title: Modulation of soy isoflavones bioavailability and subsequent effects on bone health in ovariectomized rats: the case for equol.
abstract: BACKGROUND
  Soy products are of particular interest because of their potential health benefits in a range of hormonal conditions, such as osteoporosis, due to their high content in phytoestrogens. Because equol, the main metabolite from soy isoflavones, is thought to be powerful, the present study was designated to evaluate the bone-sparing effects of equol by either providing the molecule through the diet or by eliciting its endogenous production by modulating intestinal microflora by short-chain fructooligosaccharides (sc-FOS) or live microbial (Lactobacillus casei) together with daidzein, its precursor.
  
  
  METHODS
  A comparison with daidzein and genistein was also performed. Rats (3 months old) were ovariectomised (OVX) or sham-operated (SH). Ovariectomised rats were randomly assigned to six experimental diets for 3 months: a control diet (OVX), the control diet supplemented with either genistein (G), or daidzein (D), or equol (E) at the level of 10 microg/g body weight/d. The remaining OVX rats were given daidzein at the dose of 10 mug/g body weight/d, simultaneously with short-chain FOS (Actilight, Beghin-Meiji) (D+FOS) or Lactobacillus casei (Actimel, Danone) (D+L). The SH rats were given the same control diet as OVX.
  
  
  RESULTS
  Genistein, daidzein or equol exhibited a bone sparing effect. Indeed, total femoral bone mineral density (BMD) was significantly enhanced (compared to that of OVX rats), as was the metaphyseal compartment. Bone strength was improved by E consumption, but not by genistein or daidzein given alone. As far as the FOS diet is concerned, the addition of prebiotics significantly raised efficiency of the daidzein protective effect on both femoral BMD and mechanical properties. The effects of lactobacillus were similar, except that the increase in metaphyseal-BMD was not significant.
  
  
  CONCLUSIONS
  In conclusion, long-term equol consumption, like genistein and daidzein, in the ovariectomized rat, provides bone sparing effects. Adding indigestible sugars, such as FOS or live microbial as L. casei, in the diet significantly improves daidzein protective effects on the skeleton.
authors.affiliation: Groupe Ostéoporose, U3M, INRA Theix, Saint Genès-Champanelle, France.
authors.forename: J
authors.initials: J
authors.lastname: Mathey
authors.forename: J
authors.initials: J
authors.lastname: Mardon
authors.forename: N
authors.initials: N
authors.lastname: Fokialakis
authors.forename: C
authors.initials: C
authors.lastname: Puel
authors.forename: S
authors.initials: S
authors.lastname: Kati-Coulibaly
authors.forename: S
authors.initials: S
authors.lastname: Mitakou
authors.forename: C
authors.initials: C
authors.lastname: Bennetau-Pelissero
authors.forename: V
authors.initials: V
authors.lastname: Lamothe
authors.forename: M J
authors.initials: MJ
authors.lastname: Davicco
authors.forename: P
authors.initials: P
authors.lastname: Lebecque
authors.forename: M N
authors.initials: MN
authors.lastname: Horcajada
authors.forename: V
authors.initials: V
authors.lastname: Coxam
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis; D001835:Body Weight / Q000502:physiology; D015519:Bone Density / Q000502:physiology*; D001862:Bone Resorption / Q000503:physiopathology; D004195:Disease Models, Animal; D060754:Equol; D005260:Female; D005269:Femur / Q000187:drug effects / Q000378:metabolism; D019833:Genistein / Q000097:blood / Q000494:pharmacology; D007529:Isoflavones / Q000097:blood / Q000494:pharmacology*; D009929:Organ Size; D015675:Osteocalcin / Q000097:blood; D010024:Osteoporosis / Q000378:metabolism / Q000517:prevention & control*; D010052:Ovariectomy; D048789:Phytoestrogens / Q000097:blood / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013025:Glycine max / Q000737:chemistry*; D014599:Uterus / Q000473:pathology
chemical_list: C007610:4',7-dihydroxy-3,4-dihydroisoflavone; D015415:Biomarkers; D007529:Isoflavones; D048789:Phytoestrogens; D015675:Osteocalcin; D060754:Equol; C004742:daidzein; D019833:Genistein