Pop quiz: What is the one modifiable lifestyle factor associated with the lowest rate of decline in mental function with age? (Hint: It isn’t doing Sudoku or crossword puzzles, though I am a fan.) (Another hint: This is a blog about the health benefits of wine.)
With rare exception, wine consumed regularly and in moderation is the only lifestyle factor that appears protective against age-related dementia and overall mental decline in every large population study on the subject.[i] Whether due to associated behaviors or something biochemically powerful in wine, there is no escaping the conclusion that wine drinkers have better brains as they age. If you are familiar with this topic, you may be tempted to attribute this to resveratrol, wine’s miracle molecule. Some studies show that it may have unique properties against the plaques in the brain associated with Alzheimer’s, while others find enhancement of certain brain functions. But there isn’t a lot of resveratrol in anything normally consumed, including wine, and a large study in Italy found no correlation of resveratrol metabolites (a measure of consumption of resveratrol-containing foods & wine) to health status, including mental function.[ii] Resveratrol is not solely responsible for the benefits of wine on the brain.
How alcohol helps clear toxins from the brain
So if not resveratrol, then what? Surprisingly, it may actually be the alcohol itself, at least to a degree. In recent years, the brain’s waste-clearance apparatus, called the glymphatic system, has been characterized.[iii] The glymphatic system works the way the lymphatic system does in the rest of the body, flushing away the toxic flotsam of various metabolic processes. Known methods of enhancing glymphatic flow include regular sleep and exercise.
And alcohol, in the right amounts. In 2018, scientists at the University of Rochester and others reported a J-shaped curve for alcohol and glymphatic flow, with moderate levels enhancing it and high levels inhibiting.[iv] This parallels the relationship of overall wine consumption and degenerative disease. But while such a correlation is intriguing, in and of itself it isn’t compelling without a plausible explanation of why and how they might be related. Fortunately a recent study provides some insight into how alcohol promotes glymphatic flow and thereby taps the brakes on age-related deterioration of brain performance.[v] Via a specific effect related to dilation of the blood vessels of the central nervous system and the glymphatics that course alongside them, alcohol was found to produce enhanced clearance of metabolic waste products. This included the beta-amyloid proteins associated with Alzheimer’s disease!
So think of a glass of wine as a sort of lymphatic massage
for your brain.
[i] See Chapter 8 in my book Health and Wine: Making sense of the new science and what it means for wine lovers, Wine Appreciation Guild, San Francisco, 2019.
[ii] Semba RD, Ferrucci L, Bartali B, Urpí-Sarda M, Zamora-Ros R, Sun K, Cherubini A, Bandinelli S, Andres-Lacueva C. Resveratrol levels and all-cause mortality in older community-dwelling adults. JAMA Intern Med. 2014 Jul;174(7):1077-84.
[iii] Blanchette M, Daneman R. The amazing brain drain. J Exp Med. 2017 Dec 4;214(12):3469-3470.
[iv] Lundgaard I, Wang W, Eberhardt 2, Vinitsky HS, Reeves B, Peng S, Lou N, Hussain R, Nedergaard M. Beneficial effects of low alcohol exposure, but adverse effects of high alcohol intake on glymphatic function.
Sci Rep. 2018 Feb 2;8(1):2246.
[v] Cheng Y, Liu X, Ma X, Garcia R, Belfield K, Haorah J. Alcohol promotes waste clearance in the CNS via brain vascular reactivity. Free Radic Biol Med. 2019 Nov 1;143:115-126.