(P09-015-25) Impact of 5-Hydroxytryptophan Supplementation on Cognitive Function in Singapore Older Adults: A Randomized Controlled Trial

Objectives: Like many countries, Singapore's population is aging rapidly and with an increased life expectancy and rapidly aging population in Singapore, cognitive impairment is a growing health concern. Among multiple factors that can attenuate cognitive impairment, 5-Hydroxytryptophan (5-HTP) has been shown to improve or maintain cognitive function by increasing the production of serotonin levels in the brain as serotonin is a neurotransmitter that regulates mood, cognition, and other physiological processes. However, such clinical evidence is notably lacking, especially in older adults hence, this study aimed to assess the impact of 5-HTP supplementation on cognitive function in Singapore older adults.

Methods: This was a single-blinded, 12-week parallel randomized controlled trial and 30 older adults (66 ± 3 years, mean ± SD) were randomly assigned to either consume (5-HTP group) or not consume (Control group) 100 mg 5-HTP daily. Cognitive function and mental health status were assessed via validated tools including montreal cognitive assessment (MoCA), geriatric anxiety inventory (GAI) and geriatric depression scale (GDS) every 4-week. Blood samples were collected before and after intervention and blood levels of amyloid beta (Aβ)40, Aβ42, gamma-aminobutyric acid and serotonin were measured.

Results: There were no differences in baseline cognitive function and mental health status, levels of cognitive function-related biomarkers and dietary intake between groups. After 12-week 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 ± 1.4 a.u. vs 27.6 ± 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.

Funding Sources: NUS iHealthtech Microbiome in Health, Disease and Ageing.