High concordance of daidzein-metabolizing phenotypes in individuals measured 1 to 3 years apart

Br J Nutr. 2005 Dec;94(6):873-6. doi: 10.1079/bjn20051565.


Particular intestinal bacteria are capable of metabolizing the soya isoflavone daidzein to equol and/or O-desmethylangolensin (O-DMA), and the presence of these metabolites in urine after soya consumption are markers of particular intestinal bacteria profiles. Prevalences of equol producers and O-DMA producers are approximately 30-50 % and 80-90 %, respectively, and limited observations have suggested that these daidzein-metabolizing phenotypes are stable within individuals over time. Characterizing stability of these phenotypes is important to understand their potential as markers of long-term exposure to particular intestinal bacteria and their associations with disease risk. We evaluated concordance within an individual for the equol-producer and O-DMA-producer phenotypes measured at two time points (T1, T2), 1-3 years apart. Phenotypes were ascertained by analysing equol and O-DMA using GC-MS in a spot urine sample collected after 3 d soya (source of daidzein) supplementation. In ninety-two individuals without recent (within 3 months before phenotyping) or current antibiotics use, 41 % were equol producers at T1 and 45 % were equol producers at T2, and 90 % were O-DMA producers at T1 and 95 % were O-DMA producers at T2. The percentage agreement for the equol-producer phenotype was 82 and for the O-DMA-producer phenotype was 89. These results indicate that these phenotypes are stable in most individuals over time, suggesting that they provide a useful biomarker for evaluating disease risk associated with harbouring particular intestinal bacteria responsible for, or associated with, the metabolism of the soya isoflavone daidzein.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / therapeutic use
  • Bacterial Infections / diagnosis
  • Bacterial Infections / urine
  • Biomarkers / urine
  • Dietary Supplements
  • Equol
  • Female
  • Humans
  • Intestines / microbiology*
  • Isoflavones / biosynthesis*
  • Isoflavones / metabolism*
  • Isoflavones / urine
  • Male
  • Phenotype
  • Phytoestrogens / metabolism*
  • Time Factors


  • 4',7-dihydroxy-3,4-dihydroisoflavone
  • Anti-Bacterial Agents
  • Biomarkers
  • Isoflavones
  • Phytoestrogens
  • Equol
  • daidzein
  • O-desmethylangolensin