Can even one drink of alcohol a day raise dementia risk?

When it comes to keeping your brain healthy, there’s no safe amount of alcohol consumption. That’s according to a new international study that says even light imbibing raises the risk of dementia.

The research, which was led by the University of Oxford, Yale University and the University of Cambridge, refutes the notion that a drink here and there can even be healthy. The findings are published in BMJ Evidence-Based Medicine.

Alcohol consumption is widespread and has already been linked to a number of health risks, including more risk of certain kinds of cancer, such as breast and colorectal cancer. Research has also found that sleep patterns suffer from alcohol use.

Per a news release from Oxford, “Heavy drinking has previously been linked to higher risk of dementia,” the researchers reported, while noting the “connection between moderate levels of drinking and higher risk of dementia was uncertain, with some studies suggesting that moderate drinking may even reduce dementia risk. However, recent studies involving brain scans have shown that drinking alcohol even at low levels may increase the risk of dementia.”

For the study, researchers looked at observational data from more than a half-million participants in either the U.S. Million Veteran Program or the UK Biobank to see if self-reported alcohol use was linked with risk of developing some type of dementia.

They also looked at links between genetically predicted likelihood of consuming alcohol and alcohol use disorder for more than 2.4 million participants in 45 different studies. The role of that effort was distinguishing between correlation and causation, the researchers said.

Challenging common beliefs about drinking

Among the study highlights:

• The observational analysis seemed to support earlier findings that current light and moderate drinking has less dementia risk compared to no drinking and heavy drinking. But that could be skewed by the fact that some current nondrinkers were previously heavy drinkers, which could have raised their dementia risk.
• Genetic analysis found a “continuously increasing trend of higher dementia risk with greater alcohol intakes, suggesting that any level of alcohol consumption increases the risk of dementia.” The study found no evidence that drinking alcohol has a protective effect.
• A threefold increase in the number of alcohol drinks per week increased the risk of dementia by 15%, while a doubling of a person’s genetically predicted risk of alcohol use disorder was linked to a 16% higher risk of dementia.
• As for the earlier findings that alcohol could be protective, the study found “people who later developed dementia reduced their alcohol intake before diagnosis,” suggesting the supposed benefit was not a true one.

“Our findings challenge the common belief that low levels of alcohol are beneficial for brain health,” said psychiatrist Dr. Anya Topiwala, senior clinical researcher at Oxford Population Health and the study’s lead author. “Genetic evidence offers no support for a protective effect; in fact, it suggests the opposite. Even light or moderate drinking may increase the risk of dementia, indicating that reducing alcohol consumption across the population could play a significant role in dementia prevention.”

Dr. Stephen Burgess, a Cambridge statistician, said the findings hold not only for those with a genetic predisposition. “For anyone who chooses to drink, our study suggests that greater alcohol consumption leads to higher risk of dementia.”

The release said the study adds to growing evidence that there is no safe threshold when it comes to brain health and alcohol. The researchers said it boosts the case for preventive strategies to reduce alcohol consumption in the general population.

“Our study findings support a detrimental effect of all types of alcohol consumption on dementia risk, with no evidence supporting the previously suggested protective effect of moderate drinking,” the study concluded.

Is there a safe amount of alcohol?

It’s not the only study to suggest that so-called positive effects of alcohol consumption have been overblown. In late summer 2024, Deseret News reported on a number of studies that reject the idea of health benefits linked to drinking.

The research noted that alcohol-related deaths in the U.S. are increasing and while risk is higher the more someone drinks, there’s “no safe amount” of alcohol.

Per the article, “It’s estimated that for about 1 in 5 people, drinking leads to significant alcohol use disorder. But others may develop related health problems.”

Deseret News also reported on research linking heart disease and alcohol for women.

The World Health Organization has concluded there’s no safe level of alcohol consumption, but early this year Deseret News reported that the U.S. Dietary Guidelines have fallen behind some of the research and continue to suggest that moderate drinking provides some slight health benefits.

The guideline report has been controversial because it is at odds with most of the research and policies of many other high-income nations. From that article: “The UK’s National Health Service reports that ‘cutting back on booze can be a really effective way to improve your health, boost your energy, lose weight and save money.’ And it touts the importance of ‘drink-free days’ every week, including a downloadable app by that name."

The Washington Post reported that “in studies of heavy drinkers who stop, they can recover some cognition and brain volume."

The article noted that brain imaging studies see harmful brain outcomes even at low levels of alcohol consumption over time. “Topiwala and her colleagues found that moderate alcohol intake was associated with smaller gray matter and increased iron in the brain, which has been linked to neurodegenerative diseases such as Alzheimer’s and Parkinson’s."