title: Higher bioavailability of isoflavones after a single ingestion of aglycone-rich fermented soybeans compared with glucoside-rich non-fermented soybeans in Japanese postmenopausal women.
abstract: BACKGROUND
  There have been conflicting study results concerning how the food matrix affects the bioavailability of isoflavone aglycone and glucoside. In this study the bioavailability of isoflavones after a single ingestion of aglycone-rich fermented soybeans (Fsoy) and glucoside-rich non-fermented soybeans (Soy) was compared. Eleven healthy postmenopausal Japanese women were recruited for a randomised, double-blind, crossover trial and consumed Fsoy or Soy powder dissolved in hot water. Blood samples were collected 0, 1, 2, 3, 4, 6, 8, 12 and 24 h and urine samples from 0 to 48 h after ingestion of the powders. The Fsoy and Soy powders ingested had the same total isoflavone content (95 µmol), but the former was rich in aglycone (90.6 µmol) while the latter was rich in glucoside (81.9 µmol).
  
  
  RESULTS
  Serum concentrations of total isoflavones after 1-4 h were significantly higher in the Fsoy group than in the Soy group. The Fsoy group showed significantly higher maximum concentration (Cmax: 2.79 ± 0.13 vs 1.74 ± 0.13 µmol L(-1) ) and area under the curve (AUC(0-24 h) : 23.78 ± 2.41 vs 19.95 ± 2.03 µmol day L(-1) ) and lower maximum concentration time (Tmax: 1.00 ± 0.00 vs 5.00 ± 0.67 h) compared with the Soy group. The cumulative urinary excretion of total isoflavones after 2 h was significantly higher in the Fsoy group than in the Soy group. Individual isoflavones (daidzein, genistein and glycitein) showed similar trends to total isoflavones. Equol (a metabolite from daidzein) did not differ between the two groups.
  
  
  CONCLUSIONS
  The results of this study demonstrated that the isoflavones of aglycone-rich Fsoy were absorbed faster and in greater amounts than those of glucoside-rich Soy in postmenopausal Japanese women.
authors.affiliation: Research Institute for Health Fundamentals, Ajinomoto Co., Inc., 1-1, Suzuki-cho, Kawasaki 210-8681, Japan. yuki_okabe@ajinomoto.com
authors.forename: Yuki
authors.initials: Y
authors.lastname: Okabe
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Shimazu
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tanimoto
mesh_terms: D000368:Aged; D019540:Area Under Curve; D001682:Biological Availability; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D005285:Fermentation; D005960:Glucosides / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D006801:Humans; D007529:Isoflavones / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D007564:Japan; D008875:Middle Aged; D010936:Plant Extracts / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D017698:Postmenopause; D012639:Seeds / Q000737:chemistry* / Q000382:microbiology; D013025:Glycine max / Q000737:chemistry*
chemical_list: D005960:Glucosides; D007529:Isoflavones; D010936:Plant Extracts