Protein Supplementation Increases Muscle Mass Gain During Prolonged Resistance-Type Exercise Training in Frail Elderly People: A Randomized, Double-Blind, Placebo-Controlled Trial

Objectives: Protein supplementation has been proposed as an effective dietary strategy to augment the skeletal muscle adaptive response to prolonged resistance-type exercise training in elderly people. Our objective was to assess the impact of protein supplementation on muscle mass, strength, and physical performance during prolonged resistance-type exercise training in frail elderly men and women. Design/setting/participants: A randomized, double-blind, placebo-controlled trial with 2 arms in parallel among 62 frail elderly subjects (78 1 year). These elderly subjects participated in a progressive resistance-type exercise training program (2 sessions per week for 24 weeks) during which they were supplemented twice daily with either protein (2 * 15 g) or a placebo. Measurements: Lean body mass (DXA), strength (1-RM), and physical performance (SPPB) were assessed at baseline, and after 12 and 24 weeks of intervention. Results: Lean body mass increased from 47.2 kg (95% CI, 43.5e50.9) to 48.5 kg (95% CI, 44.8e52.1) in the protein group and did not change in the placebo group (from 45.7 kg, 95% CI, 42.1e49.2 to 45.4 kg, 95% CI, 41.8e48.9) following the intervention (P value for treatment time interaction ¼ .006). Strength and physical performance improved significantly in both groups (P ¼ .000) with no interaction effect of dietary protein supplementation. Conclusions: Prolonged resistance-type exercise training represents an effective strategy to improve strength and physical performance in frail elderly people. Dietary protein supplementation is required to allow muscle mass gain during exercise training in frail elderly people. Trial Registration: clinicaltrials.gov identifier: NCT01110369.