Objective: To determine the prevalence of sarcopenia in a population of obese older women and to assess the effect of a diet moderately rich in proteins on lean mass in sarcopenic obese older women.
Materials and methods: A total of 1,030 females, >65 years old, body mass index >30 kg/m(2), were investigated about their nutritional status. Muscle mass (MM) was estimated according to the Janssen equation (MM =0.401× height(2)/resistance measured at 50 kHz +3.825× sex -0.071× age +5.102). Sarcopenia was defined according to the MM index, MM/height2 (kg/m(2)), as two standard deviations lower than the obesity-derived cutoff score (7.3 kg/m(2)). A food-frequency questionnaire was used to measure participants' usual food intake during the previous 3 months. Moreover, a group of sarcopenic obese older women (n=104) was divided in two subgroups: the first (normal protein intake [NPI], n=50) administered with a hypocaloric diet (0.8 g/kg desirable body weight/day of proteins), and the second treated with a hypocaloric diet containing 1.2 g/kg desirable body weight/day of proteins (high protein intake [HPI], n=54), for 3 months. Dietary ingestion was estimated according to a daily food diary, self-administered, and three reports of nonconsecutive 24-hour recall every month during the follow-up.
Results: The 104 women were classified as sarcopenic. After dieting, significant reductions in body mass index were detected (NPI 30.7±1.3 vs 32.0±2.3 kg/m(2), HPI 30.26±0.90 vs 31.05±2.90 kg/m(2); P<0.01 vs baseline). The MM index presented significant variations in the NPI as well as in the HPI sarcopenic group (NPI 6.98±0.1 vs 7.10±0.2 kg/m(2), HPI 7.13±0.4 vs 6.96±0.1 kg/m(2); P<0.01 vs baseline).
Conclusion: A diet moderately rich in proteins was able to preserve MM in sarcopenic women. Therefore, adequate protein intake could contribute to the prevention of lean-mass loss associated with weight reduction in obese older people.
Keywords: aging; lean body mass; obesity; protein intake; sarcopenia.