Effect of Protein Supplementation on Physical Performance in Older People With Sarcopenia-A Randomized Controlled Trial.

Objectives: To test the long-term effects of whey-enriched protein supplementation on muscle and physical performance.

Design: A 12-month randomized controlled double blind trial with a 43-month of post-trial follow-up.

Setting: Porvoo, Finland.

Participants: A total of 218 older (>74 years of age) community-dwelling people with sarcopenia.

Intervention: (1) Control with no supplementation; (2) isocaloric placebo; and (3) 20 g × 2 whey-enriched protein supplementation. All participants were given instructions on home-based exercise, dietary protein, and vitamin D supplementation of 20 μg/d.

Measurements: Physical performance was assessed by short physical performance battery and continuous summary physical performance scores. Hand grip strength and calf intracellular resistance based skeletal muscle index were measured by bioimpedance spectroscopy. The measurements were performed at 0, 6, and 12 months. The post-trial follow-up was performed by a postal questionnaire and national census record data.

Results: The participants were older (75-96 years of age) and mostly women (68%). The test supplements had no significant effects on physical performance; the 12-month changes for short physical performance battery were -0.55, -.05, and 0.03 points in control, isocaloric, and protein groups (P = .17), respectively. The changes in continuous summary physical performance scores were similar between the intervention groups (P = .76). The hand grip strength decreased significantly in all intervention groups, and the 12-month changes in calf intracellular resistance-based skeletal muscle index were minor and there were no differences between the intervention groups. One-half of the patients (56%) in both supplement groups reported mild gastrointestinal adverse effects. Differences were found neither in the all-cause mortality nor physical functioning in the post-trial follow-up.

Conclusions: The whey-enriched protein supplementation in combination with low intensity home-based physical exercise did not attenuate the deterioration of muscle and physical performance in community-dwelling older people with sarcopenia.