“Even small amounts of alcohol can harm your brain,” says Anya Topiwala, doctor of psychiatry, senior clinical researcher at the University of Oxford, and lead author of the study. “We found that the amount people said that they drank was related to the amount of iron in their brain. The more they drank, the more iron there seemed to be.” Those increased iron levels were also associated with demonstrable cognitive effects. “We also did memory tests on these people, and it seemed that higher iron levels in the brain meant worse performance on memory tests,” Dr. Topiwala says.
Even Modest Amounts of Alcohol Are Tied to Brain Risks
The University of Oxford team analyzed brain scans and self-reported alcohol data from a subset of 20,000 people who contributed to the the UK Biobank, a massive collection of health information from half a million adults ages 40 to 69, collected from 2006 to 2010. Topiwala notes that while the Biobank data is valuable and large, it skews more middle class, whiter, and better educated than the United Kingdom as a whole. The average amount of consumption for the study participants was about 18 units per week, or six glasses of wine or seven beers. In the study, people who drank as little as seven units of alcohol per week — about two to three glasses of wine — showed higher levels of iron in the brain, which according to the study authors may put them at risk of future cognitive deficits. In 2018, the latest year for which data is available, about two-thirds of American adults reported drinking in the previous 12 months, according to the Centers for Disease Control and Prevention. About half reported light drinking, defined as less than three drinks per week, while 15 percent reported moderate drinking, defined as 4 to 7 drinks per week for women and 4 to 14 drinks per week for men. The remaining 5 percent reported heavy drinking.
It’s the Amount, Not the Type of Alcohol That Matters
Researchers looked at the effects of wine, beer, and spirits and did not see differences between the types of alcohol. “It was the amount of alcohol you drank, rather than what you drank it in,” says Topiwala. The cognitive deficits include both executive function, such as problem solving, and fluid intelligence, such as puzzle solving. People were slower in both categories when they had more iron in their brain. Because the results are cumulative, says Topiwala, cutting back by a few drinks per week could decrease the amount of iron that accumulates in your brain. People in the study who drank seven units of alcohol per week had less iron in their brain than people who drank more. This study is the first to look at moderate drinking and cognitive decline. Previous research had suggested that having a few drinks per week could actually have positive health impacts. “Originally, we were told that moderate drinking was protective for the brain,” says Topiwala. “This is another piece in the puzzle to suggest that actually it’s probably not — it’s probably harmful.” Topiwala says that future research on the topic could prove more definitively that high iron levels are responsible for damage in the brain that leads to memory problems, which could help healthcare providers and their patients discuss interventions that may prolong cognitive health.
