title: High concordance of daidzein-metabolizing phenotypes in individuals measured 1 to 3 years apart.
abstract: 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.
authors.affiliation: Department of Epidemiology, University of Washington, Seattle, WA 98109-1024, USA.
authors.forename: Cara L
authors.initials: CL
authors.lastname: Frankenfeld
authors.forename: Charlotte
authors.initials: C
authors.lastname: Atkinson
authors.forename: Wendy K
authors.initials: WK
authors.lastname: Thomas
authors.forename: Alex
authors.initials: A
authors.lastname: Gonzalez
authors.forename: Tuija
authors.initials: T
authors.lastname: Jokela
authors.forename: Kristiina
authors.initials: K
authors.lastname: Wähälä
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Schwartz
authors.forename: Shuying S
authors.initials: SS
authors.lastname: Li
authors.forename: Johanna W
authors.initials: JW
authors.lastname: Lampe
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001424:Bacterial Infections / Q000175:diagnosis / Q000652:urine; D015415:Biomarkers / Q000652:urine; D019587:Dietary Supplements; D060754:Equol; D005260:Female; D006801:Humans; D007422:Intestines / Q000382:microbiology*; D007529:Isoflavones / Q000096:biosynthesis* / Q000378:metabolism* / Q000652:urine; D008297:Male; D010641:Phenotype; D048789:Phytoestrogens / Q000378:metabolism*; D013997:Time Factors
chemical_list: C007610:4',7-dihydroxy-3,4-dihydroisoflavone; D000900:Anti-Bacterial Agents; D015415:Biomarkers; D007529:Isoflavones; D048789:Phytoestrogens; D060754:Equol; C004742:daidzein; C050052:O-desmethylangolensin