Role of soy protein with normal or reduced isoflavone content in reversing bone loss induced by ovarian hormone deficiency in rats
Open Access
- 1 December 1998
- journal article
- research article
- Published by Elsevier BV in The American Journal of Clinical Nutrition
- Vol. 68 (6), 1358S-1363S
- https://doi.org/10.1093/ajcn/68.6.1358s
Abstract
Soy protein, a rich source of isoflavones, fed immediately after an ovariectomy prevents bone loss in rats. Reports of the effectiveness of natural and synthetic isoflavones in preventing or treating osteoporosis led us to examine the effect of soy protein in reversing established bone loss. Seventy-two 95-d-old female Sprague-Dawley rats were assigned to 6 groups. The rats were either sham operated (SHAM; 2 groups) or ovariectomized (OVX; 4 groups) and then fed a casein-based, semipurified diet. Thirty-five days after surgery, 1 SHAM and 1 OVX group were killed to examine the occurrence of bone loss. Thereafter, the other SHAM and 1 OVX groups continued to receive the casein-based diet. Whereas the remaining 2 OVX groups received diets in which casein was replaced by soy protein with normal (OVX+SOY) or reduced (OVX+SOY-) isoflavone content for 65 days. The OVX control group had significantly lower femoral and fourth lumbar vertebral bone densities than the SHAM group. Femoral density of rats fed SOY or SOY- diets were not significantly different from SHAM or OVX controls. This suggests a slight reversal of cortical bone loss that may be partially due to higher femoral insulin-like growth factor I mRNA transcripts resulting from both the SOY and SOY- diets. The ovariectomy-induced increases in indexes of bone turnover were not ameliorated by either of the soy diets, suggesting that any positive effect of soy was achieved through enhanced bone formation rather than slowed bone resorption. Long-term consumption of soy or its isoflavones may be needed to produce small but continued increments in bone mass.Keywords
This publication has 33 references indexed in Scilit:
- Estrogens, the menopause, and osteoporosisBone, 1996
- Effects of progesterone on serum levels of IGF-1 and on femur IGF-1 mRNA in ovariectomized ratsJournal of Bone and Mineral Research, 1996
- Growth hormone stimulates bone formation and strength of cortical bone in aged ratsJournal of Bone and Mineral Research, 1995
- High-calorie total parenteral nutrition reduces hepatic insulin-like growth factor-I mRNA and alters serum levels of insulin-like growth factor—Binding protein-1, -3, -5, and -6 in the ratMetabolism, 1995
- Effect of growth hormone on bone: Bone mineral density, trabecular bone volume, and alkaline phosphatase improve or are restored in the dwarf rat treated with growth hormoneJournal of Bone and Mineral Research, 1995
- Binding and Bioeffects of Ipriflavone on a Human Preosteoclastic Cell LineBiochemical and Biophysical Research Communications, 1994
- Journal of Bone and Mineral ResearchJournal of Bone and Mineral Research, 1993
- Putting osteoporosis in perspectiveJournal of the American Dietetic Association, 1993
- Prevention and treatment of osteoporosisThe Lancet, 1993
- Osteoporosis—The Treatment ControversyNutrition Today, 1992