tag:theconversation.com,2011:/global/topics/french-paradox-10360/articlesFrench paradox – The Conversation2024-03-18T18:24:24Ztag:theconversation.com,2011:article/2222672024-03-18T18:24:24Z2024-03-18T18:24:24ZCheers to health? Uncovering myths around the health benefits of moderate drinking<figure><img src="https://images.theconversation.com/files/582572/original/file-20240318-22-wdfo1c.jpg?ixlib=rb-1.1.0&rect=15%2C31%2C3270%2C2206&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Many studies exaggerated the benefits of moderate drinking due to methodological flaws known as selection biases.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>The notion that enjoying a casual beer or sipping on your favourite wine could not only be harmless but actually beneficial to one’s health is a tantalizing proposition for many. This belief, often backed by claims of research findings, has seeped into social conversations and <a href="https://www.cbc.ca/news/science/moderate-drinking-may-be-heart-healthy-says-new-research-1.293437">media headlines</a>, painting moderate alcohol consumption in a positive light. </p>
<p>As researchers at the Canadian Institute for Substance Use Research, we find ourselves frequently revisiting this topic, delving deep into the evidence to separate fact from wishful thinking. Can we confidently say, “Cheers to health?”</p>
<h2>Unpacking beliefs about moderate drinking</h2>
<p>The <a href="https://doi.org/10.1046/j.1360-0443.2001.96464113.x">commonplace belief</a> that moderate drinking can be beneficial to health can be traced back to the 1980s when researchers found an association suggesting that French people were less likely to suffer from heart disease, despite eating a diet high in saturated fat. </p>
<p>This contradiction was thought to be explained by the assumption that the <a href="https://doi.org/10.5344/ajev.2011.11013">antioxidants and alcohol found in wine</a> might offer health benefits, leading to the term “<a href="https://doi.org/10.1016/S0140-6736(94)92883-5">French paradox</a>.”</p>
<p>This concept reached a broader audience in the 1990s, following a segment on the American news show <em>60 Minutes</em> which had a <a href="https://doi.org/10.1108/07363769410058894">profound impact on wine sales</a>. Later <a href="https://doi.org/10.1111/j.1360-0443.2012.03780.x">research expanded on this idea</a>, suggesting that frequently drinking small amounts of any type of alcoholic beverage might be good for health.</p>
<p>This idea was formalized into what is now known as the <a href="https://doi.org/10.1016/j.jacc.2017.07.710">J-shaped curve hypothesis</a>. Put simply, the J-shaped curve is a graphical representation of the apparent relationship between alcohol consumption and death or disease. According to this model, abstainers and heavy drinkers are at higher risk of certain conditions, <a href="https://doi.org/10.1111/j.1360-0443.2012.03780.x">such as heart disease</a>, compared to moderate drinkers, whose risk is lower.</p>
<figure class="align-center ">
<img alt="An illustration of the J-shaped Curve." src="https://images.theconversation.com/files/580343/original/file-20240307-20-h2zkss.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/580343/original/file-20240307-20-h2zkss.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580343/original/file-20240307-20-h2zkss.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580343/original/file-20240307-20-h2zkss.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580343/original/file-20240307-20-h2zkss.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580343/original/file-20240307-20-h2zkss.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580343/original/file-20240307-20-h2zkss.png?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 J-shape curve is a graphical representation of the apparent relationship between alcohol consumption and death or disease. According to this model, abstainers and heavy drinkers are at higher risk compared to moderate drinkers, whose risk is lower.</span>
</figcaption>
</figure>
<h2>Current perspectives on moderate drinking</h2>
<p>People used to think that tobacco use was good for health, <a href="https://doi.org/10.1017/S0025727300012333">historically describing it as a remedy for all disease</a>. As scientific understanding has advanced, however, tobacco use has been increasingly recognized as a <a href="https://iris.who.int/bitstream/handle/10665/372043/9789240077164-eng.pdf?sequence=1">leading cause of preventable disease and death</a>.</p>
<p>Like tobacco, alcohol was once used in medicine and has since become recognized as a <a href="https://doi.org/10.1016/S0140-6736(22)02123-7">major cause of preventable mortality and illness</a>. For instance, recent global estimates suggest <a href="https://doi.org/10.1016/S2468-2667(19)30231-2">alcohol is responsible for 5.3 per cent of all deaths</a>. </p>
<p>Furthermore, in Canada, the revenue generated from selling alcohol does not come close to covering the damage it causes, leaving the government <a href="https://www.uvic.ca/research/centres/cisur/assets/docs/cape/cape3/fed-results-en.pdf">$6.20 billion short every year</a>. However, much of these costs can be attributed to heavy drinking. </p>
<p>So where does this leave moderate drinkers? We recently set out to answer this question by analyzing data from over 4.8 million people from more than 100 studies, covering more than 40 years. </p>
<p>We found that many studies exaggerate the benefits of moderate drinking due to methodological flaws known as <a href="https://doi.org/10.1111/add.13451">selection biases</a>. No matter if we <a href="https://doi.org/10.1001/jamanetworkopen.2023.6185">analyzed the studies as one big group</a>, using statistical methods to try and lessen these mistakes, or if we <a href="https://doi.org/10.15288/jsad.23-00283">separated the good studies from the not-so-good ones</a>, one thing was clear: moderate alcohol consumption does not appear to offer the health benefits once believed.</p>
<h2>Explaining the contradiction</h2>
<p>Selection biases represent data distortions caused by how research participants are selected. Such biases lead to unfair comparisons between groups, which skews analyses towards finding a J-shape curve. Essentially, it is like comparing two runners in a race, where one wears heavy boots and the other wears lightweight running shoes. Concluding that the second runner is more talented misses the point; it is not a fair comparison.</p>
<p>Here are five examples of selection bias in the context of the alcohol J-shaped curve which can accumulate as people age:</p>
<ol>
<li><p><a href="https://doi.org/10.1016/S0140-6736(88)92890-5">Poor health, less alcohol</a>. As health declines, especially in older age, people often reduce their alcohol consumption. Not distinguishing between those who cut back or quit for health reasons can falsely indicate that moderate drinking is healthier.</p></li>
<li><p><a href="https://doi.org/10.1136/jech-2013-202576">Unhealthy lifetime abstainers</a>. Comparing moderate drinkers with individuals who have never consumed alcohol due to chronic health issues may falsely attribute health advantages to alcohol consumption.</p></li>
<li><p><a href="https://doi.org/10.1016/j.amepre.2005.01.011">Moderate in other ways.</a> Moderate drinkers often lead balanced lifestyles in other areas, too, which may contribute to their perceived better health. It is not just moderate drinking, but also their healthier overall opportunities and choices, such as better health-care access and self-care, that make them seem healthier.</p></li>
<li><p><a href="https://doi.org/10.1177/009145090403100304">Measurement error.</a> Assessing alcohol consumption over a short period of time, like a week or less, can lead to a misclassification of drinkers. Heavy drinkers who happened to not consume alcohol during the week of assessment would be incorrectly classified as abstainers, for example.</p></li>
<li><p><a href="https://doi.org/10.1111/add.13709">Early alcohol-attributable deaths.</a> The inevitable exclusion of individuals who may have died from alcohol-related causes before a study of older people starts can result in a “healthy survivor” bias, overlooking the earlier detrimental effects of alcohol.</p></li>
</ol>
<h2>Continuing the conversation</h2>
<p>We should be skeptical of results suggesting that moderate drinking is healthy because selection biases can muddy the waters. For instance, multiple implausible J-shape curve relationships have been published, <a href="https://doi.org/10.1002/hep.510230513">including between moderate drinking and liver disease</a>.</p>
<p>We are well aware that this news might not be what you were hoping to hear. <a href="https://doi.org/10.1080/08870446.2024.2316681">It might even stir up feelings of unease or skepticism</a>. For many people, limited alcohol consumption <a href="https://doi.org/10.1007/s40750-016-0058-4">is enjoyable</a>. However, it is not without risk and it is important for people to understand these risks to make informed decisions about their health.</p>
<p>The risks are reflected in the 2023 <a href="https://www.ccsa.ca/sites/default/files/2023-05/CGAH-Drinking-Less-is-Better-en.pdf">Canadian Drinking Guidance</a>. The guidance attempts to “meet people where they are at,” suggesting that one to two drinks per week represent a low risk of harm, three to six drinks a week represent a moderate risk, and seven or more drinks a week represent an increasingly high risk. Ultimately, they enable people to make informed decisions that best suit their health and well-being.</p><img src="https://counter.theconversation.com/content/222267/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors 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>It’s time to revisit the evidence for the health benefits of moderate drinking, and separate fact from wishful thinking. Can we confidently say, ‘Cheers to good health?’James M. Clay, Postdoctoral Research Fellow, Canadian Institute for Substance Use Research, University of VictoriaTim Stockwell, Scientist, Canadian Institute for Substance Use Research and Professor of Psychology, University of VictoriaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/859542017-10-26T21:20:55Z2017-10-26T21:20:55ZIs drinking wine really good for your heart?<figure><img src="https://images.theconversation.com/files/191920/original/file-20171025-28045-heo7yc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Some research studies have found light to moderate drinking to be protective of heart health; others have found long term drinking to be damaging.</span> <span class="attribution"><span class="source"> (AP Photo/Richard Drew)</span></span></figcaption></figure><p>As the weekend approaches, people are opening wine bottles in bars and restaurants and homes around the world, ready to kick back and relax.</p>
<p>This relationship with wine has a long history. The oldest known winery, dating back to 4100 B.C, was <a href="https://news.nationalgeographic.com/news/2011/01/110111-oldest-wine-press-making-winery-armenia-science-ucla/">discovered in 2010 by archeologists in an Armenian cave</a>. Wine was used in ceremonies by the Egyptians, traded by the Phoenicians, honoured by the Greek God Dionysus and the Roman God Bacchus. By 2014, humanity was consuming <a href="https://www.wineinstitute.org/resources/statistics">more than 24 billion litres of wine</a> every year globally. Now there is some fear that extreme weather events in western Europe during 2017 <a href="http://www.theprovince.com/news/world/98extreme+weather+events+mean+could+paying+more+wine+very+soon/15346425/story.html">have reduced production substantially</a> and prices of this high-demand commodity are set to rise.</p>
<p>So why is wine so popular? Aside from its flavours, and capacity to help people relax, wine has gained something of a reputation as a “healthy” alcohol — with researchers in the past noting associations between red wine drinking in France, and lower incidence of heart disease.</p>
<p>However, wine drinking is also known to increase risks of serious health issues, including <a href="http://doi.org/10.1111/j.1465-3362.2009.00153.x">liver cirrhosis</a>, <a href="http://doi.org/10.1136/hrt.68.11.443">sudden cardiac death</a>, <a href="http://doi.org/10.1016/S0735-1097(00)00565-9">alcoholic cardiomyopathies</a> and <a href="http://doi.org/10.1016/j.jacc.2016.08.074">cardiac rhythm disorders</a>. Excessive consumption and chronic misuse of alcohol are risk factors contributing to an increase in global disease. </p>
<p>How does the average drinker know what to believe? And how much wine is safe? As medical researchers, we recently published an <a href="http://doi.org/10.1161/CIRCULATIONAHA.117.030387">in-depth analysis of the anatomy of wine</a>. This included analysis of the risks and benefits of consumption, comparisons with other alcoholic beverages and a discussion around wine’s much publicised health benefits. </p>
<h2>Wine and heart disease</h2>
<p>Modern scientific intrigue surrounding wine has grown immensely since the 1970s, when <a href="http://doi.org/10.1016/S0140-6736(79)92765-X">large, international studies</a> first reported a link between light-to-moderate consumption of alcohol and lower rates of ischemic heart disease (IHD) occurrence and associated deaths. IHDs are a group of diseases characterised by a reduced blood flow to the heart, and account for significant deaths worldwide.</p>
<p>Similar results have been reported individually for wine, specifically red wine. This phenomenon was eventually <a href="http://doi.org/10.1016/0140-6736(92)91277-F">coined “the French paradox”</a> after Renaud and de Lorgeril, two scientists who became known for this work, observed a relatively low risk of IHD-associated mortality in red wine drinkers despite a consumption of a diet rich in saturated fat.</p>
<p></p>
<p>Does this mean red wine is good for the heart? This is a complex question and as yet there is no consensus on the answer. More than one factor needs to be considered in order to explain this situation. Drinking patterns, lifestyle characteristics and dietary intake are all important for individuals to obtain a healthy cardiovascular profile.</p>
<p>The Mediterranean diet has been put forward as one explanation. This diet emphasizes consumption of plant-based foods in addition to the moderate consumption of red wine and has <a href="http://doi.org/10.1161/01.CIR.103.13.1823">been labelled as beneficial by scientific advisory committees</a>.</p>
<p>In the Mediterranean diet, the low-consumption of saturated fat, emphasis on a healthy lifestyle, and more independently, alpha-linoleic acid (an essential fatty acid) and red wine, may allow this diet to confer the much researched cardio-protective benefits.</p>
<h2>Cholesterol, inflamation, blood pressure</h2>
<p>Red wine contains over 500 different chemical substances. One class, called “polyphenols,” has been widely investigated for imparting the apparent antioxidant and anti-inflammatory effects of red wine.</p>
<p>Alcohol and polyphenols are thought to have several positive health impacts. One is a contribution to an increase in <a href="http://doi.org/10.1079/BJN2001369">HDL-cholesterol</a> or “good cholestrol” and a decrease in <a href="http://ajcn.nutrition.org/content/68/2/258.long">LDL-oxidation</a> or “bad cholesterol.” They also contribute to a decrease in <a href="http://doi.org/10.1111/j.1538-7836.2007.02527.x">inflammation</a>. They are thought to increase <a href="http://doi.org/10.2337/diacare.17.2.115">insulin sensitivity</a>. And they are understood to improve <a href="http://doi.org/10.1161/01.HYP.25.5.1106">blood pressure</a>.</p>
<p>
</p><p>There is no consistent pattern when wine is compared to beer and spirits. Some report wine’s superiority in a reduction from IHD and mortality. Others report it for beer and spirits. Others suggest there is no difference. This suggests that alcohol and polyphenols both contribute to explaining the French paradox, in addition to lifestyle factors.</p>
<p>Despite the beneficial effects of wine and alcohol consumption, drinking is still a potential risk-factor for atrial fibrillation, the most-common “rhythm alteration” of the heart.</p>
<h2>How much should you drink?</h2>
<p>In much of the research, adverse effects were increasingly observed with excessive or binge-consumption of wine, while low-to-moderate intakes lowered IHD and mortality risks. </p>
<p>In response, various governing bodies have come forth with guidelines for alcohol consumption. These follow similar patterns, but vary remarkably by country and source. And the definition of “<a href="http://doi.org/10.1111/add.13341">one standard drink</a>” used in each guideline is highly variable, and discrepant between country borders. This causes great confusion. Readers should be wary of this when interpreting alcohol consumption guidelines.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/191987/original/file-20171026-28071-ehn9yr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/191987/original/file-20171026-28071-ehn9yr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/191987/original/file-20171026-28071-ehn9yr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/191987/original/file-20171026-28071-ehn9yr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/191987/original/file-20171026-28071-ehn9yr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/191987/original/file-20171026-28071-ehn9yr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/191987/original/file-20171026-28071-ehn9yr.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">Most guidelines suggest a moderate consumption of no more than one or two alcoholic drinks per day. But is yours a 4 oz. or an 8 oz. glass?</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>The <a href="http://apps.who.int/iris/bitstream/10665/67210/1/WHO_MSD_MSB_01.6b.pdf">World Health Organization</a> recommends low-risk alcohol consumption of no more than two standard drinks per day with at least two non-drinking days during the week. Here one standard drink is defined as 10 g of pure ethanol.</p>
<p>The <a href="http://www.heart.org/HEARTORG/HealthyLiving/HealthyEating/Nutrition/Alcohol-and-Heart-Health_UCM_305173_Article.jsp#.Wef3zmhSxPY">American Heart Association</a> recommends alcohol in moderation — less than or equal to one to two drinks per day for men and one drink per day for women. Here one drink is defined as 12 oz. of beer, 4 oz. of wine, 1.5 oz. of 80-proof spirits, or 1 oz. of 100-proof spirits.</p>
<p>The <a href="https://health.gov/dietaryguidelines/2015/resources/2015-2020_Dietary_Guidelines.pdf"><em>Dietary Guidelines for Americans 2015 – 2020</em></a> developed by the United States Department of Agriculture recommends a moderate consumption of alcohol. This equates to up to two standard drinks per day for men and one for women. Here, one standard drink is defined as 14 g of pure ethanol.</p>
<p>The <a href="http://www.camh.ca/en/hospital/health_information/a_z_mental_health_and_addiction_information/alcohol/Pages/low_risk_drinking_guidelines.aspx">Canadian Centre for Addiction and Mental Health</a> guidelines recommend low-risk alcohol consumption — up to three drinks per day for men and two for women. One drink is defined as 12 oz. of 5 per cent beer, 5 oz. of 12 per cent wine, and 1.5 oz. of 40 per cent spirits.</p>
<h2>Future research opportunities</h2>
<p>Observational data around alcohol consumption and heart health suggests that a light-to-moderate intake, in regular amounts, appears to be healthy. However, when mathematical models have been applied to determine causation (an approach known as Mendelian randomization) the results have been mixed.</p>
<p>Some studies have found <a href="http://doi.org/10.1136/bmj.g4164">light-to-moderate drinking beneficial</a>, while others have reported <a href="http://doi.org/10.1093/eurheartj/eht081">long-term alcohol consumption to be harmful</a> for the heart. </p>
<p>For doctors, it is quite clear what to recommend to patients when it comes to diet, exercise and smoking. Given the inconsistencies in the findings relating to alcohol, and wine specifically, recommendations for consumption are less obvious. </p>
<p>For wine drinkers too, definitive answers on wine and health remain elusive. There is, however, immense research potential in this area for the future. </p>
<p>And as all the guidelines say, one or two glasses of red wine tonight will be just fine.</p>
<p><em>This is a corrected version of a story originally published Oct. 26, 2017. The earlier story mistakenly said as of 2014, more than 24 million litres of wine are consumed annually. The correct figure is 24 billion litres.</em></p><img src="https://counter.theconversation.com/content/85954/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors 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>Is a glass or two of red wine good for your heart? What about your cholesterol and blood pressure? Our experts explain the controversies.Adrian Baranchuk, Professor of Medicine, Queen's University, OntarioBryce Alexander, Medical Student, Queen's University, OntarioSohaib Haseeb, Student, Queen's University, OntarioLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/781962017-07-10T14:04:26Z2017-07-10T14:04:26ZThe ‘French paradox’ turned out to be an illusion, but it led to some interesting research<figure><img src="https://images.theconversation.com/files/171183/original/file-20170526-6402-12w26pr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Pourquoi si sain?</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/">Hadrian/Shutterstock.com</a></span></figcaption></figure><p>Everybody loved the French paradox. It was a term <a href="https://academic.oup.com/ije/article-lookup/doi/10.1093/ije/dyr138">coined</a> in 1980 by French scientists in <a href="http://www.sciencedirect.com/science/article/pii/S0140673680917961">their paper</a> on heart disease and fat intake. It refers to the fact that, despite consuming a diet high in saturated fat, French people have relatively low levels of <a href="http://www.nhs.uk/Conditions/Coronary-heart-disease/Pages/Introduction.aspx">coronary heart disease</a>, especially when compared with people in Britain. </p>
<p>A slew of studies followed, all <a href="http://www.sciencedirect.com/science/article/pii/S014067367992765X">seeming to support this idea</a>. In looking to explain the paradox, some scientists pointed to the fact that French people consume <a href="https://www.ncbi.nlm.nih.gov/pubmed/7996999?access_num=7996999&link_type=MED&dopt=Abstract">more wine per capita</a> than many other nations. Perhaps, they posited, red wine is some kind of superfood that has protective qualities.</p>
<p>It seemed, for a glorious few years, that we could gorge on cheese and saucisson, and then unclog our arteries with a bottle of claret. But, as the saying goes, if something sounds too good to be true, then it probably is. </p>
<p>Studies like those above are epidemiological and rely on making correlations between factors, such as heart health and red-wine drinking. But correlation is not causation, and one factor that had been ignored was that the French diet was generally healthier than other nations at the time, falling under the definition of a <a href="https://theconversation.com/what-is-the-mediterranean-diet-and-why-is-it-good-for-you-12656">Mediterranean diet</a>. This diet consists largely of fruits, vegetables, whole grains, legumes and olive oil, with limited amounts of lean protein from fish and poultry. Trials have <a href="http://hal.univ-grenoble-alpes.fr/hal-00395451/">demonstrated</a> that adhering to the Mediterranean diet is good for cardiovascular health.</p>
<h2>Not a complete waste of time</h2>
<p>So controlled trials support the role of a healthier diet in cardiovascular health rather than red wine consumption alone. However, disregarding the French paradox completely would be misguided – because researchers also identified a group of plant chemicals present in fruits, vegetables and wine that have health-giving properties, including protecting the heart. These chemicals are called polyphenols. One of the most studied polyphenols is resveratrol, which is found most abundantly in grapes and, therefore, red wine.</p>
<p>In nature, resveratrol is a protective chemical, supporting the plant when it comes under attack from insects, bacteria or too much ultraviolet light. These same protective properties are also seen in animal and human research trials with resveratrol. The problem is that humans would have to consume an inordinate amount of wine to equal the doses given in these studies. The 500mg resveratrol doses used in many human trials would equate to about 40 litres of wine. You’d be dead from alcohol poisoning before you could get this experimental dose. So why, you might wonder, do people still study resveratrol when it clearly cannot explain the French paradox? </p>
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<img alt="" src="https://images.theconversation.com/files/174524/original/file-20170619-22089-11v1bf1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/174524/original/file-20170619-22089-11v1bf1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/174524/original/file-20170619-22089-11v1bf1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/174524/original/file-20170619-22089-11v1bf1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/174524/original/file-20170619-22089-11v1bf1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/174524/original/file-20170619-22089-11v1bf1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/174524/original/file-20170619-22089-11v1bf1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Resveratrol helps fruit flies live longer.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/157780298?src=m3_VjZHZ94V5i8koPNna8A-1-0&size=medium_jpg">Roblan/Shutterstock</a></span>
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<h2>Boosting brain performance</h2>
<p>Despite the relatively high doses used in trials, resveratrol has provided some fantastic research findings. This began about a decade ago when it was found to significantly <a href="http://www.sciencedirect.com/science/article/pii/S0960982206010207">increase lifespan</a> in yeast, flies, worms and fish by essentially slowing their metabolism down. There is no evidence that resveratrol increases human lifespan, but findings suggests that resveratrol could slow the ageing process with its antioxidant and anti-inflammatory properties. </p>
<p>Resveratrol also acts like the female hormone oestrogen, and dietary phytoestrogen (plant-based oestrogen) has been shown to have a positive effect on <a href="http://journals.lww.com/menopausejournal/Abstract/2005/12020/Cognitive_improvement_after_6_weeks_of_soy.14.aspx">mood and mental performance</a> in women during the menopause, when oestrogen levels begin to decline. It may also help with osteoarthritis which is often experienced during the drop in oestrogen during the menopause. This research is still ongoing in humans in labs in Australia.</p>
<p>At the <a href="https://www.northumbria.ac.uk/about-us/academic-departments/psychology/research/brain-performance-and-nutrition-research-centre/">Brain Performance and Nutrition Research Centre</a> at Northumbria University, we are investigating the ability of resveratrol to improve blood flow in the human brain and the hypothesis that this can boost mental performance. </p>
<p>How does resveratrol do this? Simply by piggybacking on the body’s natural ability to raise blood flow when your brain is active – when you’re working out a sum for example – which involves a neurochemical called nitric oxide widening the blood vessels to that area of the brain. This extra blood provides more fuel (the sugar and oxygen in the blood) for greedy brain cells so that they can work out that sum quicker and more accurately. Resveratrol boosts this nitric oxide response further and so it might be expected that more fuel means better mental performance.</p>
<p>However, when we put this theory to the test on young, healthy volunteers, they didn’t seem to get a brain boost from <a href="http://ajcn.nutrition.org/content/91/6/1590.short">resveratrol</a>, and this is probably because they simply don’t need it. However, ongoing trials in our lab, which will be published later this year, will hopefully show that older people (50 to 70 years old) do benefit from this increased fuel provision; a finding we recently saw with other polyphenols – such as those <a href="http://ajcn.nutrition.org/content/101/3/538.short">found in cocoa</a>. So red wine can’t explain the French paradox but the polyphenols, like resveratrol, found in wine have a range of promising health benefits, and one of these might be to boost our brain power as we age.</p><img src="https://counter.theconversation.com/content/78196/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Emma Wightman 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>Red wine may not explain the French paradox but chemicals within it do have a positive effect on health.Emma Wightman, Senior lecturer in biological (specifically nutrition) psychology, Northumbria University, NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/264882014-05-12T20:21:40Z2014-05-12T20:21:40ZAnd now the bad news: red wine is not great for health after all<figure><img src="https://images.theconversation.com/files/48250/original/vwy5c3pj-1399870669.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Resveratrol, found in cocoa and red wine among other things, is just one of hundreds of potential health-promoting components in food.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/katewares/7530234326">Kate Ware/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>Nutrition research often loses sight of the wood for the trees by focusing on a single component of food. The latest example of this comes from <a href="http://archinte.jamanetwork.com/article.aspx?articleid=1868537">a study published in JAMA Internal Medicine</a> today that shows the much-hyped resveratrol may not be as super as previously touted.</p>
<p>Resveratrol is a naturally occurring plant chemical found in the skin of grapes, red wine, peanuts, cocoa powder, and certain berries and roots. There’s interest in the chemical because of its proposed antioxidant, anti-inflammatory, and potential anticancer effects. </p>
<p>Combine that with a possible role in extending lifespan (there’s <a href="https://www.landesbioscience.com/journals/epigenetics/FernandezEPI6-7.pdf">some evidence for this</a> in yeast and flies), and you can see why this common substance has captured the imagination of medical researchers and the public alike.</p>
<p>But despite all this interest, there’s little research linking resveratrol to favourable health outcomes when it’s a normal part of the diet. </p>
<p>Sure, using high doses of the stuff in supplement form has shown mixed benefits on inflammation and markers of heart disease in short-term studies. But there’s need for caution; studies with supplements are far removed from normal diets – a person would need to drink a case of red wine each day to get similar doses of resveratrol.</p>
<p>This latest <a href="http://archinte.jamanetwork.com/article.aspx?articleid=1868537">JAMA Internal Medicine paper</a> has filled this gap by looking at real-world diets and resveratrol consumption.</p>
<h2>What the study found</h2>
<p>The study authors looked for a link between resveratrol and health and longevity in a group of 783 elderly adults from the Chianti region of Italy. Rather than use dietary records to estimate how much each person was consuming from food, the researchers measured breakdown products of resveratrol metabolism in their urine.</p>
<p>So, with a more robust measure of resveratrol on hand, how had the health of this group of Italians fared when they were followed up nine years later? The answer was as you would expect; rates of cardiovascular disease, cancer, and mortality had no link with amounts of resveratrol metabolites in participants’ urine.</p>
<p>Even blood markers of inflammation, which lie at the heart of metabolic disease risk, had no link with resveratrol levels.</p>
<p>Still, one research study can’t prove or disprove a theory so it would be foolish to put too much weight on these results. Besides, there are problems with the study too – the number of participants is relatively small, and urinary resveratrol metabolites were only measured at the beginning of the study. </p>
<p>It could be that higher amounts of dietary resveratrol are needed for a beneficial effect. Still, as this was a group of people from Chianti following their traditional lifestyle, they were likely consuming ample wine and foods high in the chemical. </p>
<p>The authors did find that people with the highest levels of urinary resveratrol metabolites also drank the most alcohol, so wine was its most likely source.</p>
<h2>Drilling too far down</h2>
<p>Much of the interest in resveratrol comes from a theory that seeks to explain what’s known as the “French paradox”. The paradox is that the French have relatively low heart disease rates despite high consumption of saturated fat. </p>
<p>The resveratrol in red wine is thought to be the reason for this. Correlation does not prove causality but this theory about the French paradox has attained a life of its own. </p>
<p>In fact, the red wine and resveratrol theory is just one of dozens of plausible potential explanations for the link.</p>
<p>The French eat most of their meals at home, prepared from a wide variety of ingredients. Contrast that with diets containing similar amounts of saturated fat from mostly take-away or processed sources. </p>
<p>The fact is, saturated fat tells you little about the overall nutritional quality of a person’s diet. And this is the salient point here. Throwing the spotlight on individual nutrients, such as resveratrol, as being a health saviour or unfairly demonising single foods, such as sugar or saturated fat, takes the focus off the whole diet.</p>
<p>A dietary pattern of mostly unprocessed plant foods, which is also low in highly-processed foods and sugar, consistently comes out on top in offering the best long-term health.</p>
<p>Resveratrol is just one of hundreds of potential health-promoting components found in food, especially fruit and vegetables. It may yet prove to be another over-hyped field of nutrition research where individual nutrients are trumped by the whole diet. </p>
<p>Still, enjoying an odd glass of red and eating plenty of plant-based foods that don’t come in packages hedges your bets either way.</p><img src="https://counter.theconversation.com/content/26488/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim Crowe 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>Nutrition research often loses sight of the wood for the trees by focusing on a single component of food. The latest example of this comes from a study published in JAMA Internal Medicine today that shows…Tim Crowe, Associate Professor in Nutrition, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.