Low Protein Intake Magnifies Detrimental Effects of Ovariectomy and Vitamin D on Bone

C MAROTTE; GONZALES CHAVES M; G PELLEGRINI; FRIEDMAN S; LIFSHITZ F; MANDALUNIS P; N. ZENI

CALCIFIED TISSUE INTERNATIONAL

SPRINGER

Lugar: Berlin; Año: 2013 p. 184 - 192

0171-967X

homeostasis could potentially be greater in the elderly and in women at risk for osteoporosis. We hypothesize that a low protein intake would magnify the negative changes in bone metabolism seen in vitamin D (vitD) insufficiency and/or estrogen deficiency. The present study was undertaken to better understand how a low protein diet along with vitD insufficiency could affect bone metabolism using a rodent ovariectomized (OVX) model. Rats (n = 60) underwent ovariectomy (OVX) or sham operation. The first 15 days after surgery, all ratswere fed a standard rodent diet. Thereafter, rats (n = 10/group) were fed a low protein diet (LP; 2.5 %) or a control diet (NP; 12.5 %) with 100 IU% vitD (?D; cholecalciferol) or without vitD (-D) for 45 days. The groups were as follows: 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 ? Dgroups increasedwhile those feeding the LP diet, 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 bonemineral content, proximal tibia bone mineral density, bone volume and trabecular 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 bone mass and magnified the detrimental effects of vitD and/or estrogen deficiencies.