But the tide is turning. Last month, a review of studies on the topic found that much of this previous research didn't control for confounding factors, casting doubt on the premise that moderate drinking comes with a protective health halo.
On Monday, a new study was released that goes further: published in BMJ, it suggests that moderate drinking can actually lead to cognitive decline.
Researchers used data from a study that tracked 550 health men and women between 1985 and 2015. After controlling for a variety of factors, including age, education, physical and social activity, social class, and medical history, they found a link between alcohol consumption and an increased risk of cognitive decline.
While this connection was strongest for the heaviest drinkers, it was also present for moderate drinkers, i.e. those who consumed between 14 to 21 units per week —or about seven to 10 drinks. By the end of the study, this group was three times more likely to exhibit hippocampal atrophy, an early marker of Alzheimer’s disease, as those who didn’t drink. They also exhibited a 17% decline in language fluency, a measure of executive functioning, compared to participants who drank less than seven units per week.
Author Anya Topiwala, a clinical lecturer at the University of Oxford, says these results should serve as a wake up call for anyone who believes moderate drinking is a healthy activity. Previous studies have made this seductive claim, but many failed to control for key variables, such as IQ and physical activity. (Drinkers tend to have stronger social networks and more education than non-drinkers.) Once you level the playing field, alcohol's deleterious impact on the brain comes into sharper focus.
Taken to its extreme, the study suggests it's time to rethink how we view casual drinking, now widely seen as a harmless, social activity. Memory loss is an area that "doesn't have many cures," Topiwala says. But the negative side-effects that come with moderate drinking "is something we can prevent.”
For everyone out there who likes to relax after work with a glass of wine—or two—this is disheartening news. Topiwala feels your pain: “We were disappointed, too."