Even Moderate Drinking Found To Be Linked to Brain Changes and Cognitive Decline

A recent study found that drinking seven or more units of alcohol a week is linked to brain changes and cognitive decline.

A study involving over 21,000 participants that was recently published in PLOS Medicine found a correlation between weekly alcohol use of seven or more units and greater levels of iron in the brain. Iron buildup in the brain has been associated with Parkinson’s and Alzheimer’s diseases and may be a contributing factor to the cognitive decline brought on by alcohol use.

There is increasing evidence that even moderate alcohol use can have a negative impact on brain health. Anya Topiwala of the University of Oxford in the United Kingdom and colleagues investigated the links between alcohol consumption and brain iron levels.

Their 20,965 volunteers from the UK Biobank provided information on their own alcohol consumption, and magnetic resonance imaging (MRI) was used to examine their brains. To determine the amounts of systemic iron, almost 7,000 people had their livers scanned using MRI as well. A series of basic tests were taken by each person to assess their cognitive and motor abilities.

Iron Accumulation in the Brain and Cognitive Function

The average age of the participants was 55, and 48.6% of them were female. Although 2.7% of respondents identified as non-drinkers, the average weekly consumption was 18 units or about 7.5 cans of beer or 6 large glasses of wine. The researchers discovered that alcohol consumption of more than seven units per week was connected with markers of increased iron in the basal ganglia, a set of brain regions involved with motor control, procedural learning, eye movement, cognition, emotion, and other functions. Iron accumulation in some brain regions was linked to worse cognitive function.

This is the largest study to date of moderate alcohol consumption and iron accumulation. Although drinking was self-reported and could be underestimated, this was considered the only feasible method to establish such a large cohort’s intake. A limitation of the work is that MRI-derived measures are indirect representations of brain iron, and could conflate other brain changes observed with alcohol consumption with changes in iron levels.

Given the prevalence of moderate drinking, even small associations can have a substantial impact across whole populations, and there could be benefits in interventions to reduce consumption in the general population.

Topiwala adds, “In the largest study to date, we found drinking greater than 7 units of alcohol weekly associated with iron accumulation in the brain. Higher brain iron in turn linked to poorer cognitive performance. Iron accumulation could underlie alcohol-related cognitive decline.”

Reference: “Associations between moderate alcohol consumption, brain iron, and cognition in UK Biobank participants: Observational and mendelian randomization analyses” by Anya Topiwala, Chaoyue Wang, Klaus P. Ebmeier, Stephen Burgess, Steven Bell, Daniel F. Levey, Hang Zhou, Celeste McCracken, Adriana Roca-Fernández, Steffen E. Petersen, Betty Raman, Masud Husain, Joel Gelernter, Karla L. Miller, Stephen M. Smith and Thomas E. Nichols, 14 July 2022, PLOS Medicine.
DOI: 10.1371/journal.pmed.1004039

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