Scientists have reached a consensus that no amount of alcohol use is safe for our health. Now a new study published in the journal Neurology has found that having eight or more alcoholic drinks per week raises the risk of developing brain lesions — areas of abnormal or damaged tissue associated with dementia.
“Our study highlights specific brain changes associated with alcohol use, and underscores the importance of being mindful of alcohol use and its potential consequences on health,” says lead study author Alberto Fernando Oliveira Justo, PhD, a researcher with the University of Sao Paulo Medical School in Brazil.
Any Amount of Alcohol Raises the Risk of Brain Damage
To evaluate alcohol’s impact on the brain, Dr. Justo and his team examined brain tissue obtained through autopsies performed on more than 1,700 people who had died at 75 on average.
The scientists looked for signs of brain injury, including tau tangles (abnormal accumulations of protein linked to Alzheimer’s disease) and hyaline arteriolosclerosis (a condition that causes small blood vessels to narrow and become thick and stiff). Hyaline arteriolosclerosis makes it harder for blood to flow, which can cause brain lesions.
Relying on details from family members, researchers divided subjects into four groups:
- People who never drank
- Moderate drinkers, meaning seven or fewer drinks per week
- Heavy drinkers, meaning eight or more drinks per week
- Former heavy drinkers who stopped up to three months before dying
One drink was defined as 12-ounce of beer, a standard 5-ounce glass of wine, or a 1.5 ounce pour of distilled spirits.
After accounting for other factors that could negatively impact brain health (such as age at death, smoking, and lack of physical activity), heavy drinkers were 133 percent more likely to have brain lesions compared with those who never drank. Those odds were 89 percent higher for former heavy drinkers and 60 percent higher for moderate drinkers.
“Our findings indicate that even moderate alcohol consumption can lead to neuropathological changes, challenging the notion that only heavy drinking poses a risk to brain health,” says Justo. “The impact of alcohol on the brain may occur at lower levels of consumption.”
The results also showed that heavy and former heavy drinkers had higher odds of developing tau tangles (41 percent and 31 percent higher odds, respectively).
Cognitive abilities of the deceased were determined by input from the next of kin, who had at least weekly contact with the study subjects during the six months preceding death. While researchers didn’t find a direct effect between alcohol consumption and cognition, they concluded that hyaline arteriolosclerosis may impair cognitive symptoms in people who drink alcohol.
Heavy drinkers were less likely to have hypertension and stroke — a result that may seem counterintuitive. But Justo and his team suggest this may be because heavy drinkers died 13 years earlier on average than those who never drank.
“Essentially, many heavy drinkers may not live long enough to develop these conditions, which typically occur later in life,” says Justo.
‘Heavy Drinking’ May Be Relative
For some Americans, heavy drinking may go far beyond the 8-drinks-or more-a-week definition in this study.
“The threshold for ‘heavy drinking’ was relatively conservative in this study,” says Mollie Monnig, PhD, an assistant professor of behavioral and social sciences with the Center for Alcohol and Addiction Studies at Brown University in Providence, Rhode Island. “Individuals with the highest level of heavy drinking in the U.S. would seem to be at greater risk for negative health outcomes measured in this study and in general.”
Dr. Monnig, who was not involved in this research, views the findings as an important step forward, as there have been few post-mortem brain studies with such large populations that have characterized the biological as well as cognitive outcomes.
She notes that data collected here on drinking habits and cognition cannot be regarded as entirely reliable because the information was determined by interviews with next of kin. Furthermore, the study observes associations between alcohol consumption and brain changes, but cannot definitively prove that one causes the other.
How to Have a Healthier Relationship With Alcohol
Christopher Kahler, PhD, a professor of behavioral and social sciences and director of Brown University’s Center for Alcohol and Addiction Studies, stresses that reducing drinking lowers health risk, and can have other mental and physical benefits.
He recommends following these tips to develop healthy habits around alcohol:
- Track how much you drink each day. This will help you know how heavily you may be drinking.
- Take a break to see how alcohol affects you. Alcohol can impact sleep, mood, and energy. For many people, taking a break from alcohol for a couple of weeks or a month gives them a chance to evaluate how they feel without drinking. Dr. Kahler, who was not involved in the study, adds that a break may also benefit memory and reduce blood pressure. “Events like Sober October and Dry January can be a great opportunity to try out abstinence as part of a national community,” he says.
- Alternate alcohol and nonalcoholic drinks. This habit can reduce how much alcohol you drink.
- Pause between drinks. Wait 15 minutes after you finish a drink before you start another. “This lets you experience how much you have drunk and whether you really want that next one,” Kahler says.
- Know the signs of a drinking problem. “If it is hard for you to avoid drinking when you want to, or you often end up drinking much more than you intended, you may have an alcohol use disorder,” says Kahler. “If drinking is affecting your work or interest in other activities, your relationships, or your mental health, it has become a problem.” If this is the case for you, Kahler urges you to talk to a trusted medical professional or seek out reliable information online such as the Rethinking Drinking website.