Nutrient-rich dairy proteins improve appendicular skeletal muscle mass and physical performance, and attenuate the loss of muscle strength in older men and women subjects: a single-blind randomized clinical trial.

BACKGROUND: At present, it is unknown whether the use of nutrient-rich dairy proteins improves the markers of sarcopenia syndrome. Therefore, our proposal was to investigate whether adding 210 g of ricotta cheese daily would improve skeletal muscle mass, handgrip strength, and physical performance in non-sarcopenic older subjects. SUBJECTS AND METHODS: This was a single-blind randomized clinical trial that included two homogeneous, randomized groups of men and women over 60 years of age. Participants in the intervention group were asked to consume their habitual diet but add 210 g of ricotta cheese (IG/HD + RCH), while the control group was instructed to consume only their habitual diet (CG/HD). Basal and 12-week follow-up measurements included appendicular skeletal muscle mass (ASMM) by dual-energy X-ray absorptiometry, handgrip strength by a handheld dynamometer, and physical performance using the short physical performance battery (SPPB) and the stair-climb power test (SCPT). The main outcomes were relative changes in ASMM, strength, SPPB, and SCPT. RESULTS: ASMM increased in the IG/HD + RCH (0.6±3.5 kg), but decreased in the CG/HD (-1.0±2.6). The relative change between groups was statistically significant (P=0.009). The relative change in strength in both groups was negative, but the loss of muscle strength was more pronounced in CG/HD, though in this regard statistical analysis found only a tendency (P=0.07). The relative change in the balance-test scores was positive for the IG/HD + RCH, while in the CG/HD it was negative, as those individuals had poorer balance. In this case, the relative change between groups did reach statistical significance. CONCLUSION: The addition of 210 g of ricotta cheese improves ASMM and balance-test scores, while attenuating the loss of muscle strength. These results suggest that adding ricotta cheese to the habitual diet is a promising dietetic strategy that may improve the markers of sarcopenia in subjects without a pronounced loss of ASMM or sarcopenia.

Insufficient amounts and inadequate distribution of dietary protein intake in apparently healthy older adults in a developing country: implications for dietary strategies to prevent sarcopenia.

BACKGROUND: Both low dietary protein intake and inadequate distribution of protein over the three mealtimes have been reported in older Caucasian adults, but the association between protein intake at each meal and muscle mass has not been studied. The purpose of this study was to evaluate dietary protein intake and distribution by mealtimes, and to explore their association with appendicular skeletal muscle mass in apparently healthy older adults. METHODS: This was a cross-sectional pilot study that included 78 people over the age of 60 years. Caloric and protein intake were estimated on the basis of three nonconsecutive 24-hour diet recalls and appendicular skeletal muscle mass by dual-energy X-ray absorptiometry. RESULTS: Men consumed 13.4 g of protein/day more than women (P < 0.05). The estimated value of dietary protein intake was 0.9 g/kg/day. In this sample, 28% of subjects did not cover 100% of the dietary reference intake for protein. Lower consumption of dietary protein was found at breakfast and dinnertime compared with the recommended amount of 25-30 g (P < 0.05). Also, the study observed that appendicular skeletal muscle mass in men and women who consumed <25 g of protein at each mealtime was different from that found in the group that consumed >25 g of protein at one, two, or three mealtimes. CONCLUSION: While protein intake was higher than current recommendations, it failed to achieve the values reported as necessary to prevent sarcopenia. In addition, there was under-consumption of protein per mealtime, especially at breakfast and dinner.