TY - JOUR
T1 - Dietary soy protein and isoflavones
T2 - Minimal beneficial effects on bone and no effect on the reproductive tract of sexually mature ovariectomized Sprague-Dawley rats
AU - Bahr, Janice M.
AU - Nakai, Masaaki
AU - Rivera, Alexander
AU - Walsh, Jane
AU - Evans, Glenda L.
AU - Lotinun, Sutada
AU - Turner, Russell T.
AU - Black, Molly
AU - Jeffery, Elizabeth H.
PY - 2005
Y1 - 2005
N2 - Objective: The present study was conducted to determine the effects of dietary soy protein and isoflavones on bone and the reproductive tract in the absence of the ovary. Design: Three-month-old Sprague-Dawley rats (n = 56) were either sham-operated or ovariectomized and then fed diets containing casein or soy protein ±isoflavone extract for 12 weeks. The amounts of casein, soy protein, and extract (per kg diet) in each group were as follows: (1) Ovariectomy, 200 g of casein; (2) Ovariectomy+low soy, 100 g of casein + 100 g of soy protein; (3) Ovariectomy+high soy, 200 g of soy protein; (4) Ovariectomy+low extract, 200 g of casein + 17.2 g of extract; (5) Ovariectomy+high extract, 200 g of casein + 34.4 g of extract; (6) Ovary intact, 200 g of casein; (7) Ovariectomy+estradiol-17β, 200 g of casein. Diet consumption, body weight, uterine weight, urine deoxypyridinoline, and bone mineral density of the femur and lumbar vertebrae were measured. The femur rigidity was evaluated by histomorphometry. The reproductive tract (uterus, vagina, and cervix) was studied histologically. Results: The Ovariectomy group showed significant increases in body weight, diet consumption, and deoxypyridinoline, decreases in uterine weight and bone mineral density, and negative changes in histomorphometry compared with the Ovary intact group. Neither soy protein nor extract diets abrogated these alterations, except for the Ovariectomy+high extract group that showed statistically significant positive changes in histomorphometric parameters. There were no histological differences in the reproductive tract among Ovariectomy, Ovariectomy+soy, and Ovariectomy+extract groups. The estradiol-17β replacement abrogated ovariectomy-induced alterations. Conclusion: Dietary intake of isoflavones by sexually mature ovariectomized rats has a minimal beneficial effect on bone with no effect on the reproductive tract.
AB - Objective: The present study was conducted to determine the effects of dietary soy protein and isoflavones on bone and the reproductive tract in the absence of the ovary. Design: Three-month-old Sprague-Dawley rats (n = 56) were either sham-operated or ovariectomized and then fed diets containing casein or soy protein ±isoflavone extract for 12 weeks. The amounts of casein, soy protein, and extract (per kg diet) in each group were as follows: (1) Ovariectomy, 200 g of casein; (2) Ovariectomy+low soy, 100 g of casein + 100 g of soy protein; (3) Ovariectomy+high soy, 200 g of soy protein; (4) Ovariectomy+low extract, 200 g of casein + 17.2 g of extract; (5) Ovariectomy+high extract, 200 g of casein + 34.4 g of extract; (6) Ovary intact, 200 g of casein; (7) Ovariectomy+estradiol-17β, 200 g of casein. Diet consumption, body weight, uterine weight, urine deoxypyridinoline, and bone mineral density of the femur and lumbar vertebrae were measured. The femur rigidity was evaluated by histomorphometry. The reproductive tract (uterus, vagina, and cervix) was studied histologically. Results: The Ovariectomy group showed significant increases in body weight, diet consumption, and deoxypyridinoline, decreases in uterine weight and bone mineral density, and negative changes in histomorphometry compared with the Ovary intact group. Neither soy protein nor extract diets abrogated these alterations, except for the Ovariectomy+high extract group that showed statistically significant positive changes in histomorphometric parameters. There were no histological differences in the reproductive tract among Ovariectomy, Ovariectomy+soy, and Ovariectomy+extract groups. The estradiol-17β replacement abrogated ovariectomy-induced alterations. Conclusion: Dietary intake of isoflavones by sexually mature ovariectomized rats has a minimal beneficial effect on bone with no effect on the reproductive tract.
KW - Bone
KW - Isoflavones
KW - Ovariectomized rat
KW - Reproductive tract
KW - Soy
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U2 - 10.1097/00042192-200512020-00011
DO - 10.1097/00042192-200512020-00011
M3 - Article
C2 - 15772564
AN - SCOPUS:16244415540
SN - 1072-3714
VL - 12
SP - 165
EP - 173
JO - Menopause
JF - Menopause
IS - 2
ER -