title: Comparison of isoflavones among dietary intake, plasma concentration and urinary excretion for accurate estimation of phytoestrogen intake.
abstract: Biological effects of dietary isoflavones, such as daidzein and genistein are of interest in preventive medicine. We estimated the dietary intake of isoflavones from dietary records and compared the values with the plasma concentrations and urinary excretions in Japanese middle-aged women. The dietary intake of daidzein and genistein was 64.6 and 111.6 mumol /day/capita (16.4 and 30.1 mg/day/capita), respectively. The isoflavones intake was mostly attributable to tofu, natto and miso. The median of plasma daidzein and genistein concentration was 72.46 and 206.09 nmol/L, respectively. The median of urinary excretion was 20.54 mumol /day for daidzein, 10.79 for genistein, 15.74 for equol and 1.64 for O-desmethylangolensin (O-DMA). Equol and O-DMA were excreted by 50% and 84% of all participants, respectively. Equol metabolizers were significantly lower the plasma and urinary daidzein and urinary O-DMA. The dietary intake of daidzein and genistein after the adjustment for total energy intake was significantly correlated with the urinary excretion (r = 0.365 for daidzein and r = 0.346 for genistein) and plasma concentration (r = 0.335 for daidzein and r = 0.429 for genistein). The plasma concentration of isoflavones was also significantly correlated with the urinary excretion. We conclude that in epidemiological studies measurements of plasma concentration or urinary excretion of these isoflavones are useful biomarkers of dietary intake and important for studies on their relation to human health.
authors.affiliation: Department of Nutritional Science, Faculty of Applied Bioscience, Tokyo University of Agriculture, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Arai
authors.forename: M
authors.initials: M
authors.lastname: Uehara
authors.forename: Y
authors.initials: Y
authors.lastname: Sato
authors.forename: M
authors.initials: M
authors.lastname: Kimira
authors.forename: A
authors.initials: A
authors.lastname: Eboshida
authors.forename: H
authors.initials: H
authors.lastname: Adlercreutz
authors.forename: S
authors.initials: S
authors.lastname: Watanabe
mesh_terms: D000328:Adult; D000368:Aged; D016588:Anticarcinogenic Agents / Q000008:administration & dosage / Q000097:blood / Q000652:urine; D015415:Biomarkers / Q000097:blood / Q000652:urine; D002839:Chromans / Q000097:blood / Q000652:urine; D004032:Diet; D015930:Diet Records; D002149:Energy Intake; D060754:Equol; D004968:Estrogens, Non-Steroidal / Q000008:administration & dosage*; D005260:Female; D019833:Genistein / Q000008:administration & dosage / Q000097:blood / Q000652:urine; D006801:Humans; D007529:Isoflavones / Q000008:administration & dosage* / Q000097:blood / Q000652:urine; D008875:Middle Aged; D008996:Monoamine Oxidase Inhibitors / Q000097:blood / Q000652:urine; D048789:Phytoestrogens; D028321:Plant Preparations; D010944:Plants; D012044:Regression Analysis; D013025:Glycine max
chemical_list: C007610:4',7-dihydroxy-3,4-dihydroisoflavone; D016588:Anticarcinogenic Agents; D015415:Biomarkers; D002839:Chromans; D004968:Estrogens, Non-Steroidal; D007529:Isoflavones; D008996:Monoamine Oxidase Inhibitors; D048789:Phytoestrogens; D028321:Plant Preparations; D060754:Equol; C004742:daidzein; D019833:Genistein; C050052:O-desmethylangolensin