One drop won’t hurt: A new research shows how brain changes under light and moderate alcohol consumption

Alcohol use disorder (AUD) is one of the most prevalent mental health conditions worldwide, and alcohol consumption, in general, is one of the leading contributors to the global burden of disease. Chronic excessive alcohol consumption carries multiple adverse effects, including cardiovascular disease, cancer, accelerated aging, and nutritional deficiency. Chronic alcohol use is also strongly associated with changes in brain connectivity and structure. As seen from neuroimaging studies, chronic heavy alcohol consumption (for women – 3 or more drinks per day, for men – 4 or more drinks per day) can produce tissue volume changes, especially in frontal regions, additionally accelerating the effects of aging.  

Despite the extensive body of research on the influence of alcohol on brain structure in individuals with AUD, there are limited data on such associations on regular alcohol consumers. Some studies of middle-aged and older adults show that moderate alcohol consumption resulted in lower total cerebral volume, gray matter atrophy, and lower density of gray matter in multiple brain regions. But other studies fail to show this association.  Such inconclusiveness of evidence mainly results from a small number of people studied and not accounting for biasing factors, such as sex, body mass index, and age.

Daviet et al. employed the data from the UK Biobank – the largest prospective cohort study of the United Kingdom population aged 40-69 years – to examine the association between alcohol intake and changes in gray and white matter. The authors analyzed more than 36 thousand MRI scans of people whose reported alcohol consumption ranged from low (1-2 drinks per day) to high (more than 4 drinks per day). A negative relationship between alcohol intake and gray and white matter measures was generally observed. The changes were widespread across the brain, and their magnitude increased with the average number of drinks consumed. Notably, adverse changes were observed even in people with low alcohol consumption. For both sexes, the alcohol effect was similar, and the study showed weak evidence for the interactive effect between alcohol and sex on the brain. However, other studies have reported greater volume changes in women than men.

Several limitations of this study were mentioned by the researchers, among them that the study was limited only to the individuals of European ancestry living in the United Kingdom. The generalizability of the study to other populations and age groups, thus, will have to be tested in future research. Another limitation is not accounting for the past experience of AUD, which might have also influenced the results. However, this study lays an important cornerstone for future research into light and moderate consumption of alcohol, and how it can influence out bodies.

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