O070 - LIMITING AMINO ACIDS IN PEA AND SOY PROTEINS REDUCES AMINO ACID BIOAVAILABILITY AND NET PROTEIN SYNTHESIS COMPARED TO WHEY IN OLDER ADULTS

O070

LIMITING AMINO ACIDS IN PEA AND SOY PROTEINS REDUCES AMINO ACID BIOAVAILABILITY AND NET PROTEIN SYNTHESIS COMPARED TO WHEY IN OLDER ADULTS

S. B. Knezek^1,*, M. P. Engelen¹, M. C. Kang¹, S. Mistry¹, D. Campos¹, S. R. Gondi¹, N. E. Deutz¹

¹Texas A&M University, College Station, United States

Rationale: Older adults increasingly consume plant-based proteins despite their lower quality (essential amino acid (EAA) poor) compared to dairy protein; thus, assessing the anabolic response of plant proteins is needed. Using a stable-isotope pulse approach, we compared the anabolic response and amino acid (EAA/NEAA) disposal of whey (WP), soy (SP), and pea (PP) proteins in older adults.

Methods: 32 older adult participants (20m/12f), age (55-90y) participated in a randomized single blind crossover design over four non-consecutive study days. They consumed 45g of whey protein (WP), soy protein (SP), pea protein (PP), or water (postabsorptive state) via sip feeding every 20 minutes for 5 hours. 3 hours into feeding, an amino acid IV stable-isotope pulse was given to assess prandial amino acid kinetics. Tracer enrichment was analyzed by LC-MS/MS. Phenylalanine (PHE) (% bioavailability) intracellular amino acid disposal/amount given in the meal. Data are mean (µmol/min) [95% CI], stats by GLMM with lean body mass, sex, and age as fixed effects.

Results: WP showed a greater anabolic response compared to PP; 100% [69, 130] of PHE from WP intake contributing to net protein synthesis (NetPS) (SP=85% [65,105], PP=70% [55,85], p=0.028). SP and PP had lower disposal than WP for EAAs methionine (SP=-16.6, p<0.001; PP=-15.1, p=0.003), lysine (-134, p=0.001; -152, p<0.001), leucine (-62, p=0.009; -56, p=0.014), tryptophan (-36, p<0.001; -32, p<0.001), threonine (-68, p<0.001; -65, p<0.001) and valine (-33, p<0.001; -37, p<0.001).

Conclusion: All proteins exhibit amino acid-specific limitations, indicated by increased demand for those amino acids from other endogenous pools. Our data indicate that targeted nutritional strategies focusing on limiting amino acids are needed to enhance anabolic capacity and optimize plant-based proteins to support muscle health in older adults.

Disclosure of Interest: S. Knezek Grant / Research Support from: ESPEN Research Fellowship, M. Engelen: None declared, M. Kang: None declared, S. Mistry: None declared, D. Campos: None declared, S. Gondi: None declared, N. Deutz: None declared