New Evidence Challenges the “Glass-of-Wine-a-Day” Myth: Any Amount of Alcohol May Increase Dementia Risk

For decades, light drinking has been painted as a heart-healthy habit — even touted as “good for the brain.” But a new landmark study published in BMJ Evidence-Based Medicine (September 2025) challenges that long-standing belief, providing the clearest genetic evidence to date that any level of alcohol use increases dementia risk.

What the Study Found

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Researchers from Oxford, Yale, and Harvard analyzed data from over 2.4 million people across the U.S. Million Veteran Program and the UK Biobank. They combined traditional population data with Mendelian randomization — a genetic method that helps distinguish correlation from true causation.

• Observational results (based on self-reported alcohol use) showed a familiar U-shaped curve: nondrinkers and heavy drinkers appeared to have higher dementia risk, while light drinkers seemed to fare best.

• Genetic analysis, however, told a different story. When researchers used genetic markers that predict lifetime alcohol consumption, the curve disappeared. Instead, dementia risk increased steadily with greater alcohol intake, with no safe or protective level found.

In other words, the supposed benefits of “moderate drinking” likely reflect reverse causation — meaning people in the early stages of cognitive decline may naturally cut back on drinking, making it seem like moderate drinkers are healthier.

Key Numbers

• Every 1 standard deviation increase in genetically predicted alcohol consumption (roughly equivalent to a few extra drinks per week) was associated with a 15% higher risk of dementia.

• Having a genetic predisposition to alcohol use disorder raised dementia risk by 16%.

• Researchers estimate that halving the population prevalence of alcohol use disorder could prevent up to 16% of dementia cases.

What This Means for You

This research upends the old narrative that a little alcohol is neuroprotective. The genetic data suggest that even “moderate” drinking — whether a nightly glass of wine or weekend cocktails — contributes to long-term brain aging and cognitive decline.

It also highlights an important point in brain health: what feels normal in midlife can have silent, cumulative effects on the brain’s resilience decades later.

For patients in my concierge and longevity practice, we discuss alcohol not in moral terms, but as a modifiable neurotoxin. The focus is on protecting the brain’s vascular and metabolic health — reducing inflammation, improving sleep, and preserving cognition through nutrition, movement, and restorative therapies.

The Bottom Line

This BMJ study reinforces what advanced neuroimaging and longevity science have been suggesting for years: there’s no truly “safe” level of alcohol when it comes to brain health. The healthiest brain is one that doesn’t rely on ethanol for relaxation, reward, or social connection.

That doesn’t mean perfection — but it does mean awareness. Each drink is a choice that tilts the balance between short-term pleasure and long-term cognitive preservation.

Reference:

Topiwala A, Levey DF, Zhou H, et al. Alcohol use and risk of dementia in diverse populations: evidence from cohort, case–control and Mendelian randomisation approaches. BMJ Evidence-Based Medicine. Epub ahead of print, September 2025. DOI: 10.1136/bmjebm-2025-113913