Think Moderate Drinking Can Protect You From Stroke? Not So Fast

Bad news for those of us who have a drink with dinner every night — this old health claim doesn’t hold up, thanks to new evidence.

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If you’ve been using the claim that alcohol can protect you from stroke as an excuse to keep up your regular drinking habits, we have bad news for you: That claim has now been debunked.

While previous research suggested that having one or two drinks a day could reduce your risk of stroke, a large new genetic study published in The Lancet has disproved this idea.

While we already knew that heavy drinking increases your risk of stroke, people have come to believe moderate drinking (one to two drinks daily) was actually a way to protect against stroke — that’s because past research showed that people who drank that much had lower risks of heart attack and stroke compared with people who didn’t drink. But what we didn’t know then was whether that reduced risk was the result of the non-drinking, or the result of other underlying health problems — the old “correlation does not imply causation” conundrum.

But this new study gives us the answer, at least for strokes: Moderate drinking is not protective. In fact, it’s the opposite.

So how did the researchers figure this out once and for all? With the help of genetics. Turns out, there are some common genetic variants in East Asian populations that lower a person’s alcohol tolerability significantly. Basically, after people with these gene variants drink, they have a super unpleasant reaction (think red, flushed, or blotchy skin). As a result, these people tend to drink less. And these gene variants are passed down from parent to child at random, so using them in a study like this helps researchers get a clearer picture of their data.

"Using genetics is a novel way to assess the health effects of alcohol, and 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,” said lead study author Dr. Iona Millwood, from the Medical Research Council Population Health Research Unit at the University of Oxford, in a press release.

The study was huge, involving 500,000 Chinese adults — 160,000 of whom had the genetic variants known to reduce drinking. For the men in the study, the variants reduced the average alcohol intake dramatically (from about four drinks a day to nearly zero) — and stroke risk and blood pressure also dropped in these men. The study found that alcohol increases stroke risk by about one-third (35%) for every four additional drinks per day (280 grams of alcohol in a week). And, unfortunately for those of us who enjoy a glass of wine or two with dinner, they found no protective effects with light or moderate drinking (two or fewer drinks), either.

"Even moderate alcohol consumption increases the chances of having a stroke,” said Zhengming Chen, co-author from the Nuffield Department of Population Health, University of Oxford, in the press release. “The findings for heart attack were less clear-cut, so we plan to collect more evidence."

“But what about women?” you may ask. Here’s the thing: Chinese women aren’t big drinkers — less than 2% of the women in the study drank most weeks, and those who did drank less than the men. Because of this, the researchers used women as a control group to help confirm that stroke risk differences in the men truly were caused by alcohol consumption, rather than other factors.

However, the study authors still believe their findings apply to people worldwide — men and women. So instead of reaching for that after-work beer every day, maybe opt for a healthy smoothie or plain old water instead.

Beyond alcohol, there are plenty of other steps you can take to lower your stroke risk:

  • Quit smoking! Compared with nonsmokers, smokers have at least double the risk of stroke.
  • Watch your blood pressure. Making sure it’s in normal range can significantly reduce your stroke risk.
  • Treat heart disease if you have it.
  • Maintain a healthy weight — being overweight increases your risk.
  • Exercise, exercise, exercise! Inactivity is a key risk factor for stroke.
  • Eat a healthy diet: Lots of fruits and veggies, and try to cut down on the salt.

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