New research from the University of Surrey and the University of Roehampton is adding to evidence that the gut microbiome may influence brain function, after scientists found associations between microbial pathways in the gut and levels of key brain chemicals in healthy young women.
Human data points to a gut-brain link
The study, published in Molecular Psychiatry, examined 61 healthy participants aged 17 to 25 and combined stool analysis with proton magnetic resonance spectroscopy, a non-invasive brain-imaging technique. The researchers reported that microbial pathways involved in producing and breaking down neuroactive compounds were associated with levels of GABA and glutamate in specific brain regions.
GABA and glutamate are two of the brain’s major chemical messengers, with GABA generally dampening neural activity and glutamate promoting excitation. According to the team, the balance between them is important for neuroplasticity, cognition and mental health.
What the researchers found
The anterior cingulate cortex showed a distinct pattern involving microbial glutamate and propionate pathways, while the dorsolateral prefrontal cortex showed a more selective association involving a microbial GABA-production pathway. The researchers said the findings provide new human evidence for a biological link between the gut microbiome and brain neurochemistry.
Professor Kathrin Cohen Kadosh said the study helps narrow down microbial pathways that should now be tested experimentally, while lead author Dr Nicola Johnstone said the work connected microbial genes, brain neurochemistry and psychological measures in the same participants.
Why the findings matter for future research
The scientists stressed that their results do not show bacteria directly producing neurotransmitters that travel to the brain. Instead, they said the biology is likely to involve indirect routes such as the vagus nerve, immune signalling, the intestinal barrier and other metabolites produced in the gut.
The team noted that the study measured genetic potential rather than directly measuring the metabolites produced by the bacteria, and said larger longitudinal and intervention studies will be needed to test whether changing these pathways can alter brain chemistry.
The research sits within a growing body of work exploring the gut-brain axis and may help inform future studies into cognition, mental health and related disorders. Source article
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