Groundbreaking Genetic Study Finds That Even Moderate Drinking Can Still Increase Stroke Risk

There were studies claiming that small amounts of alcohol may help lower the risk of heart diseases and stroke. However, some studies show the only safe level of alcohol consumption is zero.

A large cohort study in Chinese population contradicts previous researchers suggesting that drinking one to two glasses a day might protect against stroke.

The Dietary Guidelines for Americans Trusted Source defines one standard drink of alcohol as:

  1. a bottle of regular beer
  2. a small glass of wine
  3. a single measure of distilled spirits

The study which was conducted by the team from the University of Oxford, Peking University and the Chinese Academy of Medical Sciences and was published in 2016 in the journal BMC Medicine has found even drinking one to two glasses a day increased stroke risk by 10 to 15 percent.

The co-author author and Oxford Nuffield Department of Population Health professor Zhengming Chen told Reuters that:

“The key message here is that, at least for stroke, there is no protective effect of moderate drinking. The genetic evidence shows the protective effect is not real.”

For heavy drinkers, such as those who drink four or more glasses a day, they had an average of 38 percent higher risk of stroke.

The study consists of 500, 000 people from China (both men and women with 33 percent of the male subjects and 2 percent of the women consumed alcohol) were followed for 10 years. Researchers tracked their drinking habits and cardiovascular incidents such as heart attack or stroke. If they are going to base the results on the self-reporting of alcohol consumption, they found that that drinking 100 grams of alcohol a week (one to two drinks a day) did seem to ward off stroke. But when researchers predicted the mean amount of alcohol consumption by participants based on the genetic data and location, the protected effect disappeared. Results revealed that every additional 280 grams of alcohol consumption each week can increase the risk for stroke by 38 percent.

The study author and Oxford epidemiologist Iona Millwood explained that:

“Using genetics is a novel way … to sort out whether moderate drinking really is protective, or whether it’s slightly harmful. Our genetic analyses have helped us understand the cause-and-effect relationships.”

After results were revealed, researchers were confident enough about it because they were able to separate the impact of alcohol on health from other factors through the use of a unique genetic variant common in the Asian population.

David Spiegelhalter, a University of Cambridge Winton Professor for the Public Understanding of Risk and was not involved with the research commented that:

“This is a very impressive study which shows that men who, by chance, have a combination of genes that put them off drinking alcohol have a lower risk of stroke compared with those without these genes.”

“The fact that this is not true for Chinese women, who tend not to drink whatever their genes, suggests this effect is due to the alcohol rather than the genes themselves. I have always been reasonably convinced that moderate alcohol consumption was protective for cardiovascular disease, but now I am having my doubts.”