Study reveals chronic drinking disrupts blood-brain barrier via the gut - Video

Chronic alcohol consumption quietly destabilizes one of the brain’s most vital defenses-the blood-brain barrier (BBB)-through disruptions in the gut-brain axis, leading to cognitive decline.

Researchers explored this link in a recent study published in Communications Biology, investigating whether the gut microbiome changes caused by alcohol use disorder (AUD) directly impair BBB integrity and whether a probiotic, Faecalibacterium prausnitzii, could restore brain health.

The BBB protects the brain by restricting harmful substances, but alcohol-induced damage allows toxins and inflammatory molecules to flood neural circuits, undermining memory and mood. The gut microbiome, shaped by diet and alcohol, communicates with the brain via metabolites and immune signals, playing a key role in BBB regulation. Yet, until now, causal evidence between alcohol, microbiome changes, BBB disruption, and cognition was missing.

The study enrolled 30 adult males with AUD and 30 healthy controls, measuring cognitive function with MMSE and MoCA, mood via anxiety and depression scales, sleep quality, and clinical chemistry related to liver function. Fecal DNA sequencing showed AUD subjects had depleted beneficial Faecalibacterium and increased harmful Streptococcus bacteria. Plasma metabolomics revealed altered lipid and amino acid profiles linked to these microbial changes but did not establish direct cognitive correlations.

To prove causation, researchers transplanted fecal microbiota from AUD patients or healthy donors into germ-free mice. AUD microbiota recipients showed increased BBB leakage in the prefrontal cortex and hippocampus, reduced tight junction proteins (ZO-1, occludin, claudin-5), and impaired memory in maze and object recognition tests. Supplementing ethanol-exposed mice with Faecalibacterium prausnitzii restored BBB integrity, boosted short-chain fatty acids (SCFAs), and improved cognitive performance.

These SCFAs help strengthen endothelial junctions, modulate inflammatory pathways, and support neurovascular health. Although the microbial community was altered rather than fully restored, supplementation of this next-generation probiotic presents a promising therapeutic avenue to protect against alcohol-related brain damage. Future work must clarify optimal dosing, sex-specific effects, and integration with lifestyle modifications.

This study highlights a critical gut-brain mechanism by which everyday alcohol use can silently raise neurovascular and cognitive risks and supports microbiome-targeted strategies for safeguarding brain health in AUD populations.

REFERENCE: Li, C., Wang, H., Lin, X., Zeng, G., Li, X., Chen, W., Lu, H., Pan, J., Zhang, X., Rong, X., He, L., & Peng, Y. (2025). Chronic alcohol consumption disrupts the integrity of the blood-brain barrier through the gut-brain axis. Commun Biol. DOI: 10.1038/s42003-025-09235-w. https://www.nature.com/articles/s42003-025-09235-w