Drinking reasonable amounts of red wine and other alcohol for the health benefits has long been touted by wine aficionados and casual drinkers alike. But the widely reported and beloved tidbit of conventional pop science wisdom — moderate drinking is good for your health! — has always been less reliable than the rhetoric might have indicated, and new research is casting more doubt on the finding.
A team led by Tim Stockwell, the director of the Centre for Addictions Research at the University of Victoria in Canada, examined 45 studies of drinking behavior and health outcomes and found little evidence of a causal benefit from drinking moderate amounts of alcohol. The meta-analysis was published this month in the Journal of Studies on Alcohol and Drugs.
“We can’t ‘prove’ it one way or the other,” Stockwell said. “But we can say there are grounds for a healthy skepticism around the idea that moderate drinking is good for you.”
Red wine has typically been touted as producing nearly magical health benefits, but the evidence for the effects of this specific drink in humans has long been slim. Instead, the research has pointed to benefits from moderate drinking of any alcohol.
However, this research has always had a troubling flaw: It was largely based on observational studies. Scientists use observational studies to detect associations between different variables in the environment. Many studies found that people who drank moderately also appeared to have better health outcomes on a variety of measures than people who abstained from drinking. (People who binge drink, as we know, face many health risks.)
Sometimes researchers can infer causal stories from these types of studies — the research linking smoking and lung cancer was largely of this sort — but they can also lead to spurious results. An observational study might tell you, for instance, that people with white hair are much more at risk at heart attack than other people. But this doesn’t mean white hair is causing heart attacks; it simply tells us what we already know, which is that older people are both more likely to have white hair and more likely to have heart health issues.
Instead of using observational studies, Stockwell and his team instead looked at cohort studies, which track a set group of people and their behaviors over a set period of time. They found that the correlation between moderate drinking and some beneficial health outcomes may be spurious, just like the connection between white hair and heart attacks.
“We know that people generally cut down on drinking as they age, especially if they have health problems,” Stockwell said. “People who continue to be moderate drinkers later in life are healthier,” Stockwell said. People who stop drinking, on the other hand, often do so because they’re sick or because they take medications that could interact with alcohol.
In other words, it may be true that people who drink moderately are healthier than those who don’t, but that doesn’t mean that moderate drinking causes people to have better health outcomes.
He added: “The notion that one or two drinks a day is doing us good may just be wishful thinking.”