Volume 57, Issue 6 p. 1073-1079

Increasing Dietary Protein Requirements in Elderly People for Optimal Muscle and Bone Health

Erin Gaffney-Stomberg MS, RD

Erin Gaffney-Stomberg MS, RD

From the Departments of * Allied Health Sciences and Nutritional Sciences, University of Connecticut, Storrs, Connecticut; and Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, Connecticut.

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Karl L. Insogna MD

Karl L. Insogna MD

From the Departments of * Allied Health Sciences and Nutritional Sciences, University of Connecticut, Storrs, Connecticut; and Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, Connecticut.

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Nancy R. Rodriguez RD, PhD

Nancy R. Rodriguez RD, PhD

From the Departments of * Allied Health Sciences and Nutritional Sciences, University of Connecticut, Storrs, Connecticut; and Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, Connecticut.

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Jane E. Kerstetter RD, PhD

Jane E. Kerstetter RD, PhD

From the Departments of * Allied Health Sciences and Nutritional Sciences, University of Connecticut, Storrs, Connecticut; and Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, Connecticut.

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First published: 29 May 2009
Citations: 162
Address correspondence to Jane E. Kerstetter, Department of Allied Health Sciences, 358 Mansfield Road, Box U-2101, University of Connecticut, Storrs, CT 06269. E-mail: [email protected]

Abstract

Osteoporosis and sarcopenia are degenerative diseases frequently associated with aging. The loss of bone and muscle results in significant morbidity, so preventing or attenuating osteoporosis and sarcopenia is an important public health goal. Dietary protein is crucial for development of bone and muscle, and recent evidence suggests that increasing dietary protein above the current Recommended Dietary Allowance (RDA) may help maintain bone and muscle mass in older individuals. Several epidemiological and clinical studies point to a salutary effect of protein intakes above the current RDA (0.8 g/kg per day) for adults aged 19 and older. There is evidence that the anabolic response of muscle to dietary protein is attenuated in elderly people, and as a result, the amount of protein needed to achieve anabolism is greater. Dietary protein also increases circulating insulin-like growth factor, which has anabolic effects on muscle and bone. Furthermore, increasing dietary protein increases calcium absorption, which could be anabolic for bone. Available evidence supports a beneficial effect of short-term protein intakes up to 1.6 to 1.8 g/kg per day, although long-term studies are needed to show safety and efficacy. Future studies should employ functional measures indicative of protein adequacy, as well as measures of muscle protein synthesis and maintenance of muscle and bone tissue, to determine the optimal level of dietary protein. Given the available data, increasing the RDA for older individuals to 1.0 to 1.2 g/kg per day would maintain normal calcium metabolism and nitrogen balance without affecting renal function and may represent a compromise while longer-term protein supplement trials are pending. J Am Geriatr Soc 57:1073–1079, 2009.