Soybean isoflavones reduce postmenopausal bone resorption in female Japanese immigrants in Brazil: a ten-week study.
OBJECTIVE
Some human studies and animal models of experimental osteoporosis have shown that soy isoflavones may be effective on bone health. In this study, we carried out an intervention study to explore the effects of dietary isoflavone on bone metabolism.


METHODS
Forty healthy female postmenopausal Japanese immigrants living in Brazil were divided into two groups: isoflavone-administered (n = 20) or placebo (n = 20). Subjects in the isoflavone-administered group ingested 37.3 mg per day for 10 weeks. The collection of 24-hour urine and the measurement of bone stiffness were performed at 0 and 10 weeks. Urinary excretion of isoflavones and bone resorption markers were analyzed.


RESULTS
Urinary isoflavone excretion in the isoflavone-administered group was significantly increased at weeks 3 and 10. Urinary excretion of bone resorption markers was reduced in the isoflavone-administered group, while the placebo group did not show any significant reduction. Differences in levels of urinary isoflavones and bone resorption markers between the two groups were significant.


CONCLUSIONS
This study demonstrated that the bone resorption was associated with the intake of soy isoflavones in postmenopausal women, and continuous dietary intake of isoflavone may inhibit postmenopausal osteoporosis.
Yamori
Yukio
Y
WHO Collaborating Center for Research on Primary Prevention of Cardiovascular Diseases, Kyoto, Japan. Yukio.Yamori@ma3.seikyou.ne.jp
Moriguchi
Emilio H
EH
Teramoto
Takanori
T
Miura
Ayako
A
Fukui
Yutaka
Y
Honda
Kei-ich
KI
Fukui
Masakazu
M
Nara
Yasuo
Y
Taira
Kazuhiko
K
Moriguchi
Yukio
Y
D015415:Biomarkers / Q000652:urine; D015519:Bone Density / Q000187:drug effects* / Q000502:physiology; D001862:Bone Resorption / Q000208:ethnology / Q000517:prevention & control*; D001842:Bone and Bones / Q000378:metabolism*; D001938:Brazil; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007529:Isoflavones / Q000008:administration & dosage* / Q000652:urine; D007564:Japan / Q000208:ethnology; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000208:ethnology / Q000517:prevention & control*; D017698:Postmenopause; D013025:Glycine max / Q000737:chemistry*
D015415:Biomarkers; D007529:Isoflavones