TheRoleoftheGutMicrobiotainDietary InterventionsforDepressionandAnxiety

Abstract

Thereisemergingevidencethatanunhealthydietarypatternmayincreasetheriskofdevelopingdepressionoranxiety,whereasahealthydietary pattern may decrease it. This nascent research suggests that dietary interventions could help prevent, or be an alternative or adjunct therapy for, depressionandanxiety.Therelation,however,iscomplex,affectedbymanyconfoundingvariables,andisalsolikelytobebidirectional,withdietary choicesbeingaffectedbystressanddepression.Thiscomplexityisreflectedinthedata,withsometimesconflictingresultsamongstudies.Asthe research evolves, all characteristics of the relation need to be considered to ensure that we obtain a full understanding, which can potentially be translatedintoclinicalpractice.Aparallelandfast-growingbodyofresearchshowsthatthegutmicrobiotaislinkedwiththebraininabidirectional relation, commonly termed the microbiome–gut–brain axis. Preclinical evidence suggests that this axis plays a key role in the regulation of brain function and behavior. In this review we discuss possible reasons for the conflicting results in diet–mood research, and present examples of areas of the diet–mood relation in which the gut microbiota is likely to be involved, potentially explaining some of the conflicting results from diet and depression studies. We argue that because diet is one of the most significant factors that affects human gut microbiota structure and function, nutritionalinterventionstudiesneedtoconsiderthegutmicrobiotaasanessentialpieceofthepuzzle