Jourdan M, Farigon N, Bongers A, Salles J, Chanet A, Boirie Y, Walrand S, Blot A, Hafnaoui N, Giraudet C, Cano N, Luiking Y, Patrac V, Pouyet C, Pidou V, Verlaan S
Background: A promising strategy to help older adults preserve or build muscle mass is to optimize muscle anabolism through providing an adequate amount of high-quality protein at each meal.Objective: This "proof of principle" study investigated the acute effect of supplementing breakfast with a vitamin D and leucine-enriched whey protein medical nutrition drink on postprandial muscle protein synthesis and longer-term effect on muscle mass in healthy older adults.Methods: A randomized, placebo-controlled, double-blind study was conducted in 24 healthy older men [mean ± SD: age 71 ± 4 y; body mass index (in kg/m2) 24.7 ± 2.8] between September 2012 and October 2013 at the Unit of Human Nutrition, University of Auvergne, Clermont-Ferrand, France. Participants received a medical nutrition drink [test group; 21 g leucine-enriched whey protein, 9 g carbohydrates, 3 g fat, 800 IU cholecalciferol (vitamin D3), and 628 kJ] or a noncaloric placebo (control group) before breakfast for 6 wk. Mixed muscle protein fractional synthesis rate (FSR) was measured at week 0 in the basal and postprandial state, after study product intake with a standardized breakfast with the use of l-[2H5]-phenylalanine tracer methodology. The longer-term effect of the medical nutrition drink was evaluated by measurement of appendicular lean mass, representing skeletal muscle mass at weeks 0 and 6, by dual-energy X-ray absorptiometry.Results: Postprandial FSR (0-240 min) was higher in the test group than in the control group [estimate of difference (ED): 0.022%/h; 95% CI: 0.010%/h, 0.035%/h; ANCOVA, P = 0.001]. The test group gained more appendicular lean mass than the control group after 6 wk (ED: 0.37 kg; 95% CI: 0.03, 0.72 kg; ANCOVA, P = 0.035), predominantly as leg lean mass (ED: 0.30 kg; 95% CI: 0.03, 0.57 kg; ANCOVA, P = 0.034).Conclusions: Supplementing breakfast with a vitamin D and leucine-enriched whey protein medical nutrition drink stimulated postprandial muscle protein synthesis and increased muscle mass after 6 wk of intervention in healthy older adults and may therefore be a way to support muscle preservation in older people. This trial was registered at www.trialregister.nl as NTR3471.
