You might have heard that drinking some alcohol can be beneficial to your health. Some doctors might even advise drinking a glass of wine now and then, relying on studies that show the health benefits of moderate drinking. But it turns out that might be the wrong conclusion we’ve collectively taken from a series of studies with a significant problem that a new piece of research uncovered.
Scientists from Canada looked at 107 studies about drinking habits and longevity and discovered a huge flaw. Such research often compares two groups of people. For alcohol consumption, we have drinkers and people who abstain or consume very little alcohol. But the problem with the second category is that it might contain former heavy drinkers who quit along the way for various reasons, including health issues.
As a result, the group of abstainers or moderate drinkers might suffer from health issues directly related to former alcohol use, which can impact their life expectancy. But for the sake of those studies, they’d be labeled as non-drinkers.
In theory, the group of non-drinkers and light drinkers should be healthier than the drinkers. That’s not the case if you look at many old studies.
The group of people who don’t consume alcohol or drink very little contains former drinkers. As a result, the average health of this group is negatively impacted, making it look like moderate alcohol intake is good for you.
“It’s been a propaganda coup for the alcohol industry to propose that moderate use of their product lengthens people’s lives,” Dr. Tim Stockwell told The Guardian. “The idea has impacted national drinking guidelines, estimates of alcohol’s burden of disease worldwide and has been an impediment to effective policymaking on alcohol and public health.”
Stockwell and his team initially looked at the studies without disputing the quality of the non-drinkers group. The combined data suggested that light to moderate drinkers had a 14% lower risk of dying compared to abstainers. Light to moderate drinkers consumed between one drink a week and two a day.
They then started comparing the quality of the two groups in these studies. The highest-quality studies included younger people. Those papers also ensured that former and occasional drinkers were not considered non-drinkers. The conclusions of those studies were completely different. They saw no evidence that light to moderate drinkers would live longer than those who didn’t consume alcohol.
Only the studies that didn’t separate former drinkers from the group of abstainers saw health improvements for moderate alcohol use.
Stockwell further explained that the people who stopped drinking for health reasons and were then included in the abstainers group in the biased studies made those people who were healthy enough to keep drinking look healthier.
The Guardian points out that adults in the UK are told not to drink more than 14 units a week to reduce risk. Half a pint of beer is considered one unit, while 125ml (4.40 fl oz) of wine accounts for 1.5 units.
For the US, a quick search will get you to this (Centers for Disease Control and Prevention (CDC) page that says moderate drinking means two drinks or less a day for men and one drink a day for women.
However, the CDC also points out that no amount of alcohol intake will offer health benefits. The agency cites recent studies that say even moderate drinking increases the overall risk of death and chronic disease, including cancer and heart disease, compared to not drinking.
The next time your doctor tells you that drinking a glass of wine might be good for you, you might want to point them to the full study in the National Library of Medicine.
