Excessive alcohol consumption is harmful to humans. The largest study on this topic to date has now examined whether moderate alcohol consumption also has a negative effect on the brain.

Oxford (England). According to various studies, excessive alcohol consumption is harmful to humans and leads, among other things, to increased diffusion in the extracellular spaces of the brain. A moderate consumption of alcohol as a stimulant, on the other hand, is considered unproblematic both by the general public and by many scientists. Some studies even came to the conclusion that small amounts of alcohol have a positive effect on health and increase cognitive performance, for example.

Other studies, on the other hand, have found that even small amounts of alcohol affect brain metabolism and accelerate the aging of the brain. Due to the unclear study situation, scientists from the University of Oxford is now being re-examined whether the brain is negatively affected by even small amounts of alcohol.

Neurodegeneration from alcohol?

There is a thesis in medicine that even moderate drinking can trigger iron deposits in the brain. It is known from patients with hereditary iron overload disorders that increased iron levels in the brain can negatively affect thinking. In addition, studies recently provided evidence that iron deposits in the brain can promote neurodegenerative diseases such as Alzheimer’s and Parkinson’s.

The profile of alcohol-related dementia also overlaps with these diseases. Observational studies also provided evidence that alcohol dependence can also lead to accumulations of iron in the brain. However, it was not yet known whether moderate alcohol consumption can also cause iron deposits in the brain.

Large-scale study with almost 21,000 subjects

According to their publication in the specialist magazine Plos Medicine The researchers led by Anya Topiwala therefore examined the connection between iron deposits in the brain and the consumption of alcohol. The researchers also took into account amounts of alcohol that are considered harmless according to various professional societies.

20,965 women and men between the ages of 40 and 69 took part in the largest study on this topic to date. The subjects were asked about their alcohol consumption. The researchers also measured the iron levels in the liver and brain using magnetic resonance imaging. The subjects’ cognitive performance was recorded using various tests that measured attention, reaction speed, motor skills, logic and memory.

Increased iron levels due to moderate alcohol consumption

According to the evaluation of the study data, 56 grams of alcohol per week already cause iron deposits in six of the seven brain regions examined. This is an amount considered to be ‘low risk’ under UK guidelines.

The subjects with the elevated iron levels also had poorer results in the cognitive performance tests. In terms of reaction speed, attention span and logic puzzles in particular, the moderate alcohol consumers performed worse than the subjects who consumed significantly less alcohol or no alcohol at all. The study thus shows that even moderate alcohol consumption can lead to an imbalance in the human iron balance.

Plos Medicine, doi: 10.1371/journal.pmed.1004039