tag:theconversation.com,2011:/us/topics/polyphenols-5699/articlesPolyphenols – The Conversation2023-12-13T13:07:58Ztag:theconversation.com,2011:article/2196492023-12-13T13:07:58Z2023-12-13T13:07:58ZDo you get a headache after a good red wine? This might be why<figure><img src="https://images.theconversation.com/files/564858/original/file-20231204-16-cef1p6.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6313%2C4338&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/es/image-photo/red-wine-pouring-bottle-into-glass-1707012739">Shutterstock</a></span></figcaption></figure><p>Headaches affect 16% of the world’s population <a href="https://doi.org/10.1186%2Fs10194-022-01402-2">on a daily basis</a>, and alcohol consumption is one of the main causes. </p>
<p>Although excessive consumption of any alcohol can cause headaches, <a href="https://doi.org/10.1007%2Fs11916-017-0642-8">red wine is the biggest culprit</a>: the headaches it causes <a href="https://doi.org/10.1007%2Fs10194-008-0006-1">come on more quickly</a> than those caused by white wine, beer or spirits. Another important difference is that red wine headaches can be caused by only a glass or two, while other drinks only cause problems once a large amount has been ingested. </p>
<p>When our livers metabolise ethanol (the chemical name for alcohol), it turns into <a href="https://en.wikipedia.org/wiki/Acetate">acetate</a> via a two step process. The first stage is the reaction that converts it into the to the highly toxic substance acetaldehyde. When we consume large amounts of alcohol, our bodies accumulate this chemical, which is twenty times more toxic than alcohol itself and <a href="http://monographs.iarc.fr/ENG/Monographs/vol71/mono71.pdf">highly carcinogenic</a>. This molecule is the main cause of the characteristic hangover symptoms: nausea, sweating, facial flushing and headaches.</p>
<p>The second step is the subsequent conversion of acetaldehyde to acetate by an enzyme called aldehyde dehydrogenase (ALDH). One particular type of this enzyme, <a href="https://es.wikipedia.org/wiki/ALDH2_(aldeh%C3%ADdo_dehydrogenase),%20is%20essential%20for%20removing%20poisonous%20acetaldehyde%20from%20the%20blood:%20it%20reduces%20its%20concentration%20by%20%5Bone%20thousand%20times%5D(https://doi.org/10.1111%2Facer.13904">ALDH2</a> from the levels it reaches in the liver.</p>
<p>An accumulation of acetaldehyde is responsible for the strong facial flushing effect which is seen in approximately 40% of people of Asian descent. This is because of a genetic predisposition to <a href="https://www.sciencedirect.com/science/article/abs/pii/S0140673694916292">producing a dysfunctional</a> variant of ALDH.</p>
<p>Certain drugs, such as <a href="https://en.wikipedia.org/wiki/Disulfiram">disulfiram</a>, can even be used to discourage alcohol consumption by inhibiting ALDH production, causing an accumulation of acetaldehyde. This leads directly to unpleasant hangover-like effects when alcohol is consumed, including headaches, without the prior intoxication.</p>
<h2>Headaches and wine</h2>
<p>Red wine headaches are often <a href="https://doi.org/10.1159%2F000237304">attributed to certain components in the drink</a>, such as amines, sulphites, or tannins, but so far no convincing evidence has been found to support these hypotheses, nor has an alternative explanation been proposed. However, the higher concentration of flavonoids in red wine – which is ten times higher than in white wine – makes them <a href="https://doi.org/10.1111%2Fhead.12365">the main suspects</a> for causing headaches.</p>
<p>A <a href="https://www.nature.com/articles/s41598-023-46203-y#:%7E:text=With%20the%20concurrent%20consumption%20of,needed%20to%20verify%20this%20hypothesis.">research paper</a> published on 20 November may well have identified the culprit: a flavonoid called quercetin, one of the <a href="https://www.sobreestoyaquello.com/2020/07/flavonoides-una-botica-en-la-nevera.html">9,000 recorded flavonoids</a> found in many foods such as cabbage, onions, capers, coriander, cranberries, green tea, apples and grapes.</p>
<p>When several flavonoids in wine known to block ALDH2 were tested, the most potent was <a href="https://pubchem.ncbi.nlm.nih.gov/compound/Querciturone">quercetin-3-glucuronide</a>. This compound inhibited ALDH2 almost three times more than any other. This suggests that when we drink red wine, the liver converts quercetin into quercetin-3-glucuronide, which causes us to accumulate acetaldehyde.</p>
<p>It is important to note that quercetin alone does not cause headaches. Onions, for example, contain much more quercetin than wine, but few people complain of headaches after eating them: alcohol and quercetin act together to cause a buildup of poisonous acetaldehyde.</p>
<h2>The better the wine, the stronger the headache</h2>
<p>If the combination of quercetin and ethanol causes headaches, why is it that some people can drink red wine without any effect, while others experience headaches when they drink it? There are several potential factors that may explain this.</p>
<p>Although <a href="https://www.nature.com/articles/cas-redirect/1:CAS:528:DC%2BD1cXhsVyltLjL">red wine has a significantly higher quercetin content</a> than white, concentrations can vary considerably between red wines of different types and origins. This has been found in, among others, <a href="https://www.ajevonline.org/content/56/2/139">Spanish wines</a>.</p>
<p>Different <a href="https://doi.org/10.1021%2Fjf9909757">winemaking processes</a>, such as fermentation and ageing, also affect the chemical content that ends up in a bottle. One well-known factor is the <a href="https://doi.org/10.5344%2Fajev.2002.53.3.171">amount of sun exposure</a> that grapes receive. In vineyards that produce high quality wines, practices such as trellising, vine thinning and defoliation (removing leaves) cause the grapes to receive more sunlight and accumulate more quercetin than conventional vineyards that produce cheaper wines.</p>
<p>A study showed that the total flavonoid content was four times higher in <a href="https://www.ajevonline.org/content/50/1/91">“ultra-premium”</a> wines than in lower quality ones. This suggests that one way to avoid headaches might be, unexpectedly, to buy cheaper wine.</p>
<p>Lastly, it is possible that the enzymes that digest quercetin differ from one person to another. Acetaldehyde may also trigger headaches only in genetically predisposed individuals, as is the case in a higher proportion of Asian people.</p><img src="https://counter.theconversation.com/content/219649/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Manuel Peinado Lorca is a member of the PSOE Federal Biodiversity Group.</span></em></p>Researchers have linked red wine headaches to the chemical compound quercetin, which is much more present in high quality wines.Manuel Peinado Lorca, Catedrático emérito. Director del Real Jardín Botánico de la Universidad de Alcalá, Universidad de AlcaláLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2154002023-10-26T08:10:33Z2023-10-26T08:10:33ZA century of research shows eating these compounds can help protect against heart disease and Alzheimer’s<figure><img src="https://images.theconversation.com/files/555869/original/file-20231025-21-skp7lj.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C2695%2C1786&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/es/image-photo/freshly-harvested-artichokes-garden-vegetables-healthy-722286292">Valentina G / Shutterstock</a></span></figcaption></figure><p>Perhaps the word “polyphenol” means little to you, but they certainly mean a lot to your health. Polyphenols are a family of chemical compounds present in foods of vegetable origin and seaweed that have been studied over the last century for their health effects.</p>
<h2>The beginning: taste and technology</h2>
<p>Polyphenols were used for their technological properties long before they were named. Uses <a href="https://www.fs.usda.gov/wildflowers/ethnobotany/tannins.shtml#:%7E:text=The%20word%20tannin%20comes%20from,convert%20animal%20hides%20into%20leather.">date back to Ancient Egypt</a>, when chemicals in the bark of certain trees were found to bind with the collagen in animal skin, making leather. Indeed, this process came to be known as tanning for its ability to impart a deep colour, and when the compounds involved – a class of polyphenols – were identified, they were named “tannins”.</p>
<p>This ability of some polyphenols to bind with proteins is the same as what causes dryness in your mouth when drinking tea or wine. This sensation, known as astringency, comes from the interaction between tannins and salivary proteins in your mouth.</p>
<h2>Natural antioxidants</h2>
<p>In the 20th century, polyphenol uses were found to go beyond the merely sensory or technological. Polyphenols are natural antioxidants, which means they can counteract <a href="https://www.medicalnewstoday.com/articles/318652">harmful free radicals</a> in the body. These are particles known to cause common yet harmful conditions such as <a href="https://en.wikipedia.org/wiki/Atherosclerosis">atherosclerosis</a>.</p>
<p>In plants, polyphenols play the role of protecting against environmental hazards such as drought and UV radiation. When animals eat a plant, the polyphenols’ antioxidant properties then in turn counteract free radicals in the animal’s body. This antioxidant effect from foods is important for human health, since many diseases (cardiovascular diseases, cancer, type 2 diabetes, etc.) are characterised partly by an imbalance of free radicals, also known as <a href="https://en.wikipedia.org/wiki/Oxidative_stress">high oxidative stress</a>.</p>
<p>This generated widespread interest in polyphenols due to their potential health effects, and many studies were performed to test their antioxidant properties. However, the antioxidant effects which were clearly observable under laboratory conditions <a href="https://www.tandfonline.com/doi/full/10.3109/10715760903407293">were much lower in human studies</a>. This raised the question of whether polyphenols had beneficial health effects on the human body.</p>
<h2>Much more than antioxidants</h2>
<p>Over the last two decades, a few key pieces of the polyphenol puzzle have been added. This happened when several studies found that, once consumed, polyphenols are transformed by our bodies, <a href="https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/colonic-metabolites-of-berry-polyphenols-the-missing-link-to-biological-activity/512CCBFF39C3282C3E605099D9E459B0">mostly by our gut microbiota</a>. What means that the compounds circulating in our bodies – known as “metabolites” once ingested and changed by our bodies – are quite different from the original polyphenols in the foods we eat, and they are present at lower concentrations after ingestion. For this reason, previous laboratory studies were partially inaccurate because they tested different forms and doses of polyphenols to those present in our bodies after eating foods which contained them.</p>
<p>But the good news was that, besides their antioxidant activity, polyphenols were also discovered to have many more properties. Their ability to interact with proteins – the same ability that tans leather and flavours wine – is also present inside our body. This means polyphenols have other positive effects on our bodies, such as <a href="https://www.mdpi.com/2073-4409/10/6/1474">promoting insulin signaling</a> or <a href="https://www.sciencedirect.com/science/article/pii/S0955286321000541?pes=vor">decreasing inflammation</a>. Over 8,000 different polyphenolic compounds have been identified in plants, which helps to explain why they interact with so many different proteins in our bodies and have so many different effects on our health.</p>
<p>Moreover, as mentioned, polyphenols are transformed by our gut microbiota to create useful metabolites. These metabolites are also, interestingly, food for many beneficial species of bacteria, so <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/mnfr.201900952">consuming polyphenols may also be associated with a healthier overall gut microbiota profile</a>.</p>
<p>The combined effect of all these properties means that polyphenols help to lower the risk of cardiovascular diseases and type 2 diabetes. This has not only been observed in test tubes, but also in <a href="https://www.sciencedirect.com/science/article/pii/S0002916522029148?pes=vor">multiple clinical trials in different populations</a>. </p>
<h2>The gut-brain axis</h2>
<p>Dietary polyphenols, it seems, still have more to show us, as we have seen over the last decade. Although much more research is still needed, some promising evidence shows that polyphenols may also help our <a href="https://www.sciencedirect.com/science/article/pii/S0939475309001379?pes=vor">cognitive function</a> and <a href="https://www.sciencedirect.com/science/article/pii/S1087079223001004">improve our sleep</a>. The mechanism for this is not easy to understand, as we typically think of our brains as being protected by the <a href="https://en.wikipedia.org/wiki/Blood%E2%80%93brain_barrier">blood-brain barrier</a>, which prevents many substances from entering our brains. There is, however, something known as the <a href="https://en.wikipedia.org/wiki/Gut%E2%80%93brain_axis">gut-brain axis</a>.</p>
<p>It has been shown that some of the previously mentioned polyphenol metabolites, which are later absorbed by our digestive systems, <a href="https://www.mdpi.com/2072-6643/11/11/2678">can cross the blood-brain barrier</a>. This means that they can enter the brain and have effects such as reducing inflammation in the brain, something <a href="https://theconversation.com/alzheimers-exercise-may-reduce-brain-inflammation-helping-to-protect-us-from-the-disease-172258">associated with many neurological diseases</a>.</p>
<p>Also, the previously mentioned effects that polyphenols have on the bacteria living in our colon are capable of affecting our mental health. Recent research has shown that our brains and intestines are connected by various signals and receptors.</p>
<p>This means we can link gut health to mental health by identifying, for example, the “<a href="https://www.sciencedirect.com/science/article/pii/S0261561418325433?pes=vor">melancholic microbes</a>” that are associated with depression.</p>
<p>Polyphenols may, therefore, affect multiple processes in our brains because of their derived metabolites and how they modify our gut microbiota. This new field of research is very much in its infancy, with much left to be explored.</p>
<h2>The future for polyphenol research</h2>
<p>We have come a long way in our knowledge of dietary polyphenols over the last century. There are still many aspects to be studied: <a href="https://link.springer.com/article/10.1007/s00394-019-02095-1?utm_source=getftr&utm_medium=getftr&utm_campaign=getftr_pilot">why not all individuals respond to polyphenols in the same way</a>; <a href="https://www.cambridge.org/core/journals/nutrition-research-reviews/article/nonextractable-polyphenols-a-major-dietary-antioxidant-occurrence-metabolic-fate-and-health-effects/AD8E3C7180353F9F2DDE850F2BD6144F">the understudied field of macromolecular polyphenols</a>; <a href="https://www.sciencedirect.com/science/article/pii/S0963996921005548?pes=vor">how to develop high quality intervention studies</a>, and many others. Hopefully, we will have answers to some of these questions in years to come.</p>
<p>In the meantime, one thing we can be certain of is that increasing your daily intake of polyphenols through any food of plant origin will be beneficial for your health. So why not start today?</p><img src="https://counter.theconversation.com/content/215400/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jara Pérez Jiménez ha recibido, como investigadora principal, fondos en los últimos cinco años del Ministerio de Ciencia e Innovación (España) y la Comisión para la Uva de la Mesa de California.</span></em></p><p class="fine-print"><em><span>Cara Frankenfeld is currently a co-investigator on a United States Department of Agriculture (USDA) funded grant that is evaluating apple polyphenols (Grant number 2022-67017-41032, “Gut Microbial Metabolites Of Apple Polyphenols: Interrogating Individual Differences To Establish Functional Biomarker Utility”)</span></em></p><p class="fine-print"><em><span>Margaret Slavin has received, as principal investigator, funding over the past five years from the United States Department of Agriculture, George Mason University, and the American Egg Board/Egg Nutrition Center.</span></em></p><p class="fine-print"><em><span>Léopold L Fezeu Kamedjie y Valentina A. Andreeva no reciben salarios, ni ejercen labores de consultoría, ni poseen acciones, ni reciben financiación de ninguna compañía u organización que pueda obtener beneficio de este artículo, y han declarado carecer de vínculos relevantes más allá del puesto académico citado.</span></em></p>They’re in your wine, tea and all the plants we eat. Polyphenols can benefit our health in many different ways, some of which are still yet to be discovered.Jara Pérez Jiménez, Doctora en Ciencia y Tecnología de los Alimentos. Científico Titular en el ICTAN-CSIC. Centro de Investigación Biomédica en Red en Diabetes y Enfermedades Metabólicas, Instituto de Ciencia y Tecnología de Alimentos y Nutrición (ICTAN - CSIC)Cara Frankenfeld, Faculty Scientist, MaineHealth Institute for Research (NOT University of Puget Sound), University of Puget SoundLéopold L Fezeu Kamedjie, Maître de conférences, Université Sorbonne Paris NordMargaret Slavin, Associate Professor, Nutrition and Food Science, University of MarylandValentina A. Andreeva, research scientist, Université Sorbonne Paris NordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2013632023-06-07T17:44:04Z2023-06-07T17:44:04ZThe invisible effects of human activity on nature<figure><img src="https://images.theconversation.com/files/515229/original/file-20230314-2080-67ctev.JPG?ixlib=rb-1.1.0&rect=27%2C0%2C4573%2C3414&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Lake surrounding a mining site in Northern Québec.</span> <span class="attribution"><span class="source">(Maxime Thomas)</span></span></figcaption></figure><p>Discussions at the recent COP15 biodiversity conference in Montréal highlighted once again the <a href="https://www.unep.org/news-and-stories/story/cop15-ends-landmark-biodiversity-agreement">impact of human activities on wildlife</a>. Many species are <a href="https://doi.org/10.1016/j.scitotenv.2022.158038">forced to migrate</a>, <a href="https://www.un.org/sustainabledevelopment/blog/2019/05/nature-decline-unprecedented-report/">are seeing their populations declining, or worse, are finding themselves on the brink of extinction</a>. For example, the populations of woodland caribou (<em>Rangifer tarandus</em>) are declining <a href="https://www.canada.ca/en/environment-climate-change/services/species-risk-public-registry/cosewic-assessments-status-reports/caribou-specific-populations-2014/part-2.html">as a result of the damage of logging on their habitat</a>.</p>
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<p><strong>This article is part of <em>La Conversation Canada’s</em> series <a href="https://theconversation.com/ca-fr/topics/foret-boreale-138017">The boreal forest: A thousand secrets, a thousand dangers</a></strong></p>
<p><br><em>La Conversation Canada invites you to take a virtual walk in the heart of the boreal forest. In this series, our experts focus on management and sustainable development issues, natural disturbances, the ecology of terrestrial wildlife and aquatic ecosystems, northern agriculture and the cultural and economic importance of the boreal forest for Indigenous peoples. We hope you have a pleasant — and informative — walk through the forest!</em></p>
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<p>However, the consequences of human activities are not always visible. Before being driven into decline, <a href="https://doi.org/10.1111/j.1365-294X.2007.03484.x">some species are able to adapt to disturbances in their habitat</a> — but only up to a point. This is particularly true of plants, which cannot move to avoid disturbances in their environment, and as a result, are necessarily subjected to the impact of human activities. </p>
<p>Our work in forest ecology at the Université du Québec en Abitibi-Témiscamingue (UQAT) is allowing us to demonstrate the invisible effects of human activities on boreal flora. </p>
<h2>Adapting, but not without consequences…</h2>
<p>The capacity of plants to adapt is actually a double-edged sword. On the one hand, it makes it possible to put off a decline in their populations due to human activity. On the other hand, it can lead researchers to underestimate the consequences that human activities are having on the environment.</p>
<p>When a species adapts to disturbances in its habitat, its nutritional and medicinal properties may change. This is because plants respond to these disturbances by producing chemical compounds. <a href="https://www.canada.ca/en/health-canada/services/food-nutrition/reports-publications/food-safety/glycoalkaloids-foods.html">Some of these compounds can have harmful effects on the health of the humans who consume them</a>. In the boreal forest, this can take the form of toxins in the seeds of <a href="https://m.espacepourlavie.ca/en/biodome-flora/ground-hemlock">ground hemlock</a> and the leaves of <a href="https://espacepourlavie.ca/en/biodome-flora/sheep-laurel">sheep laurel</a>.</p>
<p><a href="https://doi.org/10.1016/j.jarmap.2018.11.004">However, other compounds are sought after for their benefits to human health</a>. For example, antioxidants, which are highly valued in food for their health benefits, have the primary function of <a href="https://doi.org/10.1007/978-981-10-5254-5_1">protecting plants from sunlight and various pollutants</a>. One example of these is <a href="http://www5.agr.gc.ca/resources/prod/doc/misb/fb-ba/nutra/pdf/polyphenols_eng.pdf">polyphenols, found in some boreal forest berries, such as blueberries and cranberries</a>.</p>
<h2>…especially for Indigenous communities</h2>
<p>People whose diet consists of wild plants are particularly affected by the changes in chemical composition that take place when plants are adapting to disturbances in their habitat. This is the case for Indigenous communities, who <a href="https://mackiki.uqat.ca/index.php">gather dozens of species in their traditional territories for food and medicinal purposes</a>.</p>
<p>To study how the adaptation of plants affects their chemical properties, we conducted a project in partnership with three Indigenous communities in northwestern Québec. Members of the communities suggested that we work on <a href="https://espacepourlavie.ca/en/biodome-flora/labrador-tea">Labrador tea</a> because of its cultural importance and medicinal uses. Labrador tea leaves are <a href="https://doi.org/10.1186/1746-4269-8-7">used in infusion to treat many ailments, such as osteoarthritis, diabetes or kidney problems</a>. <a href="https://doi.org/10.1016/j.jep.2015.12.021">The leaves contain antioxidants</a> called flavonoids in <a href="https://doi.org/10.1002/pca.1203">large quantities</a>.</p>
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<img alt="Labrador tea plants in the forest" src="https://images.theconversation.com/files/508419/original/file-20230206-21-5q16bp.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/508419/original/file-20230206-21-5q16bp.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/508419/original/file-20230206-21-5q16bp.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/508419/original/file-20230206-21-5q16bp.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/508419/original/file-20230206-21-5q16bp.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/508419/original/file-20230206-21-5q16bp.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/508419/original/file-20230206-21-5q16bp.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">
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<span class="caption">Labrador tea is an understory plant, 30 to 120 centimetres tall. It is found in moist forest environments in Canada and the northern United States.</span>
<span class="attribution"><span class="source">(Maxime Thomas), provided by the author</span></span>
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<h2>Disturbances have different effects</h2>
<p>The members of the communities we met expressed their concerns about the consequences of two human disturbances on their territories: hydroelectric transmission lines and the exploitation of mining sites. The hydroelectric transmission lines create an artificial opening in the forest, which overexposes the plants to the sun. Mining sites <a href="https://doi.org/10.1007/s11157-017-9453-y">generate heavy metal pollution</a>. In both cases, <a href="https://doi.org/10.1155/2013/162750">Labrador tea plants adapt by producing flavonoids</a>.</p>
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<img alt="Labrador tea plants under a hydroelectric transmission line" src="https://images.theconversation.com/files/508420/original/file-20230206-21-nh0rng.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/508420/original/file-20230206-21-nh0rng.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/508420/original/file-20230206-21-nh0rng.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/508420/original/file-20230206-21-nh0rng.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/508420/original/file-20230206-21-nh0rng.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/508420/original/file-20230206-21-nh0rng.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/508420/original/file-20230206-21-nh0rng.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">Plants under hydroelectric lines are much more exposed to the sun than in the surrounding forest.</span>
<span class="attribution"><span class="source">(Maxime Thomas), provided by the author</span></span>
</figcaption>
</figure>
<p>After analyzing the chemical composition of Labrador tea plants sampled from the territories of three Indigenous communities, we found contrasting effects of human disturbances. On the one hand, plants under hydroelectric transmission lines produced more flavonoids to protect themselves from the sun. On the other hand, plants near mining sites produced less flavonoids, due to a degradation of their metabolism by heavy metals.</p>
<p>However, before jumping to the conclusion that plants under hydroelectric transmission lines are healthier, other factors need to be considered. For example, chemicals potentially harmful to human health, such as <a href="https://doi.org/10.1093/annhyg/meh106">triclopyr</a> or <a href="https://www.cbc.ca/news/canada/new-brunswick/transmission-line-herbicide-1.3221418">glyphosate</a>, may be used to maintain hydroelectric transmission lines.</p>
<p>The flavonoid analysis only tells part of the story, so further analysis of factors such as the content of plant pollutants would be needed to gain a full picture of the effects of human disturbance on plant properties.</p>
<p>Biodiversity is important for the functioning of ecosystems, and also for the services it provides to humans. Indigenous peoples <a href="https://e360.yale.edu/features/native-knowledge-what-ecologists-are-learning-from-indigenous-people">have extensive knowledge of plants and their environment</a>, which should be valued. </p>
<p>Human disturbances affect the plants, the benefits they provide and the Indigenous knowledge that depends on them.</p><img src="https://counter.theconversation.com/content/201363/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Les auteurs ne travaillent pas, ne conseillent pas, ne possèdent pas de parts, ne reçoivent pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'ont déclaré aucune autre affiliation que leur organisme de recherche.</span></em></p>Human activities can affect plants and have consequences for the human populations that consume them.Maxime Thomas, Doctorant en sciences de l'environnement, Université du Québec en Abitibi-Témiscamingue (UQAT)Hugo Asselin, Professeur titulaire, Université du Québec en Abitibi-Témiscamingue (UQAT)Mebarek Lamara, Professeur, Université du Québec en Abitibi-Témiscamingue (UQAT)Nicole Fenton, Professeure, écologie végétale/Professor, plant ecology, Université du Québec en Abitibi-Témiscamingue (UQAT)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1824862022-05-09T16:46:08Z2022-05-09T16:46:08ZUnlocking the secrets of maple syrup, one molecule at a time<figure><img src="https://images.theconversation.com/files/461824/original/file-20220506-18-5xkyt0.jpg?ixlib=rb-1.1.0&rect=42%2C67%2C5565%2C3665&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Maple syrup contains bioactive molecules whose benefits go far beyond the simple pleasure of a sweet treat.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Nature conceals a phenomenal number of molecules as varied as they are imperceptible. The plant kingdom is particularly chemically complex. </p>
<p>Plant evolution has taken place over hundreds of millions of years, giving plants the ability to respond to various environmental stresses and threats. Several species have developed an arsenal of molecules allowing them to adapt and to protect themselves against competitors and predators. Some of these molecules also have health benefits for the animals that consume them.</p>
<p>Advances in food science over recent decades show that many plants provide a wealth of benefits that, until recently, were largely unknown. Taken together, these discoveries support more than ever the fact that a varied and balanced diet offers benefits that go beyond simple energy intake. As a result, consumer demand for plant-based foods with higher nutritional value is currently at record highs. This trend has yet to run out of steam. At the same time, sugary foods are increasingly marginalized and categorized as unhealthy. </p>
<p>But in the realm of sweets, maple syrup is finally claiming its rightful place! Maple syrup is no longer only the jewel of Canada’s culinary heritage, its nutritional reputation is also improving. Because of its unique natural source and manufacturing process, maple syrup contains bioactive molecules whose benefits go far beyond the simple pleasure of a sweet treat.</p>
<h2>Benefits that go beyond energy intake</h2>
<p>In eastern Canada, March and April herald maple sugaring time. Higher temperatures cause <a href="https://doi.org/10.1139/b03-079">maple trees to convert their energy reserves (stored as complex carbohydrates) into soluble sugars</a> that mix with the water in the tree. Producers collect the flavoured sap by drilling holes in the trees.</p>
<figure class="align-center ">
<img alt="Maple syrop in a bottle on a wooden table." src="https://images.theconversation.com/files/459344/original/file-20220422-18-zenfms.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/459344/original/file-20220422-18-zenfms.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=461&fit=crop&dpr=1 600w, https://images.theconversation.com/files/459344/original/file-20220422-18-zenfms.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=461&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/459344/original/file-20220422-18-zenfms.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=461&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/459344/original/file-20220422-18-zenfms.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=580&fit=crop&dpr=1 754w, https://images.theconversation.com/files/459344/original/file-20220422-18-zenfms.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=580&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/459344/original/file-20220422-18-zenfms.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=580&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Maple syrup, Canada’s liquid gold, contains bioactive molecules whose benefits go far beyond the simple pleasure of sweet treats.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>The sap is approximately 98 per cent water, and it takes about 40 litres of this maple water to generate one litre of syrup. During this concentration process, the levels of sugars and nutrients increase substantially. The high temperature that comes from boiling the sap causes a series of chemical reactions as the excess water evaporates.</p>
<p>The main components of maple syrup are sucrose and water. Glucose and fructose also contribute to the sweet taste of the syrup, but to a lesser extent. While these three simple carbohydrates are sources of energy, maple syrup is also an excellent source of manganese and riboflavin (vitamin B2), as well as a significant source of other <a href="http://www.internationalmaplesyrupinstitute.com/uploads/7/0/9/2/7092109/__nutrition_and_health_benefits_of_pure_maple_syrup.pdf">vitamins and minerals (zinc, potassium, calcium and magnesium)</a>.</p>
<p>The composition of phenolic compounds of maple syrup is even more impressive. Since the beginning of the 20th century, <a href="https://doi.org/10.1016/j.foodchem.2021.131817">researchers have discovered more than 100 of these molecules in plants</a>. Many of them are antioxidants, and contribute to the taste, aroma, colour of maple syrup. They are primarily responsible for its recent superfood status. </p>
<p>One of the most promising phenolic components (in terms of biological activities) is a molecule found nowhere other than in Canada’s most famous product.</p>
<h2>A molecule worthy of national pride</h2>
<p>Quebecol – named after the province where <a href="https://www.worldatlas.com/articles/the-world-s-top-producers-of-maple-syrup.html">the majority of the world’s maple syrup production originates</a> – is a polyphenolic compound (carrying several phenol groups), <a href="https://doi.org/10.1016/j.jff.2011.02.004">first isolated in 2011 by a team led by Navindra Seeram at the University of Rhode Island</a>. This compound is so exclusive to maple syrup that it is not even present in raw maple sap! Rather, current knowledge suggests that it is the product of chemical reactions that occur during the transformation of sap into syrup.</p>
<figure class="align-center ">
<img alt="Molecular structure of quebecol" src="https://images.theconversation.com/files/461819/original/file-20220506-22-8urv2e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/461819/original/file-20220506-22-8urv2e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=434&fit=crop&dpr=1 600w, https://images.theconversation.com/files/461819/original/file-20220506-22-8urv2e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=434&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/461819/original/file-20220506-22-8urv2e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=434&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/461819/original/file-20220506-22-8urv2e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=546&fit=crop&dpr=1 754w, https://images.theconversation.com/files/461819/original/file-20220506-22-8urv2e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=546&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/461819/original/file-20220506-22-8urv2e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=546&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Structure of quebecol [2,2,3-tris(4-hydroxy-2-methoxyphenyl)propan-1-ol], a molecule exclusively found in maple syrup whose secrets are just beginning to be revealed.</span>
<span class="attribution"><span class="source">(Sébastien Cardinal)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Early laboratory studies, <a href="https://patents.google.com/patent/WO2012167364A1/en">quebecol inhibited cell proliferation of breast cancer and colon cancer cells</a>. But only a small quantity of polyphenol could be isolated, and these tests didn’t go beyond the preliminary stage. More than 20 litres of maple syrup is needed to isolate less than a milligram of quebecol.</p>
<p>Judging that this syrup would be of better use in kitchens than in laboratories, Normand Voyer, a chemistry professor at Laval University, and I (Sébastien) decided to tackle this supply problem. When I was a PhD candidate in 2013, <a href="https://doi.org/10.1016/j.tetlet.2013.07.048">we published a chemical synthesis pathway to build this natural molecule much more efficiently in the laboratory from simple precursors</a>. As this work made quebecol much more accessible, the investigation of its properties continued and deepened.</p>
<p>In particular, Normand Voyer, Daniel Grenier and their teams, in the faculty of dentistry of Laval University, published two studies <a href="https://doi.org/10.1016/j.bmc.2017.01.050">demonstrating the molecule’s anti-inflammatory properties</a>. This research also made it possible to <a href="https://doi.org/10.1016/j.bmcl.2015.11.096">determine the active portion of the molecular structure</a>.</p>
<h2>A compound still relevant today</h2>
<p>Our 2021 study showed that quebecol’s <a href="https://doi.org/10.1021/acsomega.1c03312">anti-inflammatory properties may benefit periodontal disease</a>, a severe infection of the gums. We expect additional studies to be published this year, including one showing that quebecol might help with the treatment of a skin condition.</p>
<p>Although the evidence of biological activity of quebecol has been limited to in vitro experiments, these results certainly encourage further study in more complex systems. It is also important to note that the results came from using the isolated pure molecule. </p>
<p>These studies do not propose using pure maple syrup as a medicinal agent against different conditions. Given the quantity of maple syrup one would have to eat to get the necessary dose of quebecol, the harms from a massive ingestion of sugar would obscure any benefit. It’s also difficult to establish the distribution of the molecule in the human body when it’s taken orally.</p>
<p>In any case, these discoveries once again highlight the uniqueness of maple syrup and help to strengthen its status as a singular food. Perhaps it contains other equally promising molecules just waiting to be discovered. Let’s bet that this local treasure has not yet revealed all its secrets!</p><img src="https://counter.theconversation.com/content/182486/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Les auteurs ne travaillent pas, ne conseillent pas, ne possèdent pas de parts, ne reçoivent pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'ont déclaré aucune autre affiliation que leur organisme de recherche.</span></em></p>Apart from being a jewel of Canada’s culinary heritage, maple syrup has a complex chemical constitution.Sébastien Cardinal, Professeur en chimie organique, Université du Québec à Rimouski (UQAR)Amy McMackin, Candidate MSc Chimie, Université du Québec à Rimouski (UQAR)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1766372022-02-14T13:36:58Z2022-02-14T13:36:58ZExtra virgin olive oil: why it’s healthier than other cooking oils<figure><img src="https://images.theconversation.com/files/446280/original/file-20220214-25-1p2kbo4.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4288%2C2848&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The benefits of extra virgin olive oil might just make it worth the extra cost.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/typical-extra-virgin-olive-oil-sicilian-163003097">Bruno D Andrea/ Shutterstock</a></span></figcaption></figure><p>It’s common advice for people watching their waistlines or looking to eat healthier to beware of the amount of oil they use while cooking. But that doesn’t mean we should cut oil entirely from our diet. This is because extra virgin olive oil in particular can have many benefits for our health. </p>
<p>Numerous studies have shown that consuming olive oil – in particular extra virgin olive oil (EVOO) – can have many different benefits for our health. For example, the Spanish Predimed study (the largest randomised control trial ever conducted on the Mediterranean diet) showed that women who ate a Mediterranean diet supplemented with extra virgin olive oil had a <a href="https://pubmed.ncbi.nlm.nih.gov/26365989/">62% lower risk</a> of breast cancer compared to women who were advised to eat a low fat diet. </p>
<p>Experts who have since examined multiple scientific studies looking at the Mediterranean diet and its effect on chronic diseases conclude that a primary reason the diet protects against breast cancer is <a href="https://pubmed.ncbi.nlm.nih.gov/29804831/">because of EVOO</a>. There’s also evidence that EVOO may protect against <a href="https://pubmed.ncbi.nlm.nih.gov/28394365/">type 2 diabetes</a> and possibly even <a href="https://pubmed.ncbi.nlm.nih.gov/34895363/">Alzheimer’s disease</a>. </p>
<p>So what makes extra virgin olive oil better for us than other types of cooking oil? The answer lies in its composition.</p>
<p>Alongside its fat, EVOO also contains many natural substances, such as polyphenols. Polyphenols occur naturally in plants, and have been linked to many health benefits, such as reducing the risk of <a href="https://pubmed.ncbi.nlm.nih.gov/23953879/">cardiovascular disease</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/22475317/">cognitive disorders</a>. Studies also seem to show that a major reason why EVOO is beneficial to our health is because of the polyphenols it contains. Polyphenols are thought to have <a href="https://pubmed.ncbi.nlm.nih.gov/34577008/">many benefits</a> in the body, such as improving the gut microbiome. </p>
<p>Research shows that the polyphenols in extra virgin olive oil are linked with lower risk of cardiovascular disease. In fact, when researchers stripped EVOO of its polyphenols, they found it <a href="https://pubmed.ncbi.nlm.nih.gov/16954359/">didn’t protect</a> the heart from disease as well. It’s believed that one of the benefits of EVOO on heart health is because its polyphenols prevent <a href="https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa.2011.2033">cholesterol becoming oxidised</a>. It’s when cholesterol reacts with oxygen and is oxidised that it damages blood vessels. </p>
<figure class="align-center ">
<img alt="Freshly pressed olive oil pours out of a spigot into a large metal container." src="https://images.theconversation.com/files/446272/original/file-20220214-23-e6hudj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446272/original/file-20220214-23-e6hudj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446272/original/file-20220214-23-e6hudj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446272/original/file-20220214-23-e6hudj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446272/original/file-20220214-23-e6hudj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446272/original/file-20220214-23-e6hudj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446272/original/file-20220214-23-e6hudj.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 simple production method helps EVOO retain polyphenols.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/extraction-oil-olives-modern-farm-1050735893">pointbreak/ Shutterstock</a></span>
</figcaption>
</figure>
<p>The reason EVOO contains such high levels of polyphenols is because it’s produced by simply crushing olives. More processed versions of olive oil – such as light olive oil or spreads – don’t contain as many of these polyphenols. This is because to create these requires more processing, resulting in most of the polyphenols being lost.</p>
<h2>Other cooking oils</h2>
<p>Most other cooking oils, such as sunflower oil or rapeseed oil, are made from seeds. Seeds are very difficult to extract oil from, so they need to be heated and the oil extracted with solvents. This means that most of the polyphenols in seeds are lost during production.</p>
<p>It’s sometimes claimed that <a href="https://pubmed.ncbi.nlm.nih.gov/25322908/">rapeseed oil</a> (also known as canola oil or vegetable oil) is a healthy alternative to EVOO. While there is some evidence that <a href="https://pubmed.ncbi.nlm.nih.gov/25322908/">raw rapeseed oil</a> (meaning it hasn’t been heated during cooking) can temporarily lower cholesterol levels, there’s currently no evidence it can lower risk of developing diseases associated with high cholesterol – such as heart disease. </p>
<p>Of course, most of us use oils for cooking. But when an oil is heated at too high a temperature it reacts with the oxygen in the air, causing the fat in the oil to break down. This can lead to the formation of harmful substances that <a href="https://link.springer.com/article/10.1007/s11746-013-2242-z">irritate the eyes</a> and even <a href="https://pubmed.ncbi.nlm.nih.gov/15291498/">carcinogens</a>. Rapeseed oil is particularly prone to this process - called oxidation - especially when used repeatedly for deep fat frying. </p>
<p>Polyphenols help prevent fats from oxidising and so EVOO <a href="https://pubmed.ncbi.nlm.nih.gov/25322908/">remains stable</a> even when used at the temperatures needed to shallow fry foods. Because rapeseed oil and other oils such as sunflower oil contain lower levels of polyphenols, the fats aren’t so well protected from breaking down during cooking. </p>
<p>Another important reason for EVOO’s stability is that its main type of fat is monounsaturated fat. This is both a healthy fat and quite resistant to oxidation. Monounsaturated fat is also the main type of fat in rapeseed oil. But unlike EVOO, rapeseed oil also contains quite high levels of a polyunsaturated fat called alpha-linolenic acid. This is not very stable and is another reason why heating rapeseed oil too much is not a good idea. </p>
<p>Coconut oil is often advocated as a healthy oil to use. But coconut oil contains high levels of saturated fats, which can <a href="https://pubmed.ncbi.nlm.nih.gov/31928080/">significantly increase</a> low-density lipoprotein (or LDL) cholesterol levels (sometimes know as the “bad” cholesterol). Elevated LDL-cholesterol is linked to cardiovascular disease, and there’s evidence that the saturated fat in coconut oil <a href="https://pubmed.ncbi.nlm.nih.gov/27881409/">increases the risk of heart disease</a>.</p>
<p>One of the important messages about EVOO is that it seems to be far more effective when eaten as part of a Mediterranean diet – which is typically high in vegetables, fruits, legumes, grains, fish and olive oil. This is probably because extra virgin olive oil and its beneficial polyphenols <a href="https://pubmed.ncbi.nlm.nih.gov/30487558/">interact with other foods</a> incuding the vegetables eaten as part of this diet. The Mediterranean diet is linked with lower risk of <a href="https://pubmed.ncbi.nlm.nih.gov/34423871/">many chronic diseases</a> including cancer, cardiovascular disease and Alzheimer’s disease. This might just make the extra price of EVOO worth paying for.</p><img src="https://counter.theconversation.com/content/176637/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Richard Hoffman is the author of two books on the Mediterranean diet: The Mediterranean Diet: Health and Science (2011) and More Healthy Years - Why a Mediterranean Diet is best for you and for the planet (2020).</span></em></p>Extra virgin olive oil contains polyphenols, which studies have linked to a range of different health benefits.Richard Hoffman, Associate lecturer, Nutritional Biochemistry, University of HertfordshireLicensed 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/1555522021-03-31T19:19:15Z2021-03-31T19:19:15ZChocolate’s secret ingredient is the fermenting microbes that make it taste so good<figure><img src="https://images.theconversation.com/files/392677/original/file-20210330-21-2fmbyo.jpg?ixlib=rb-1.1.0&rect=0%2C249%2C4899%2C3408&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Underneath the shiny wrapper, a chocolate bunny is a fermented food.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/march-2021-brandenburg-hornow-chocolate-easter-bunnies-are-news-photo/1231995539">Patrick Pleul/picture alliance via Getty Images</a></span></figcaption></figure><p>Whether baked as chips into a cookie, melted into a sweet warm drink or molded into the shape of a smiling bunny, chocolate is one of the world’s <a href="https://doi.org/10.1016/j.clnu.2018.05.019">most universally consumed foods</a>.</p>
<p>Even the biggest chocolate lovers, though, might not recognize what this ancient food has in common with kimchi and kombucha: its flavors are due to fermentation. That familiar chocolate taste is thanks to tiny microorganisms that help transform chocolate’s raw ingredients into the much-beloved rich, complex final product.</p>
<p>In labs from Peru to Belgium to Ivory Coast, self-proclaimed <a href="https://scholar.google.com/citations?user=QjIM6yUAAAAJ&hl=en&oi=ao">chocolate scientists like me</a> are working to understand just how fermentation changes chocolate’s flavor. Sometimes we create artificial fermentations in the lab. Other times we take cacao bean samples from real fermentations “in the wild.” Often, we make our experimental batches into chocolate and ask a few lucky volunteers to taste it and tell us what flavors they detect.</p>
<p>After decades of running tests like this, researchers have solved many of the mysteries that govern cacao fermentation, including which microorganisms participate and how this step governs chocolate flavor and quality.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/392678/original/file-20210330-15-1c6otxd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="man reaches up toward pods growing from trunk of cacao tree" src="https://images.theconversation.com/files/392678/original/file-20210330-15-1c6otxd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/392678/original/file-20210330-15-1c6otxd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/392678/original/file-20210330-15-1c6otxd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/392678/original/file-20210330-15-1c6otxd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/392678/original/file-20210330-15-1c6otxd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/392678/original/file-20210330-15-1c6otxd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/392678/original/file-20210330-15-1c6otxd.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">A plantation owner in Ivory Coast checks the pods on one of his cacao trees.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/david-youant-a-plantation-owner-checks-his-cocoa-trees-in-news-photo/77612213">Issouf Sanogo/AFP via Getty Images</a></span>
</figcaption>
</figure>
<h2>From seed pod to chocolate bar</h2>
<p>The food you know as chocolate starts its life as the seeds of <a href="https://doi.org/10.19103/as.2017.0021.01">football-shaped pods of fruit</a> growing directly from the trunk of the <em>Theobroma cacao</em> tree. It looks like something Dr. Seuss would have designed. But as long as <a href="https://doi.org/10.1038/s41559-018-0697-x">3,900 years ago the Olmecs of Central America</a> had figured out a multi-step process to transform these giant seed pods into an edible treat.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/392680/original/file-20210330-19-1h808e1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="woman holds a halved pod displaying the seeds" src="https://images.theconversation.com/files/392680/original/file-20210330-19-1h808e1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/392680/original/file-20210330-19-1h808e1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=691&fit=crop&dpr=1 600w, https://images.theconversation.com/files/392680/original/file-20210330-19-1h808e1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=691&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/392680/original/file-20210330-19-1h808e1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=691&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/392680/original/file-20210330-19-1h808e1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=868&fit=crop&dpr=1 754w, https://images.theconversation.com/files/392680/original/file-20210330-19-1h808e1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=868&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/392680/original/file-20210330-19-1h808e1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=868&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Inside the pods are seeds and pulp.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/close-up-on-cocoa-beans-in-a-halved-pod-on-septembre-25-news-photo/1270250558">Camille Delbos/Art In All of Us/Corbis via Getty Images</a></span>
</figcaption>
</figure>
<p>First, workers crack the brightly colored fruit open and scoop out the seeds and pulp. The seeds, now called “beans,” cure and drain over the course of three to 10 days before drying under the Sun. The dry beans are roasted, then crushed with sugar and sometimes dried milk <a href="https://www.newfoodmagazine.com/article/1949/using-science-to-make-the-best-chocolate/">until the mixture feels so smooth</a> you can’t distinguish the particles on your tongue. At this point, the chocolate is ready to be fashioned into bars, chips or confections.</p>
<p>It’s during the curing stage that <a href="https://doi.org/10.1080/10408690490464104">fermentation naturally occurs</a>. Chocolate’s complex flavor consists of <a href="https://doi.org/10.1021/jf0114177">hundreds of individual compounds</a>, many of which are generated during fermentation. Fermentation is the process of improving the qualities of a food through the controlled activity of microbes, and it allows the bitter, otherwise tasteless cacao seeds to <a href="https://doi.org/10.1080/10408390701719272">develop the rich flavors associated with chocolate</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/392681/original/file-20210330-15-16bcdtk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Drying beans fill trays outside under a sunny blue sky" src="https://images.theconversation.com/files/392681/original/file-20210330-15-16bcdtk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/392681/original/file-20210330-15-16bcdtk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/392681/original/file-20210330-15-16bcdtk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/392681/original/file-20210330-15-16bcdtk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/392681/original/file-20210330-15-16bcdtk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/392681/original/file-20210330-15-16bcdtk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/392681/original/file-20210330-15-16bcdtk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Beans dry in the Sun at a plantation in Madagascar, and microbes invisibly do their work.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/cocoa-harvest-on-the-millot-plantation-in-the-north-west-of-news-photo/590675091">Andia/Universal Images Group via Getty Images</a></span>
</figcaption>
</figure>
<h2>Microorganisms at work</h2>
<p>Cacao fermentation is a multi-step process. Any compound microorganisms produced along the way that changes the taste of the beans will also change the taste of the final chocolate. </p>
<p>The first fermentation step may be familiar to home brewers, because it involves yeasts – some of them the <a href="https://doi.org/10.1111/jam.13045">same yeasts that ferment beer and wine</a>. Just like the yeast in your favorite brew, yeast in a cacao fermentation produces alcohol by digesting the sugary pulp that clings to the beans.</p>
<p>This process generates fruity-tasting molecules called esters and floral-tasting fusel alcohols. These compounds soak into the beans and are later present in the finished chocolate. </p>
<p>As the pulp breaks down, oxygen enters the fermenting mass and the <a href="https://doi.org/10.1080/10408690490464104">yeast population declines as oxygen-loving bacteria take over</a>. These bacteria are known as acetic acid bacteria because they convert the alcohol generated by the yeast into acetic acid.</p>
<p>The acid soaks into the beans, causing biochemical changes. The sprouting plant dies. Fats agglomerate. Some enzymes break proteins down into smaller peptides, which become very “chocolatey”-smelling during the subsequent roasting stage. Other enzymes break apart the <a href="https://doi.org/10.3389/fnut.2018.00087">antioxidant polyphenol molecules</a>, <a href="https://doi.org/10.1093/jaoac/102.5.1388">for which chocolate has gained renown as a superfood</a>. As a result, contrary to its reputation, most chocolate contains very few polyphenols, or even none at all.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/392682/original/file-20210330-13-1ygq6ov.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A man in a hat rakes a large tray of drying cacao seeds" src="https://images.theconversation.com/files/392682/original/file-20210330-13-1ygq6ov.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/392682/original/file-20210330-13-1ygq6ov.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/392682/original/file-20210330-13-1ygq6ov.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/392682/original/file-20210330-13-1ygq6ov.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/392682/original/file-20210330-13-1ygq6ov.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/392682/original/file-20210330-13-1ygq6ov.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/392682/original/file-20210330-13-1ygq6ov.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">As the drying progresses, different microorganisms naturally emerge to do their job preparing the beans.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/man-dries-cacao-beans-at-a-plantation-in-jutiapa-news-photo/1001093156">Orlando Sierra/AFP via Getty Images</a></span>
</figcaption>
</figure>
<p>All the reactions kicked off by acetic acid bacteria have a major impact on flavor. These acids encourage the degradation of heavily astringent, deep purple polyphenol molecules into milder-tasting, brown-colored chemicals called o-quinones. Here is where cacao beans turn from bitter-tasting to rich and nutty. This flavor transformation is accompanied by a color shift from reddish-purple to brown, and it is the reason the chocolate you’re familiar with is brown and not purple.</p>
<p>Finally, as acid slowly evaporates and sugars are used up, other species – including <a href="https://doi.org/10.1080/10408690490464104">filamentous fungi and spore-forming <em>Bacillus</em> bacteria</a> – take over.</p>
<p>As vital as microbes are to the chocolate-making process, sometimes organisms can ruin a fermentation. <a href="https://doi.org/10.1016/j.foodres.2014.04.032">An overgrowth of the spore-forming <em>Bacillus</em> bacteria</a> is associated with compounds that lead to rancid, cheesy flavors.</p>
<h2>Terroir of a place and its microbes</h2>
<p>Cacao is a wild fermentation – farmers rely on natural microbes in the environment to create unique, local flavors. This phenomenon is known as “terroir”: the characteristic flair imparted by a place. In the same way that grapes take on regional terroir, these wild microbes, combined with each farmer’s particular process, confer terroir on beans fermented in each location.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/392683/original/file-20210330-23-1kgttxf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a chocolate maker's hands remove finished candies from a chocolate mold" src="https://images.theconversation.com/files/392683/original/file-20210330-23-1kgttxf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/392683/original/file-20210330-23-1kgttxf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/392683/original/file-20210330-23-1kgttxf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/392683/original/file-20210330-23-1kgttxf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/392683/original/file-20210330-23-1kgttxf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/392683/original/file-20210330-23-1kgttxf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/392683/original/file-20210330-23-1kgttxf.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">High-end chocolate-makers are choosy about their beans.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/chocolate-production-royalty-free-image/175490857">twohumans/E+ via Getty Images</a></span>
</figcaption>
</figure>
<p>Market demand for these <a href="https://damecacao.com/craft-chocolate-continue-to-grow/">fine, high-quality beans is growing</a>. Makers of gourmet, small-batch chocolate hand-select beans based on their distinctive terroir in order to produce chocolate with an impressive range of flavor nuances. </p>
<p>If you’ve experienced chocolate only in the form of a bar you might grab near the grocery store checkout, you probably have little idea of the range and complexity that truly excellent chocolate can exhibit.</p>
<p>[<em>Over 100,000 readers rely on The Conversation’s newsletter to understand the world.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=100Ksignup">Sign up today</a>.]</p>
<p>A bar from Akesson’s Madagascar estate may be reminiscent of raspberries and apricots, while Canadian chocolate-maker Qantu’s wild-fermented Peruvian bars taste like they’ve been soaked in Sauvignon Blanc. Yet in both cases, the bars contain nothing except cacao beans and some sugar. </p>
<p>This is the power of fermentation: to change, convert, transform. It takes the usual and make it unusual – thanks to the magic of microbes.</p><img src="https://counter.theconversation.com/content/155552/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Caitlin Clark 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>Sauerkraut, sourdough, beer…and chocolate? They’re all fermented foods that rely on microbes of various types to transform the flavor of their raw ingredients into something totally different.Caitlin Clark, Ph.D. Candidate in Food Science, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1489022020-10-30T03:38:12Z2020-10-30T03:38:12ZYes, Adele has sung its praises. But the Sirtfood diet may be just another fad<figure><img src="https://images.theconversation.com/files/365700/original/file-20201027-17-12pw73h.jpg?ixlib=rb-1.1.0&rect=5%2C5%2C3844%2C3290&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Monika Grabkowska/UNSPLASH</span></span></figcaption></figure><p>The Sirtfood diet has been <a href="https://nypost.com/2020/10/24/snl-host-adeles-weight-loss-with-sirtfood-diet-inspires-fans/">in the news</a> again this week after singer Adele showed off her slimmed-down figure on US comedy show Saturday Night Live.</p>
<p>Adele has <a href="https://coach.nine.com.au/diet/sirtfood-diet-behind-adeles-weight-loss-explained-by-a-dietitian/552b4d0e-c543-4095-8564-e9e819489215">previously credited</a> her significant weight loss to the Sirtfood diet. Following her appearance on SNL, there was a spike in people searching the diet <a href="https://trends.google.com.au/trends/explore?q=Sirtfood&geo=US">on Google</a>.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1320841953467129857"}"></div></p>
<p>But what exactly is the Sirtfood diet, and does it work?</p>
<h2>What’s the premise?</h2>
<p>Two nutritionists in the United Kingdom launched the Sirtfood diet <a href="https://www.bbcgoodfood.com/howto/guide/what-sirtfood-diet">in 2016</a>.</p>
<p>The premise is that a group of proteins called <a href="https://en.wikipedia.org/wiki/Sirtuin">sirtuins</a>, which are involved in <a href="https://pubmed.ncbi.nlm.nih.gov/24115767/">regulation of metabolism, inflammation and ageing</a>, can be accelerated by eating specific foods rich in a class of phytonutrients called polyphenols. </p>
<p><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</a> are chemical compounds plants produce to help them grow well or defend themselves. Research is continuing to shed light on their potential benefits for human health.</p>
<hr>
<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>
</strong>
</em>
</p>
<hr>
<p>The idea is that eating <a href="https://pubmed.ncbi.nlm.nih.gov/21045839/">foods rich in polyphenols</a>, referred to as “Sirtfoods”, will increase the body’s ability to burn fat, boosting metabolism and <a href="https://pubmed.ncbi.nlm.nih.gov/23043250/">leading to dramatic weight loss</a>.</p>
<p>Common Sirtfoods include, apples, soybean, kale, blueberries, strawberries, dark chocolate (85% cocoa), red wine, matcha green tea, onions and olive oil. The Sirtfood diet gets some of its fame because red wine and chocolate are on the list. </p>
<h2>Two phases</h2>
<p>The diet involves <a href="https://www.bbcgoodfood.com/howto/guide/what-sirtfood-diet">two phases</a> over three weeks. During the first three days, total energy intake is restricted to 4,200 kilojoules per day (or 1,000 Calories). </p>
<p>To achieve this, you drink three sirtfood green juice drinks that include kale, celery, rocket, parsley, matcha green tea and lemon juice. You also eat one “Sirtfood” meal, such as a chicken and kale curry. </p>
<p>On days four to seven, you have 2-3 green juices and one or two meals up to a total energy intake of 6,300 kJ/day (1,500kcal).</p>
<p>During the next two weeks — phase two — total energy intake should be in the range of 6,300-7,500 kJ/day (1,500-1,800 kcal) with three meals, one green juice, and one or two Sirtfood snacks. </p>
<p>There’s a <a href="https://metro.co.uk/2020/10/25/adele-weight-loss-what-is-the-sirtfood-diet-and-is-there-a-sirtfood-diet-recipe-book-13476892/">diet book</a> available for purchase which gives you the recipes.</p>
<p>After three weeks, the recommendation is to eat a “balanced diet” rich in Sirtfoods, along with regular green juices.</p>
<figure class="align-center ">
<img alt="People clink glasses of red wine." src="https://images.theconversation.com/files/366570/original/file-20201030-13-unxc75.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/366570/original/file-20201030-13-unxc75.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/366570/original/file-20201030-13-unxc75.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/366570/original/file-20201030-13-unxc75.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/366570/original/file-20201030-13-unxc75.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/366570/original/file-20201030-13-unxc75.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/366570/original/file-20201030-13-unxc75.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">Red wine is a ‘Sirtfood’. But it should still be enjoyed in moderation.</span>
<span class="attribution"><span class="source">Kelsey Knight/Unsplash</span></span>
</figcaption>
</figure>
<h2>Positives</h2>
<p>The idea of losing a lot of weight in just three weeks will appeal to many people. </p>
<p>The eating plan encourages a range of polyphenol-rich foods that are also good sources of vitamins, minerals and dietary fibre, and would be recommended in a range of diets designed to assist with weight management, or as part of a healthy, balanced eating plan. </p>
<p>A weight loss diet will be effective if it achieves sustained total daily energy restriction. So the biggest benefit of the Sirtfood diet is the daily energy restriction — you are likely to lose weight if you stick to it. </p>
<p>Also, the exclusion of energy-dense, ultra-processed “junk” foods will help <a href="https://pubmed.ncbi.nlm.nih.gov/33012621/">lower the risk for chronic disease</a>. </p>
<p>But there are drawbacks to consider too.</p>
<h2>Negatives</h2>
<p>It would be wise to watch the portion size for some of the foods listed, such as red wine and chocolate.</p>
<p>Like most restrictive diets, phase one may be challenging and is not recommended for people with <a href="https://pubmed.ncbi.nlm.nih.gov/31207126/">underlying health conditions</a> without the supervision of a health professional.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-whats-the-best-diet-for-weight-loss-21557">Health Check: what's the best diet for weight loss?</a>
</strong>
</em>
</p>
<hr>
<p>The rapid weight loss in the first phase will reflect a loss of water and <a href="https://en.wikipedia.org/wiki/Glycogen">glycogen</a>, the stored form of energy in muscles and the liver, rather than being all body fat. </p>
<p>Rapid weight loss can increase the risk of <a href="https://theconversation.com/got-gallstones-heres-what-to-eat-and-avoid-53229">gallstones</a> and <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/menstruation-amenorrhoea">amenorrhoea</a> (missing menstrual periods). </p>
<p>The food list includes specific products that may be hard to locate in Australia, such as <a href="https://en.wikipedia.org/wiki/Lovage">lovage</a>, a European leafy green plant whose leaves can used used as a herb, roots as a vegetable and seeds as a spice. Some other items on the list can be expensive. </p>
<figure class="align-center ">
<img alt="A person steps onto bathroom scales." src="https://images.theconversation.com/files/366577/original/file-20201030-19-chddkv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/366577/original/file-20201030-19-chddkv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/366577/original/file-20201030-19-chddkv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/366577/original/file-20201030-19-chddkv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/366577/original/file-20201030-19-chddkv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/366577/original/file-20201030-19-chddkv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/366577/original/file-20201030-19-chddkv.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 Sirtfood diet can result in rapid weight loss, but that’s not always a good thing.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Sirt science</h2>
<p>Most research has looked at the <a href="https://pubmed.ncbi.nlm.nih.gov/24115767/">sirtuin-mediated effects</a> of energy restriction in worms, mice or specific body tissues. No studies have tested the effect of diets that vary polyphenol content on the action of sirtuins in mediating weight loss. </p>
<p>A search on PubMed, the scientific database of research studies, didn’t locate any human trials of the Sirtfood diet. So the short answer about whether the Sirtfood diet works or not is we don’t know.</p>
<p>The authors’ claims about effectiveness are based on anecdotal information from their own research and from personal testimonials, such as the one from Adele. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-a-balanced-diet-anyway-72432">What is a balanced diet anyway?</a>
</strong>
</em>
</p>
<hr>
<p>Considering the hype surrounding the Sirtfood diet against a checklist on <a href="https://theconversation.com/blood-type-pioppi-gluten-free-and-mediterranean-which-popular-diets-are-fads-104867">spotting a fad diet</a> sounds alarm bells. For example:</p>
<ul>
<li><p>does it promote or ban specific foods?</p></li>
<li><p>does it promote a one-size-fits-all approach?</p></li>
<li><p>does it promise quick, dramatic results?</p></li>
<li><p>does it focus only on short-term results?</p></li>
<li><p>does it make claims based on personal testimonials?</p></li>
</ul>
<p>Looking at the Sirtfood diet, the answers to most of these questions seem to be “yes”, or at least a partial yes.</p>
<p>The best diet for weight loss is one that meets your nutrient requirements, promotes health and well-being, and that you can stick with long-term.</p>
<hr>
<p><em>If you’d like to learn more about weight loss, enrol in <a href="https://www.newcastle.edu.au/study/online-learning/the-science-of-weight-loss">our free online course</a> The Science of Weight Loss – Dispelling Diet Myths, which begins on January 27, 2021.</em></p><img src="https://counter.theconversation.com/content/148902/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, Bill and Melinda Gates Foundation, nib foundation, Rijk Zwaan Australia and Greater Charitable Foundation. She has consulted to SHINE Australia, Novo Nordisk, Quality Bakers, the Sax Institute and the ABC. She was a team member conducting systematic reviews to inform the Australian Dietary Guidelines update and the Heart Foundation evidence reviews on meat and dietary patterns.</span></em></p><p class="fine-print"><em><span>Lee Ashton is affiliated with the Priority Research Centre for Physical Activity and Nutrition at the University of Newcastle, NSW, Australia.</span></em></p><p class="fine-print"><em><span>Rebecca Williams is affiliated with the Priority Research Centre for Physical Activity and Nutrition at the University of Newcastle. </span></em></p>If you follow the Sirtfood diet, you’ll probably lose some weight in a short period because you’re consuming fewer calories. But the evidence behind the diet is lacking.Clare Collins, Professor in Nutrition and Dietetics, University of NewcastleLee Ashton, Postdoctoral research fellow, University of NewcastleRebecca Williams, Postdoctoral Researcher, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1386402020-09-03T14:48:26Z2020-09-03T14:48:26ZWhy low and alcohol free beers could be considered health drinks<figure><img src="https://images.theconversation.com/files/355848/original/file-20200901-14-1dwem69.jpg?ixlib=rb-1.1.0&rect=0%2C36%2C4893%2C3220&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Refreshing in the scientific-medical sense, not just the pints-after-work sense.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/people-men-leisure-friendship-celebration-concept-464199170">Syda Productions/Shutterstock</a></span></figcaption></figure><p>It is often said that weak beer was drunk in preference to dirty water in European towns during the middle ages. This fact is <a href="https://onlinelibrary.wiley.com/doi/10.1002/9783527623488.ch1">probably overstated</a>, but the idea that beer was nutritionally important in the medieval period seems more likely. Weaker, so-called “small beers” would have been low in alcohol but a <a href="https://www.upenn.edu/pennpress/book/14037.html">valuable source of energy and nutrients</a>, helping medieval labourers meet their high energy requirements of 3,000 calories a day. </p>
<p>The industrialisation of brewing led to higher alcohol levels in modern beers, which together with their energy and carbohydrate content means beer is now associated with <a href="https://www.sheffield.ac.uk/polopoly_fs/1.538671!/file/Drinking_Guidelines_Final_Report_Published.pdf">poor health and disease</a>. Growing concerns about the health effects of excessive beer consumption has driven increased interest in no-alcohol and low-alcohol (<a href="https://www.theguardian.com/business/2020/jan/20/uk-brewers-invest-in-low-alcohol-drinks-trend">“nolo”</a>) beers, especially in adults under 30. The acceptability of these beers has increased recently, in part due to brewing developments that require less heat and so retain more of the original flavours.</p>
<p>Research shows that moderate beer intake, as with wine, is associated with a reduced risks of <a href="https://www.ncbi.nlm.nih.gov/pubmed/30166641">heart disease</a>. So it’s plausible that nolo beers could also offer these health and nutritional benefits, but without the negative effects linked to the alcohol and calorie content.</p>
<p>In a <a href="https://www.mdpi.com/2306-5710/6/2/25">recent review</a>, we set out to determine the health benefits of nolo beers and whether they could find a place as nutritious drinks with everyday uses, rather than being drunk typically only by teetotallers and designated drivers. Antioxidants and gut health are areas about which there is considerable interest among the health-conscious and among food producers, and nolo beers can provide for both. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/346627/original/file-20200709-62-1h8us8q.jpg?ixlib=rb-1.1.0&rect=0%2C4%2C2764%2C1711&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/346627/original/file-20200709-62-1h8us8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=373&fit=crop&dpr=1 600w, https://images.theconversation.com/files/346627/original/file-20200709-62-1h8us8q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=373&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/346627/original/file-20200709-62-1h8us8q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=373&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/346627/original/file-20200709-62-1h8us8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=469&fit=crop&dpr=1 754w, https://images.theconversation.com/files/346627/original/file-20200709-62-1h8us8q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=469&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/346627/original/file-20200709-62-1h8us8q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=469&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Alcohol-free beer: like a sports drink, but tastes better.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/pleia2/30252646627">Elizabeth K. Joseph</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Probiotics</h2>
<p>Many people think <a href="https://theconversation.com/the-science-behind-probiotics-and-choosing-one-that-works-132804">probiotics</a> are the bacteria in yoghurts and perhaps kombucha, but beer can be probiotic too – that is, it contains live, beneficial bacteria – due to its yeast. A number of yeasts such as <em>Saccharomyces boulardii</em> have been found to play a role in managing <a href="https://journals.sagepub.com/doi/10.1177/1756283X11428502">gastrointestinal disorders</a>, and although this type of beer is yet to be tested to see if it improves gut health, a number of studies are <a href="https://link.springer.com/article/10.1007/s12602-020-09680-5">in the pipeline</a>. A beer using alternative yeasts such as this also could reduce the beer’s sugar content, or through slow fermentation, produce less alcohol. </p>
<p>Other styles of beer such as sour beers and lambics use bacteria similar to those you would find in live yoghurt. But, as with yoghurts, it may not be possible to get an approved health claim, and many products are treated to extend shelf life and in doing so reduce or remove any potential probiotic microorganisms. To contain any live probiotics linked to maintaining a healthy gut and immune system, the beer needs to be fresh, not pasteurised and unfiltered. But this would reduce its shelf-life and risk the production of “off” flavours. </p>
<h2>Polyphenols</h2>
<p>Polyphenols are a large group of compounds found in hops and grains that have been linked to a reduced risk of disease. They have been shown in laboratory tests to be powerful antioxidants, which can mop up dangerous free radicals in the body’s cells, which if left unchecked can increase the risk of diseases, such as heart disease and cancer. While there is doubt about whether this is the <a href="https://ifst.onlinelibrary.wiley.com/doi/10.1111/ijfs.14135">mechanism</a> by which antioxidants keep us healthy, what is clear is that diets rich in a variety of these compounds are <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6115785/">a good thing</a>.</p>
<p>Beer and nolo beer are rich in polyphenols due to the barley and hops, which means beer can contain <a href="http://europepmc.org/article/med/25442616">over 50 different compounds</a> that could provide benefits from affecting gastrointestinal health to controlling bacteria growth. Beers containing more hops, such as IPAs, tend to contain even more of these <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/1541-4337.12352">potential health-promoting polyphenols</a> than lagers.</p>
<p>There is now recognition that nolo beers can potentially be marketed as health products. German brewer Erdinger’s <a href="https://int.erdinger.de/beer/alkoholfrei.html">alcohol-free wheat beer</a> contains electrolytes that can aid the absorption of water to help digestion – something often referred to as “isotonic” when found in a sports drink. The beer is also a source of folate and vitamin B12 due to the action of the yeast in the bottled beer (particularly important for vegans, for whom there are few natural sources of vitamin B12 available). </p>
<p>Erdinger market this beer as “isotonic” and “a sporty thirst quencher”, which suggests it has identified that the beer is both suitable for, and is of interest to, groups beyond those wishing to avoid alcohol. The sports drink potential of nolo beers has been tested in the lab too, with low alcohol beers being <a href="https://www.frontiersin.org/articles/10.3389/fnut.2016.00045/full">almost as good</a> as sports drinks for rehydrating, especially if a <a href="https://journals.humankinetics.com/view/journals/ijsnem/23/6/article-p593.xml">pinch of salt</a> is added. </p>
<p>While nolo beers are <a href="https://www.theguardian.com/business/2020/jan/20/uk-brewers-invest-in-low-alcohol-drinks-trend">growing in popularity</a>, it may be that traditional beer fans may struggle to accept them as “real ales”, given the poor reputation of low-alcohol beers in the past. But with improving brewing and alcohol-removal methods, the flavour and potentially the health benefits of low alcohol beers can be retained, while reducing the negatives of excess alcohol and calories. Even the most ardent beer fans may yet be won over.</p><img src="https://counter.theconversation.com/content/138640/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ray Carson is a Director of Beertorrent Ltd. </span></em></p><p class="fine-print"><em><span>Bishoy Hanna-Khalil and Duane Mellor 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>Remove the alcohol and calories, and it turns out beer is a drink that has many qualities found in health drinks.Duane Mellor, Senior Teaching Fellow, Aston Medical School, Aston UniversityBishoy Hanna-Khalil, Clinical Teaching Fellow, Aston UniversityRay Carson, Senior Lecturer and Medical Studies Co-ordinator, Aston UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1107472019-02-01T11:53:48Z2019-02-01T11:53:48ZSo you went vegan in January – now what?<figure><img src="https://images.theconversation.com/files/256866/original/file-20190201-75085-15u5zn.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/604314275?src=YumHIBhoddB-Oj18pMcuag-1-49&size=medium_jpg">Anna Shepulova/Shutterstock</a></span></figcaption></figure><p>Many people will have had their fill of cheese, chocolate and meat over Christmas and have felt much more energised after going vegan in January (an event known as <a href="https://veganuary.com/">Veganuary</a>). This invigorating feeling is largely due to the increase in fruit, vegetables, nuts and pulses as opposed to the cutting out of meat and dairy, but it’s still a big win.</p>
<p>One of the main benefits of a more plant-based diet is the increase in fibre. Fibre has been in the press recently after a <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)31809-9/fulltext">major review</a> in The Lancet reported that getting more than 25g of fibre per day significantly reduces the risk of heart attacks, strokes and type 2 diabetes.</p>
<p>A <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3967195/pdf/nutrients-06-01318.pdf">2015 study</a> of different dietary patterns showed that vegans had an average daily fibre intake of 41g, compared with vegetarians, flexitarians and pescatarians at 34g. Omnivores get a mere 27g of fibre a day, on average.</p>
<p>Keeping up the habits you adopted in Veganuary that keeps your fibre intake high is likely to be of great benefit to your long-term health.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/256645/original/file-20190131-127151-62prsn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/256645/original/file-20190131-127151-62prsn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/256645/original/file-20190131-127151-62prsn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/256645/original/file-20190131-127151-62prsn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/256645/original/file-20190131-127151-62prsn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/256645/original/file-20190131-127151-62prsn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/256645/original/file-20190131-127151-62prsn.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">Dietary fibre reduces the risk of cardiovascular disease and type 2 diabetes.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/1037908300?src=Lc-v2CCHcz7IadcOGZiZoQ-1-6&size=medium_jpg">marilyn barbone/Shutterstock</a></span>
</figcaption>
</figure>
<h2>What to take forward from Veganuary</h2>
<p>While the jury is still out on whether a vegan diet is healthier than a well-balanced omnivorous diet in the long run, you may well have picked up some new recipes and ideas for eating more plants. And we know that increasing fruit and veg intake is great for your body and may even help <a href="https://www.ncbi.nlm.nih.gov/pubmed/29759102">prevent depression</a>.</p>
<p>Eating a rainbow of fruit and vegetables has been a message we’ve been hearing for a while, but with the progressing research into polyphenols, which are the compounds that dictate the colour of the plant, getting the benefit of the full range of polyphenols on offer is likely to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5465813/">optimise your health in many ways</a>.</p>
<p>Maybe you’ve experimented with a few new fruits or vegetables, so keep up with the increased variety.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/256647/original/file-20190131-110834-8e5sg5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/256647/original/file-20190131-110834-8e5sg5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/256647/original/file-20190131-110834-8e5sg5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/256647/original/file-20190131-110834-8e5sg5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/256647/original/file-20190131-110834-8e5sg5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/256647/original/file-20190131-110834-8e5sg5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/256647/original/file-20190131-110834-8e5sg5.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">Keep your diet colourful.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/1096384175?src=lTl-gdlTS1j8PiVmmlKZcQ-1-16&size=medium_jpg">Peangdao/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Reintroduce meat or animal products?</h2>
<p>The latest publication from <a href="https://www.thelancet.com/commissions/EAT">EAT-Lancet</a> suggests that the best diet for your health and for the planet includes around 45g of meat per day (or one small portion on alternate days) and 28g of fish per day, which is about the amount you might have in a sandwich. They also recommend 250g of dairy per day, which could be a glass of milk.</p>
<p>This diet has come under fire for being <a href="https://www.fwi.co.uk/livestock/the-eat-lancet-diet-is-nutritionally-deficient-says-obesity-expert">nutritionally inadequate</a>, but most experts agree that reducing meat consumption to one portion per day and having more plants instead protects your health.</p>
<p>So, if you’ve been managing on a vegan diet but just can’t wait for your first bacon sandwich, burger or mac ‘n’ cheese, remember that there are no rules to following a plant-based diet. While having meat or fish a few times per week and including yogurts and cheese might not make you a vegan, you are still benefiting from being more of a planty person.</p>
<h2>How best to reintroduce excluded foods</h2>
<p>Most people won’t have any problem reintroducing meat and dairy into their diet. Some people might notice that they have slight changes in their bowel habit. Others might notice that they feel a bit less tired or sleep a bit better with the extra iron, B vitamins and amino acids coming back into their diet. Humans are supposed to be omnivorous, so we are well designed to handle changes in our diet.</p>
<p>If you do choose to stay on a completely vegan diet, make sure you are supplementing your diet with B12, calcium, algae (for essential fatty acids not available from other sources) and iron, or make sure you are having plenty of fortified foods and check your intake of micronutrients every day. And please remember to only take dietary advice from regulated healthcare professionals.</p><img src="https://counter.theconversation.com/content/110747/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sophie Medlin 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>Don’t lose the benefits of a more plant-based diet as you head into February.Sophie Medlin, Lecturer in Nutrition and Dietetics, King's College LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/693292016-11-24T16:01:07Z2016-11-24T16:01:07ZWhy frequent dieting makes you put on weight – and what to do about it<figure><img src="https://images.theconversation.com/files/147443/original/image-20161124-15333-xchos5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Grapefruit diet? Probably not worth it.</span> <span class="attribution"><span class="source">Sophie Jonasson from Sweden</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span></figcaption></figure><p>People who regularly go on diets tend to lose weight initially but bounce back and even gain weight after stopping the regime. This phenomenon – dubbed yo-yo dieting – is associated with changes in metabolism and is one reason why the vast majority of calorie-based diets fail. But exactly what causes these metabolic changes has remained a mystery – until now.</p>
<p>Previous studies in identical twins who differed in dieting patterns have shown that <a href="https://www.ncbi.nlm.nih.gov/pubmed/21829159">non-genetic factors are largely responsible</a>. The working hypothesis was that when you gain weight you somehow “reset” your internal thermostat corresponding to the higher weight level and so when you lose weight – your body does all it can to return to that new higher set point. Now new research, <a href="http://nature.com/articles/doi:10.1038/nature20796">published in Nature</a>, explains why this happens to some people more than others and, importantly, how it could be reversed.</p>
<p>The study, by an Israeli group of scientists, mimicked human yo-yo dieters in lab mice. The researchers fed the mice in several cycles of alternating weight gaining and losing diets. They started with big, high-fat portions to fatten them up then slimmed them down with a diet of normal, light meals, then repeated the regime. Like humans, the mice slowly gained weight compared to other mice on steady diets of similar calories – even those on continuous high-fat diets.</p>
<p>Mice who bounced back and had increased weight regain after dieting had a lower energy expenditure than those on steady diets but still ate the same amount of food. We know this change in body metabolism occurs in yo-yo dieters. But the new study managed to figure out why – by looking at a forgotten organ of the body.</p>
<p>In humans, this organ weighs nearly as much as the liver and is located in our lower intestines. It is the microbiome – the community of microbes that outnumber our cells and have a hundred-fold more genes and enzymes <a href="https://theconversation.com/your-gut-bacteria-dont-like-junk-food-even-if-you-do-41564">capable of digesting food</a> and regulating our metabolism and immune systems. It turns out that changes to the gut microbes were responsible.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/147263/original/image-20161123-19692-w52ll7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/147263/original/image-20161123-19692-w52ll7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/147263/original/image-20161123-19692-w52ll7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/147263/original/image-20161123-19692-w52ll7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/147263/original/image-20161123-19692-w52ll7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/147263/original/image-20161123-19692-w52ll7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/147263/original/image-20161123-19692-w52ll7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Such hard work dieting, and no pay-off.</span>
<span class="attribution"><span class="source">cunaplus</span></span>
</figcaption>
</figure>
<p>There were marked differences in the gut microbes of the yo-yo dieting mice compared to the normal ones – including a reduction in diversity, which is <a href="https://theconversation.com/how-the-bacteria-in-our-gut-affect-our-cravings-for-food-33141">correlated with obesity</a> and other metabolic problems in humans. When they transplanted these disordered microbes from the weight regainers into normal mice on normal diets they saw them gain weight – showing that the altered microbes were ultimately responsible. They could explain how the microbes caused weight gain by looking at how they digested the plant fibre – <a href="https://theconversation.com/eat-your-fibre-or-face-the-flesh-eating-microbe-cannibals-69126">their staple diet</a>. </p>
<p>The study found that the altered microbes were under-producing healthy compounds generated from the plants called <a href="http://ajcn.nutrition.org/content/79/5/727.full">polyphenols (flavonoids)</a> in the gut after dieting. These polyphenols are key to a healthy gut and the reason why many brightly-coloured foods are gut friendly. Taking poyphenols has in fact <a href="https://www.ncbi.nlm.nih.gov/pubmed/26823518">been associated with</a> better health and less obesity. The exciting result of this is that, because microbes are involved, the changes post-diet are potentially reversible.</p>
<h2>Avoiding the yo-yo trap</h2>
<p>The researchers tried a number of methods to reduce the weight gain in the yo-yo dieting mice. First, they gave them antibiotics which altered the microbes and increased polyphenol levels. This cured the problem, but isn’t exactly a practical solution for humans. They then tried fecal transplants <a href="https://theconversation.com/why-poo-transplants-are-nothing-to-be-sniffed-at-49319">which also worked</a>, but are again a bit drastic in humans. As taking a tablet is safer and easier, they then tried to replace some of these specific polyphenols by supplementation in the diet. Luckily, even this could reduce the weight gain. </p>
<p>So what are the lessons for humans? Assuming a similar mechanism is at work in humans, which is likely, it’s pretty clear. Episodic weight loss can be metabolically dangerous – damaging your microbes and making you burn less energy. The solution – while we await some magic supplements – is looking after your microbes as you transition back onto normal foods after a diet. In particular, you need to feed them plenty of fibre and polyphenol-rich foods which, as well as the obvious fruit and veg, include nuts, seeds, olive oil (extra virgin), coffee, dark chocolate and even a glass of red wine. </p>
<p>The best approach if you really want to lose weight long term is to avoid crash diets and calorie counting altogether, which are doomed to fail. Instead eat real diverse food, plenty of fibre and let your microbes take care of the rest. </p>
<hr>
<p><em>More on evidence-based articles about diets:</em></p>
<ul>
<li><p><em><a href="https://theconversation.com/do-you-get-diabetes-from-eating-too-much-sugar-95833?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=IsItTrue">Do you get diabetes from eating too much sugar?</a></em></p></li>
<li><p><em><a href="https://theconversation.com/low-carb-paleo-or-fasting-which-diet-is-best-89685?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=IsItTrue">Low carb, Paleo or fasting – which diet is best?</a></em></p></li>
<li><p><em><a href="https://theconversation.com/should-you-eat-breakfast-53129?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=IsItTrue">Should you eat breakfast?</a></em></p></li>
</ul><img src="https://counter.theconversation.com/content/69329/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim Spector receives funding from several bodies including MRC, Wellcome Trust, EU and NIHR. He is co-founder of the British Gut project and Map My Gut Ltd. He advises Optibiotix Ltd.
He is author of "The Diet Myth: the real science behind what we eat" - Orion 2016 </span></em></p>The mystery of the yo-yo dieting effect has finally been solved.Tim Spector, Professor of Genetic Epidemiology, King's College LondonLicensed as Creative Commons – attribution, no derivatives.