Consumption of seven or more units of alcohol per week is associated with higher levels of iron in the brain, according to a study by Oxford researchers.
Accumulation of iron in the brain has been linked with Alzheimer’s and Parkinson’s diseases and is a potential mechanism for alcohol-related cognitive decline.
The study, which involved researchers from a number of University of Oxford departments and was supported by the NIHR Oxford Biomedical Research Centre (BRC), was published in the open access journal PLOS Medicine.
There is growing evidence that even moderate alcohol consumption can adversely impact brain health. The team, led by Anya Topiwala of the University’s Psychiatry department and Big Data Institute, explored relationships between alcohol consumption and brain iron levels.
Their 20,965 participants from the UK Biobank reported their own alcohol consumption, and their brains were scanned using magnetic resonance imaging (MRI). Almost 7,000 also had their livers imaged using MRI to assess levels of systemic iron. All individuals completed a series of simple tests to assess cognitive and motor function.
Participants’ mean age was 55 years old and 48.6% were female. Although 2.7% classed themselves as non-drinkers, the average intake was around 18 units per week, which translates to about 7½ cans of beer or 6 large glasses of wine.
The team found that alcohol consumption above seven units per week was associated with markers of higher iron in the basal ganglia, a group of brain regions associated with control of motor movements, procedural learning, eye movement, cognition, emotion and more. Iron accumulation in some brain regions was associated with worse cognitive function.
Dr Topiwala said: ‘In the largest study to date, we found that drinking greater than seven units of alcohol weekly was associated with iron accumulation in the brain. Higher brain iron in turn is linked to poorer cognitive performance, such as executive function (problem solving) and fluid intelligence (puzzle tasks). Iron accumulation could underlie alcohol-related cognitive decline.”
Professor Klaus Ebmeier, of the University’s Department of Psychiatry, added: “This is one in a series of Oxford studies done in the large UK Biobank data set that suggest even ‘normal’ drinking comes with a risk for ageing, mental and physical brain health. Everyone who consumes alcohol needs to balance this against their potential enjoyment of having a drink.”