(OR06-03-25) The Influence of Different Types of Higher Protein Intakes With a Healthy Dietary Pattern on Gut Microbiota-Derived Metabolites in Older Adults: A Randomised Controlled Trial

Objectives: Higher protein (HP) intakes have been reported to elicit deleterious changes in the levels of various gut microbiota-derived metabolites, with different sources of HP intakes likely differentially influencing the gut microbiota metabolic profile. Healthy dietary patterns have been suggested to exhibit synergistic effects with HP intakes on the gut microbiota metabolic profile by potentially mitigating the detrimental changes in microbiota-derived metabolites. However, such clinical evidence is notably lacking, especially in older adults. Hence, this study aimed to explore the influence of different sources of HP intakes with a healthy dietary pattern on the gut microbiota metabolic profile in Singaporean older adults.

Methods: This was a 16-week, parallel, single-blinded randomized controlled trial where 55 older adults (66 ± 1 y, mean ± SEM) were randomly assigned to either the control (n = 19), casein (n = 18), or soy (n = 18) group. All participants were instructed to follow a healthy dietary pattern either with or without a HP intake, with the casein and soy groups additionally consuming 20 g/d of casein (animal) and soy (plant) protein isolates respectively. Fecal and serum short-chain fatty acids (SCFAs), along with plasma uremic toxin (indoxyl sulfate, p-cresyl sulfate, trimethylamine N-oxide) levels were quantified at weeks 0, 8, and 16 by GC-MS-FID and UPLC-MS/MS respectively.

Results: A significant time effect was observed for plasma indoxyl sulfate, which was primarily driven by the reduction in the soy group from week 8 to 16 (-1.5 ± 0.5 µM). Serum propionic acid was also shown to be significantly lower in the soy group at week 16 compared to week 8 (-1.3 ± 0.4 µM). No changes in other SCFAs and plasma uremic toxins were observed across all groups throughout the study.

Conclusions: The consumption of HP intakes with a healthy dietary pattern does not generally alter the levels of most gut microbiota-derived metabolites, although different sources of HP intakes may influence changes in different gut microbiota-derived metabolites.

Funding Sources: NUS Mind-Science Centre, Singapore