Drinking More Than 8 Glasses a Week Is 'Overdrinking'... What Are the Effects on the Brain?

Increased Risk of Brain Damage, Including Memory and Cognitive Decline

New research has found that excessive drinking of more than eight drinks per week increases the risk of brain damage, including memory and cognitive decline.

On the 9th (local time), the US CNN reported on a recent study published in the journal Neurology. The media spoke with Dr. Lina Wen, a professor of emergency medicine at George Washington University and former Baltimore health commissioner, about the study's findings.

According to previous knowledge, alcohol consumption disrupts the brain's communication pathways, making it difficult for the brain to control thinking, coordination, balance, language, and judgment. Additionally, consuming a large amount of alcohol in a short period can cause severe functional impairment, paralyzing critical areas that regulate breathing and heart rate. People with alcohol use disorder may experience progressive brain changes affecting cognition and thinking. For example, Wernicke-Korsakoff syndrome, associated with severe alcohol use, can cause permanent disability and long-term memory loss.

This study conducted a postmortem analysis of more than 1,700 individuals with an average age of 75 at the time of death. The researchers examined their brain tissue for signs of brain damage, including hyaline arteriolosclerosis, related to memory and cognitive impairment, and tau tangles associated with Alzheimer's disease.

Separately, the researchers asked the families of the subjects about their alcohol consumption during their lifetime. The subjects were divided into four groups: those who never drank, those who drank seven or fewer drinks per week, those who drank eight or more drinks per week (defined as excessive drinking), and those who previously drank excessively but had since quit.

The results showed that excessive drinkers had a 133% higher risk of developing hyaline arteriolosclerosis compared to non-drinkers, even after accounting for other factors that could affect brain health, such as smoking. Moderate drinkers had a 60% higher risk of developing hyaline arteriolosclerosis.

Heavy drinkers were also more likely to develop tau tangles. They were found to potentially die an average of 13 years earlier than those who did not drink at all. Among the study subjects, heavy drinkers were more likely to develop tau tangles associated with Alzheimer's disease. Although evidence of ongoing brain damage was found in those who had previously binge drank, the risk appeared to decrease after stopping excessive drinking.

However, the study has limitations. It did not measure the duration of alcohol consumption and did not distinguish between those who regularly drink one or two drinks at night and those who drink heavily intermittently.

Dr. Wen explained, "For adult women, no more than one drink per day, and for men, no more than two drinks per day should be consumed." She added, "Another way to identify excessive drinking is by binge drinking." According to the US Centers for Disease Control and Prevention (CDC), binge drinking is defined as consuming four or more drinks at one time for women and five or more drinks at one time for men. Binge drinkers are known to have a higher risk of injuries such as traffic accidents and falls and to place greater stress on organs." Dr. Wen also cautioned, "People who drink excessively should be careful not to quit suddenly, as sudden withdrawal symptoms can be dangerous," and added, "Those who want to reduce their alcohol intake should consult their healthcare provider."