Microbiome in brain function and mental health

- A healthy gut microbiota composition in early life and adulthood is outlined.
- Signalling pathways of the microbiota-gut-brain axis are described.
- The gut microbiota in psychiatric disorders is reviewed.
- Functional foods with beneficial brain effects are considered.
- Directions for future research are provided.

BackgroundOver recent years it has become evident that the physiological influence of the gut microbiota extends beyond the periphery to the central nervous system (CNS). Current data derived from preclinical studies indicate that the gut microbiota can influence CNS function. Despite limited attempts to translate these findings to clinical populations, emerging evidence suggests that alterations in the composition of the gut microbiota, across the lifespan, may have a fundamental role in the pathophysiology of a number of mental health disorders. Moreover, accumulating evidence demonstrates the central role of food consumed in programming gut microbiota composition, diversity and functionality throughout life.Scope and approachIn this review, we outline what is considered a healthy infant and adult gut microbiota composition followed by describing how the gut microbiota can influence the CNS via signalling pathways of the microbiota-gut-brain axis. Current findings from preclinical investigations, observation and intervention studies in humans, indicating the gut microbiota in brain function and mental health are reviewed. Finally, we consider microbiota-targeted functional food interventions with potential application in promoting normal brain function.Key findings and conclusionsMuch work is yet to be performed in determining the role of the gut microbiota in brain function and behaviour in human populations. Nevertheless, the potential for microbiota-targeted functional food interventions is evident. As new findings emerge in this rapidly developing field, it is envisaged that a greater understanding of microbe-brain interactions will herald a new era of psychotropic therapies to promote normal brain function and mental health.