Skip to main content
ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #37489
Title: INCREASED PROTEIN REQUIREMENTS IN ELDERLY PEOPLE: NEW DATA AND RETROSPECTIVE REASSESSMENTS

Author
item CAMPBELL WAYNE W - PENN STATE
item CRIM MARILYN C - TUFTS-HNRCA
item DALLAL GERARD E - TUFTS-HNRCA
item YOUNG VERNON E - MIT
item EVANS WILLIAM J - PENN STATE

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/1994
Publication Date: N/A
Citation: N/A

Interpretive Summary: There have been insufficient data available to determine the protein requirements of the elderly. This population differs from younger populations in body composition, physical activity, food intake and disease incidence, factors which may affect protein requirements. In this study, the dietary protein requirements of the elderly were determined in twelve men and women, aged 56 to 80 years, using the short-term nitrogen balance technique which measures the difference between the amount of nitrogen ingested and excreted by the body. If nitrogen intake is greater, a posi- tive balance exists. If more nitrogen is excreted than ingested, a nega- tive balance exists. The volunteers were randomly assigned to groups that consumed protein intakes equivalent to the Recommended Dietary Allowance (RDA) or twice the RDA. Net nitrogen balance was negative for the lower protein group and positive for the higher protein group. The average protein intake required to achieve nitrogen equilibrium was estimated to b significantly higher than the RDA. Nitrogen balance data from 3 previous protein requirement studies in the elderly were recalculated as recommended by the 1985 Joint FAO/WHO/UNU Expert Consultation and combined with the data from the current study data. Together, the current and retrospective nitrogen balance data suggest that a safe protein allowance for essentially all elderly adults would require intakes of protein considerably higher than the current RDA. These results are of direct benefit to scientists, agencies providing for the nutrition of elderly populations, and, even more so, to the elderly consumers by providing evidence of higher protein requirements in this population.

Technical Abstract: Dietary protein requirements of the elderly were determined by short-term nitrogen balance techniques using calculations recommended by the 1985 Joint FAO/WHO/UNU Expert Consultation. Twelve men and women, aged 56 to 80 yrs, were randomly assigned to groups that consumed total protein in- takes of either 0.80 +/- 0.01 or 1.62 +/- 0.02 g.kg**-1.d**-1 (mean +/- SEM). Net nitrogen balance was negative for the lower protein group (-4.6 +/- 3.4 mg N.kg**-1.d**-1), and positive for the higher protein group (13.6 +/- 1.0 mg N.kg**-1.d**-1). The mean protein intake required to achieve nitrogen equilibrium was estimated to be 1.00 g.kg**-1.d**-1. Nitrogen balance data from three previous protein requirement studies in the elderly were recalculated using the same balance formula and combined with the current study data to provide an overall weighted mean protein requirement estimate of 0.91 +/- 0.043 g.kg**-1.d**-1. The estimated mean protein requirements recalculated from these earlier studies were 0.65 +/- 0.19, 0.81 +/- 0.09 and 0.93 +/- 0.05 g.kg**-1.d**-1. Together, the current and retrospective nitrogen balance data suggest that the mean protein requirement in elderly adults is considerably greater than the 0.60 g.kg**-1.d**-1 established by the 1985 Joint FAO/WHO/UNU Expert Consultation. A safe protein allowance for elderly adults would require intakes of 1.0 to 1.25 g.kg**-1.d**-1 protein from a diet providing high quality protein.