A glass of wine a day is meant to bolster longevity and healthy living, but now the scientific evidence behind this, is being questioned. New research analysing 87 studies into the effects of moderate drinking found that many had a flawed methodology.
It turns out many studies showing that moderate drinkers live longer than non-drinkers suffer from a big flaw: The "abstainers" category includes people who used to drink but have stopped, sometimes for health reasons. They may be inherently less healthy, as a group, than people who drink in moderation. That doesn't mean that drinking in moderation causes people to live longer.
‘If people choose to drink - usually for reasons other than health - they should not exceed two drinks on any given day to minimise their health risks.’
Researchers at the University of Victoria in British Columbia examined 87 studies on the relationship between alcohol and mortality that together involved nearly four million people. Only 13 of them strictly separated life-long non-drinkers from people who used to drink or those who imbibe only occasionally.
Analyzing the studies that were free from "abstainer bias" showed no significant benefits for moderate drinkers compared to lifetime abstainers. And when they compared moderate drinkers with those "occasional drinkers" who consumed alcohol less than once a week, they found no benefit to drinking more often, said Tim Stockwell, lead author of the paper and director of the Center for Addictions Research of BC.
"People should not drink for health - health benefits can be obtained in many ways and drinking in any pattern is not a reliable means to this end," Stockwell added by email. "Most of us enjoy alcohol, and drinking lightly and occasionally presents the least risk."
The research on potential health benefits of alcohol needs a more skeptical evaluation, by scientists, journalists, and the public alike, said Stockwell, the study's lead author.
Charles Parry, an alcohol and drug abuse epidemiologist at the South African Medical Research Council, found that more and more scientific literature challenged the supposed health benefits of moderate drinking. "The pendulum is going against the health benefits of moderate drinking," he said.