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.
Picherit
C
C
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
Bennetau-Pelissero
C
C
Chanteranne
B
B
Lebecque
P
P
Davicco
M J
MJ
Barlet
J P
JP
Coxam
V
V
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