Drinking any amount of alcohol may increase your risk of developing dementia, according to the largest study of its kind, published in the journal BMJ Evidence Based Medicine.
Many people believe that drinking a small amount of alcohol can protect the brain, especially in older age. However, this new research suggests that’s not true. In fact, the risk of dementia goes up as alcohol consumption increases—even at low levels.
Researchers wanted to get a clearer picture than previous studies, which often looked only at older adults or failed to separate people who had never drunk alcohol from those who stopped drinking later in life.
These problems made it hard to understand whether alcohol truly affects dementia risk.
To solve this, scientists used data from two major sources: the US Million Veteran Program (MVP) and the UK Biobank. These databases include health and genetic information from hundreds of thousands of people.
The study included 559,559 adults between the ages of 56 and 72. Most participants reported drinking alcohol, and all were tracked over time to see who developed dementia or passed away.
During the study, 14,540 people developed dementia, and 48,034 died. At first glance, the results seemed to show a U-shaped pattern.
People who didn’t drink at all and people who drank heavily (more than 40 drinks per week) had a higher risk of dementia than those who drank lightly (fewer than 7 drinks per week). People who were alcohol dependent had an even greater risk—51% higher.
But the researchers didn’t stop there. They also used genetic data to dig deeper. By analyzing specific genes related to alcohol use, they were able to estimate a person’s lifetime drinking risk. This method, called Mendelian randomization, helps rule out other factors that might affect the results, such as lifestyle or health problems.
The genetic analysis showed a different story. It found no protective effect of light drinking. Instead, the more genetically predicted alcohol a person was likely to consume, the higher their risk of dementia.
Even just 1–3 extra drinks per week raised the risk by 15%. People with a high genetic risk for alcohol dependency had a 16% greater chance of developing dementia.
The researchers also noticed that many people who developed dementia had already started drinking less before their diagnosis. This suggests that earlier studies might have been misled by reverse causation—people may drink less because of early memory problems, not because light drinking is good for the brain.
One limitation of the study is that most of the strongest results were found in people of European ancestry, because they made up the largest group of participants. And like all genetic studies, Mendelian randomization relies on certain assumptions that can’t always be tested.
Still, the researchers believe their findings are important. They say the idea that small amounts of alcohol protect the brain is likely a myth. Their conclusion is simple: all levels of alcohol appear to increase the risk of dementia, and cutting back may help prevent it.
If you care about brain health, please read studies about Vitamin B9 deficiency linked to higher dementia risk, and cranberries could help boost memory.
For more health information, please see recent studies about heartburn drugs that could increase risk of dementia, and results showing this MIND diet may protect your cognitive function, prevent dementia.
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