PP355 - INGESTION OF 20 G WHEY PROTEIN OR A PLANT PROTEIN BLEND WITH OR WITHOUT ADDED LEUCINE DOES NOT INCREASE MUSCLE PROTEIN SYNTHESIS RATES IN OLDER MALES

PP355

INGESTION OF 20 G WHEY PROTEIN OR A PLANT PROTEIN BLEND WITH OR WITHOUT ADDED LEUCINE DOES NOT INCREASE MUSCLE PROTEIN SYNTHESIS RATES IN OLDER MALES

L. Kuin^1,2,*, W. Hermans¹, N. Boot¹, C. Fuchs¹, J. Senden¹, A. Zorenc¹, A. Overman¹, J. van Kranenburg¹, J. Goessens¹, L. Verdijk¹, M. van Dijk³, M. Furber³, A. van Helvoort^3,4, L. van Loon¹

¹Department of Human Biology, ²Department of Gastroenterology-Hepatology, Maastricht University Medical Centre+, Maastricht, ³Danone Research & Innovation, Utrecht, ⁴Department of Respiratory Medicine, Maastricht University Medical Centre+, Maastricht, Netherlands

Rationale: The lower anabolic properties of plant-derived versus animal-derived proteins may be improved by fortification with free leucine, and by forming blends of plant-derived proteins. This study aimed to compare post-prandial muscle protein synthesis rates following ingestion of a single bolus of a soy-pea protein blend, with a soy-pea protein blend fortified with leucine, or whey protein in older males.

Methods: In this randomized, double-blind, parallel-group design, 45 healthy older males (69±5y) were selected to ingest a 20g protein blend combining 12g soy plus 8g pea protein (PLANT), 20g of the soy-pea protein blend fortified with 2g leucine (PLANT+LEU), or 20g whey protein (WHEY). Primed continuous L-[ring-¹³C₆]-phenylalanine infusions were applied, with blood and muscle sampling over 4h after protein ingestion to assess plasma amino acid profiles and muscle protein synthesis rates. Data were analyzed by one- and two-way repeated measures ANOVA.

Results: WHEY increased plasma essential amino acid concentrations more than PLANT and PLANT+LEU over the 4h post-prandial period (iAUC:135±20, 99±21, and 105±21 mmol∙240 min∙L^-1, respectively; P<0.001). Post-prandial muscle protein synthesis rates averaged 0.034±0.010, 0.035±0.012, and 0.034±0.010 %∙h^-1 following PLANT, PLANT+LEU, and WHEY ingestion, respectively (P-treatment=0.828), and were not increased when compared to basal values.

Conclusion: Ingestion of 20g whey protein or a plant-derived protein blend (with or without added leucine) increases plasma essential amino acid concentrations, but does not increase muscle protein synthesis rates in older males. This indicates that irrespective of protein source or quality, ingestion of 20g protein consumed without other nutrients is insufficient to robustly stimulate muscle protein synthesis in an older population.

Disclosure of Interest: L. Kuin Grant / Research Support from: Funding of this research was obtained from Danone Research & Innovation (Utrecht, the Netherlands) as part of the Top-sector Agri&Food (Project LWV21.286). , Other: Received research grants, consulting fees, speaking honoraria, or a combination of these for research on the impact of exercise and nutrition on muscle metabolism. A full overview on research funding is provided at: https://www.maastrichtuniversity.nl/l.vanloon, W. Hermans: None declared, N. Boot: None declared, C. Fuchs: None declared, J. Senden: None declared, A. Zorenc: None declared, A. Overman: None declared, J. van Kranenburg: None declared, J. Goessens: None declared, L. Verdijk Other: Received research grants, consulting fees, speaking honoraria, or a combination of these for research on the impact of exercise and nutrition on muscle metabolism. A full overview on research funding is provided at: https://www.maastrichtuniversity.nl/l.vanloon, M. van Dijk Other: Employee of Danone Research & Innovation, M. Furber Other: Employee of Danone Research & Innovation, A. van Helvoort Other: Employee of Danone Research & Innovation, L. van Loon Other: Received research grants, consulting fees, speaking honoraria, or a combination of these for research on the impact of exercise and nutrition on muscle metabolism. A full overview on research funding is provided at: https://www.maastrichtuniversity.nl/l.vanloon