Marked Individual Variation in Isoflavone Metabolism After a Soy Challenge Can Modulate the Skeletal Effect of Isoflavones in Premenopausal Women

• Published in: Journal of Korean medical science Vol. 24; no. 5; pp. 867 - 873
• Main Authors: Kwak, Ho Seok, Park, So Young, Kim, Mi Gyeong, Yim, Chang Hoon, Yoon, Hyun Koo, Han, Ki Ok
• Format: Journal Article
• Language: English
• Published: Korea (South) The Korean Academy of Medical Sciences 01.10.2009; 대한의학회
• Subjects: Adult; Amino Acids - urine; Bone and Bones - drug effects; Bone and Bones - metabolism; Double-Blind Method; Estrogen Antagonists - pharmacokinetics; Estrogen Antagonists - pharmacology; Estrogen Antagonists - urine; Female; Humans; Isoflavones - pharmacokinetics; Isoflavones - pharmacology; Isoflavones - urine; Middle Aged; Original; Osteocalcin - blood; Premenopause; 의학일반; Premenopausal Women; Estrogen Antagonists; Bone Turnover; Genistein; Equol; Isoflavones
• ISSN: 1011-8934; 1598-6357; 1598-6357
• DOI: 10.3346/jkms.2009.24.5.867

Soy-isoflavones may act as estrogenic agonists or antagonists depending on the endogenous hormone status. These clinical effects can be exerted variably in individuals by the metabolic ability to produce a more potent metabolite than precursors. The objective of this randomized, double-blind, placebo-controlled study was to investigate the skeletal effect of isoflavones according to their metabolic variability in premenopausal women. Volunteers were randomly assigned to receive either soy-extract isoflavones (n=32) or lactose (n=21) once a day for three menstrual cycles. After intervention, the urinary excretions of isoflavones and their metabolites were significantly higher in the soy group than in the placebo group and showed a large inter-individual variation. Women in the soy group were divided into subgroups according to their ability to excrete more potent metabolites. Serum osteocalcin and urine deoxypyridinoline showed a tendency to increase after a challenge in equol high-excretors. Serum osteocalcin concentration in the genistein high-excretors increased significantly after a challenge (P=0.04) but did not increase in either the placebo or genistein low-excretors. An estrogenic antagonistic effect of isoflavones on bone turnover was observed in premenopausal women who are able to produce more potent metabolites.