Serum steroid hormones, sex hormone-binding globulin concentrations, and urinary hydroxylated estrogen metabolites in post-menopausal women in relation to daidzein-metabolizing phenotypes

J Steroid Biochem Mol Biol. 2004 Apr;88(4-5):399-408. doi: 10.1016/j.jsbmb.2004.01.006.


Equol and O-desmethylangolensin (O-DMA) are products of bacterial metabolism of daidzein, an isoflavone in soybeans; thus, the presence or absence of equol and/or O-DMA in urine is a marker of particular intestinal bacteria profiles. Plasma hormone concentrations may be lower in pre-menopausal women who harbor the bacteria capable of producing equol (equol producers) compared to women who do not (equol non-producers). We evaluated concentrations of serum hormones, sex hormone-binding globulin (SHBG), and urinary 2-hydroxyestrone (2-OH E(1)) and 16alpha-hydroxyestrone (16alpha-OH E(1)) in relation to equol-producer and O-DMA-producer phenotypes in 89 post-menopausal women. Follicle stimulating hormone (FSH) was 23% greater in O-DMA-producers compared to non-producers (P = 0.04). No significant differences in serum estrogens, androgens, metabolic hormones, or SHBG were observed in relation to either daidzein-metabolizing phenotype. Compared with non-producers within each phenotype, age-adjusted 2-OH E(1):16alpha-OH E(1) was 27% greater (P = 0.06) in equol-producers and 9% greater (P > 0.10) in O-DMA-producers, and 2-OH E(1) concentrations were 24% greater in equol producers (P = 0.07) and 42% greater in O-DMA producers (P = 0.02). No significant differences in 16alpha-OH E(1) were observed in relation to either phenotype. These results suggest that interindividual variability in intestinal bacteria may be related to differences in products of hormone metabolism in post-menopausal women.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aged
  • Bacteria / metabolism
  • Equol
  • Female
  • Gonadal Steroid Hormones / blood*
  • Gonadal Steroid Hormones / metabolism
  • Humans
  • Hydroxyestrones / urine*
  • Intestines / microbiology
  • Isoflavones / analysis
  • Isoflavones / metabolism*
  • Middle Aged
  • Phenotype
  • Postmenopause / metabolism*
  • Sex Hormone-Binding Globulin / analysis*
  • Soybeans / metabolism


  • 4',7-dihydroxy-3,4-dihydroisoflavone
  • Gonadal Steroid Hormones
  • Hydroxyestrones
  • Isoflavones
  • Sex Hormone-Binding Globulin
  • Equol
  • daidzein
  • O-desmethylangolensin