Much ado has been made about the latest study on the effects of alcohol on brain power with advancing age, though we really shouldn’t be surprised that it found support for moderate drinking. The study was impressive in scope: nearly 20 000 individuals drawn from the “Health and Retirement Study” across the U.S. had their cognitive function tested regularly over a period of more than 9 years. Analysis of lifestyle factors revealed that low-to-moderate drinking was associated with “a consistently high cognitive function trajectory and a lower rate of cognitive decline.” They fared better than never drinkers and heavy drinkers alike, and the effect applied for both men and women. Previous studies have found similar patterns, but the scale of this one lends a hefty level of support.
Previous studies of this type have been criticized for lumping former drinkers together with never drinkers, which could skew the comparative risk for that group; if former drinkers have worse health status or impairment from previous alcohol abuse for example, it brings the average down (“sick quitter” hypothesis.) This study addressed that issue by separating “never drinkers” from former drinkers, adding support to the findings. The J-shaped curve for moderate regular drinkers remained.
Unfortunately the study didn’t attempt to separate wine drinkers from consumers of mostly beer or spirits. Likely this was due to a recognition that few Americans have truly consistent drinking habits in the traditional sense, which would make parsing such data unreliable. There is good reason to attribute much of the benefit to wine however. For one, a consistent finding across most studies on lifestyle and senile dementia is an inverse correlation to moderate regular wine consumption. Among the possible explanations is that the hippocampus, a brain structure associated with memory processing, retains volume better in wine drinkers as they age, according to a Framingham Study cohort that underwent serial brain MRIs.
The trap here is conflating correlation with causation. Wine drinkers are generally a smarter and better educated set to begin with. Or maybe it is resveratrol’s vaunted effects on the brain. Neither one fully explains this study’s findings, however, which is actually one of its strengths. What the study tracked was rate of decline in cognitive function, which is not necessarily affected by starting out smarter. And finding a benefit to moderate drinking with all types of drinkers lumped together strongly suggests that there is a role for alcohol beyond and above any particular component in wine. So to get the benefits of wine, you have to drink the wine.
But then you knew that.
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 Andrade S, Ramalho MJ, Pereira MDC, Loureiro JA. Resveratrol Brain Delivery for Neurological Disorders Prevention and Treatment. Front Pharmacol. 2018;9:1261.