45I-23 |
Soy isoflavones and n-3 fatty acids conserve bone following ovariectomy in rats |
S. REINWALD1, Y. Li1, M. F. Seifert2, and B. A. Watkins1. (1) Dept. of Food Science, Purdue Univ., Center for Enhancing Foods to Protect Health, 745 Agriculture Mall Dr., West Lafayette, IN 47907-2009, (2) Dept. of Anatomy & Cell Biology, Indiana Univ. Purdue Univ., Indianapolis, School of Medicine, 259 Medical Science Bldg., Indianapolis, IN 46202 Estrogen insufficiency is known to diminish the normal bone remodeling process and accelerate bone loss. Various hormone replacement therapies that contribute to bone conservation have recently come under medical scrutiny following evidence suggesting health risks associated with their use. Safe and protective alternative therapies are required, and we hypothesize that a regular dietary intake of soy isoflavones in combination with omega-3 polyunsaturated fatty acids (PUFA) can minimize the excessive bone loss commensurate with an estrogen deficiency. The research objective was to examine the combined effects of two levels of soy isoflavones, trace (IF-) or high (IF+) (0.04 and 3.98 mg/g protein respectively), and two levels of n-3 PUFA, low (L3) and high (H3) on bone conservation in 2-month-old sexually mature ovariectomized female Sprague-Dawley rats. pDEXA bone densitometry was used to measure right femur and tibia bone mineral density (BMD) and bone mineral content (BMC) of rats at 4 wk intervals. After 12 wks the rats were killed. Sequential in vivo and ex vivo analysis of cortical and trabecular subregions of interest on the femur and tibia were performed based on original whole bone DEXA images. Serum pyridinoline crosslink (PYD) concentrations were measured as a marker of bone turnover. Whole hind limb bones and trabecular subregions revealed a trend towards a positive bone conserving effect related to (IF+) at each level of n-3 PUFA. Rats fed H3 diets in addition to IF+ had a significantly higher distal femur BMD and BMC and an increased tibia BMC. The concentration level of PYD was also significantly lower in the H3IF+ group. These results demonstrate the positive effect and potential benefit of an isoflavone and n-3 PUFA dietary combination on bone preservation in the OVX rats, which is an FDA-approved model for research on preventing bone loss.
Session 45I, Nutrition: General
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