Possible role of equol status in the effects of isoflavone on bone and fat mass in postmenopausal Japanese women: a double-blind, randomized, controlled trial.
OBJECTIVE
Equol is more biologically active than its precursor daidzein, which is the principal isoflavone found in soybean. There are interindividual differences in the ability to produce equol; these may lead to differences in the effects of isoflavone intervention on human health. This study aimed to investigate whether the effects of soy isoflavones on bone and fat mass are related to an individual's equol status.


METHODS
We performed a 1-year double-blind, randomized trial to compare the effects of isoflavone (75 mg of isoflavone conjugates/day) with those of placebo on bone mineral density, fat mass, and serum isoflavone concentrations in early postmenopausal Japanese women who were classified based on their equol-producer phenotype.


RESULTS
After 1 year, the isoflavone intervention significantly increased the serum equol concentration in the equol producers but not in the nonproducers. In the isoflavone group, the annualized changes in the bone mineral density of the total hip and intertrochanteric regions were -0.46% and -0.04%, respectively, in the equol producers and -2.28% and -2.61%, respectively, in the nonproducers; these values were significantly different (P<0.05 for both the regions). Significant differences were observed between the equol producers and nonproducers in the isoflavone group with regard to the annualized changes in the fat mass. No significant difference in the annualized changes in bone mineral density and fat mass was observed between the equol producers and nonproducers in the placebo group.


CONCLUSIONS
Our data suggest that the preventive effects of isoflavones on bone loss and fat accumulation in early postmenopausal women depend on an individual's equol-producing capacity.
Wu
Jian
J
Nutritional Epidemiology Program, National Institute of Health and Nutrition, Tokyo, Japan.
Oka
Jun
J
Ezaki
Junko
J
Ohtomo
Takuya
T
Ueno
Tomomi
T
Uchiyama
Shigeto
S
Toda
Toshiya
T
Uehara
Mariko
M
Ishimi
Yoshiko
Y
D050154:Adiposity / Q000187:drug effects*; D044466:Asian People; D001823:Body Composition / Q000187:drug effects*; D015519:Bone Density / Q000187:drug effects; D001842:Bone and Bones / Q000378:metabolism*; D004311:Double-Blind Method; D060754:Equol; D005260:Female; D006801:Humans; D007529:Isoflavones / Q000008:administration & dosage / Q000494:pharmacology*; D007564:Japan; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000517:prevention & control; D048789:Phytoestrogens / Q000008:administration & dosage / Q000494:pharmacology*; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
C007610:4',7-dihydroxy-3,4-dihydroisoflavone; D007529:Isoflavones; D048789:Phytoestrogens; D060754:Equol