Soybean isoflavones dose-dependently reduce bone turnover but do not reverse established osteopenia in adult ovariectomized rats.
We assessed the dose-dependent effects of daily soybean isoflavone (IF) consumption in reversing bone loss in adult ovariectomized rats. On d 0, female Wistar rats (7 mo old; n = 55) were either sham-operated (SH; n = 14) or ovariectomized (n = 41). On d 80, intermediate rats (SH: n = 5; ovariectomized: n = 5) were killed to confirm the ovariectomy-induced bone loss. The remaining ovariectomized rats were randomly assigned to one of four groups of nine rats each and fed soybean IF (mixed with a soy protein-free semipurified diet) at 0 (OVX), 20 (IF20), 40 (IF40) or 80 (IF80) mg/(kg body. d) for 84 d. Simultaneously, SH rats were fed the semipurified diet without any additional compound and killed on d 164, as were the other rats. As expected, both bone mineral density in the total femur and in its diaphyseal and metaphyseal subregions and cancellous bone area/measured surface in the distal femur metaphysis were lower in OVX than in SH rats (P: < 0.05). OVX rats had higher plasma osteocalcin concentration and urinary deoxypyridinoline excretion than SH rats (P: < 0.05). On d 164, osteocalcin and deoxypyridinoline concentrations were lower in IF40 or IF80 rats than in OVX rats (P: < 0.05). Nevertheless, neither bone mineral density nor cancellous bone area was greater in IF-fed rats than in OVX rats. Therefore, in adult ovariectomized rats, daily soybean IF consumption decreased bone turnover but did not reverse established osteopenia.
Groupe Ostéoporose, Laboratoire des Maladies Métaboliques et Micronutriments, Institut National de la Recherche Agronomigue Clermont-Ferrand/Theix, 63122 Saint Genès Champanelle, France. picherit@clermont.inra.fr
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Bennetau-Pelissero
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Chanteranne
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Lebecque
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Davicco
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Barlet
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Coxam
D000596:Amino Acids / Q000652:urine; D000818:Animals; D001851:Bone Diseases, Metabolic / Q000188:drug therapy* / Q000378:metabolism; D001842:Bone and Bones / Q000378:metabolism*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005260:Female; D005269:Femur; D007091:Image Processing, Computer-Assisted; D007529:Isoflavones / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D015675:Osteocalcin / Q000097:blood; D010024:Osteoporosis / Q000517:prevention & control*; D010052:Ovariectomy; D008517:Phytotherapy; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013025:Glycine max / Q000737:chemistry / Q000627:therapeutic use; D013997:Time Factors
D000596:Amino Acids; D007529:Isoflavones; D015675:Osteocalcin; C036020:deoxypyridinoline