Céline Gryson1, Stéphane Walrand1, Christophe Giraudet1, Paulette Rousset1, Carole Migné1, Cécile Bonhomme2, Pascale Le Ruyet2, Yves Boirie3. 1. INRA, UMR1019, UNH, CRNH Auvergne, F-63000 Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000 Clermont-Ferrand, France. 2. Lactalis, Lactalis R&D, Retiers F-35000, France. 3. INRA, UMR1019, UNH, CRNH Auvergne, F-63000 Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, Unité de Nutrition Humaine, BP 10448, F-63000 Clermont-Ferrand, France; CHU Clermont-Ferrand, Clinical Nutrition Department, Clermont-Ferrand F-63003, France. Electronic address: Yves.Boirie@clermont.inra.fr.
Abstract
BACKGROUND & AIMS: Adequate protein intake is crucial to maintain body protein content in elderly subjects, but quality of dietary proteins should be also considered since amino acid composition and rate of protein digestion modulate amino acid availability. This study investigates whether the efficacy of optimal protein intake levels for protein retention in the elderly is influenced by protein quality. METHODS: We investigated the effect of a 10-day adequate-protein (AP) or high-protein (HP) diet together with the protein source as caseins (CAS) or soluble milk proteins (PRO) on whole-body (WB) protein synthesis (PS) and protein breakdown (PB) in 4 groups of healthy elderly men (mean ± SEM: 71.8 ± 24.4 yr). The study consisted of two periods of 4 h each: a post-absorptive period and a postprandial period. The fed state was defined by consumption every 20 min and for 4 h, of either 15 g or 30 g of PRO or CAS. Steady-state WB and splanchnic leucine kinetics were measured using a continuous infusion of L-[1-13C]leucine in the postabsorptive state and L-[1-13C]leucine infusion plus oral L-[5,5,5-2H3]leucine in the postprandial state. RESULTS: WB PS was stimulated by feeding only with HP diets, whereas WB PB corrected for splanchnic extraction showed a similar pattern of post-feeding decrease in all groups. Consequently, net leucine balance was greater in the postprandial state after HP meals than after AP meals, with PRO meals leading to a better postprandial leucine balance (3.63 ± 0.16 μmol kg FFM(-1) min(-1)vs. 2.77 ± 0.21 μmol kg FFM(-1) min(-1) for PRO HP and CAS HP, respectively; P = 0.005). CONCLUSION:Postprandial protein retention was better improved in elderly men by an increase in protein intake when the protein supplementation was provided as fast-digesting proteins that induce high leucine availability.
RCT Entities:
BACKGROUND & AIMS: Adequate protein intake is crucial to maintain body protein content in elderly subjects, but quality of dietary proteins should be also considered since amino acid composition and rate of protein digestion modulate amino acid availability. This study investigates whether the efficacy of optimal protein intake levels for protein retention in the elderly is influenced by protein quality. METHODS: We investigated the effect of a 10-day adequate-protein (AP) or high-protein (HP) diet together with the protein source as caseins (CAS) or soluble milk proteins (PRO) on whole-body (WB) protein synthesis (PS) and protein breakdown (PB) in 4 groups of healthy elderly men (mean ± SEM: 71.8 ± 24.4 yr). The study consisted of two periods of 4 h each: a post-absorptive period and a postprandial period. The fed state was defined by consumption every 20 min and for 4 h, of either 15 g or 30 g of PRO or CAS. Steady-state WB and splanchnic leucine kinetics were measured using a continuous infusion of L-[1-13C]leucine in the postabsorptive state and L-[1-13C]leucine infusion plus oral L-[5,5,5-2H3]leucine in the postprandial state. RESULTS: WB PS was stimulated by feeding only with HP diets, whereas WB PB corrected for splanchnic extraction showed a similar pattern of post-feeding decrease in all groups. Consequently, net leucine balance was greater in the postprandial state after HP meals than after AP meals, with PRO meals leading to a better postprandial leucine balance (3.63 ± 0.16 μmol kg FFM(-1) min(-1)vs. 2.77 ± 0.21 μmol kg FFM(-1) min(-1) for PRO HP and CAS HP, respectively; P = 0.005). CONCLUSION: Postprandial protein retention was better improved in elderly men by an increase in protein intake when the protein supplementation was provided as fast-digesting proteins that induce high leucine availability.
Authors: Manu V Chakravarthy; Mohammad S Siddiqui; Mikael F Forsgren; Arun J Sanyal Journal: Front Endocrinol (Lausanne) Date: 2020-12-23 Impact factor: 5.555
Authors: Nicolas Babault; Gaëlle Deley; Pascale Le Ruyet; François Morgan; François André Allaert Journal: J Int Soc Sports Nutr Date: 2014-07-11 Impact factor: 5.150