tag:theconversation.com,2011:/uk/topics/green-tea-8178/articlesGreen tea – The Conversation2023-04-04T11:07:01Ztag:theconversation.com,2011:article/2027822023-04-04T11:07:01Z2023-04-04T11:07:01ZMatcha tea: what the current evidence says about its health benefits<figure><img src="https://images.theconversation.com/files/519271/original/file-20230404-24-ye6cnz.jpg?ixlib=rb-1.1.0&rect=17%2C0%2C5973%2C3988&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Matcha comes from green tea leaves, which are ground up into a powder.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/green-matcha-tea-drink-accessories-on-1054049189">Ekaterina Markelova/ Shutterstock</a></span></figcaption></figure><p>Although matcha tea has been around for centuries, it’s recently increased in popularity. This may be due to its favour with celebrities such as Jennifer Aniston and Gwyneth Paltrow, and because of its purported health benefits – with many claiming matcha has even greater benefit for our health than <a href="https://pubmed.ncbi.nlm.nih.gov/20370896/">green tea</a> does. </p>
<p>All green tea comes from the same plant: <em>Camellia sinensis</em>. Green tea (known as sencha) is produced from the unfermented leaves of this plant. <a href="https://www.mdpi.com/1420-3049/26/1/85">Matcha tea</a> (known as tencha) involves shading the plant from less intense sunlight, then harvesting, steaming and drying the leaves before they’re ground into a powder.</p>
<p>So whereas green tea is consumed as brewed dried leaves, matcha tea involves consuming the whole leaf powder – which means it may potentially provide <a href="https://www.mdpi.com/1420-3049/26/1/85">more nutritional benefit</a> than a regular cup of green tea. However, research into matcha is just beginning – meaning there’s still a lot we don’t know yet about just how beneficial it may be.</p>
<h2>Benefits of green tea</h2>
<p>Green tea is thought to have <a href="https://www.tandfonline.com/doi/abs/10.1080/13590840802518785;https://www.tandfonline.com/doi/abs/10.1080/07315724.2006.10719518">many health benefits</a>. This is due to certain compounds found in green tea called polyphenols, which have antioxidant properties – meaning these compounds may interact with other unstable molecules that can cause damage to our cells.</p>
<p>The polyphenols in green tea have been associated with modest reductions in <a href="https://nutritionj.biomedcentral.com/articles/10.1186/s12937-020-00557-5">cholesterol levels</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2855614/#:%7E:text=This%20beneficial%20effect%20has%20been,stroke%20and%20coronary%20heart%20disease.">blood pressure</a> in humans.
Furthermore, two meta-analyses suggest that drinking green tea <a href="https://pubmed.ncbi.nlm.nih.gov/36505265/">may reduce the risk </a> of <a href="https://ajcn.nutrition.org/article/S0002-9165(23)02217-7/fulltext">developing heart disease</a>. It’s thought that specific polyphenol compounds called <a href="https://biomeddermatol.biomedcentral.com/articles/10.1186/s41702-020-0057-8">catechins</a> found in green tea may contribute to its protective effects. </p>
<p>Other studies suggest that green tea may <a href="https://pubmed.ncbi.nlm.nih.gov/30205425/">lower the risk of certain types of cancer</a> as these catechins may interfere with <a href="https://www.sciencedirect.com/science/article/pii/S1756464620303960">cancer cell growth</a>.</p>
<p>Additionally, green tea may also affect the <a href="https://pubmed.ncbi.nlm.nih.gov/25650043">body’s metabolism</a> in the short term by enhancing the body’s ability to <a href="https://pubmed.ncbi.nlm.nih.gov/18326618/">burn fat during exercise</a> somewhat. In the longer term, green tea may potentially influence changes to the expression of <a href="https://pubmed.ncbi.nlm.nih.gov/23493529/">certain genes associated with fat burning</a>. This could mean that regular green tea consumption may, in part, modestly influence our <a href="https://pubmed.ncbi.nlm.nih.gov/19074207/">ability to lose fat</a> over time, especially in combination with exercise. </p>
<h2>How matcha measures up</h2>
<p>A typical cup of green tea might contain about <a href="https://www.mdpi.com/2076-3417/11/11/5087/htm">70mg of catechins</a>, which is about double that of black tea (although <a href="https://pubmed.ncbi.nlm.nih.gov/21115335/">many factors</a>, such as water temperature and how long the tea is brewed, can affect this). Matcha tea, however, could contain more than <a href="https://www.sciencedirect.com/science/article/pii/S2665927122002180">three times</a> the amount of catechins per serving, with one study reporting a staggering <a href="https://pubmed.ncbi.nlm.nih.gov/14518774/">137 times more</a> catechins than regular green tea. </p>
<p>This means matcha <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7231151/">contains more antioxidants</a> than other tea, which could explain its benefits for <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7231151/">cardiovascular and immune health</a>. </p>
<p>And because you’re consuming the whole tea leaf, matcha may contain more potent amounts of other natural ingredients – including amino acids such as L-theanine. In both animal and human studies, the L-theanine in matcha has been associated with both <a href="https://pubmed.ncbi.nlm.nih.gov/30308973/">reduced anxiety</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/31111111/">stress</a>. </p>
<figure class="align-center ">
<img alt="The leaves of the Camellia sinensis (green tea) plant." src="https://images.theconversation.com/files/519274/original/file-20230404-18-cnrfkl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519274/original/file-20230404-18-cnrfkl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519274/original/file-20230404-18-cnrfkl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519274/original/file-20230404-18-cnrfkl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519274/original/file-20230404-18-cnrfkl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519274/original/file-20230404-18-cnrfkl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519274/original/file-20230404-18-cnrfkl.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">Matcha and green tea are derived from the same plant.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/tea-camellia-sinensis-upper-leaves-on-2108031074">AnnaNel/ Shutterstock</a></span>
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</figure>
<p>Matcha also contains <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7796401/">higher levels of caffeine</a> by weight – around 20-40mg per gram, which is 2-4 times higher than that found in an equivalent amount of coffee beans. As such, recent studies investigating matcha have looked at the combined effects of its catechin and caffeine content. Two recent studies looking at women in their late twenties found that drinking matcha tea modestly improved the <a href="https://pubmed.ncbi.nlm.nih.gov/29345213/">amount of fat burned</a> while walking by <a href="https://pubmed.ncbi.nlm.nih.gov/32875933/">up to 35%</a>. </p>
<p>These results are broadly <a href="https://pubmed.ncbi.nlm.nih.gov/33652910/">similar to other studies</a> conducted <a href="https://pubmed.ncbi.nlm.nih.gov/18326618">using green tea extract</a>, suggesting that matcha is just as effective, but not more so, than green tea. As such, matcha may provide some additional benefits when used alongside exercise. But it will be important for future studies to investigate whether matcha also boosts the effect of exercise in other groups.</p>
<h2>Other possible benefits</h2>
<p>Matcha has also been <a href="https://pubmed.ncbi.nlm.nih.gov/28056735/">shown to improve</a> alertness, decision-making, memory and focus. In one study, participants who were given 4g of matcha powder as a drink scored better on <a href="https://pubmed.ncbi.nlm.nih.gov/28784536/">cognitive tests</a> looking at attention, information processing, reflexes and memory compared to those who were given a placebo. </p>
<p>Other research also indicates that several cups of green tea a day may prevent <a href="https://www.mdpi.com/1420-3049/26/16/4897">age-related cognitive decline</a>. This may be, in part, linked with the stress-reducing effects of L-theanine, as well as a potent catechin called “epigallocatechin gallate” or EGCG which is particularly <a href="https://www.sciencedirect.com/science/article/pii/S2665927122002180">high in matcha</a>. So while it’s likely matcha will have a similar cognitive benefit as green tea, it will be important for future studies to look at matcha more specifically. </p>
<p>Research in this area is still young, and more studies – particularly with adults – are needed to truly understand just how beneficial matcha may be. But if you’re someone who likes to start their day with a cup of tea or coffee, you may want to consider <a href="https://pubmed.ncbi.nlm.nih.gov/36582446/">switching to matcha</a>. Not only is this a great way to get your caffeine fix, but it may also potentially have other benefits to your health. Between <a href="https://www.sciencedirect.com/science/article/pii/S2665927122002180">2-4g of matcha a day</a> (equivalent to 2-4 cups) may be enough get some of these reported benefits over time.</p><img src="https://counter.theconversation.com/content/202782/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Justin Roberts works for both Anglia Ruskin University and Danone Nutricia Research in the area of Nutritional Physiology and Functional Nutrients. He has previously received project funding specific to green tea research (not matcha) from both High5 Ltd and Biocare Ltd, and has published research in this area.</span></em></p><p class="fine-print"><em><span>Henry Chung 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>Matcha may potentially provide more nutritional benefit than a regular cup of green tea.Justin Roberts, Associate Professor, Nutritional Physiology for Health and Exercise, Anglia Ruskin UniversityHenry Chung, Lecturer in Sport and Exercise Science, University of EssexLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/926952018-03-05T15:00:13Z2018-03-05T15:00:13ZTraditional African medicine and conventional drugs: friends or enemies?<figure><img src="https://images.theconversation.com/files/208655/original/file-20180302-65522-t1neoh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Herbs, roots and plants can have health benefits. But they can also interact negatively with Western medicines.</span> <span class="attribution"><span class="source">Michel Piccaya/Shutterstock</span></span></figcaption></figure><p>Africa is home to an extensive and diverse medicinal plant life. This includes commonly used herbs like Rooibos (<em>Aspalathus linearis</em>), Devil’s claw (<em>Harpagophytum procumbens</em>), Buchu (<em>Agathosma betulina</em>), Cape Aloe (<em>Aloe ferox</em>) and Hoodia (<em>Hoodia gordonii</em>).</p>
<p>These plant - or herb-based treatments have been a <a href="https://scialert.net/fulltext/?doi=rjphyto.2010.154.161">key part</a> of the continent’s traditional medicinal practices for thousands of years. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3252714/">Up to 80%</a> of people in some areas regularly use traditional medicines and consult traditional health practitioners. In some areas, traditional treatments are <a href="https://www.ncbi.nlm.nih.gov/pubmed/17052873">the main</a> or only treatment because they are accessible, affordable and culturally accepted.</p>
<p>Numerous traditional African medicines are <a href="https://www.sciencedirect.com/science/article/pii/S0378874108002808">undeniably beneficial</a> in treating disease or maintaining good health. Some have even been the source of many prescription medicines. But there are challenges. These include the fact that many consumers automatically assume “natural equals safe”. Another problem arises when people use traditional or herbal remedies together with prescribed medicines. </p>
<p>Part of <a href="https://www.ncbi.nlm.nih.gov/pubmed/22612723">the research</a> my colleagues and I do at North-West University in South Africa is focused on understanding these combinations. Which are harmful? Which could be beneficial? We’re <a href="https://www.ncbi.nlm.nih.gov/pubmed/29268027">looking at</a> what’s known as “interactions” – the effect herbal medicines may have on the normal uptake, breakdown or activity of prescribed medicines. </p>
<p>Knowledge is key. Scientists need to conduct proper research to understand such interactions. Consumers need to be taught about these interactions, whether good or bad, and to tell their healthcare providers about everything they’re taking. </p>
<h2>Understanding interactions</h2>
<p>Prescriptions of traditional African medicines tend to be secretive. They’re based on knowledge passed from generation to generation of traditional healers. This can result in vague doses. Patients <a href="https://www.tandfonline.com/doi/abs/10.1517/17425255.2015.1064110">have been known</a> to overuse some remedies while self-medicating. This can have severe health consequences. <a href="https://www.sciencedirect.com/science/article/pii/S2213422014000262">These include</a> stomach upsets, liver damage and even kidney failure. Some widely used natural health plant products which have been associated with adverse health effects because of misuse include <em>Aloe vera</em>, Echinacea (<em>Echinacea purpurea</em>) and Green tea (<em>Camellia sinensis</em>). </p>
<p>All of these natural remedies are generally considered “safe”, or even healthy by consumers since their use is not regulated or restricted. Nothing indicates to the user that “too much of a good thing” could be dangerous.</p>
<p>Thanks partly to efforts by the World Health Organisation, access to Western medicine – especially for diseases like HIV/AIDS – <a href="http://apps.who.int/iris/bitstream/10665/95461/1/AFR_RC50_20.pdf">is increasing</a> across Africa. More and more people tend to be using traditional medicine in combination with prescription medicines. Often none of their healthcare providers know about this and so cannot warn about possible interactions.</p>
<p>Some traditional African medicines may interfere with the normal metabolism of drugs. For example, St. John’s Wort is a natural remedy frequently used for depression. But it’s <a href="https://www.ncbi.nlm.nih.gov/pubmed/15914127">been shown</a> to increase the removal of medicines, such as some oral contraceptives, from the body. This can lead to ineffective levels of the prescribed medicine, putting women at risk of pregnancy when they think they are protected.</p>
<p>On the other hand, the interaction could also result in reduced clearance of a drug. This may lead to higher levels of the prescribed medicine in the body, which produces negative side effects and could even lead to toxicity. </p>
<p>These interactions happen at a metabolic level. So even herbal products that are safe when used on their own <a href="https://www.tandfonline.com/doi/abs/10.1080/17425255.2018.1421171?needAccess=true&journalCode=iemt20">may pose a risk</a> when taken in combination with Western medicine – that is, synthetic pharmaceutical agents.</p>
<p>Some of the best known examples of drug interactions are the effects of citrus, particularly grapefruit juice, and alcohol of many prescribed medicines. These combinations should be avoided.</p>
<p>Another example of particular importance in Africa is Cancer bush (<em>Sutherlandia frutescens</em>). It is widely used in the treatment of diseases such as HIV/AIDS and TB, especially in countries like Zambia, Swaziland, Zimbabwe and South Africa, as it is believed to generally improve quality of life in these patients. But it has <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3876690/">been shown</a> to lower the plasma levels of the antiretroviral drug, atazanavir, to sub-therapeutic levels when they’re taken together, reducing its anti-HIV efficacy.</p>
<p>This traditional remedy <a href="https://www.ncbi.nlm.nih.gov/pubmed/27155670">can also interfere</a> with isoniazid therapy, which is used as a preventative measure in TB treatment.</p>
<p>Despite these known interactions, policy makers still <a href="https://www.omicsonline.org/open-access/african-traditional-medicine-use-amongst-people-living-with-hivaids-insubsaharan-africa-in-the-era-of-antiretroviral-therapy-.php?aid=79780">promote the use</a> of these herbal remedies in the management of HIV/AIDS and associated illnesses. Clearly more public engagement is needed so patients understand the risks of interaction.</p>
<h2>And the good news</h2>
<p>But it’s not all bad news. Interactions between African traditional medicines and prescribed medicines can potentially be exploited for good.</p>
<p>One of the biggest problems in the development of new medicines is the low uptake of these compounds into the body, or its quick removal. In some studies, traditional medicines have been shown to have the ability to increase uptake or decrease the metabolism of prescription drugs. Applying these effects could enable the development of new herb-drug combinations with increased efficacy and reduced side-effects.</p>
<p>But studies that characterise and evaluate the healing properties or potential toxicity and drug interactions of traditional African medicines are very limited. This is further complicated by the fact that so many medicinal plants (more than 5000) are being used. So healthcare practitioners have limited information and often can’t make proper recommendations to patients who use such traditional remedies.</p>
<p>Whether positive or negative drug interactions are at play, African countries need to improve their regulation around traditional medicines. Only a few, among them Nigeria, Cameroon and South Africa, <a href="https://www.sciencedirect.com/science/article/pii/S2213422014000262">have incorporated</a> traditional African medicines into their adverse drug reaction reporting systems.</p><img src="https://counter.theconversation.com/content/92695/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chrisna Gouws works for the North-West University. She receives funding from the National Research Foundation (NRF) of
South Africa and the South African Medical Research Council (MRC). Opinions expressed and conclusions arrived at, are those of the author and are not necessarily to be attributed to the NRF or the MRC.</span></em></p>Numerous traditional African medicines are undeniably beneficial in treating disease or maintaining good health.Chrisna Gouws, Senior Lecturer, North-West UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/873532017-12-15T01:36:44Z2017-12-15T01:36:44ZScience or Snake Oil: do skinny teas boost weight loss?<figure><img src="https://images.theconversation.com/files/198743/original/file-20171212-9383-1e2tlrz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">'Skinny teas' might not have any properties to help you lose weight, but they might remind you you're on a diet. </span> <span class="attribution"><span class="source">from www.shutterstock.com</span></span></figcaption></figure><p>Weight loss teas are becoming common, with advertisements claiming dramatic results often appearing online. Do the big promises match the results, or do they only match the price tag? </p>
<p>A search of the medical research database <a href="https://www.ncbi.nlm.nih.gov/books/NBK3827/#pubmedhelp.PubMed_Quick_Start">pubmed</a> found there are no studies specifically on the use of “slimming teas” for weight loss, but there are studies on green and black tea.</p>
<p>One <a href="https://www.ncbi.nlm.nih.gov/pubmed/26075637">review of five research trials</a> compared changes in body weight in more than 300 adults at high risk of type 2 diabetes and heart disease. They gave people either green tea, a fermented tea called Puehr or tea extracts and compared the weight change to people who were given either placebo (non-active) tea extracts or no tea at all.</p>
<p>They found that in the group of people who had the most risk factors for type 2 diabetes and heart disease, <em>and</em> who also ate more healthy foods and exercised more, those having the tea or tea extracts had a weight reduction of about 4kg. Interestingly, in the group who were not given healthy lifestyle advice and who did not have many risk factors, the average weight loss was only about 350 grams.</p>
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<a href="https://theconversation.com/health-check-six-tips-for-losing-weight-without-fad-diets-52496">Health Check: six tips for losing weight without fad diets</a>
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<p>These results suggest most of the weight loss was due to the impact of following the healthy lifestyle advice, and that there may have been some extra motivation to stick to that advice among those who were at high risk of other health problems.</p>
<p>An <a href="https://www.ncbi.nlm.nih.gov/pubmed/21366839">analysis of six studies</a> examined the effect of tea mixtures that contain added catechins (a chemical compound found in tea that have a bitter flavour) and caffeine or caffeine-only supplements on the body’s energy expenditure. They found both significantly increased the amount of energy the body burns over the day, by approximately 5%. That may not sound like much, but it’s equivalent to about 430 kilojoules per day, or the kilojoules in a medium banana.</p>
<p>In another review of the effects of <a href="https://www.ncbi.nlm.nih.gov/pubmed/19597519">green tea and added tea extracts on body weight regulation</a>, consuming green tea with the tea extract added was associated with a 1.3 kilogram greater weight loss compared to not consuming them over about three months. </p>
<p>Slimming teas can have herbal tea components, herbal extracts or other additives mixed in with the tea. There’s limited good quality research on the effectiveness of these compounds, although some have been around for decades. But there has been a case report of heart failure triggered from using a <a href="https://www.ncbi.nlm.nih.gov/pubmed/27414728">herbal weight loss tea</a> that was thought to have illegally contained weight loss drugs known to cause heart problems, so caution must be exercised.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/198744/original/file-20171212-9392-1dnhbcp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/198744/original/file-20171212-9392-1dnhbcp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/198744/original/file-20171212-9392-1dnhbcp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/198744/original/file-20171212-9392-1dnhbcp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/198744/original/file-20171212-9392-1dnhbcp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/198744/original/file-20171212-9392-1dnhbcp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/198744/original/file-20171212-9392-1dnhbcp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/198744/original/file-20171212-9392-1dnhbcp.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">It’s important to look at what’s in the tea you’re drinking.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com">from www.shutterstock.com</a></span>
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<p>Botanical compounds that might be added to slimming tea include the following, so check the label:</p>
<ol>
<li><p><a href="https://www.webmd.com/vitamins-supplements/ingredientmono-652-SENNA.aspx?activeIngredientId=652&activeIngredientName=SENNA">Senna</a>, a laxative used to treat constipation;</p></li>
<li><p><a href="https://www.webmd.com/vitamins-supplements/ingredientmono-870-valerian.aspx?activeingredientid=870&activeingredientname=valerian">Valerian root</a>, which has some evidence that it may improve sleep quality;</p></li>
<li><p>Roots of the <a href="https://en.wikipedia.org/wiki/Arctium">burdock plant</a>, which are thought to contain chemicals that act as a diuretic (and increase urine production);</p></li>
<li><p><a href="https://en.wikipedia.org/wiki/Yerba_mate">Yerba mate</a>, a plant common in South America. The leaves are used to make a drink high in <a href="https://en.wikipedia.org/wiki/Polyphenol">polyphenols</a>, a group of compounds found in plants that help the body defend itself against disease. Yerba mate also contains caffeine, so it has a stimulatory effect similar to coffee. A <a href="https://www.ncbi.nlm.nih.gov/pubmed/25621503">recent review suggests</a> it may be helpful in lowering blood cholesterol levels;</p></li>
<li><p><a href="https://www.webmd.com/vitamins-supplements/ingredientmono-706-dandelion.aspx?activeingredientid=706&activeingredientname=dandelion">Dandelion leaf</a> contains chemicals thought to have a diuretic effect, but there’s no strong evidence to support this effect;</p></li>
<li><p>Celery seed can be used as a spice or flavouring, the active ingredient apiole has been thought to have <a href="https://www.ncbi.nlm.nih.gov/pubmed/23361270">anti-cancer effects (in mice)</a>; and</p></li>
<li><p>Calendula flowers are edible and <a href="https://www.ncbi.nlm.nih.gov/pubmed/24347926">a review of their medicinal use through out history</a> found potential wound healing and anti-swelling properties.</p></li>
</ol>
<p>As long as you do not have any sensitivities or a chemical intolerance to slimming tea components, they might have a <a href="https://www.ncbi.nlm.nih.gov/pubmed/25442940">powerful placebo</a> effect and act as a timely reminder to stick to a weight loss diet. Interestingly, the <a href="https://www.ncbi.nlm.nih.gov/pubmed/24055773">placebo effect is supported by evidence</a>. </p>
<p>While the price of slimming teas vary, check the small print for disclaimers before you part with your money. They might read something like: </p>
<blockquote>
<p>For maximum health benefits this product should be consumed in conjunction with a low kilojoule diet and daily exercise, individual results may vary.</p>
</blockquote>
<p>Think about whether you get better value from A$30+ dollars worth of weight loss tea or from buying a regular box of green or black tea, and spending the price difference on buying more fruits and vegetables. The research evidence indicates <a href="https://www.ncbi.nlm.nih.gov/pubmed/23674808">higher intakes of fruit and vegetables</a> are associated with a lower risk of weight gain, heart disease, type 2 diabetes, some specific types of cancer and age-related health decline.</p><img src="https://counter.theconversation.com/content/87353/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Clare Collins is affiliated with the Priority Research Centre for Physical Activity and Nutrition, the University of Newcastle, NSW. She is an NHMRC Senior Research and Gladys M Brawn Research Fellow. She has received research grants from NHMRC, ARC, Hunter Medical Research Institute, Meat and Livestock Australia, Diabetes Australia, Heart Foundation. She has consulted to SHINE Australia, Novo Nordisk, Quality Bakers and the Sax Institute. She was a team member conducting the systematic reviews to inform the 2013 revision of the Australian Dietary Guidelines and the 2017 evidence review on dietary patterns and heart disease for the Heart Foundation.</span></em></p>You may be better off buying regular green or black tea and spending more on fruit and vegetables.Clare Collins, Professor in Nutrition and Dietetics, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/469462016-02-18T12:54:53Z2016-02-18T12:54:53ZWhy Britain is losing its taste for tea – and how hipsters could revive it<figure><img src="https://images.theconversation.com/files/111932/original/image-20160218-1252-1gu3108.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Ruth Black/Shutterstock</span></span></figcaption></figure><p>Britain is a nation of tea drinkers – but for how much longer? New <a href="http://www.independent.co.uk/life-style/food-and-drink/news/british-cup-of-tea-and-toast-on-decline-as-junk-food-increases-in-popularity-a6879926.html">research</a> released by the National Food Survey suggests that Britons are falling out of love with their morning “cuppa”. But in fact the UK has been losing its taste for tea for decades. Tea consumption has fallen steadily since “peak tea” was reached in 1956. When tea was rationed during World War II, the ration was <a href="http://www.bbc.co.uk/history/topics/rationing_in_ww2">2oz</a> (56g) per person per week. At 25g of tea per person per week, Britons now consume less than half the amount of tea they did during the war.</p>
<p>This might seem like a blow to a core component of British identity, but the British “<a href="http://www.iso.org/iso/catalogue_detail.htm?csnumber=8250">way</a>” of making tea – black tea, frequently served with milk and sugar – is comparatively recent in origin. When tea was first consumed in Britain in the 17th century, most Britons made green tea, drunk from tiny porcelain cups without handles. Though some took it with a little sugar, tea was almost always served without milk. During this period, all tea was from China, and the most popular kinds were green tea, though increasingly some preferred “bohea”, an oolong that produced a pale reddish-brown infusion.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/111935/original/image-20160218-1248-keek6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/111935/original/image-20160218-1248-keek6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=388&fit=crop&dpr=1 600w, https://images.theconversation.com/files/111935/original/image-20160218-1248-keek6m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=388&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/111935/original/image-20160218-1248-keek6m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=388&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/111935/original/image-20160218-1248-keek6m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=488&fit=crop&dpr=1 754w, https://images.theconversation.com/files/111935/original/image-20160218-1248-keek6m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=488&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/111935/original/image-20160218-1248-keek6m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=488&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Tea preparation in China, 1847.</span>
</figcaption>
</figure>
<p>It wasn’t until the 1850s that tea from India started to be imported in any quantities, and the British fondness for Assam, Darjeeling and Ceylon teas began to form. The tea they produced was more like what we expect now: tea that quickly stains the water a dark brown colour, with a pronounced and tannic flavour, suitable for taking with milk. And in its time, this shift was certainly driven to some extent by what was considered cool.</p>
<p>Tea from India and Sri Lanka was grown on substantial industrialised plantations, managed and financed by predominantly British companies, employing large numbers of indentured Indian workers. Rather than the artisanal production processes of Chinese smallholders, tea production in British India was mechanised as far as possible. By the 1920s, the introduction of new “rip-tear-curl” technology allowed the tea leaves to be processed and cured almost entirely by machine. The machines produced the super-oxidized “black tea” we are now familiar with, losing some of the more delicate flavours of the handmade method. This tea was cheaper and more efficient for tea companies to produce, and, because it made a darker and more tannic brew, was welcomed by consumers.</p>
<p>The 20th century also saw the adoption of an American invention, the teabag, which brought convenience and efficiency for the consumer, but also enacted a little economic miracle for tea companies. Teabags further reduced the quality and the quantity of tea needed to satisfy consumers. Teabags could be filled with the lowest grades of tea, the waste grades of dust and fannings. Over <a href="https://www.tea.co.uk/the-history-of-the-tea-bag#teabags">96%</a> of tea in Britain is now made with teabags. Nobody pretends this is good tea.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/111936/original/image-20160218-1283-12b4t9b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/111936/original/image-20160218-1283-12b4t9b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/111936/original/image-20160218-1283-12b4t9b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/111936/original/image-20160218-1283-12b4t9b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/111936/original/image-20160218-1283-12b4t9b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/111936/original/image-20160218-1283-12b4t9b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/111936/original/image-20160218-1283-12b4t9b.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">
<figcaption>
<span class="caption">Tea plantation in Kerala, India.</span>
<span class="attribution"><span class="source">Shutterstock.com</span></span>
</figcaption>
</figure>
<p>The decline in tea consumption might be attributed to changing tastes, and increased competition from hot drinks with more glamour, especially the various varieties of hot foamy milk and coffee served up by the espresso coffee chains. Despite the fact that some of these drinks often contain a “<a href="http://www.bbc.co.uk/news/health-35593007">dangerously</a>” high level of sugar, as Action on Sugar recently claimed, they remain enormously popular with young consumers.</p>
<p>So the decline in tea consumption is partly the fault of the tea industry. Industry analysts talk about how tea appeals to the throat and the mind. “Throat” describes how much tea is consumed, literally poured down the throat. “Mind” describes how tea is understood, and what it means. Despite commanding a considerable residual hold on the throat, tea’s share of the hot drinks market is declining because its grip on the mind is weak. To the mind, tea is comfortable, homely, ordinary – and a little boring. Tea is just not very cool, and as a result, it is slowly losing “throat appeal”.</p>
<p>In order to revive tea, some industry pundits argue they need to win the battle for the mind first. This is what coffee did: the CEO of Starbucks Howard Shultz is fond of <a href="https://books.google.co.uk/books?id=D1lrAwAAQBAJ&pg=PT36&lpg=PT36&dq=%22I+discovered+the+ritual+and+the+romance+of+coffee+bars%22+starbucks&source=bl&ots=3bcjeS4DUs&sig=5j3yg_V_cOM9IZ5X8sdE5SwQjkY&hl=en&sa=X&ved=0ahUKEwiH9rzhlIHLAhVBvxoKHXhOCooQ6AEIHDAA#v=onepage&q=%22I%20discovered%20the%20ritual%20and%20the%20romance%20of%20coffee%20bars%22%20starbucks&f=false">saying</a> his company revivified the retail coffee market in the United States by recovering “the romance of coffee”. </p>
<p>So it’s encouraging that numerous tea retailers, both small boutique operations and large conglomerates, have recently opened gourmet tea retailers on the high street, seeking to extend customers’ interest in more diverse (and higher priced!) tea experiences. There will be more, as the tea industry seeks to find ways to make the British way of taking tea an aspirational experience once again, not merely a brief encounter between a mug and teabag. Hipsters may be the only people who can transform tea’s fortunes.</p><img src="https://counter.theconversation.com/content/46946/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Markman Ellis is co-author (with Richard Coulton and Matthew Mauger) of Empire of Tea: The Asian Leaf that Conquered the World (Reaktion, 2015).
</span></em></p>It’s been a long, slow decline, so can anyone solve the Great British cuppa crisis?Markman Ellis, Professor of Eighteenth-Century Studies, Queen Mary University of LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/424192015-08-24T05:52:51Z2015-08-24T05:52:51ZHealth Check: five reasons to put the kettle on and have a cup of tea<figure><img src="https://images.theconversation.com/files/92352/original/image-20150819-12428-33wlo5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Around the world, tea is the most common drink after water. </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/jurek_durczak/17192958878/">jurek d./Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>Growing up, tea drinking was reserved for my grandmother’s visits. Making it followed a strict and fascinating ritual. Take scalding hot water. Warm the tea pot. Add one spoon of tea leaves for each person and one for the pot. Cover with a tea cosy. Turn the pot three times to the left, three to the right, then three to the left. Leave to brew. Warm the cups; milk in first, pour through a tea strainer. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/92355/original/image-20150819-12428-1ldqb67.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/92355/original/image-20150819-12428-1ldqb67.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/92355/original/image-20150819-12428-1ldqb67.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/92355/original/image-20150819-12428-1ldqb67.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/92355/original/image-20150819-12428-1ldqb67.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/92355/original/image-20150819-12428-1ldqb67.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/92355/original/image-20150819-12428-1ldqb67.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Two-thirds of over-70s are tea drinkers.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/louiseljtastefuldesire/8006220289/">Louise Lj/FLickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>My grandmother could taste any attempt you made to shortcut the process. Once Grandma approved the tea, pressure eased and conversation flowed. </p>
<p>In Australia <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">38% of the general population</a> and 67% of those aged over 70 are tea drinkers. Our median intake is two cups a day, about 400mls. </p>
<p>By world standards we <a href="https://en.wikipedia.org/wiki/List_of_countries_by_tea_consumption_per_capita">rank 55</a> for tea consumption, compared to the United States at 69, New Zealand 45 and the United Kingdom, number five. Turkey takes out the number one spot, consuming more than ten times the per capita intake of Australians. </p>
<h2>1. Tea and survival</h2>
<p>Around the world, tea is the most common drink after water. Popularity increased in the 1800s because the practise of boiling water to make the tea meant water-borne pathogens like cholera and typhoid would be killed, making it <a href="https://en.wikipedia.org/wiki/Health_effects_of_tea">safer to drink</a>.</p>
<p>Tea comes from the <a href="https://en.wikipedia.org/wiki/Camellia_sinensis">leaves and buds of the plant</a> <em>Camellia sinensis</em>. Black tea, green tea, white tea, and oolong varieties all come from the same plant, but are <a href="https://en.wikipedia.org/wiki/Tea_processing">processed into dried leaves differently</a>.</p>
<p>Science has muscled in on our tea drinking habits and started to unravel what makes us love our “cuppa”. There is a large group of bioactive components in tea <a href="https://en.wikipedia.org/wiki/Polyphenol">called polyphenols</a>, which include catechins and tannins. Concentrations of these compounds <a href="http://www.ncbi.nlm.nih.gov/pubmed/25391016">vary depending on how you make the tea</a>, including the amount of tea leaves per cup, water temperature and brewing time. </p>
<p>Catechins have anti-oxidant properties and are most abundant in green tea. Tannins, which inhibit <a href="http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Iron_explained">non-haem iron absorption</a> in the gut, are most abundant in black tea. So if you have iron deficiency, avoid drinking tea with meals. But if you have the excessive iron storage condition <a href="http://haemochromatosis.org.au">haemochromatosis</a>, drinking tea with meals will help reduce iron absorption.</p>
<h2>2. Tea and your brain</h2>
<p>Components of tea that can boost brain activity include caffeine, catechins and the amino acid, <a href="https://en.wikipedia.org/wiki/Theanine">L-theanine</a>. </p>
<p>In a systematic review of the effects of tea on <a href="http://www.ncbi.nlm.nih.gov/pubmed/24946991">mood and cognitive function</a>, the combination of L-theanine and caffeine was shown to increase alertness and attention-switching accuracy up to two hours after consumption. The researchers also found small enhancements in accuracy of visual and auditory attention. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/92521/original/image-20150820-7221-1j8za78.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/92521/original/image-20150820-7221-1j8za78.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=421&fit=crop&dpr=1 600w, https://images.theconversation.com/files/92521/original/image-20150820-7221-1j8za78.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=421&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/92521/original/image-20150820-7221-1j8za78.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=421&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/92521/original/image-20150820-7221-1j8za78.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=529&fit=crop&dpr=1 754w, https://images.theconversation.com/files/92521/original/image-20150820-7221-1j8za78.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=529&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/92521/original/image-20150820-7221-1j8za78.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=529&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Catechins and the amino acid, L-theanine, can boost brain power.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/bonehead/5796268284/">ned the head/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>Preliminary evidence also suggests catechins may have a calming effect during the second hour post-cuppa. The authors called for further research using a greater dosage range of catechin and L-theanine to help separate any effects due to caffeine intake. </p>
<p>At this stage however, there is <a href="http://www.ncbi.nlm.nih.gov/pubmed/25732217">no clear evidence</a> that drinking tea will protect people from developing dementia. </p>
<h2>3. Tea and weight loss</h2>
<p>There has been a lot of interest in whether tea, particularly green tea, can increase energy expenditure and help with weight loss. </p>
<p>Two Dutch meta-analyses have examined the evidence in studies comparing catechin-plus-caffeine mixtures versus caffeine-only supplements on energy expenditure and fat oxidation (breaking down fat). They <a href="http://www.ncbi.nlm.nih.gov/pubmed/21366839">found that</a> compared to placebo and caffeine-only groups, people who had catechin-plus-caffeine mixtures were more likely to break down fat. </p>
<p>They also evaluated whether green tea could improve body weight regulation. Their <a href="http://www.ncbi.nlm.nih.gov/pubmed/19597519">meta-analysis found</a> the group consuming catechins from green tea had a 1.3 kilogram greater weight loss and were more likely to maintain this loss; although there were some differences based on ethnicity and usual caffeine intake.</p>
<h2>4. Tea and diabetes</h2>
<p>Last year, a pooled analysis of <a href="http://www.ncbi.nlm.nih.gov/pubmed/25052177">12 cohort studies</a> compared tea drinking with risk of type 2 diabetes. Researchers found that among those who drank three to four or more cups per day there was a 16% lower risk of developing type 2 diabetes, compared to those who usually drank just one or no cups of tea. </p>
<p>But when they drilled down into the studies, the lower risk was only found in women and those of Asian ethnicity. We need to keep in mind that associations found in cohort studies do not prove causation. </p>
<p>In a meta-analysis of <a href="http://www.ncbi.nlm.nih.gov/pubmed/25689396">ten randomised controlled trials</a> that lasted eight weeks or more, totalling 608 adults with type 2 diabetes, researchers found mixed results for the impact of drinking tea, or consuming various tea extracts, on blood markers of diabetes control. </p>
<p>While there were improvements in fasting blood insulin and waist circumference, there was no impact on other markers, including fasting blood glucose, LDL (bad) or HDL (good) cholesterol, body mass index or blood pressure. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/92522/original/image-20150820-7216-1z0v5pg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/92522/original/image-20150820-7216-1z0v5pg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/92522/original/image-20150820-7216-1z0v5pg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/92522/original/image-20150820-7216-1z0v5pg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/92522/original/image-20150820-7216-1z0v5pg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/92522/original/image-20150820-7216-1z0v5pg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/92522/original/image-20150820-7216-1z0v5pg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Both green tea and black tea can significantly reduce blood pressure.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/selma90/4394776418/">Selma Broeder/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Researchers are now <a href="http://www.ncbi.nlm.nih.gov/pubmed/25988132">focusing more closely on the phenolic components in tea</a> to try and develop compounds that could be used to prevent or manage type 2 diabetes. </p>
<h2>5. Tea and heart disease</h2>
<p>A Cochrane review evaluated 11 randomised controlled trials that ran for at least three months and were aimed at <a href="http://www.ncbi.nlm.nih.gov/pubmed/23780706">preventing heart disease</a> in healthy adults or those at high risk of heart disease. </p>
<p>Pooled results showed that both green tea and black tea significantly reduced blood pressure, with black tea lowering LDL-cholesterol and green tea lowering total cholesterol. The small number of studies to date though means these results need to be interpreted with caution, but they do look promising.</p>
<p>Meanwhile, for a <a href="http://www.ncbi.nlm.nih.gov/pubmed/25391016">host of other reasons</a> it seems that my grandmother was right: a good brew does more than than just warm you up (or cool you down). So put the kettle on, get out your best tea cups, create your own tea making ritual, gather the clan and relax with a cuppa.</p><img src="https://counter.theconversation.com/content/42419/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Clare Collins is affiliated with the Priority Research Centre in Physical Activity and Nutrition, the University of Newcastle, NSW and has received funding from a range of research grants including NHMRC, ARC, Hunter Medical Research Institute, Meat and Livestock Australia. She has consulted to SHINE Australia and Novo Nordisk.</span></em></p>Put the kettle on and relax with a cuppa; your brain, heart and waistline will thank you.Clare Collins, Professor in Nutrition and Dietetics, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/209782013-12-06T14:26:08Z2013-12-06T14:26:08ZA world without antibiotics would be a dark place indeed<figure><img src="https://images.theconversation.com/files/36812/original/5wbrz3jk-1386079127.jpg?ixlib=rb-1.1.0&rect=4%2C1%2C1017%2C720&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">This little thing changed the world.</span> <span class="attribution"><span class="source">Science Museum London</span></span></figcaption></figure><p>The introduction into clinical practice of antibiotics is arguably the most significant medical advance of the 20th century. Together with immunisation and better public sanitation, they’ve had a significant impact on life expectancy. They’ve also allowed us to control infection, transplant organs, care for premature babies, treat cancer and have safe surgery and obstetric care. </p>
<p>In other words, they really are miracle drugs. Yet the use, overuse and abuse of antibiotics has led to drug resistance. And we’ve been failing to protect this precious resource.</p>
<h2>A short history</h2>
<p><em>Homo sapiens</em> originated in Africa around 200,000 years ago. And we’ve had antibiotics for less than 70. In that time they’ve changed our relationship with bacteria, which have killed multitudes throughout recorded history.</p>
<p>The European population was halved by epidemics of smallpox, typhus and particularly plague – and the Black Death – between the 14th and 15th centuries; genital tract sepsis (due to streptococci) was the leading cause of maternal mortality in the UK in the 18th, 19th and early 20th centuries; and in 1812, Napoleon Bonaparte’s 665,000-strong army was reduced to 93,000 at <a href="http://entomology.montana.edu/historybug/napoleon/typhus_russia.htm">the gates of Moscow</a> by typhus (a louse-borne bacterial infection), before survivors struggled home with the bacterium to infect or kill another 2m. </p>
<p>A century ago, the three major causes of death in the US were tuberculosis, pneumonia and gastrointestinal infections.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/36530/original/68gzdksm-1385722111.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/36530/original/68gzdksm-1385722111.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/36530/original/68gzdksm-1385722111.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/36530/original/68gzdksm-1385722111.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/36530/original/68gzdksm-1385722111.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/36530/original/68gzdksm-1385722111.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/36530/original/68gzdksm-1385722111.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">
<figcaption>
<span class="caption">Starvation, desertion, typhus and suicide cost Napoleon’s army more than the battles with Russia.</span>
<span class="attribution"><span class="source">Zilverbat</span></span>
</figcaption>
</figure>
<p>The discovery and commercial production of penicillin G in 1941 launched a golden age of antibiotic discovery and since then, potentially fatal bacterial infections have become easily treatable. </p>
<h2>The fittest survive</h2>
<p>Our thinking about most drugs stops at the clinical effects on our bodies and their toxicity. With antibiotics we have to consider a third party – microbes – which are able to adapt to what we throw at them. Bacteria, like other species, follow a selective process where the fittest survive and antibiotics make it more likely that those that do survive will be drug resistant.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/36529/original/v9ng73wp-1385721793.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/36529/original/v9ng73wp-1385721793.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/36529/original/v9ng73wp-1385721793.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/36529/original/v9ng73wp-1385721793.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/36529/original/v9ng73wp-1385721793.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/36529/original/v9ng73wp-1385721793.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/36529/original/v9ng73wp-1385721793.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">Going with the flow; but we can’t be complacent.</span>
<span class="attribution"><span class="source">Rosemary Lester</span></span>
</figcaption>
</figure>
<p>This process is driven by the presence of antibiotics in patients and hospitals but also in the environment, for example when <a href="http://www.theguardian.com/society/2013/jun/11/is-rise-farm-antibiotic-use-threat-humans">traces of antibiotics</a> enter our food chain from the widespread use of antibiotics in farming. And it’s one of the few instances of human activity increasing, rather than decreasing, biological diversity.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/36528/original/ff2xxnzp-1385721703.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/36528/original/ff2xxnzp-1385721703.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=559&fit=crop&dpr=1 600w, https://images.theconversation.com/files/36528/original/ff2xxnzp-1385721703.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=559&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/36528/original/ff2xxnzp-1385721703.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=559&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/36528/original/ff2xxnzp-1385721703.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=702&fit=crop&dpr=1 754w, https://images.theconversation.com/files/36528/original/ff2xxnzp-1385721703.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=702&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/36528/original/ff2xxnzp-1385721703.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=702&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">New approvals - or not.</span>
<span class="attribution"><span class="source">Peter Taylor</span></span>
</figcaption>
</figure>
<p>We could well be on the losing side in our continual fight to outmanoeuvre resistant bacteria. Research and development of antibiotics is at the fringe of economic viability – considered uncompetitive compared with drugs for chronic conditions and “lifestyle products”. </p>
<p>Natural product research, which provided a starting point for the medicinal chemistry (as opposed to antibiotics that are derivatives of existing drugs), has also dwindled. A marine compound with antibacterial properties that <a href="https://theconversation.com/marine-compound-first-new-natural-antibiotic-in-decades-16433">was recently discovered</a> was the first in decades. </p>
<h2>What do we do now?</h2>
<p>We can better control how we use antibiotics; not overusing them and using them properly when we do – not finishing a course of drugs can leave bacteria better equipped to fend of another dose in the future.</p>
<p>There are now alternatives to conventional antibiotic chemotherapy. Phage therapy, which uses bacteria-eating viruses to selectively attack microbes, is <a href="https://theconversation.com/bacteria-eating-viruses-return-this-time-to-fight-superbugs-19301">making a comeback</a>. The technique was used before the advent of antibiotics and is now being reconsidered to fight antibiotic-resistant superbugs like MRSA (a meticillin-resistant strain of <em>staphylococcus aureusis</em>). </p>
<p>Rather than killing the invading bacterium, we could also disable it. The idea behind this is to modify the characteristic of the bacteria to make it “less fit” within the body in order that the immune system can eliminate the threat more readily.</p>
<h2>MRSA: going into battle with green tea</h2>
<p>Extracts of green tea contain a complex mixture of bioactive molecules that can improve blood flow and lower cholesterol. Its antioxidant effect can prevent cell damage and promote weight loss by increasing metabolic rate. </p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/36820/original/gczpqnhm-1386085381.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/36820/original/gczpqnhm-1386085381.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/36820/original/gczpqnhm-1386085381.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/36820/original/gczpqnhm-1386085381.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/36820/original/gczpqnhm-1386085381.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/36820/original/gczpqnhm-1386085381.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/36820/original/gczpqnhm-1386085381.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A new foe for MRSA?</span>
<span class="attribution"><span class="source">Vordichtung</span></span>
</figcaption>
</figure>
<p>While its antibacterial properties are weak, epicatechin gallate (ECg) and epigallocatechin gallate (EGCg), complex chemical constituents of green tea, can alter the properties of MRSA by interacting with its membrane. The insertion of ECg in particular can cause a separation of two proteins that are essential for methicillin resistance, which makes it susceptible to drugs. This opens up the possibility of using ECg alongside methicillin or other penicillins that have lost effectiveness.</p>
<p>We could also help the immune system to remove dangerous invaders. <a href="http://www.ncbi.nlm.nih.gov/pubmed/23798529">We found an enzyme</a> that strips away the capsule from <em>Escherichia coli</em> K1, one of the major causes of bacterial neonatal meningitis. Administration of very small amounts of the enzyme led to prevention and cure of the infection, provided it was given early enough.</p>
<p>Many different bacteria can cause septicaemia (infection of the blood) or sepsis (inflammation of the blood circulation) – a major infectious killer of newborn babies – when normally harmless bacteria gain entry to the blood through sites of colonisation on the skin or mucous surfaces during or shortly after birth. Those that get into the central nervous system to cause meningitis have a protective external capsule. Removing the protective capsule could, therefore, prevent these dangerous pathogens from causing infection. </p>
<p>But <em>E. coli</em> is only one of a number of bacteria that cause meningitis in newborns so the enzyme isn’t likely to be developed further. However, an ideal infection for this “capsule-stripping” approach is anthrax because a sole pathogen (<em>Bacillus anthracis</em>) producing an invariant, unique and essential capsule is responsible for the disease.</p>
<h2>Waking up</h2>
<p>We are at last waking up to the threat of resistance. There is now a high level of concern about the issue and a greater willingness to develop new ways to treat infections. In UK, the implementation of basic infection control measures has contributed to a reduction in incidence of MRSA and <em>C. difficile</em>. There is also, finally, a renewed interest in antibacterial drug discovery (driven by a commitment to more funding). </p>
<p>Antibiotics are the greatest drugs ever developed but we can’t continue to use them as we have without better management. And we now need to look at fundamentally new ways to counter the present threat of bacterial infections in our hospitals and, increasingly, in our communities.</p><img src="https://counter.theconversation.com/content/20978/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter 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>The introduction into clinical practice of antibiotics is arguably the most significant medical advance of the 20th century. Together with immunisation and better public sanitation, they’ve had a significant…Peter Taylor, Professor of Microbiology, UCLLicensed as Creative Commons – attribution, no derivatives.