Fulfilled mind, healthy gut? Relationships of eudaimonic psychological well-being with the gut microbiome in postmenopausal women

Eudaimonic facets of psychological well-being (PWB), like purpose in life and sense of mastery, are associated with healthy aging. Variation in the gut microbiome may be one pathway by which mental health influences age-related health outcomes. Yet, associations between eudaimonic PWB and the gut microbiome are understudied. We examined whether purpose in life and sense of mastery, separately, were associated with features of the gut microbiome in older women.Participants were from the Mind-Body Study (N = 206, mean age = 61), a substudy of the Nurses' Health Study II cohort. In 2013, participants completed the Life Engagement Test and the Pearlin Mastery Scale. Three months later, up to two pairs of stool samples were collected, 6 months apart. Covariates included sociodemographics, depression, health status, and health behaviors. Analyses examined associations of PWB with gut microbiome taxonomic diversity, overall community structure, and specific species/pathways. To account for multiple testing, statistical significance was established using Benjamini-Hochberg adjusted p-values (i.e., q-values ≤0.25).We found no evidence of an association between PWB and gut microbiome alpha diversity. In multivariate analysis, higher purpose levels were significantly associated with lower abundance of species previously linked with poorer health outcomes, notably Blautia hydrogenotrophica and Eubacterium ventriosum (q-values ≤0.25). No significant associations were found between PWB and metabolic pathways.These findings offer early evidence suggesting eudaimonic PWB is linked with variation in the gut microbiome, and this might be one pathway by which PWB promotes healthy aging.