Effect of the Fatty Acid Intake on Cognitive Function Through Gut Microbiota and Circulating microRNAs Remodeling in Middle‐Aged and Elderly Overweight and Obese Population

This study aimed to explore the role of fatty acids in regulating cognitive function through the gut microbiota (GM) and circulating microRNAs (miRNAs) by comprehensive analysis of dietary fatty acid intake (erythrocyte membrane fatty acid composition) and the GM and miRNAs in people with different body mass index (BMI). Participants with different BMIs in Beijing (normal weight [NW], overweight [OW], and obese [OB]) were recruited according to the Chinese obesity diagnostic criteria. Compared with the NW group, cognitive decline was observed in the OW and OB groups. Dietary saturated fatty acid (SFA) intake increased and dietary unsaturated fatty acid intake decreased in NW people. In the OW group, C18:3n-3 had beneficial mediation effects for cognition. Conversely, C18:3n-6 showed adverse cognitive effects in the mediating analysis. In the OW group, hsa-miR-142-5p presented a negative correlation with cognitive function. Erythrocyte membrane C23:0, as a good indicator of dietary fat intake, was found to influence cognitive function through Fusobacteriota, Proteobacteria, and plasma hsa-miR-144-3p in OB individuals. Different types of dietary fatty acid intake may affect the interaction between GM and miRNAs, and exert cognitive effects on middle-aged and elderly population, forming an interactive network of fatty acids-GM/miRNAs-cognition.