Review: The Gut Microbiome & Brain Function
The Gut-Brain axis research group recently published a piece in The Lancet, Neurology, reviewing the current research landscape associating the microbiome as a possible key susceptibility factor for neurological disorders. Here they lay out the evidence, both pre-clinical and clinical, underscoring the importance of gut health.
Over the past two decades, a revolution has occurred in biomedicine with the realisation that the gut microbiota have a role in maintaining homoeostasis and in regulating almost every major body system, including the central nervous system. Research into the role of the gut microbiota in modulating brain function specifically, has rapidly increased over the past 10 years, albeit chiefly in pre-clinical models.
A growing number of cross-sectional clinical studies have investigated the microbiota composition in individuals with a specific neurological disorder versus healthy age-matched individuals. But more emphasis is needed on longitudinal and interventional approaches using probiotic strains, prebiotics, and, potentially, faecal micro-biota transplantation therapies. The strongest evidence in support of the role of the microbiota in neurological disorders is in Parkinson’s disease, multiple sclerosis, and autism spectrum disorder, with a growing appreciation of its role in Alzheimer’s disease and stroke.
In tandem, a large experimental effort has been directed towards attempting to dissect the various pathways of communication between the gut and the brain at key times throughout the lifespan, especially in ageing and in early life where several major potential pathways have been identified. Results of such studies are bolstering this concept of altered microbial composition contributing to the pathophysiology of such diseases.
However, most of the clinical studies to date are underpowered, often with participant selection bias, utilise differing sampling and sequencing protocols, bioinformatics pipelines, statistical methods, and confounders. As a result, to understand the intricate processes behind the microbiota–gut–brain axis involvement in neurological disorders, more well-controlled and well-designed studies are needed. The question remains, how can gut-microbiota be successfully targeted as an intervention strategy to prevent disease and minimise symptoms in patients.
The gut microbiome in neurological disorders. Cryan JF, O’Riordan KJ, Sandhu K, Peterson V, Dinan TG. Lancet Neurol. 2020 Feb;19(2):179-194. doi: 10.1016/S1474-4422(19)30356-4. Epub 2019 Nov 18. Review. PubMed PMID: 31753762.