“…Research indicates that the gut microbiota is associated with health in the elderly, with those in long‐term care having a less diverse microbiota than those living in the community (Claesson et al, ), although there is substantial distinctiveness at an interindividual level (Claesson et al, ). Even under conditions of healthy ageing, there can be a decline in some aspects of cognition (e.g., Koen & Yonelinas, ), but given the rising global health burden of dementia (Prince et al, ), as well as the psychological and physiological toll this can take upon caregivers (e.g., Allen, Curran et al, ; Etters, Goodall, & Harrison, ; Kiecolt‐Glaser, Dura, Speicher, Trask, & Glaser, ) a greater understanding of how gut health may impact upon the psychological health in ageing is critical. Despite this initial interest in gut microbiota changes with advancing age, there has been a relative lack of long‐term longitudinal research examining changes in the human gut microbiota.…”