A major new study has found that drinking alcohol—even in small amounts—likely increases the risk of developing dementia.
This finding challenges the common belief that light or moderate drinking may be good for brain health. The study, published in BMJ Evidence Based Medicine, is the largest of its kind and used both observational and genetic data to examine how alcohol affects dementia risk.
The researchers looked at data from two large databases: the US Million Veteran Program (MVP) and the UK Biobank (UKB).
These databases include hundreds of thousands of people from different backgrounds. Most of the participants were between the ages of 56 and 72 when the study began. The researchers followed them for several years to see who developed dementia.
In total, more than 559,000 people were included in the study. Over 14,500 developed dementia during the follow-up period, and nearly 50,000 died. Alcohol use was measured through surveys and a clinical screening tool called AUDIT-C, which tracks risky drinking habits, including binge drinking (defined as having six or more drinks at once).
When researchers looked at the data, they saw a U-shaped curve in the observational results. This meant that both people who drank heavily and people who didn’t drink at all had a higher risk of dementia compared to light drinkers. However, when the researchers used genetic data to study alcohol’s effects, they found something different.
They used a method called Mendelian randomization, which uses genetic information to get a clearer idea of cause and effect. This method avoids some of the problems that come with observational studies, like lifestyle differences between people who drink and those who don’t. Genetic risk for drinking was used as a stand-in for actual drinking behavior.
The results showed that as genetic risk for drinking increased, so did the risk of dementia. There was no U-shaped curve. Even a small increase in alcohol use—just one to three extra drinks a week—raised dementia risk by 15%. People with double the genetic risk of alcohol dependency had a 16% higher chance of developing dementia.
This suggests that the protective effect seen in earlier studies may not be real. In fact, people who later developed dementia tended to reduce their drinking in the years before their diagnosis. This could mean that early signs of cognitive decline caused them to drink less—not that drinking less protected their brains.
The researchers say their findings show that no level of alcohol is safe when it comes to dementia risk. They also noted that most of the strongest results came from people of European ancestry, so more research is needed to confirm these findings in other groups.
In conclusion, this large and detailed study suggests that any alcohol consumption, even light drinking, likely increases the risk of dementia. The researchers say that cutting back on alcohol could be an important step in preventing the disease, especially as the global population continues to age.
If you care about dementia, please read studies about dietary strategies to ward off dementia, and how omega-3 fatty acids fuel your mind.
For more health information, please see recent studies about Choline deficiency linked to Alzheimer’s disease, and what to eat (and avoid) for dementia prevention.
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