemical is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4288269/pdf/102.pdf">soda for children under 12</a>. Even colas have <a href="https://cspinet.org/eating-healthy/ingredients-of-concern/caffeine-chart">lower levels of caffeine than tea or coffee</a>. </p>
<p>Kids and teens can also get caffeine from many foods and drinks, including <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4288269/pdf/102.pdf">chocolate, chocolate milk and iced tea</a>. What’s more, <a href="https://www.clinicalnutritionjournal.com/article/S0261-5614(18)30134-1/pdf">some over-the-counter medications</a> that kids might take, such as Excedrin, are significant sources of caffeine. But coffee is the main source of caffeine among Americans 12 years and up.</p>
<p>Based on my years of research, I’m confident that one daily cup of coffee won’t harm <a href="https://www.sciencedirect.com/science/article/pii/S0890856718318847?via%3Dihub">kids over the age of 12</a> – as long as they avoid all other sources of caffeine.</p>
<p>That one cup of coffee combined with, say, a can of iced tea or soda, or a chocolate bar, could put kids over the daily limit of <a href="https://healthblog.uofmhealth.org/childrens-health/parents-perk-up-to-dangers-of-caffeine-for-teens">100 milligrams</a> of caffeine doctors recommend. Adults should aim for no more than <a href="https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/caffeine/art-20045678">400 milligrams of caffeine</a>, which they could get from four cups of coffee.</p>
<p>And since caffeine is in so many different foods and drinks, it’s easy for kids – or grownups – to get more than they should without realizing it.</p>
<p><iframe id="qwlNR" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/qwlNR/3/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>Side effects</h2>
<p>Having too much caffeine can have many negative effects on kids, like putting them in a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4663646/">bad mood</a>, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5359329/">depriving them of sleep</a> and contributing to misbehavior, such as <a href="https://doi.org/10.1177%2F0269881117691568">risk-taking</a> and <a href="https://doi.org/10.1100/tsw.2008.82">aggression</a>.</p>
<p>Coffee can also make some kids feel <a href="https://psycnet.apa.org/record/1997-39117-009">jittery, nervous and anxious or nauseated</a>. It can change their <a href="https://pediatrics.aappublications.org/content/134/1/e112.long">heart rate and blood pressure</a>. In some cases, overcaffeination may make kids feel like they’ve used <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4663646/">illicit drugs</a>.</p>
<p>The threat to sleep might not sound like the most serious of all of these side effects to you. But it could be. The National Sleep Foundation, a nonprofit that funds and conducts research on sleep, recommends that <a href="https://www.sciencedirect.com/science/article/pii/S2352721815001606?via%3Dihub">teens get about nine hours of sleep per night</a>. But studies show that on average <a href="https://www.sciencedirect.com/science/article/pii/S1389945708003134">kids get much less sleep than that</a>.</p>
<p><iframe id="JIfRd" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/JIfRd/3/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>Old myths</h2>
<p>Some adults may tell kids that drinking caffeine will stunt their growth.</p>
<p>There are two reasons why some people think that. First, caffeine can <a href="https://doi.org/10.1093/jn/123.9.1611">decrease the amount of calcium in your bones</a>, which people used to think would make you not grow as tall.</p>
<p>Second, caffeine consumed later in the day can reduce sleep. <a href="https://doi.org/10.1203/00006450-198911000-00003">Growth hormone</a>, which makes you grow, is released early in sleep, so the idea was that less sleep would lead to less growth.</p>
<p>It turns out that neither of these concerns was valid. One study that followed 81 adolescents for six years found no connection between <a href="https://doi.org/10.1080/07315724.1998.10718793">caffeine and bone density</a>. Another study found <a href="https://doi.org/10.1002/ajhb.20405">no association between sleep duration and growth</a>. </p>
<p>Based on the best science that is available, I’ve been allowing my three children to have one cup of coffee first thing in the morning once they turn 12. It is important to think about what else they’re getting with their coffee, however. Some of the sweet iced and flavored coffee drinks, such as Starbucks Frappuccinos, that are popular with kids have over <a href="https://www.starbucks.com/menu/product/424/iced?parent=%2Fdrinks%2Ffrappuccino-blended-beverages%2Fcoffee-frappuccino">50 grams of sugar</a>. And consuming <a href="https://theconversation.com/sugar-isnt-just-empty-fattening-calories-its-making-us-sick-49788">too much added sugar</a> can also have negative health consequences.</p>
<p>Any negative effects of the caffeine they get from that morning jolt wear off long before bedtime. But I don’t let them have any caffeine-containing products after 3 p.m. to protect their sleep.</p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/129133/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jennifer L. Temple receives funding from the National Institutes of Health.</span></em></p>Since caffeine is in so many different foods and drinks, it’s easy for kids – or grownups – to get more than they should without realizing it.Jennifer L. Temple, Associate Professor of Nutrition; Director, Nutrition and Health Research Laboratory, University at BuffaloLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1291792020-01-19T13:25:11Z2020-01-19T13:25:11ZThe biology of coffee, one of the world’s most popular drinks<figure><img src="https://images.theconversation.com/files/310681/original/file-20200117-118365-i8xvtw.jpg?ixlib=rb-1.1.0&rect=53%2C17%2C6000%2C3943&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">From drip coffee to pourovers to stovetop espresso, the variations in coffee-based drinks are plenty.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>You’re reading this with a cup of coffee in your hand, aren’t you? Coffee is the most popular drink <a href="https://www.pewresearch.org/fact-tank/2013/12/20/chart-of-the-week-coffee-and-tea-around-the-world/">in many parts of the world</a>. Americans drink more coffee than soda, juice and tea — <a href="https://www.marketwatch.com/story/international-coffee-day-americans-drink-more-coffee-than-soda-tea-and-juice-combined-2017-09-29">combined</a>. </p>
<p>How popular is coffee? When news first broke that Prince Harry and Meghan were considering Canada as their new home, Canadian coffee giant Tim Hortons offered free coffee for life as an extra enticement.</p>
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<p>Given coffee’s popularity, it’s surprising how much confusion surrounds how this hot, dark, nectar of the gods affects our biology.</p>
<h2>Coffee’s ingredients</h2>
<p>The main biologically active ingredients in coffee are caffeine (a stimulant) and a suite of antioxidants. What do we know about how caffeine and antioxidants affect our bodies? The fundamentals are pretty simple, but the devil is in the details and the speculation around how coffee could either help or harm us runs a bit wild.</p>
<p>The stimulant properties of caffeine mean that you can count on a cup of coffee to wake you up. In fact, coffee, or at least the caffeine it contains, is the most <a href="https://doi.org/10.1016/0165-0173(92)90012-B">commonly used psychoactive drug in the world</a>. It seems to work as a stimulant, at least in part, by blocking adenosine, which promotes sleep, from binding to its receptor. </p>
<p>Caffeine and adenosine have similar ring structures. Caffeine acts as a molecular mimic, filling and blocking the adenosine receptor, preventing the body’s natural ability to be able a rest when it’s tired. </p>
<p>This blocking is also the reason why too much coffee can leave you feeling jittery or sleepless. You can only postpone fatigue for so long before the body’s regulatory systems begin to fail, leading to simple things like the jitters, but also more serious effects like <a href="https://doi.org/10.1016/0165-0173(92)90012-B">anxiety or insomnia</a>. Complications may be common; a possible link between coffee drinking and insomnia was identified <a href="https://www.doi.org/10.2307/1413116">more than 100 years ago</a>. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/TTDy-L0NKIg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The National Film Board of Canada produced a documentary on the cultural history of coffee called ‘Black Coffee: Part One, The Irresistible Bean’</span></figcaption>
</figure>
<h2>Unique responses</h2>
<p>Different people respond to caffeine differently. At least some of this variation is from having <a href="https://doi.org/10.1038/sj.clpt.6100102">different forms of that adenosine receptor</a>, the molecule that caffeine binds to and blocks. There are <a href="https://academic.oup.com/hmg/article/20/10/2071/680367">likely other sites of genetic variation as well</a>. </p>
<p>There are individuals who don’t process caffeine and to whom drinks like coffee <a href="https://www.sciencedirect.com/science/article/pii/S0273230015301379">could pose medical danger</a>. Even away from those extremes, however, there is variation in how we respond to that cup of coffee. And, like much of biology, that variation is a function of environment, our past coffee consumption, genetics and, honestly, just random chance. </p>
<p>We may be interested in coffee because of the oh-so-joyous caffeine buzz, but that doesn’t mean that caffeine is the most biologically interesting aspect of a good cup of coffee. </p>
<p>In one study using rats, caffeine triggered smooth muscle contraction, so it is possible that <a href="https://doi.org/10.1016/S0016-5085(19)38364-7">caffeine directly promotes bowel activity</a>. Other studies, though, have shown that decaffeinated coffee can have as strong an effect on bowel activity as regular coffee, suggesting <a href="http://dx.doi.org/10.1136/gut.31.4.450">a more complex mechanism involving some of the other molecules in coffee</a>. </p>
<h2>Antioxidant benefits</h2>
<p>What about <a href="https://dx.doi.org/10.3390%2Fantiox2040230">the antioxidants in coffee</a> and the buzz that surrounds them? Things actually start out pretty straightforward. Metabolic processes produce the energy necessary for life, but they also create waste, often in the form of oxidized molecules that can be harmful in themselves or in damaging other molecules. </p>
<p>Antioxidants are a broad group of molecules that can scrub up dangerous waste; all organisms produce antioxidants as part of their metabolic balance. It is unclear if supplementing our diet with additional antioxidants can augment these natural defences, but that hasn’t stopped speculation. </p>
<p>Antioxidants have been linked to almost everything, including <a href="https://doi.org/10.1111/j.1743-6109.2005.20236.x">premature ejaculation</a>. </p>
<p>Are any of the claims of positive effects substantiated? Surprisingly, the answer is again a resounding maybe.</p>
<h2>Coffee and cancer</h2>
<p>Coffee won’t cure cancer, but it may help to prevent it and possibly other diseases as well. Part of answering the question of coffee’s connection to cancer lies in asking another: what is cancer? At its simplest, cancer is uncontrolled cell growth, which is fundamentally about regulating when genes are, or are not, actively expressed. </p>
<p>My research group studies <a href="https://doi.org/10.1534/g3.114.012484">gene</a> <a href="https://dx.doi.org/10.1534%2Fgenetics.111.133231">regulation</a> and I can tell you that even a good cup of coffee, or boost of caffeine, won’t cause genes that are turned off or on at the wrong time to suddenly start playing by the rules. </p>
<p>The antioxidants in coffee may actually have <a href="https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/antioxidants-fact-sheet">a cancer-fighting effect</a>. Remember that antioxidants fight cellular damage. One type of damage that <a href="https://doi.org/10.1002/(SICI)1521-1878(199903)21:3%3C238::AID-BIES8%3E3.0.CO;2-3">they may help reduce is mutations to DNA</a>, and cancer is caused by mutations that lead to the misregulation of genes. </p>
<p>Studies have shown that <a href="https://doi.org/10.1007/978-1-4615-9561-8_45">consuming coffee fights cancer in rats</a>. Other studies in humans have shown that <a href="https://www.ncbi.nlm.nih.gov/pubmed/26656410">coffee consumption is associated with lower rates of some cancers</a>.</p>
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<a href="https://images.theconversation.com/files/310678/original/file-20200117-118359-48wui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/310678/original/file-20200117-118359-48wui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/310678/original/file-20200117-118359-48wui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/310678/original/file-20200117-118359-48wui.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/310678/original/file-20200117-118359-48wui.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/310678/original/file-20200117-118359-48wui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/310678/original/file-20200117-118359-48wui.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/310678/original/file-20200117-118359-48wui.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Several studies have shown that coffee consumption reduces the rates of some diseases in rats and mice.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
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</figure>
<p>Interestingly, coffee consumption has also been linked to reduced rates of other diseases as well. Higher coffee consumption is linked to <a href="http://doi.org/10.3233/JAD-2010-091525">lower rates of Parkinson’s disease</a> and some other forms of dementia. Strikingly, at least one experimental study in mice and cell culture shows that <a href="https://dx.doi.org/10.1073%2Fpnas.1813365115">protection is a function of a combination of caffeine and antioxidants in coffee</a>. </p>
<p>Higher coffee consumption has also been linked to <a href="https://doi.org/10.3945/ajcn.112.048603">lower rates of Type 2 diabetes</a>. Complexity, combined effects and variation between individuals seems to be the theme across all the diseases. </p>
<p>At the end of the day, where does all this leave us on the biology of coffee? Well, as I tell my students, it’s complicated. But as most reading this already know, coffee will definitely wake you up in the morning.</p>
<p><em>This is an updated version of a story originally published on Jan. 19, 2020. The original story called coffee the world’s most popular beverage. The term “most popular” can be defined differently. <a href="https://www.huffingtonpost.ca/entry/coffee-is-more-popular-than-tea_n_5901430">Retail sales of coffee outpace tea globally</a>, but <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5871637/">tea is the most consumed beverage after water</a>.</em></p>
<p>[ <em>Deep knowledge, daily.</em> <a href="https://theconversation.com/ca/newsletters?utm_source=TCCA&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/129179/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Thomas Merritt receives funding from Natural Sciences and Engineering Research Council of Canada. </span></em></p>How does one of the most popular drinks in the world actually work on our bodies?Thomas Merritt, Professor and Canada Research Chair, Chemistry and Biochemistry, Laurentian UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1197402019-07-04T19:47:27Z2019-07-04T19:47:27ZResearch Check: can drinking coffee help you lose weight?<figure><img src="https://images.theconversation.com/files/282584/original/file-20190704-126391-cjagi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">As keen as we may be to hear about any health benefits of drinking coffee, the headlines aren't always what they seem.</span> <span class="attribution"><span class="source">Janko Ferlic/Unsplash</span></span></figcaption></figure><p>Researchers from the University of Nottingham in the UK recently published a study in the journal <a href="https://www.nature.com/articles/s41598-019-45540-1">Scientific Reports</a> suggesting caffeine increases brown fat. </p>
<p>This caught people’s attention because brown fat activity burns energy, which may help with weight loss. Headlines <a href="https://www.independent.co.uk/news/health/coffee-cup-weight-loss-study-research-brown-fat-a8973201.html">claimed</a> drinking coffee can help you lose weight, and that coffee is possibly even the “<a href="https://www.dailymail.co.uk/health/article-7174757/How-coffee-secret-fighting-obesity.html">secret to fighting obesity</a>”.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1143291381089296384"}"></div></p>
<p>Unfortunately, it’s a little more complicated than that. The researchers did find caffeine stimulated brown fat, but this was mainly in cells in a lab. </p>
<p>For a human to reap the benefits seen in the cells, we estimate they’d need to drink at least 100 cups of coffee.</p>
<p>Although part of this research did look at people, the methods used don’t support coffee or caffeine as weight-loss options. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/these-5-foods-are-claimed-to-improve-our-health-but-the-amount-wed-need-to-consume-to-benefit-is-a-lot-116730">These 5 foods are claimed to improve our health. But the amount we'd need to consume to benefit is... a lot</a>
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</em>
</p>
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<h2>What is brown fat?</h2>
<p><a href="https://www.ncbi.nlm.nih.gov/pubmed/28707455">Brown adipose</a> (fat) tissue is found deep within the torso and neck. It contains fat cell types which differ from the “white” fat we find around our waistlines.</p>
<p>Brown fat cells adapt to our environment by increasing or decreasing the amount of energy they can burn when “activated”, to produce heat to warm us up. </p>
<p>When people are cold for days or weeks, their brown fat gets better at burning energy. </p>
<p>We understand caffeine may be able to indirectly accentuate and prolong some of these processes, mimicking the effects of cold exposure in stimulating brown fat.</p>
<p>Brown fat – and anything thought to increase its activity – has generated significant research interest, in the hope it might assist in the treatment of obesity.</p>
<h2>What did the researchers do in this latest study?</h2>
<p>The research team first conducted experiments where cells taken from mice were grown into fat cells in petri dishes. They added caffeine to some samples, but not others, to see whether the caffeinated cells acquired more brown fat attributes (we call this “browning”).</p>
<p>The dose of caffeine (one millimolar) was determined based on what would be the highest concentration that browned the cells but didn’t kill them. </p>
<p>The fat cell culture experiment showed adding caffeine did “brown” the cells. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/can-brown-fat-really-help-with-weight-loss-85987">Can 'brown fat' really help with weight loss?</a>
</strong>
</em>
</p>
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<p>The researchers then recruited a group of nine people who drank a cup of instant coffee, or water as a control. </p>
<p>Before and after the participants drank coffee, the researchers measured their brown fat activity by assessing the temperature of the skin near the neck, under which a major region of brown fat is known to lie.</p>
<p>Skin temperature increased over the shoulder area after drinking coffee, whereas it didn’t after drinking only water.</p>
<h2>How should we interpret the results?</h2>
<p>Some people will criticise the low number of human participants (nine). We shouldn’t make broad recommendations on human behaviour or medicine based on small studies like this, but we can use them to identify new and interesting aspects of how our bodies work – and that’s what these researchers sought to do.</p>
<p>But whether the increased skin temperature after drinking coffee is significant cannot be determined for a few important reasons. </p>
<p>Firstly, although the study showed an increase in skin temperature after drinking coffee, the statistical analysis for the human experiment doesn’t include enough data to accurately compare the coffee and water groups, which prevents meaningful conclusions. That is, it doesn’t use appropriate methods we apply in science to decide if something really changed or only happened by chance.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/282592/original/file-20190704-126400-2m1x3s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/282592/original/file-20190704-126400-2m1x3s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=390&fit=crop&dpr=1 600w, https://images.theconversation.com/files/282592/original/file-20190704-126400-2m1x3s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=390&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/282592/original/file-20190704-126400-2m1x3s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=390&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/282592/original/file-20190704-126400-2m1x3s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=491&fit=crop&dpr=1 754w, https://images.theconversation.com/files/282592/original/file-20190704-126400-2m1x3s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=491&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/282592/original/file-20190704-126400-2m1x3s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=491&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Enjoy coffee for the taste, or the buzz. But don’t expect it to affect your waistline.</span>
<span class="attribution"><span class="source">From shutterstock.com</span></span>
</figcaption>
</figure>
<p>Second, measuring skin temperature is not necessarily the most accurate indicator for brown fat in this context. Skin temperature has been validated as a way to measure brown fat after cold exposure, but not after taking drugs which mimic the effects of cold exposure – which caffeine is in the context of this study.</p>
<p>Myself and other researchers <a href="https://www.ncbi.nlm.nih.gov/pubmed/30203462">have shown</a> the effects of these “mimic” drugs result in diverse effects including increased blood flow to the skin. Where we don’t know if changes in the skin temperature are due to brown fat or unrelated factors, relying on this measure may be problematic. </p>
<p>Although also suffering its own limitations, PET (poistron emission tomography) imaging is currently our best option for directly measuring active brown fat.</p>
<h2>It’s the dose that matters most</h2>
<p>The instant coffee used in the study contained 65mg of caffeine, which is standard for a regular cup of instant coffee. Brewed coffees vary and might be double this. </p>
<p>Regardless, it’s difficult to imagine this dose could increase brown fat energy burning when studies using <a href="https://www.ncbi.nlm.nih.gov/pubmed/23064293">large doses</a> of more potent “cold-mimicking” drugs (such as ephedrine) cause no, or at best modest, increases in brown fat activity.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-can-caffeine-improve-your-exercise-performance-114087">Health check: can caffeine improve your exercise performance?</a>
</strong>
</em>
</p>
<hr>
<p>But let’s look at the caffeine dose used in the cell experiments. The one millimolar concentration of caffeine is a 20-fold larger dose than <a href="https://www.ncbi.nlm.nih.gov/pubmed/30747558">300-600mg of caffeine</a> dose used by elite athletes as a performance-boosting strategy. And this dose is five to ten times higher than the amount of caffeine you’d get from drinking an instant coffee.</p>
<p>Rough calculations therefore suggest we’d need to drink 100 or 200 cups of coffee to engage the “browning” effects of caffeine. </p>
<p>So people should continue to drink and enjoy their coffee. But current evidence suggests we shouldn’t start thinking about it as <a href="https://www.ncbi.nlm.nih.gov/pubmed/1318281">a weight loss tool</a>, nor that it has anything meaningful to do with brown fat in humans. <strong>– Andrew Carey</strong></p>
<hr>
<h2>Blind peer review</h2>
<p>This Research Check is a fair and balanced discussion of the study. The limitations identified by this Research Check apply equally to diabetes, which the study encompassed, but didn’t get picked up as much in the headlines. </p>
<p>Coffee contains more than caffeine, and while there is some evidence that modest coffee consumption may reduce diabetes risk, <a href="https://www.ncbi.nlm.nih.gov/pubmed/28675917">decaffeinated coffee seems to be as effective as caffeinated coffee</a>. This is consistent with the point made by the Research Check that you would need to drink an implausible number of cups of coffee to produce the effect seen with caffeine in the cultured fat cells. <strong>– Ian Musgrave</strong></p>
<hr>
<p><em>Research Checks interrogate newly published studies and how they’re reported in the media. The analysis is undertaken by one or more academics not involved with the study, and reviewed by another, to make sure it’s accurate.</em></p><img src="https://counter.theconversation.com/content/119740/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Carey has received funding from the National Health and Medical Research Council of Australia, Diabetes Australia Research Program, CASS Foundation, Clive and Vera Ramaciotti Foundation and the Helen Macpherson Smith Trust.</span></em></p><p class="fine-print"><em><span>Ian Musgrave has received funding from the National Health and Medical Research Council to study adverse reaction to herbal medicines and has previously been funded by the Australian Research Council to study potential natural product treatments for Alzheimer's disease. He has collaborated with SA water on studies of cyanobacterial toxins and their implication for drinking water quality.</span></em></p>Caffeine may be able to increase the function of what we call ‘brown fat’. But we shouldn’t immediately scramble for the closest long black or flat white and expect to see the kilos drop.Andrew Carey, Group Leader: Metabolic and Vascular Physiology, Baker Heart and Diabetes InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1140872019-04-16T03:48:56Z2019-04-16T03:48:56ZHealth check: can caffeine improve your exercise performance?<figure><img src="https://images.theconversation.com/files/267751/original/file-20190405-114919-uy20zh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">There's good evidence drinking coffee before exercise can marginally improve your performance.</span> <span class="attribution"><span class="source">From shutterstock.com</span></span></figcaption></figure><p>Coffee is one of the most popular drinks in the world. Nearly half the adult population <a href="http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/by%20Subject/4364.0.55.007%7E2011-12%7EMain%20Features%7ENon-alcoholic%20beverages%7E701">in Australia</a> drink it. </p>
<p>Aside from enjoying the taste, the main reason we drink coffee is to get caffeine into our bloodstream. <a href="https://www.ncbi.nlm.nih.gov/pubmed/20888549">Caffeine can</a> help keep you awake, increase alertness, improve your concentration, enhance cognitive performance, and sharpen short-term memory and problem-solving skills.</p>
<p>It can also enhance physical performance. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-why-do-i-get-a-headache-when-i-havent-had-my-coffee-100163">Health Check: why do I get a headache when I haven't had my coffee?</a>
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</em>
</p>
<hr>
<h2>We’ve reviewed the evidence</h2>
<p>In a recent <a href="https://bjsm.bmj.com/content/early/2019/03/29/bjsports-2018-100278">umbrella review</a>, we summarised the findings from all meta-analyses that explored the effects of caffeine on exercise performance. A meta-analysis is a method that allows us to combine results from multiple studies to estimate the true effect.</p>
<p>Our review included more than 300 primary studies with more than 4,800 participants. </p>
<p>We found improvements in sports performance following caffeine intake that range from <a href="https://bjsm.bmj.com/content/early/2019/03/29/bjsports-2018-100278">2% to 16%</a>. </p>
<p>Those who respond most strongly to caffeine might see improvements of around 16%, but this is unusual. For the average person, improvements will likely be between about 2% and 6%.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/267753/original/file-20190405-114881-on8swi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/267753/original/file-20190405-114881-on8swi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/267753/original/file-20190405-114881-on8swi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/267753/original/file-20190405-114881-on8swi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/267753/original/file-20190405-114881-on8swi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/267753/original/file-20190405-114881-on8swi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/267753/original/file-20190405-114881-on8swi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A cup of coffee before you hop on your bike could help you cycle just that bit further.</span>
<span class="attribution"><span class="source">From shutterstock.com</span></span>
</figcaption>
</figure>
<p>This may not seem like much in the context of everyday life. But particularly in competitive sports, relatively small improvements in performance can make a big difference.</p>
<p>We found caffeine can enhance our <a href="https://www.ncbi.nlm.nih.gov/pubmed/7775331">ability to run</a> and cycle for longer periods, or to complete a <a href="https://www.ncbi.nlm.nih.gov/pubmed/29876876">given distance</a> in a shorter time frame. It could also allow us to perform <a href="https://www.sciencedirect.com/science/article/abs/pii/S0765159716000563">more repetitions</a> with a given weight in the gym, or to increase the <a href="https://www.tandfonline.com/doi/abs/10.1080/17461391.2017.1330362?journalCode=tejs20">total weight</a> lifted.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-what-should-our-maximum-heart-rate-be-during-exercise-107963">Health Check: what should our maximum heart rate be during exercise?</a>
</strong>
</em>
</p>
<hr>
<h2>How does caffeine have these effects?</h2>
<p>When we get tired, a chemical called adenosine binds to its receptors in the brain. The chemical structure of caffeine is <a href="https://www.ncbi.nlm.nih.gov/pubmed/27612937">similar to that of adenosine</a>, and when ingested, it competes with adenosine for these receptors – which tell our brains how fatigued we are. </p>
<p>During waking hours, adenosine slows down brain activity and results in feelings of fatigue. When we have caffeine, the caffeine binds to the adenosine receptors and has the opposite effect of adenosine. It reduces fatigue and <a href="https://www.ncbi.nlm.nih.gov/pubmed/15773860">our perception of effort</a> (for example, how hard it feels to perform an exercise).</p>
<p>Researchers once thought the effects of caffeine would be reduced in people who regularly drink a lot of coffee, but studies have shown that caffeine has performance-enhancing effects <a href="https://www.ncbi.nlm.nih.gov/pubmed/28495846">regardless of habits</a>.</p>
<h2>Does coffee = caffeine?</h2>
<p>In <a href="https://www.ncbi.nlm.nih.gov/pubmed/23573201">one study</a>, drinking coffee or taking caffeine in a capsule resulted in similar improvements in cycling performance. When the caffeine dose is matched, caffeine and coffee seem to be equally beneficial for improving performance.</p>
<p>But the dose of caffeine in a coffee may vary based on the type of coffee bean, preparation method, and size of the cup. It may also vary between <a href="https://www.sciencedirect.com/science/article/pii/S0889157512001548">different coffee brands</a>, and even within the <a href="https://www.ncbi.nlm.nih.gov/pubmed/30392444">same brand</a> at different times.</p>
<p>On average though, one cup of brewed coffee usually contains <a href="http://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/caffeine/art-20049372">between 95 and 165mg</a> of caffeine.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/267754/original/file-20190405-114899-1rito3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/267754/original/file-20190405-114899-1rito3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/267754/original/file-20190405-114899-1rito3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/267754/original/file-20190405-114899-1rito3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/267754/original/file-20190405-114899-1rito3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/267754/original/file-20190405-114899-1rito3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/267754/original/file-20190405-114899-1rito3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">About half of Australian adults drink coffee.</span>
<span class="attribution"><span class="source">Nathan Dumlao/Unsplash</span></span>
</figcaption>
</figure>
<p>Experts believe caffeine doses <a href="https://jissn.biomedcentral.com/articles/10.1186/1550-2783-7-5">between 3 and 6 mg/kg</a> are needed to improve performance. That’s 210 to 420mg for a 70kg person, or about two cups of coffee.</p>
<p>For safety reasons, those who don’t normally drink coffee should begin with a lower dose. The optimal dose, of course, <a href="https://www.ncbi.nlm.nih.gov/pubmed/28853006">varies between individuals</a>, so there’s room to experiment a little.</p>
<p>Aside from caffeine capsules or coffee, researchers are exploring <a href="https://link.springer.com/article/10.1007/s40279-017-0848-2">other sources</a> of caffeine for their effects on exercise performance. These include chewing gums, bars, mouth rinses, and energy drinks. But this area of research is relatively new and needs further investigation.</p>
<h2>How long before my workout should I drink coffee?</h2>
<p>Experts recommend ingesting caffeine roughly 45-90 minutes before exercising. Some forms of caffeine such as <a href="https://www.ncbi.nlm.nih.gov/pubmed/29368182">caffeine gum</a> are absorbed faster and can elicit a performance-enhancing effect even when consumed ten minutes before exercise.</p>
<p>Does this mean we should all start loading up on caffeine? Well, perhaps not just yet. Although people who ingest caffeine usually improve their performance, for some, the effects may be negligible.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/exercise-motivation-gets-you-started-but-routine-keeps-you-going-65041">Exercise: motivation gets you started, but routine keeps you going</a>
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<p>And overdosing on caffeine can have some really unpleasant <a href="http://www.webmd.com/vitamins-supplements/ingredientmono-979-caffeine.aspx?activeingredientid=979">side effects</a>, including insomnia, nervousness, restlessness, stomach irritation, nausea, vomiting, and headaches.</p>
<p>A certain amount of individual experimentation is needed to find out if caffeine will improve your exercise performance, or just give you a headache. </p>
<p>But for those looking for simple ways to gain a slight performance edge, getting more caffeine into your bloodstream might just be the ticket.</p><img src="https://counter.theconversation.com/content/114087/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brad Schoenfeld is affiliated with Dymatize Nutrition, a supplement company that has products containing caffeine, serving as a member of their scientific advisory board</span></em></p><p class="fine-print"><em><span>Craig is affiliated with DNAFit Life Sciences, a direct-to-consumer genetic testing company. </span></em></p><p class="fine-print"><em><span>David Bishop, Jozo Grgic, Pavle Mikulic, and Željko Pedišić do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Many people drink coffee for that extra bit of energy to go about their day. As well as sharpening our minds, there’s evidence caffeine can give us a physical boost, too.Jozo Grgic, PhD candidate at the Institute of Sport and Health (IHES), Victoria UniversityBrad Schoenfeld, Assistant Professor, Exercise Science, City University of New YorkCraig Pickering, Head of Sports Science (Genetics), University of Central LancashireDavid Bishop, Research Leader, Sport, Institute of Sport, Exercise and Active Living, Victoria UniversityPavle Mikulic, Associate Professor, Faculty of Kinesiology, University of ZagrebŽeljko Pedišić, Associate Professor, Victoria UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1099822019-01-17T11:36:31Z2019-01-17T11:36:31ZCoffee: 60% of wild species are at risk of extinction due to climate change<figure><img src="https://images.theconversation.com/files/254313/original/file-20190117-32825-1mio4p5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/cup-coffee-smoke-beans-burlap-sack-582329227?src=LF-5eBaFLgxMgQ8xUzJmeQ-1-29">Amenic181/Shutterstock</a></span></figcaption></figure><p>Is your morning coffee an espresso or a skinny latte? Is it from a darkly roasted French or Italian blend? If it’s a high quality brew, it’s almost certainly made with beans from the Arabica species (<em>Coffea arabica</em>), which is known for its finer flavours. Examples would be Javan coffees, Ethiopian sidamo, and the expensive Jamaican blue mountain.</p>
<p>If you’ve stirred together an instant blend, it’s probably from a different species, Robusta (<em>Coffea canephora</em>), <a href="https://www.cirad.fr/en/our-research/tropical-supply-chains/coffee/plant-and-uses">known for its harsher taste</a>. But there are <a href="https://doi.org/10.1111/j.1095-8339.2006.00584.x">more than 100 species of coffee</a> in the wild. All produce similar beans that you could make a recognisable coffee drink from.</p>
<p>Robusta is sometimes openly mixed with Arabica in commercial products – and is often <a href="https://doi.org/10.1016/j.foodchem.2017.12.034">secretly used to adulterate</a> “100% Arabica” products, too. A third species, <em>Coffea liberica</em>, native to west and central Africa, is widely grown for local use in tropical countries, but is not globally traded because of its more bitter taste. </p>
<p>A fourth species <em>Coffea eugenoides</em> bred with Robusta to give rise to Arabica, a crossbreed. Another 38 closely related species are known or assumed to have <a href="http://advances.sciencemag.org/content/5/1/eaav3473">fertile pollen transfer with commercial coffees</a>.</p>
<p>There are a further 82 species which are more distantly related to the commercial breeds, but scientists could interbreed them with commercial coffees in a lab. All these coffee relatives can help enhance the genetic diversity of commercial coffee species, making them more adaptable to changes in their environment.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/254131/original/file-20190116-163274-1u0u5re.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/254131/original/file-20190116-163274-1u0u5re.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/254131/original/file-20190116-163274-1u0u5re.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/254131/original/file-20190116-163274-1u0u5re.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/254131/original/file-20190116-163274-1u0u5re.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/254131/original/file-20190116-163274-1u0u5re.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/254131/original/file-20190116-163274-1u0u5re.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Arabica coffee beans growing in Colombia.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/closeup-coffee-fruit-farm-plantations-manizales-325255673?src=DfSQ0C3IhkISjNQ_X49WKg-1-6">Fotos593/Shutterstock</a></span>
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<h2>Dark days ahead for coffee</h2>
<p>Climate change is <a href="https://theconversation.com/climate-change-is-causing-havoc-for-global-coffee-yields-25685">threatening global coffee yields</a> as changing temperatures and rainfall patterns affect plant growth. The changing climate may also be leaving plants <a href="https://doi.org/10.1098/rstb.2015.0458">more vulnerable to disease</a>.</p>
<p>All major commercial coffee growing countries have been badly affected by the fungal disease “<a href="http://www.bbc.com/future/story/20171106-the-disease-that-could-change-how-we-drink-coffee">coffee leaf rust</a>”, which spread across Africa and into Asia during the early 20th century, then to South America, becoming entrenched globally by the turn of the millennium.</p>
<p>The <a href="https://worldcoffeeresearch.org/work/applied-rd-coffee-leaf-rust/">Central American coffee rust outbreak</a> that began in the 2011-2012 harvest season affected 70% of farms in the region, resulting in over 1.7m lost jobs and US$3.2 billion in damage and lost income.</p>
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Read more:
<a href="https://theconversation.com/climate-change-is-causing-havoc-for-global-coffee-yields-25685">Climate change is causing havoc for global coffee yields</a>
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<p>Robusta varieties used for the instant blends have been key to <a href="https://doi.org/10.1007/s12571-015-0446-9">developing resistance to coffee leaf rust</a> in Arabica varieties through cross breeding. As climate change and disease risks escalate, wild coffee species offer a crucial resource for maintaining the world’s coffee supply. Arabica has tightly limited geographic ranges in which it grows well and Robusta, while resistant to leaf rust, is vulnerable to <a href="https://www.researchgate.net/publication/277890144_Compendium_of_coffee_pests">other diseases</a>.</p>
<p><a href="http://advances.sciencemag.org/content/5/1/eaav3473">A recent study</a> led by the UK’s Kew Royal Botanic Gardens set the value of this variety in context: over 60% of coffee species are <a href="https://www.iucnredlist.org/">threatened with extinction</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/254546/original/file-20190118-100267-chbbjx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/254546/original/file-20190118-100267-chbbjx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=485&fit=crop&dpr=1 600w, https://images.theconversation.com/files/254546/original/file-20190118-100267-chbbjx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=485&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/254546/original/file-20190118-100267-chbbjx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=485&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/254546/original/file-20190118-100267-chbbjx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=610&fit=crop&dpr=1 754w, https://images.theconversation.com/files/254546/original/file-20190118-100267-chbbjx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=610&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/254546/original/file-20190118-100267-chbbjx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=610&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Leaf rust (<em>Hemileia vastatrix</em>) on a coffee plant.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Hemileia_vastatrix#/media/File:Hemileia_vastatrix.jpg">Howard F. Schwartz/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>The authors explained that wild relatives of coffee are already used as local substitutes for globally traded commercial crops. They offer different climatic tolerance ranges and disease resistance traits that can help ensure global coffee production continues to meet demand. </p>
<p>But coffee species are particularly vulnerable to extinction because they occur in a small numbers of small geographic ranges – such as pockets of <a href="https://theconversation.com/ethiopias-vulnerable-tropical-forests-are-key-to-securing-future-of-wild-coffee-56516">wild Arabica populations</a> between certain altitude ranges in the Ethiopian highlands.</p>
<p>Wild coffee species – and wild varieties of the commercial species – are almost all <a href="https://doi.org/10.1126/sciadv.aav3473">in decline</a> due to competition for land use and overharvesting of the coffee plant for timber or firewood. A number of wild coffee relatives haven’t been spotted for many decades and may be extinct. </p>
<p>One species, the <a href="http://globaltrees.org/threatened-trees/trees/cafe-marron/">cafe marron</a>, from the remote island of Rodrigues in the Indian Ocean, was known from only one sighting in 1877. A century later, a schoolboy drew an “unusual” tree while exploring and showed it to a teacher. They recognised it as a surviving cafe marron. The sole surviving specimen of that wild coffee has inspired wider forest conservation on Rodrigues. It is also being cultured in lab collections at Kew.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/254324/original/file-20190117-32825-1ys2vrf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/254324/original/file-20190117-32825-1ys2vrf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/254324/original/file-20190117-32825-1ys2vrf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/254324/original/file-20190117-32825-1ys2vrf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/254324/original/file-20190117-32825-1ys2vrf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/254324/original/file-20190117-32825-1ys2vrf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/254324/original/file-20190117-32825-1ys2vrf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Genetic diversity should also be considered in sustainability campaigns like Fairtrade.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/city-ljubljana-slovenia-europe-3-january-318452198?src=BAgreBZ5FY9FkOhNJtFwAg-1-13">Peacepix/Shutterstock</a></span>
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<p>Sadly, there may be less hope for other species. Coffee seeds don’t store well, unlike wild relatives of other crops such as wheat or maize. So we can’t rely on <a href="https://theconversation.com/after-svalbard-why-safety-of-world-seed-vaults-is-crucial-to-future-food-security-79586">storage in seed banks</a> to conserve coffee diversity and resilience. Freezing plant matter in labs or growing samples in test tubes might be an alternative, but not one that has been explored beyond existing commercial strains.</p>
<p>Preserving different coffee varieties in botanic gardens isn’t really viable for protecting genetic diversity either. Coffee species readily fertilise each other, “<a href="https://doi.org/10.1007/s10722-012-9898-3">contaminating</a>” the resource you’re trying to conserve.</p>
<p>While some experts suggest we <a href="https://worldcoffeeresearch.org/work/global-coffee-conservation-strategy/">preserve coffee diversity in collections</a>, the Kew Gardens study argues that the sustainability of coffee depends on conservation of these species where they grow, in protected areas and working with communities throughout their native distribution in Africa and Asia.</p>
<p>Conserving genetic diversity should be included in existing approaches for sustainable coffee production, such as <a href="https://theconversation.com/food-security-how-fairtrade-helps-level-the-playing-field-for-small-producers-70937">Fair Trade</a> and <a href="https://www.rainforest-alliance.org">Rainforest Alliance</a> certifications. Ensuring the continuity of the coffee trade means protecting the ecosystems coffee comes from and the livelihoods of people across the <a href="https://theconversation.com/wheres-that-bean-been-coffees-journey-from-crop-to-cafe-30207">bean to coffee cup economy</a>.</p>
<p>We can also expect new flavours and even coffees with naturally low or zero caffeine content. Naturally caffeine-free Indian Ocean island cafe marron anyone?</p><img src="https://counter.theconversation.com/content/109982/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adam Moolna does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>There are over 100 species of wild coffee, but only a few supply the world’s morning caffeine kick. Sadly, climate change and disease could be about to change that.Adam Moolna, Teaching Fellow in Environment and Sustainability, Keele UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1093832019-01-10T09:57:25Z2019-01-10T09:57:25ZDrinking tea during pregnancy may be bad for your baby’s health<figure><img src="https://images.theconversation.com/files/253044/original/file-20190109-32154-txnp93.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/465467702?src=iM6mCJOk-Ld4PDjOFHuH8g-2-23&size=medium_jpg">amenic181/Shutterstock</a></span></figcaption></figure><p>Caffeine is the most commonly used psychoactive substance in the world. And at average consumption levels, it is considered to be good for your health – or at least not bad for your health. However, <a href="https://doi.org/10.1186/s12916-014-0174-6">emerging evidence</a> suggests that consuming caffeine during pregnancy may be bad for the baby. Our <a href="https://doi.org/10.1093/ajcn/nqy219">latest study</a> adds to that evidence.</p>
<p>We wanted to know if there is a link between maternal caffeine intake and negative birth outcomes in a population where tea is the main caffeine source. To do so, we used data from an <a href="https://www.ucd.ie/lifeways/">Irish cohort study</a>. The data, on about 1,000 Irish women, provided us with the usual dietary intakes of caffeinated products during early pregnancy. We matched these with hospital records of the women’s newborns to get information on the birth size and gestational age at birth. </p>
<p>Tea was the predominant caffeine source (48%) followed by coffee (39%). Our analysis, published in The American Journal of Clinical Nutrition, showed a consistent link between both coffee and tea caffeine and adverse birth outcomes. In the highest caffeine consumption group, the risks of delivering babies with abnormally low birth weight or short gestational age at birth were about two times higher. The results were similar regardless of the caffeine source.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/253092/original/file-20190109-32151-1knewyp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/253092/original/file-20190109-32151-1knewyp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/253092/original/file-20190109-32151-1knewyp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/253092/original/file-20190109-32151-1knewyp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/253092/original/file-20190109-32151-1knewyp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/253092/original/file-20190109-32151-1knewyp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/253092/original/file-20190109-32151-1knewyp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Caffeine consumption in pregnancy is linked with low birth weight.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/967033?src=O6pUMrjwUbtH3POEZSKBRQ-1-0&size=medium_jpg">Francois Etienne du Plessis/Shutterstock</a></span>
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<h2>Time to revise recommended intake levels?</h2>
<p>While coffee is the main source of caffeine in most parts of the world (about 100mg per cup), it is less recognised that tea contains a significant amount of caffeine, too (about 33mg per cup). </p>
<p>Brewing methods and types of coffee and tea influence their caffeine contents. For example, caffeine content is higher in brewed coffee than in instant coffee, and it’s higher in black tea than in green tea. So our findings have potentially important public health implications in countries where a lot of black tea is consumed, such as Ireland and the UK. </p>
<p>The recommended caffeine intake level during pregnancy differs across health organisations and countries. The <a href="https://www.who.int/elena/titles/caffeine-pregnancy/en/">World Health Organisation</a> recommends an intake of less than 300mg per day. In contrast, organisations such as <a href="https://www.fsai.ie/faq/caffeine_and_pregnancy.html">The Food Safety Authority of Ireland</a> and <a href="https://www.ncbi.nlm.nih.gov/pubmed/20664420">The American College of Obstetricians and Gynecologists</a> recommend an intake of less than 200mg per day. However, our study shows an increased risk of adverse birth outcomes even for a maternal consumption level lower than these recommended levels.</p>
<h2>Should pregnant women abstain from caffeine?</h2>
<p>Apart from smaller birth size and shorter gestational duration, maternal caffeine intake has been linked to other negative outcomes for the child, such as a <a href="https://www.ncbi.nlm.nih.gov/pubmed/26444074">lower IQ</a>. But these findings, including our own, are from observational studies, and observational studies cannot prove that caffeine causes these outcomes, only that there is a link between them. To prove causation, scientists would need to conduct randomised controlled trials. However, to do so might be deemed ethically dubious.</p>
<p>Until more definitive evidence emerges, it is prudent to at least limit caffeine intake during pregnancy or when planning to conceive. It is not well-recognised that tea contains a significant amount of caffeine, so its consumption should also be taken into consideration when trying to adhere to the guideline caffeine intake limit during pregnancy.</p><img src="https://counter.theconversation.com/content/109383/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Ling-Wei Chen is employed with funding received from Science Foundation Ireland (PI: Dr Catherine Phillips). The Lifeways Cross Generation Cohort Study is funded by the Irish Health Research Board and is overseen by an interdisciplinary steering group. This work was supported by a research grant from the Irish Health Research Board (reference HRC/2007/13). Further support was received through an award by the ERA-Net on Biomarkers for Nutrition and Health (ERA HDHL), Horizon 2020 grant agreement number 696295, with funding provided by Science Foundation Ireland, Ireland (Grant Number SFI/16/ERA-HDHL/3360) and the European Union.</span></em></p>New study finds a link between tea drinking during pregnancy and smaller babies.Ling-Wei Chen, Postdoctoral Research Fellow in Nutritional and Life Course Epidemiology , University College DublinLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1068542018-11-15T19:00:20Z2018-11-15T19:00:20ZWhy you like coffee, and I choose tea – it’s in the genes<figure><img src="https://images.theconversation.com/files/245525/original/file-20181114-194488-1mz3w0l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Why does it cost so much to put a tea in a pot of hot water, anyway? </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/couple-love-drinking-coffee-laughing-cafe-173503769?src=TtidBWIBcgxJS5JYdmlM6g-1-3">from www.shutterstock.com </a></span></figcaption></figure><p>Do you drink freshly brewed coffee to start off your day? Or is a cup of English breakfast tea a better option for you? </p>
<p>Your choice could be a result of your genes, and how they affect your experience of bitter flavours. </p>
<p>Published today, our <a href="https://doi.org/10.1038/s41598-018-34713-z">new study</a> shows that the liklihood of a person being a coffee drinker or a tea drinker is linked with the presence or absence of key genes that shape how bitter flavours taste.</p>
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Read more:
<a href="https://theconversation.com/health-check-why-do-i-get-a-headache-when-i-havent-had-my-coffee-100163">Health Check: why do I get a headache when I haven't had my coffee?</a>
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<h2>Mmmmm tastes bitter</h2>
<p>Tea and coffee generally taste bitter because they contain bitter-tasting substances such as caffeine. Quinine is another substance that contributes to the bitterness of coffee, and is also found in tonic water. </p>
<p>A <a href="https://doi.org/10.1186/s12864-018-5058-2">recent study</a> by my colleagues and I revealed bitter taste receptor genes that are responsible for the perception of caffeine, quinine and a man-made bitter substance propylthiouracil (PROP). This latter molecule has the same bitterness as Brussels sprouts (for those of us who can taste it). </p>
<p>We knew from previous research that inherited factors play a role in the <a href="https://www.ncbi.nlm.nih.gov/pubmed/16185212">amount of coffee and tea a person drinks a day</a>, and that the ability to digest <a href="https://www.ncbi.nlm.nih.gov/pubmed/25288136">caffeine</a> plays an important role in the people’s consumption of caffeinated beverages. </p>
<p>But we didn’t know whether genes for bitter taste perception were involved in determining consumption of bitter-tasting beverages. Previous studies with small sample sizes reported no or inconsistent relationships. </p>
<p>In this new study, we examined the consumption of coffee and tea in a large <a href="https://www.ukbiobank.ac.uk/">Biobank</a> cohort of more than 400,000 men and women aged 37 to 73 in the UK for whom we also had data about their bitter receptor genes.</p>
<p>We employed a method commonly used in epidemiology called “<a href="https://www.ncbi.nlm.nih.gov/books/NBK62433/">Mendelian randomisation</a>” to compare coffee and tea intake between people who did or did not carry particular bitter taste receptor genes. </p>
<h2>Caffeine ‘super-tasters’</h2>
<p>Compared to an average person, we showed that people who carried the bitter taste receptor for caffeine were more likely to be heavy coffee drinkers, meaning they drank more than four cups of coffee a day. Every extra copy of the bitter taste receptor gene lead to a 20% higher chance of being a heavy coffee drinker. These “super-tasters” of caffeine also drank less tea. </p>
<p>As caffeine contributes to not only the bitterness of coffee but also its perceived strength and texture, people who are better at detecting caffeine may find coffee more enjoyable and flavourful. </p>
<p>In contrast, people who carried the bitter taste receptors for quinine or PROP drank less coffee and more tea. Compared to an average person, every extra copy of the quinine or PROP receptor gene was linked with a 9% or 4% higher chance of being a heavy tea drinker (meaning they drank more than 5 cups of tea a day). </p>
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Read more:
<a href="https://theconversation.com/ive-always-wondered-why-does-lemon-juice-lighten-the-colour-of-tea-91324">I've always wondered: why does lemon juice lighten the colour of tea?</a>
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<p>When there is a need for caffeine, “super-tasters” of quinine and PROP could choose tea over coffee because they tend to be more sensitive to overall bitterness.</p>
<h2>Don’t blame your genes</h2>
<p>In this study we demonstrated that genes for bitter taste perception are linked with the amount of coffee and tea we drink. </p>
<p>We’re interested to see if this finding could lead to future studies investigating whether “super-tasters” of bitter molecules are more or less prone to drink high and perhaps even unhealthy amounts of coffee and tea, or other drinks containing bitter molecules.</p>
<p>But we can’t blame everything on your genes. Even if as a child or right now you dislike the bitterness of coffee or tea, you may have noticed that your taste and dietary behaviour change over time as you grow. </p>
<p>So, even if you carried the “wrong” genes in terms of tasting bitter flavours, you could still learn to enjoy deliciously bitter-tasting foods and beverages. </p>
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Read more:
<a href="https://theconversation.com/want-to-eat-better-you-might-be-able-to-train-yourself-to-change-your-tastes-94914">Want to eat better? You might be able to train yourself to change your tastes</a>
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<p class="fine-print"><em><span>Daniel Liang-Dar Hwang is affiliated with the University of Queensland and the QIMR Berghofer Medical Research Institute.</span></em></p>How did you start today – tea or coffee? Or neither? A study of more than 400,000 men and women links specific genes for tasting bitter flavours like caffeine with hot beverage consumption.Daniel Liang-Dar Hwang, Postdoctoral Researcher, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.