Similar effects of leucine rich and regular dairy products on muscle mass and functions of older polymyalgia rheumatica patients: a randomized crossover trial.

OBJECTIVES: Leucine-rich milk and whey proteins have been suggested for prevention of age related loss of muscle mass and strength i.e. sarcopenia. The effects of milk protein supplementation and low intensity home based physical exercise on body composition and muscle functions were investigated.

DESIGN: A randomized double blind crossover trial.

SETTING: Community dwelling members of Helsinki rheumatoid association.

PARTICIPANTS: Older people (N=47, mean age 69.5 years) suffering from polymyalgia rheumatica.

INTERVENTION: Patients performed as many stand ups as possible twice a day after which they ingested a regular (Control) or a whey protein enriched dairy product with high leucine content (Test). The 8-week intervention periods were separated by a 4-week wash-out.

MEASUREMENTS: Body composition was measured by dual x-ray absorptiometry and muscle functions by hand grip strength, force platform countermovement jump performance, chair stand test, and walking speed.

RESULTS: The 16-week home-based post-exercise supplementation resulted in a 1.8% increase (p = 0.052) in lower limb muscle mass. Walking speed (+5.3%, p = 0.007) and chair stand test performance (-12.2 %, p < 0.001) were also improved. Furthermore, a tendency for increased jump power (+3.0%, p = 0.084) was observed. However, significant and consistent differences were not found in the changes of muscle mass indices or muscle functions between supplements, but the test supplement tended to prevent accumulation of body fat.

CONCLUSION: A low intensity home based exercise program combined with post-exercise milk protein supplementation is feasible despite some gastrointestinal complaints and seems effective in improving the muscle mass and functions of older persons with a inflammatory disease. Further studies are needed to establish, whether and to what extent the use of leucine-enriched whey products prevent or treat age-associated sarcopenia and whether they are superior to the present commercial milk products.