Associations of Cognitive Status, Sex and Diet in Older Adults: A Cross-Sectional Analysis of the Microbiome in Aging Gut and Brain (MiaGB) Study

every 4-week.Blood samples were collected before and after intervention and blood levels of amyloid beta (A)40, A42, gamma-aminobutyric acid and serotonin were measured.Results: There were no differences in baseline cognitive function and mental health status, levels of cognitive functionrelated biomarkers and dietary intake between groups.After 12week intervention, there was time effect on MoCA total score and this was particularly explained by a significant increase in the 5-HTP group (week 0 vs week 12: 26.6 AE 1.4 a.u.vs 27.6 AE 1.4 a.u., P < 0.05).There was time x group interaction effect on blood serotonin level by indicating significant increase in the 5-HTP group while no change in the control group.However, there were no time or time x group interaction effects in GAI, GDS, and levels of other cognitive function-related biomarkers.Conclusions: 5-HTP supplementation improved cognitive function in Singapore older adults and this improvement can be explained the regulation of neurotransmitter level.