Protect your brain from rust
Moderate alcohol consumption was associated with the accumulation of iron in the brain
Maria Azarova, Naked Science
Scientists from Oxford and Cambridge Universities, Queen Mary University of London (UK) and Yale University (USA) were looking for evidence of a causal relationship between alcohol consumption and iron levels in the brain, as well as the resulting cognitive decline.
The results of the study are published in the journal PLOS Medicine (Topiwala et al., Associations between moderate alcohol consumption, brain iron, and cognition in UK Biobank participants: Observational and mendelian randomization analyses).
Previously, it was believed that moderate alcohol consumption can pass almost without a trace for health. However, recently there are more and more scientific papers refuting this point of view. It is especially important to understand how alcoholic beverages affect, for example, the deposition of iron in the brain, because it is known that its elevated levels, among other things, lead to neurodegenerations like Alzheimer's and Parkinson's diseases. But until now, researchers did not know whether iron accumulates in the brain due to moderate alcohol consumption, what are the mechanisms of this process and the clinical consequences for minor deviations.
The authors analyzed data on 20,965 volunteers aged 40-69 (the average age is 55 years, 48.6% are women), data on which were collected from 2006 to 2010 and stored in the British Biobank. At the time of observation, none of the participants had dementia or other similar ailments. They filled out questionnaires about alcohol use, underwent MRI of the brain and liver, as well as a series of tests to assess cognitive and motor functions. The iron content in the brain was determined using quantitative mapping of magnetic susceptibility, T2*-gradient echo and sequences weighted by magnetic susceptibility.
Although almost three percent of the participants identified themselves as non-drinkers, on average, the volunteers consumed about 18 units of alcohol weekly, which is equal to ten milliliters (eight grams) of ethanol or about seven and a half cans of beer and six glasses of wine. This is more than the British experts recommend — up to 14 units, although in the case of men, 21 units per week are allowed. In the group of those who described themselves as never drinkers, there were mainly women with lower blood pressure, but diabetes was more common among them.
As the analysis of all the data showed, moderate alcohol consumption — above seven units in seven days — correlated with a lower iron content in the thalamus, but higher — in the basal ganglia, that is, clusters of neurons in the basal parts of the forebrain and midbrain involved in the regulation of movement, cognition, emotions, and so on. Iron deposits in the brain went hand in hand with the deterioration of cognitive functions: in particular, a slow reaction rate and a decline in executive functions — a set of mental abilities necessary for the control and self-regulation of behavior.
"Consumption of more than 11 units of alcohol per week was associated with higher levels of iron in the liver, measured by MRI. In women, this was observed when taking more than 17 units per week," the researchers added. According to them, there was some evidence of a causal relationship between genetically predicted alcohol consumption and the susceptibility of the basal nucleus and hippocampus, but they were not corrected by multiple tests.
Despite some deterioration, bright clinical manifestations of neurodegeneration in the study participants were not revealed — probably the fact is that the level of iron in the brain serves as an early marker of diseases.
"In our work, higher systemic iron levels explained only 32% of the total effect of alcohol on iron levels in the brain, that is, other mechanisms may be involved. Probably, among them is an increase in the permeability of the blood—brain barrier to iron, which, in turn, is mediated by a decrease in thiamine levels (this occurs in alcohol use disorders due to a combination of malnutrition, decreased absorption and metabolic changes). In patients with cerebral autosomal dominant arteriopathy with subcortical infarctions and leukoencephalopathy (CADASIL), iron leakage was associated with the permeability of the blood-brain barrier. Other possible mechanisms include dopamine release after alcohol intake or chronic inflammatory processes. An alternative option is that people with a higher iron content in the brain drink more alcohol," the scientists explained.
If it is possible to confirm that alcohol consumption leads to a decrease in cognitive functions due to increased levels of iron in the brain, existing treatment methods can be applied — for example, chelation therapy for patients with posttransfusion iron overload, the authors of the work summed up.
Portal "Eternal youth" http://vechnayamolodost.ru