'Flawed research' behind alcohol's health benefits claim: Study

Studies claiming that moderate alcohol consumption boosts longevity and reduces heart and chronic disease risks are based on "flawed research," a new study finds.

Published over the years, such studies have led to a widespread belief that alcohol can be healthy, if taken in moderation, ranging from a drink in a week to two per day.

Health benefits a myth?

Researchers found that these studies have largely focussed on moderate drinking among older adults, and compared them with 'abstainers' and 'occasional drinkers' — both these groups were found to also include older adults who had quit or cut down on drinking because they had developed health conditions.

"That makes people who continue to drink look much healthier by comparison," said lead researcher Tim Stockwell, a scientist with the Canadian Institute for Substance Use Research, University of Victoria.

Thus, by failing to account for people's lifetime drinking habits, the studies "suffer from fundamental design flaws," according to the authors. The findings are published in the Journal of Studies on Alcohol and Drugs.

No 'safe' level of drinking

"There is simply no completely 'safe' level of drinking," Stockwell said.

The team identified 107 published studies looking at the relationship between drinking habits and longevity.

Combining all the data, it looked like light to moderate drinkers had a 14 per cent lower risk of dying during the study period compared with those abstaining from alcohol, the researchers said.

However, looking at all the data more closely, they found that in "higher quality" studies — that analysed drinking habits of people on average younger than 55 and made sure that former and occasional drinkers were not counted as 'abstainers' — alcohol in moderation was not linked to a longer life.

"As predicted, studies with younger cohorts and separating former and occasional drinkers from abstainers estimated similar mortality risk (between) low-volume drinkers (and) abstainers," the authors wrote.

'Lower quality' studies

Instead, "lower quality" studies, involving older adults and not differentiating between former drinkers and lifelong abstainers, were the ones that linked moderate levels of drinking with greater longevity, the authors said.

"If you look at the weakest studies, that's where you see health benefits," Stockwell said.

Because of these biases in sample selection, the studies could create misleading links between drinking and health benefits, and "can confuse communications about health risks," the authors said.

The links between moderate alcohol consumption and health benefits are said to have been first published in 1926 in a book by American biologist Raymond Pearl, called 'Alcohol and Longevity.' In recent years, multiple studies have found that there is no such thing as a 'safe level of alcohol consumption'.

The World Health Organization (WHO) in January 2023 published a statement in The Lancet Public Health journal: "When it comes to alcohol consumption, there is no safe amount that does not affect health." 

(With agency inputs)