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For decades, scientific studies suggested that moderate drinking was better for most people’s health than not drinking at all, and that it could even contribute to longevity. Supporting this view, a previous meta-analysis of the association between alcohol use and all-cause mortality found no statistically significant reductions in mortality risk at low levels of consumption compared with lifetime nondrinkers. However, according to a recent study, the risk estimates may have been affected by the number and quality of studies then available. A recent publication in the Journal of the American Medical Association has concluded that many of these earlier studies were flawed and that the opposite is true, in particular for women and younger individuals.

“…the risks of dying prematurely increase significantly for women once they drink 25 grams of alcohol a day, which is less than … two 5-ounce glasses of wine.”

This new systematic review and meta-analysis of 107 cohort studies involving more than 4.8 million participants found no significant reductions in risk of all-cause mortality for drinkers who drank less than 25 g of ethanol per day (about 2 Canadian standard drinks compared with lifetime nondrinkers) after adjustment for key study characteristics such as median age and sex of study cohorts.

The review found that the risks of dying prematurely increase significantly for women once they drink 25 grams of alcohol a day, which is less than two standard cocktails containing 1.5 ounces of distilled spirits, two 12-ounce beers or two 5-ounce glasses of wine. The risks to men increase significantly at 45 grams of alcohol a day, or just over three drinks.

“… light and moderate drinkers are systematically healthier than current abstainers on a range of health indicators unlikely to be associated with alcohol…”

Like the majority of food and lifestyle related studies, most studies on the effects of alcohol on health have been observational, meaning they could identify links or associations caused by factors other than alcohol consumption. They could therefore be misleading and did not prove cause and effect. In particular, that light and moderate drinkers are systematically healthier than current abstainers on a range of health indicators unlikely to be associated with alcohol use such as, dental hygiene, exercise routines, diet, weight, and income. At the same time, lifetime abstainers may be systematically biased toward poorer health, including “sick quitters”, or former drinkers, many of whom cut down or stop for health reasons. In addition, people who abstain completely from alcohol are a minority, and those who aren’t teetotalers for religious reasons are more likely to have chronic health problems. These so-called confounding factors and not the moderate alcohol consumption may have caused the more positive health outcomes in several studies.

Another more important confounding factor is the close association of daily, moderate red wine consumption with longevity in so called Blue Zones, regions around the world with an increased percentage of so-called centenarians, e.g. individuals that live into their hundreds without major health problems. A large number of studies has identified several lifestyle factors, including regular moderate physical exercise, food and the regular consumption of 1-2 glasses of red wine. Even though moderate wine consumption has been practiced for thousands of years and is an essential part of the culture of Mediterranean and Latin countries, it may be the intricate association of the Mediterranean lifestyle, in particular the close social interactions, with the consumption of moderate amounts of wine that produce the observed health benefit.

“…wine — and particularly red wine — developed a reputation for having health benefits after news stories appeared around its high concentration resveratrol and other polyphenols.”

In more recent decades, wine — and particularly red wine — developed a reputation for having health benefits after news stories appeared around its high concentration resveratrol and other polyphenols. Polyphenols are large, poorly absorbable molecules which are produced by most plants, providing multiple benefits to the plants’ health, including protection against UV light, pests and drought. Once consumed by humans, these large molecules are converted by our gut microbes into smaller absorbable entities which are beneficial for the health of our gut microbiome, for gut health and for many organs in our bodies, including the brain. In addition to the stilbene Resveratrol, red wine contains different members of the Flavonoid family, including flavanols (also contained in cocoa beans), flavonols (also contained in green leafy vegetables and onions) and anthocyanins (also contained in black and blue berries). Berries as well as the skin of red grapes also have high concentration of resveratrol. It has been suggested that these health promoting molecules contained in wine not only contribute the unique flavor to different wines, but that they are the reason for the health benefit of moderate wine consumption.

But the moderate alcohol hypothesis has come under increasing criticism over the years as the alcohol industry’s role in funding polyphenol research has come to light. Newer studies have found that even moderate consumption of alcohol — including red wine — may contribute to cancers of the breast, esophagus and head and neck, high blood pressure and a serious heart arrhythmia called atrial fibrillation.

“Regular moderate consumption of red wine (e.g. 2 glasses per day) when embedded into a healthy lifestyle with regular physical exercise, a healthy diet and close social interactions are likely to have a synergistic effect which is good for our physical and mental health.”

My personal opinion on this topic is somewhat different from the recommendation based on the recent meta-analysis. Regular moderate consumption of red wine (e.g. 1 glass per day) when embedded into a healthy lifestyle with regular physical exercise, a healthy diet and close social interactions are likely to have a synergistic effect which is good for our physical and mental health. This view is not only supported by a large number of epidemiological studies; thousands of years of experience of people living in the Mediterranean basin practicing such a lifestyle cannot be wrong.