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.