Impact of energy and casein or whey protein intake on bone status in a rat model of age-related bone loss.
Br J Nutr
; 99(4): 764-72, 2008 Apr.
Article
em En
| MEDLINE
| ID: mdl-17925049
ABSTRACT
In the elderly, nutritional deficiencies, such as low energy and protein intake, are suggested to increase the risk of osteoporotic fractures. Modulation of the amount and quality of protein intake under energy deficient conditions represents an interesting strategy to prevent aged-related bone loss. We investigated the effect of a 5-month dietary restriction on bone status in 16-month-old male rats. Rats were randomised into six groups (n 10 per group). Control animals were fed a normal diet containing either casein (N-C) or whey protein (N-WP). The other groups received a 40 % protein and energy-restricted diet with casein or whey protein (PER-C and PER-WP) or a normal protein and energy-restricted diet (ER-C and ER-WP). Both restrictions (PER and ER) induced a decrease in femoral bone mineral density (BMD), consistent with impaired biomechanical properties and a reduced cortical area at the diaphysis. Plasma osteocalcin and urinary deoxypyridinoline levels suggested a decrease in bone turnover in the PER and ER groups. Interestingly, circulating insulin-like growth factor 1 (IGF-1) levels were also lowered. Overall, normal protein intake did not elicit any bone sparing effect in energy-deficient rats. Regarding protein quality, neither casein nor WP appeared to significantly prevent the BMD decrease. This study confirms that nutritional deficiencies may contribute to osteopenia through decreased IGF-1 levels. Moreover, it seems that impaired bone status could not be significantly prevented by modulating the amount and quality of dietary proteins.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Osteoporose
/
Osso e Ossos
/
Caseínas
/
Restrição Calórica
/
Proteínas do Leite
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
Br J Nutr
Ano de publicação:
2008
Tipo de documento:
Article