Study Ties 8+ Weekly Drinks to Greater Brain Damage Risk

Drinking at least eight alcoholic drinks weekly may increase the risk of brain injuries linked to cognitive decline and Alzheimer’s disease, new research suggests.

A study published April 9 in Neurology found that, as compared to those who never drank alcohol, heavy drinkers were more likely to have a type of vascular brain lesion associated with memory and thinking problems.

Researchers found the same was true for former heavy drinkers (those who had stopped consuming alcohol at least three months before they died). Both heavy drinkers and former heavy drinkers also had a higher incidence of tau tangles—clumps of protein in brain cells that are a biomarker of Alzheimer’s disease—as compared to non- or moderate drinkers.

The new study is the latest in a growing body of evidence that suggests drinking alcohol is associated with negative changes in the brain that only get worse as people drink more.

“Alcohol consumption is known to contribute to vascular damage, oxidative stress, and inflammation, which may explain the increased likelihood of brain lesions among drinkers,” study author Alberto Fernando Oliveira Justo, PhD, researcher at Heidelberg University and the Physiopathology in Aging Laboratory at the University of São Paulo Medical School, told Health.

Learning more about how people’s drinking habits affect their brains could have wide-ranging impacts on public health, the study authors noted.

More than 67% of U.S. adults reported drinking in the past year, and more than 6% reported heavy alcohol use in the past month—consuming 15 drinks or more per week for men and eight or more per week for women—according to the 2023 National Survey on Drug Use and Health.

For this study, Justo and his colleagues looked at data from 1,781 deceased Brazilian participants, all of whom had brain autopsies. The average age at death was 75 years old.

Participants’ families provided information about their drinking habits during their lives. Heavy drinkers had eight or more standard drink servings weekly, while moderate drinkers had one to seven servings of alcohol per week.

Over half of the participants—965 people—never consumed alcohol, while 319 were dubbed moderate drinkers, 129 were heavy drinkers, and 368 were former heavy drinkers.

The participants’ next of kin also answered a questionnaire to assess their family member’s cognitive abilities in the months before their death.

Then, Justo and his team examined subjects’ brain tissue for signs of poor brain health, including brain lesions and tau tangles, and also measured brain weight and height.

After adjusting for factors that could potentially affect brain health (such as smoking, physical activity, and age at death), the researchers found that heavy drinkers were 133% more likely to have vascular brain lesions than those who never drank.

Former heavy drinkers had an 89% higher risk of developing brain lesions than non-drinkers, and moderate drinkers had a 60% higher risk.

Drinking was also associated with other markers of poor brain health.

Former heavy drinkers had lower brain mass and poorer cognitive abilities than other groups, while heavy drinkers died on average 13 years younger than those who never drank. Both former heavy drinkers and heavy drinkers also had higher odds of developing tau tangles, an Alzheimer’s biomarker.

Though it’s something researchers are still investigating, this study suggests that drinking may be able to affect the brain in complex ways, even at moderate levels, explained Justo.

“Although the study can’t prove for sure that alcohol causes these brain changes, the evidence strongly suggests that alcohol is likely playing a role in both blood vessel damage and gradual breakdown of brain cells,” Mashal Khan, MD, assistant professor of clinical psychiatry at Weill Cornell Medicine, told Health.

Alcohol can damage blood vessels, reducing blood flow to the brain, and cause inflammation that injures brain tissue, said Khan.

“Over time, heavy drinking can change the brain’s structure, shrinking areas which help with decision making, memory and learning, and movement and balance,” he said. “These changes can make it harder to think clearly, remember things, and control movement.”

And, as this latest study suggests, the damage caused by heavy drinking appears to last even after someone quits, added Khan.

This isn’t the first study to look at the link between alcohol consumption and brain health, Justo said. However, few have investigated the connection by directly examining brain tissue.

“While past research has largely relied on animal models and imaging, our approach provides concrete evidence of specific brain changes linked to alcohol use in humans,” he said.

But more research still needs to be done. This study relied on information supplied by family members and didn’t follow participants’ health over time, said Edith Sullivan, PhD, professor of psychiatry and behavioral sciences at the Stanford University School of Medicine.

“Even the authors were cautious in claiming heavy drinking as causing brain abnormalities,” which could potentially be due to other mechanisms, such as old age, Sullivan told Health.

If alcohol is a big part of your life, the best thing you can do to keep your brain healthy is quit or scale back, advised Sullivan.

“First and foremost, stop drinking, or at least cut down to suggested limits of no more than one drink per day for women and two for men,” she said.

Following the guidance of this new study, though, it may be best to limit your drinks to no more than seven per week so you stay out of that “heavy drinker” category.

Current or former heavy drinkers should also pay special attention to other factors linked to cognitive health, Justo recommended.

“I’d keep my blood pressure, cholesterol, and blood sugar in check,” he said. “Quitting smoking would be a priority, and I’d make sure to stay active both physically and socially.”

There’s been a shift in people’s attitudes about drinking in recent years—alcohol consumption has dipped slightly, particularly among young people who see it as unhealthy, and in 2023, the World Health Organization released a statement acknowledging that “no level of alcohol consumption is safe for our health.”

It’s a trend that Justo hopes will continue.

“I want people to understand that alcohol consumption, even at moderate levels, may have significant impacts on brain health,” he said. “Being mindful of drinking habits and informed about the potential risks can lead to healthier choices that benefit long-term brain health and overall well-being.”