title: Levels of urinary isoflavones and lignan polyphenols in Japanese women.
abstract: OBJECTIVE
  High consumption of soybean products has been associated with a reduced risk of hormone-sensitive tumors. Soybean products contain phytoestrogens, such as daidzein, and sesame seeds contain secoisolariciresinol. These compounds are further metabolized to equol, enterodiol, and enterolactone by intestinal bacteria. However, individual differences in the metabolizing potential remain unclear. The aim of this study was to evaluate the urinary daidzein, equol, enterodiol, and enterolactone concentrations in women from several different regions of Japan according to age group.
  
  
  METHODS
  Five hundred urine samples collected from Japanese women living in Sapporo, Sendai, Kyoto, Kochi, and Naha were analyzed for daidzein, equol, enterodiol, and enterolactone concentration by gas chromatography-mass spectrometry.
  
  
  RESULTS
  The urinary isoflavone and lignan polyphenol levels did not differ significantly among the sampling sites, except for daidzein, which was highest in urine collected at Naha. The prevalence of equol producers was 39 % in the total study cohort. In equol producers, a positive correlation was observed between the urinary daidzein and equol levels (r = 0.399, p < 0.001). However, there was no significant difference between daidzein concentrations in equol producers and non-producers. Moreover, the levels of enterodiol and enterolactone were higher in equol producers than in equol non-producers. In the multivariate logistic analyses, two factors, Sendai dwelling and current smoking, were found to be significant [equol producers to non-producers: odds ratio 2.15 (95 % confidence interval: 1.17-4.02) and odds ratio 0.32 (0.15-0.63), respectively].
  
  
  CONCLUSIONS
  Our data suggest that geographic factors and smoking status should be considered during the evaluation of equol in urine samples and that the same pathway may be responsible for the metabolism of both isoflavones and lignan polyphenols.
authors: Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine, Yoshida Konoe, Sakyo, Kyoto, 606-8501, Japan.
authors: Wanyang
authors: W
authors: Liu
authors: Miyako
authors: M
authors: Tanabe
authors: Kouji H
authors: KH
authors: Harada
authors: Akio
authors: A
authors: Koizumi
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D015331:Cohort Studies; D004781:Environmental Exposure; D004784:Environmental Monitoring; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D005843:Geography; D006801:Humans; D007529:Isoflavones / Q000652:urine*; D007564:Japan; D017705:Lignans / Q000652:urine*; D008875:Middle Aged; D048789:Phytoestrogens / Q000652:urine*; D059808:Polyphenols / Q000652:urine
chemical_list: D007529:Isoflavones; D017705:Lignans; D048789:Phytoestrogens; D059808:Polyphenols
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