ABSTRACT
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.
Subject(s)
Body Composition/drug effects , Dairy Products , Leucine/therapeutic use , Milk Proteins/therapeutic use , Muscle, Skeletal/drug effects , Physical Fitness/physiology , Polymyalgia Rheumatica/drug therapy , Adipose Tissue/drug effects , Aged , Body Composition/physiology , Cross-Over Studies , Dietary Supplements , Double-Blind Method , Exercise/physiology , Exercise Therapy , Female , Food, Fortified , Humans , Leucine/pharmacology , Male , Middle Aged , Milk Proteins/chemistry , Milk Proteins/pharmacology , Movement/drug effects , Muscle Strength/drug effects , Muscle, Skeletal/anatomy & histology , Muscle, Skeletal/physiology , Organ Size/drug effects , Polymyalgia Rheumatica/pathology , Polymyalgia Rheumatica/physiopathology , Walking/physiology , Whey ProteinsABSTRACT
The beneficial cardiovascular effects of soy protein have been studied intensively in recent years. Another protein-rich legume is lupin, which has been shown to have similar effects to those of soy in lowering serum cholesterol levels. In this study we compared the effects of lupin and soy protein on hypertension and vascular functions in spontaneously diabetic Goto-Kakizaki (GK) rat, which develop hypertension when fed a high-salt diet. The rats were fed with a 6% NaCl diet containing either lupin or soy protein isolate (20% weight/weight) for two weeks. In the end of the study the SBP was 18.6 mmHg lower (p<0.001) in the lupin group, and 12.0 mmHg lower (p<0.01) in the soy group than in the control group. Lupin and soy treatments normalised the decreased vasocontraction observed in the NaCl-fed control group, but only lupin treatment improved the impaired endothelium-dependent vasorelaxation. The attenuation of hypertension is likely to be mediated by the corrected vascular dysfunction, whose precise mechanism and the possible clinical relevance remains to be studied further.
