Moderate alcohol consumption reduces brain function

Alcohol use is common and while the negative effects associated with ‘binge’ drinking are well documented, there is mixed evidence on the impacts of light to moderate drinking on our health, particularly the brain. Some research has suggested a protective effect associated with light drinking and others have observed negative outcomes. Researchers looked at data across a 30-year period, investigating the association between alcohol consumption, and structural and functional outcomes in the brain.

Thirty years of data from the Whitehall II study were analysed. The Whitehall II study commenced in 1985 in London and involved more than 10,000 civil servants. Alcohol use was assessed and divided into levels of consumption: abstinent (less than one unit of alcohol a week), light drinking (between one and seven units a week), moderate drinking (between seven and 14 units a week for women and seven and 21 units a week for men) and unsafe drinking (14 or more units a week for women and 21 or more units a week for men). Cognitive function and brain structure were assessed via verbal tests and scans. Outcomes assessed included grey matter density (the grey matter includes regions of the brain involved in muscle control and sensory perception), hippocampus structure and cognitive function including lexical fluency (assesses language and executive function) and semantic fluency.

Higher alcohol use was associated with reduced grey matter density, hippocampal atrophy (also a feature of Alzheimer’s disease) and reduced white matter structural integrity. Higher alcohol use was also associated with a faster decline in lexical fluency. No protective effect was observed in association with light consumption when compared to abstinence.

Implications

This study shows poor outcomes in both brain structure and function in people with increased alcohol consumption. Furthermore, it found no protective effect associated with light consumption of alcohol. Alcohol is a modifiable risk factor that could be targeted for management, particularly in people at risk of cognitive decline.

References

Topiwala, A et al. Moderate alcohol consumption as risk factor for adverse brain outcomes and cognitive decline: longitudinal cohort study. BMJ 2017; 357: j2353 http://dx.doi.org/10.1136/bmj.j2353.