A new review finds that moderate drinking is associated with a lower risk of memory problems and Alzheimer’s disease or other forms of dementia.
The authors analyzed results from 143 studies, dating back to 1977, which included 365,000 participants in 19 countries. The studies compared non-drinkers to drinkers: 74 of the studies looked at the risk of dementia, while the other 69 focused on memory problems.
The review found that moderate drinkers were 23% less likely than teetotalers to develop signs of memory problems or Alzheimer’s. That effect was significant in 14 of the 19 countries, including the U.S.
Heavy drinkers, on the other hand, tended to have a higher risk of memory problems and dementia than non-drinkers, but that association was not statistically significant, researchers said.
If you’re keeping score, moderate drinking means one drink a day for women and two drinks a day for men. Heavy drinking means three to five drinks or more a day. One drink is defined as 1.5 oz. of spirits, 5 oz. of wine, or 12 oz. of beer.
Wine appeared to have more of a protective effect than beer or spirits, but that finding was based on a small number of studies, so there’s not enough data to make a distinction between types of alcohol, the authors said.
While the analysis didn’t offer an explanation for why drinking may lower the risk of cognitive decline, the researchers theorized that alcohol may have anti-inflammatory properties. Inflammation is thought to play a role in Alzheimer’s disease (along with other conditions like heart disease and stroke), and moderate amounts of alcohol may suppress inflammation in the brain; too much alcohol could stimulate it, the authors suggested.
Further, reported HealthDay:
[O]ne premise suggests that alcohol might improve blood flow in the brain and thus brain metabolism, the researchers said. And they offered up another theory, that small amounts of alcohol may make brain cells more fit by slightly stressing them and increasing their ability to cope with major levels of stress that can eventually cause dementia.
The findings don’t suggest that nondrinkers start chugging alcohol to stave off Alzheimer’s. The study showed only an association, not cause and effect. It’s possible, for example, that moderate alcohol consumption was a marker for an overall healthier lifestyle — like eating a heart-healthy diet, exercising and maintaining positive social relationships — all of which may also help lower the risk of dementia.
But for those who do consume alcohol, the authors say moderation is key. “Social drinking can be a very positive thing as long as it is not excessive and doesn’t exceed a drink per day for women or two drinks for men,” Christy Tangney, an associate professor of clinical nutrition at Rush University Medical Center in Chicago, told WebMD. “Light-to-moderate drinking appears to benefit cognitive performance.”
The analysis was published in the journal Neuropsychiatric Disease and Treatment.
Meredith Melnick is a reporter at TIME. Find her on Twitter at @MeredithCM. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.