Associations of the gut microbiota with diet and mild cognitive impairment in elderly individuals: a cross-sectional study

Abstract Introduction: The role of gut microbiota in linking diet to cognitive function in the elderly remains unclear. This study investigated whether the gut microbiota is associated with dietary modulation of mild cognitive impairment (MCI). Methods: A total of 48 patients with MCI and 43 healthy controls were included in the study. Participant demographics, along with the results of a food frequency questionnaire and the Montreal Cognitive Assessment, were recorded. Faecal samples underwent 16S rRNA sequencing. Spearman’s correlation examined relationships among gut microbiota composition, dietary intake and cognitive function. Results: Compared with healthy controls, patients with MCI had lower educational levels, higher serum total cholesterol and low-density lipoprotein cholesterol levels, and lower consumption of bean curd/tofu pudding, yoghurt, freshwater fish, shrimp/crab, pine nuts and pumpkin (all P Desulfovibrio, Sutterella, UCG-003 and other taxa were enriched, whereas those of Actinomyces, Streptococcus and other taxa were decreased ( P P Actinomyces and Streptococcus abundances correlated positively with both freshwater fish and yoghurt intake and cognitive performance, whereas UCG-003 and Desulfovibrio abundances correlated negatively with both shrimp/crab and yoghurt intake and cognitive scores. Conclusion: The consumption of yoghurt, freshwater fish, crustaceans, pine nuts or pumpkin was positively associated with cognitive function. Actinomyces and Streptococcus may contribute to the positive associations between freshwater fish and yoghurt consumption and cognitive function, whereas UCG-003 and Desulfovibrio may weaken the cognitive benefits associated with crustacean and yoghurt consumption.