Microbiota and sleep: awakening the gut feeling

Various lifestyle and environmental factors are known to influence sleep. Increasingly, evidence points to a role for the microbiota in regulating brain and behaviour. This article explores how the microbiota–gut–brain axis affects sleep directly and indirectly. We summarize the possible molecular mechanisms underlying sleep–microbiome interactions and discuss how various factors interact with the gut microbiota to influence sleep. Furthermore, we present the current evidence of alterations of the microbiota–gut–brain axis in various sleep disorders and pathologies where comorbid sleep disturbances are common. Since manipulating the gut microbiota could potentially improve sleep, we outline ways in which this can be achieved. Environmental and lifestyle factors influence sleep via the microbiota–gut–brain axis.Recent studies demonstrate microbial metabolites, the serotonergic system, the vagus nerve, and immune reactions as modes of communication via the microbiota–gut–brain axis that regulate sleep.Changes in gut microbiota composition accompany several sleep disorders and pathologies with comorbid sleep disturbances.Recent studies present evidence that sleep quality can be improved by altering the gut microbiota by consumption of certain probiotics and prebiotics as well as via faecal microbiota transplant.