Alcohol: it’s not true that wine “makes good blood”

For a long time, drinking a glass (and only one!) of red wine with dinner has been a common recommendation from family physicians, due to the purported benefits of low alcohol consumption on cardiovascular health. Now, however, a study published on JAMA Network Open refutes this clich̩ Рthe result, it seems, of some methodological problems in studies on the subject.

There is no alcohol level, even moderate, that does not imply even a slight risk of heart problems. This risk remains low (but not equal to zero) if we limit ourselves to no more than seven drinks per week, but increases gradually and significantly if this threshold is exceeded.

It’s not about alcohol. In fact, some previous research has shown that modest alcohol consumption can, for unspecified reasons, protect the heart. In fact, moderate drinkers seemed to be less often affected by heart disease than not only heavy drinkers, but abstainers as well.

This apparent protective effect was also found in the new analysis conducted by Massachusetts General Hospital and the Broad Institute of MIT. But that was just a mistake: the fact is that those who consume moderate amounts of alcohol (up to 14 drinks per week) also tend to have other lifestyles that lower the risk of cardiovascular disease. , such as smoking less or not smoking, doing more .exercising and having a lower body weight than those who drink heavily or those who do not drink at all.

Clarify relationships. This conclusion was reached through analyzes of medical and genetic data from nearly 400,000 people cataloged on the UK Biobank, a large UK medical database often used for studies of genes, lifestyle and health. We focused on adult subjects with an average age of 57 years and an average alcohol consumption of 9.2 drinks per week. It is not known why those who consume alcohol in moderation tend to be healthier: but to clarify whether this is due to alcohol, i.e. to understand whether there is a cause and effect between light alcohol consumption and cardiac protection, the team used a statistical approach called Mendelian randomization.

This technique uses genetic variants of interest to be studied as a tool to isolate the effects of a behavior under study, in this case alcohol consumption. Indeed, we know that certain genetic variants predispose to heavy consumption of alcohol and others to lighter consumption. Since these variants are randomly distributed in the population, they can be used in the study in a manner equivalent to the random assignment of tasks to the subjects concerned: it is as if some were assigned the task of drinking a lot during a certain period of time and others that of drinking little, and then they pulled the strings. Except that it is not the researchers who decide but the genes inherited at birth.

Drinking alcohol is always bad. At this point, as The New York Times explains, it’s debatable whether people with variants that predispose to drinking have cardiovascular problems more often than those with genetic variants linked to softer drinking. The answer is that individuals with variants predisposing to greater alcohol consumption actually drank more than others and were also more likely to develop hypertension or coronary heart disease. This increased risk is contained at first, but then the chances of getting sick increase exponentially, they like as the number of weekly drinks or other concomitant factors, such as obesity or diabetes, increase.

For example, if a middle-aged person who does not drink alcohol has a 9% chance of getting heart disease, for those who drink a glass of wine a day the chance is 10.5%: a small increase, but beyond this limit. one drink a day the risk increases more significantly. Compared to other purely observational studies, which were limited to monitoring patients’ alcohol consumption and health problems over a period of time and measuring a correlation between the two, the new work suggests a causal relationship. more direct link between alcohol and disease. cardiac.

Misleading advice. “It’s clear from our findings that alcohol consumption should not be recommended for improving cardiovascular health,” says Krishna G. Aragam, a cardiac prevention expert at Massachusetts General Hospital and one of the study’s authors. “Indeed, reducing alcohol consumption is likely to reduce cardiovascular risk in all people, although to a different extent depending on how much they currently drink.” Since the risk increases exponentially the more alcohol one consumes, the benefits of a drastic reduction would be even more evident in those who drink more.

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