Moderate drinking may not ward off heart disease

That's the conclusion of a new research review in the May 2017 issue of the Journal of Studies on Alcohol and Drugs.

Over the years, studies have found that adults who drink moderately have lower heart disease rates than non-drinkers. That has spurred the widespread belief that alcohol, in moderation, does a heart good.

But the new analysis, of 45 previous cohort studies, reveals the flaws in that assumption: A central issue is that "non-drinkers" may, in fact, be former drinkers who quit or cut down for health reasons.

Furthermore, seniors who are healthy may be more likely to keep enjoying that glass of wine with dinner.

"We know that people generally cut down on drinking as they age, especially if they have health problems," said researcher Tim Stockwell, Ph.D., director of the Centre for Addictions Research at the University of Victoria, in British Columbia, Canada.

"People who continue to be moderate drinkers later in life are healthier," Stockwell said. "They're not sick, or taking medications that can interact with alcohol."

And in studies, that can lead to a misleading association between moderate drinking and better health.

In their analysis, Stockwell's team found that overall, "current" moderate drinkers (up to two drinks per day) did, in fact, have a lower rate of heart disease death than non-drinkers.

However, that was not the case in studies that looked at people's drinking habits at relatively young ages -- age 55 or earlier -- and followed them to their older years when heart disease might strike. Similarly, studies that rigorously accounted for people's heart health at baseline indicated no benefits from moderate drinking.

According to Stockwell, it all suggests that "abstainers" tend to be less healthy than moderate drinkers -- but not because they never drank. Instead, their health may influence their drinking choices. That is, they may not drink because their health is poor.

"We can't 'prove' it one way or the other," Stockwell noted. "But we can say there are grounds for a healthy skepticism around the idea that moderate drinking is good for you."

A second study in the same issue supports that.

That research followed more than 9,100 U.K. adults from the age of 23 to 55. Overall, researchers found that people's drinking habits evolved over time -- and few were actually lifelong "abstainers." Nearly all people who were non-drinkers at age 55 had given up alcohol.

What's more, non-drinkers -- even those in their 20s -- tended to be in poorer physical and mental health compared with those who drank moderately and did not smoke. They were also, on average, less educated, and education is an important factor in lifetime health.

However, no one is saying that people who enjoy alcohol in moderation should stop.

"The risks of low-level drinking are small," Stockwell said. But, he added, people should not drink solely because they believe it wards off disease.

"The notion that one or two drinks a day is doing us good may just be wishful thinking," Stockwell said.