Low protein intake magnifies detrimental effects of ovariectomy and vitamin D on bone

MAROTTE C; GONZALES CHAVES MACARENA MS; PELLEGRINI GG; FRIEDMAN SM; MANDALUNIS P; ZENI SN

CALCIFIED TISSUE INTERNATIONAL

SPRINGER

Lugar: Berlin; Año: 2013

0171-967X

Abstract Protein-induced changes in bone and calciumhomeostasis could potentially be greater in the elderly and inwomen at risk for osteoporosis. We hypothesize that a lowprotein intake would magnify the negative changes in bonemetabolism seen in vitamin D (vitD) insufficiency and/orestrogen deficiency. The present study was undertaken tobetter understand how a low protein diet along with vitDinsufficiency could affect bone metabolism using a rodentovariectomized (OVX) model. Rats (n = 60) underwentovariectomy (OVX) or sham operation. The first 15 days aftersurgery, all rats were fed a standard rodent diet. Thereafter, rats(n = 10/group) were fed a low protein diet (LP; 2.5 %) or acontrol diet (NP; 12.5 %) with 100 IU% vitD (?D; cholecalciferol) or without vitD (-D) for 45 days. The groups were asfollows: SHAM ? NP ? D (control); SHAM ? LP ? D;SHAM ? LP - D; OVX ? NP ? D; OVX ? LP ? D;OVX ? LP - D. Body weight (BW) of control and OVX ? NP ? D groups increased while those feeding the LPdiet, independently of vitD feedings, decreased (p \ 0.05).The OVX ? LP - D group presented the lowest serum Ca,phosphorus and osteocalcin levels and the highest CTX levels(p \ 0.05). At the end of the study, total skeleton bone mineralcontent, proximal tibia bone mineral density, bone volume andtrabecular number levels decreased as follows: SHAM ?NP ? D (controls) [ SHAM ? LP ? D [ OVX ? NP ?D[ SHAM ? LP - D[ OVX ? LP ? D[ OVX ? LP D (p \ 0.05). A low protein diet negatively affected bonemass and magnified the detrimental effects of vitD and/orestrogen deficiencies.