In:
Journal of Parenteral and Enteral Nutrition, Wiley, Vol. 23, No. 1 ( 1999-01), p. 32-37
Abstract:
Background: Protein depletion is frequent in the elderly, but the underlying mechanisms are not yet fully understood. In particular, it is unknown whether there is a defect of adaptation to a restriction of food intake in the elderly. This study was performed to compare the effects of 6‐week dietary restriction (DR) on protein metabolism in both adult and aged rats. Methods: Adult (3‐month‐old) and aged (22‐month‐old) rats were acclimatized for 2 weeks and then fed a standard diet for 6 weeks, either ad libitum (control adult [ C Adult ] and aged [ C Aged ] rats) or with only 50% of the average intake of the second week of acclimatization (restricted adult [ R Adult ] and aged [ R Aged ] rats). Protein metabolism, in terms of tissue protein content, nitrogen balance, and 3‐methylhistidine (3‐MH) urinary excretion, was evaluated. Results: C Adult rats gained 30.4% of initial weight, whereas the body weight (BW) of C Aged rats was maintained. DR induced a rapid decrease in BW during the first 2 weeks in R Adult rats, but afterward BW remained stable. In R Aged rats, BW loss was linear during the 6 weeks and significantly higher than for R Adult rats (p 〈 .01). In both restricted groups, muscle protein content was moderately affected by DR, whereas DR induced a marked decrease in visceral protein content. Nitrogen balance was decreased by DR but stayed positive in R Adult rats, whereas it became null in R Aged rats. Conclusions: In terms of protein metabolism, aged rats adapted less efficiently than adult rats to a long‐term dietary restriction. (Journal of Parenteral and Enteral Nutrition 23: 32–37,1999)
Type of Medium:
Online Resource
ISSN:
0148-6071
,
1941-2444
DOI:
10.1177/014860719902300132
Language:
English
Publisher:
Wiley
Publication Date:
1999
detail.hit.zdb_id:
2170060-6
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