The Journals of Gerontology Series A: Biological Sciences and Medical
Sciences 56:M373-M380 (2001)
2001 The Gerontological Society of America
The Recommended Dietary Allowance for Protein May Not Be Adequate for
Older People to Maintain Skeletal Muscle
Wayne W. Campbella,b, Todd A. Trappea,b, Robert R. Wolfec and William J.
Evansa,b
a The Donald W. Reynolds Department of Geriatrics, University of
Arkansas for Medical Sciences, Little Rock.
b The Geriatric Research, Education, and Clinical Center, Central
Arkansas Veterans Healthcare System, Little Rock.
c Metabolism Unit, Shriners Burns Institute and the University of Texas
Medical Branch, Galveston.
William J. Evans, Nutrition, Metabolism and Exercise Division, Renolds
Department of Geriatrics and GRECC, 4301 West Markham Street, Slot 806,
Little Rock, AR 72205 E-mail: evanswilliamj@exchange.uams.edu.
Decision Editor: John E. Morley, MB, BCh
Background. Inadequate dietary protein intake results in loss of
skeletal muscle mass. Some shorter-term nitrogen balance studies suggest
that the Recommended Dietary Allowance (RDA) of protein may not be
adequate for older people. The aim of this study was to assess the
adequacy of the RDA of protein for older people by examining longer-term
responses in urinary nitrogen excretion, whole-body protein metabolism,
whole-body composition, and mid-thigh muscle area.
Methods. This was a 14-week precisely controlled diet study. Ten
healthy, ambulatory men and women, aged 55 to 77 years, were provided
eucaloric diets that contained 0.8 g protein kg-1 day-1. The study was
conducted at a General Clinical Research Center using an outpatient
setting for 11 weeks and an inpatient setting for 3 weeks. The main
outcome measures included urinary nitrogen excretion, postabsorptive and
postprandial whole-body leucine kinetics via infusion of
L-[1-13C]-leucine, whole-body density via hydrostatic weighing, total
body water via deuterium oxide dilution, and mid-thigh muscle area via
computed tomography scans.
Results. Mean urinary nitrogen excretion decreased over time from Weeks
2 to 8 to 14 (p = .025). At Week 14, compared with Week 2, there were no
changes in postabsorptive or postprandial leucine kinetics (turnover,
oxidation, incorporation into protein via synthesis, release via
breakdown, or balance). Whole-body composition (% body fat, fat-free
mass, and protein + mineral mass) did not change over time in these
weight-stable subjects. Mid-thigh muscle area was decreased by -1.7
0.6 cm2 (p = .019) at Week 14 compared with Week 2. The loss of
mid-thigh muscle area was associated with the decrease in urinary
nitrogen excretion (Spearman r = .83, p = .010).
Conclusions. The maintenance of whole-body leucine metabolism and
whole-body composition is generally consistent with a successful
adaptation to the RDA for protein. However, the decrease in mid-thigh
muscle area and the association with decreased urinary nitrogen
excretion are consistent with a metabolic accommodation. These results
suggest that the RDA for protein may not be adequate to completely meet
the metabolic and physiological needs of virtually all older people.
J. W. Apolzan, N. S. Carnell, R. D. Mattes, and W. W. Campbell
Inadequate Dietary Protein Increases Hunger and Desire to Eat in Younger
and Older Men
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Campbell
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older humans
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[Abstract] [Full Text] [PDF]
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A Tylavsky, M. Nevitt, and T. B Harris
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Aging and Body Composition Study
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1218. [Abstract] [Full Text] [PDF]
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Protein Nutrition, Exercise and Aging
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T. J. Doherty
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J. Bohe, A. Low, R. R. Wolfe, and M. J. Rennie
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S. Chevalier, R. Gougeon, K. Nayar, and J. A Morais
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Approaches to Quantifying Protein Metabolism in Response to Nutrient
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Effect of protein source on resistive-training-induced changes in body
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