Protein turnover and energy metabolism of elderly women fed a low-protein diet.
The metabolic mechanisms of accommodation to a low-protein diet in elderly women were studied. Diets containing 1.47 (low) or 2.94 (adequate) g protein.kg body cell mass-1.d-1 (0.45 or 0.92 g.kg body weight-1.d-1, respectively) were fed for 10 wk. Fed state leucine kinetics, fasted and fed metabolic rate, and acute-phase responses to a bout of exercise were measured. Leucine uptake into protein, breakdown, and acute-phase responses were not significantly different within or between diet groups. In the low-protein group, leucine flux and oxidation were lower after 3 wk and oxidation continued to decrease throughout the 10-wk study. When expressed per body cell mass, metabolic rate increased over time in the low-protein group only. Leucine oxidation was a more sensitive index of the adequacy of protein intake than synthesis, flux, metabolic rate, or acute-phase response.
Castaneda
C
C
USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA.
Dolnikowski
G G
GG
Dallal
G E
GE
Evans
W J
WJ
Crim
M C
MC
D000222:Adaptation, Physiological / Q000502:physiology; D000368:Aged; D000375:Aging / Q000378:metabolism* / Q000502:physiology; D018753:Diet, Protein-Restricted; D004044:Dietary Proteins / Q000032:analysis / Q000378:metabolism* / Q000494:pharmacology; D004435:Eating / Q000502:physiology; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology*; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D007930:Leucine / Q000032:analysis / Q000378:metabolism / Q000493:pharmacokinetics
D004044:Dietary Proteins; D007930:Leucine