Physiological effects beyond the significant gain in muscle mass in sarcopenic elderly men: evidence from a randomized clinical trial using a protein-rich food

Abstract

Background

Sarcopenia is strongly associated with an inadequate intake of dietary protein. Dietary protein supplementation boosts muscle-protein synthesis and increases muscle mass in the elderly. This study tested whether adding a protein-rich food, ricotta cheese, to the habitual diet increased total appendicular skeletal muscle mass and strength in elderly people.

Methods

Participants (n = 40), were sarcopenic elderly men and women over 60 years of age. Two comparison groups were formed at random and followed for 3 months: the intervention group received 210 g/day of ricotta cheese plus the habitual diet, while the control group followed the habitual diet with no additional intervention. Total appendicular skeletal muscle (TASM) was assessed by dual-energy X-ray absorptiometry, while strength was measured using a handheld dynamometer at baseline and after the intervention period. The primary outcomes were the percentage of relative change in TASM and strength.

Results

The percentage of relative change in TASM was not significant between the groups after the intervention period. Muscle strength improved in the intervention group, but showed only a tendency towards significance (P = 0.06). Secondary analysis showed that the men in the intervention group gained 270 g in TASM compared to those in the control group, and improved their fasting insulin levels (P = 0.05), muscle strength, lean body mass in the arms, and body weight variables.

Conclusion

The results of this study indicate that a nutritional intervention using a high-quality protein food, specifically ricotta cheese, in order to increase the amount of protein intake might not be regarded as fully promising in elderly men and women with sarcopenia. However, the gender effects on muscle strength, lean tissue in the arms, homeostatic assessment of insulin resistance, and body weight detected in this study suggest that additional research is needed on elderly male subjects with sarcopenia.

Keywords:

• nutritional intervention
• protein-rich food
• ricotta cheese
• sarcopenia
• elderly

Acknowledgments

This project was funded by the Institute of Nutrition and Health, Kellogg’s, and CONACYT, Mexico (S0008-2010-1-140157). We are grateful to the study participants and to Ana Cristina Gallegos Aguilar, Daniel David Robles Ochoa, Bertha Isabel Pacheco Moreno, Orlando Tortoledo Ortiz, Diana Josefina Mendoza Bermudez, and José Antonio Ponce Martínez for their technical assistance. Special acknowledgement is given to José Rogelio Ramos Enríquez, manager of LACIUS, Universidad de Sonora, for his participation in the laboratory analyses.

Disclosure

The authors report no conflicts of interest in this work.