For decades, scientific research claimed moderate drinking was healthier than abstinence and may even extend life.
The research indicated that women who drink 25 grams of alcohol a day—less than two normal cocktails with 45 milliliters (1.5 ounces) of distilled spirits, two 360-ml beers, or two 150-ml glasses of wine—are more likely to die prematurely. With 45 g of alcohol a day, or three drinks, men’s chances grow dramatically.
A comprehensive study of 40 years of research found that many studies were faulty and the contrary is true.
The new research, which evaluated more than 100 studies of roughly 5 million individuals, was not meant to make drinking recommendations but to fix methodological issues in previous observational studies. These studies indicated that moderate drinkers were less likely to die from all causes, including alcohol-related ones.
Most of those studies were observational, so they could detect relationships but not establish cause and effect. Experts claimed that previous research neglected to notice that light and moderate drinkers had many other healthy behaviors and advantages, and that the abstainers employed as a comparison group typically included former drinkers who had quit following health issues.
The new report, published in JAMA Network Open last week, was co-authored by Canadian Institute for Substance Use Research scientist Tim Stockwell. “When you compare this unhealthy group to those who go on drinking, it makes the current drinkers look more healthy and like they have lower mortality,” he said.
Stockwell stated, “Lo and behold, the putative health benefits of drinking drop drastically, and become nonstatistically significant.”
Stockwell said comparing moderate drinkers to nondrinkers was incorrect for several reasons. Religious non-teetotalers are more likely to have chronic health issues, disabilities, or poor incomes.
Moderate drinkers are moderate overall. Wealthier, healthier, and less overweight, they exercise and eat well. Scientists report healthier teeth.
“They have a lot going for them that safeguard their health, that have nothing to do with their alcohol use,” Stockwell said.
Raymond Pearl, a Johns Hopkins scientist, presented a J-shaped graph in 1924 showing that moderate drinkers had the lowest rates of all-cause death.
The J’s peak symbolized heavy alcohol consumption’s hazards, such as liver disease and vehicle accidents. Left hooks represented abstainers.
Because news headlines highlighted its high percentage of resveratrol, an antioxidant found in blueberries and cranberries, wine, especially red wine, gained a reputation for being healthy.
As the alcohol industry’s role in funding research has come to light, the moderate alcohol hypothesis has come under increasing criticism, and newer studies have found that even moderate alcohol consumption, including red wine, may contribute to breast, esophagus, head and neck, high blood pressure, and atrial fibrillation.
Canada announced new guidelines in January advising individuals to drink less and warned that no quantity of alcohol is healthy. The 2011 Canadian Council on Substance Use and Addiction recommendations that women restrict themselves to 10 standard drinks a week and males to 15.
According to the Canadian organization, two normal drinks a week pose health hazards, while seven or more pose severe risks.
The U.S. dietary standards limit males to two drinks and women to one.
Several health groups now advise against drinking alcohol to improve health.
Although disagreeing with the current research, a Distilled Spirits Council scientist echoed that caveat.
Amanda Berger, Distilled Spirits Council vice president for science and health, said the new analysis still “suggests that those who drink in moderation live longer than those who do not,” but added, “no one should drink alcohol to obtain potential health benefits, and some individuals should not drink at all.”
The study’s authors found no statistically significant difference in lifespan between moderate drinkers and lifetime abstainers.