According to a study of nearly 21,000 people published in the open-access journal, July 14, higher levels of iron are associated with consuming seven or more units per week. PLOS Medicine. Iron accumulation in brain has been linked to Alzheimer’s and Parkinson’s diseases. This could be a mechanism for alcohol related cognitive decline.
Evidence is mounting that even moderate alcohol intake can have a negative impact on brain health. Anya Topiwala (University of Oxford), United Kingdom, and her colleagues investigated the relationships between alcohol intake and brain iron levels. The UK Biobank had 20,965 participants who reported their alcohol consumption. Brain scans using magnetic resonance imaging (MRI) were performed on these brains. Nearly 7,000 people had their livers scanned using MRI to check for systemic iron levels. To assess motor and cognitive function, all participants completed simple tests.
The mean age of the participants was 55, with 48.6% being female. Although 2.7% classed themselves as non-drinkers, average intake was around 18 units per week, which translates to about 7½ cans of beer or 6 large glasses of wine. The study found that alcohol intake above seven units per week was associated to higher iron levels in the basal Ganglia. This is a brain region responsible for motor movements, procedural learning and eye movement. It also has markers associated with cognitive function, emotion, cognition and other areas. An increase in iron levels in certain brain regions was associated to poor cognitive function.
This is the largest known study on moderate alcohol consumption and iron accumulation. Although the drinking habits of this cohort were self-reported, and may have been underestimated by some, it was determined to be the best method for establishing such large intakes. The work has some limitations. MRI-derived measures of brain iron are indirect representations. They could also be confused with other brain changes associated with alcohol consumption.
Because moderate drinking is common, even small associations can have a significant impact on whole populations. Interventions to reduce the consumption of alcohol in general could prove beneficial.
Topiwala says, “In the biggest study to date, it was found that drinking more than 7 units per week is associated with iron accumulation in brain.” High brain iron is linked to lower cognitive performance. Iron accumulation may be a cause of alcohol-related cognitive decline.
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