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One-month exposure to soy isoflavones did not induce the ability to produce equol in postmenopausal women.
- Source :
-
European journal of clinical nutrition [Eur J Clin Nutr] 2006 Sep; Vol. 60 (9), pp. 1039-45. Date of Electronic Publication: 2006 Feb 15. - Publication Year :
- 2006
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Abstract
- Objective: As more and more postmenopausal women are taking soy isoflavone supplementation for relieving menopausal symptoms, we investigated the impact of chronic exposure on their bioavailability, with focus on achievable plasma concentrations and potential stimulation of the capacity to produce equol.<br />Subjects: A total of 12 Caucasian postmenopausal women.<br />Intervention: Volunteers ingested 100 mg isoflavones/day (aglycone equivalents, in cereal bars and yoghurts) for 1 month. Plasma concentrations of metabolites at 2, 4, 6, 8, 10, 12 and 24 h postdose, as well as urinary excretion in fractions over 36 h were compared between days 1 and 30.<br />Results: Similar plasma kinetic curves were obtained at day 1 and day 30 for genistein and daidzein. Maximum plasma concentrations were 1.68+/-0.68 micromol/l on day 1 compared to 2.27+/-0.76 micromol/l on day 30 for daidzein (P=0.056), and 3.88+/-1.50 micromol/l on day 1 compared to 5.30+/-2.38 micromol/l on day 30 for genistein (P=0.091). Urinary excretion of daidzein and genistein did not differ significantly between days 1 and 30. Maximum plasma concentration of equol increased significantly from 0.31+/-0.27 to 0.99+/-0.51 micromol/l for equol-producer volunteers (P=0.046). However, the seven volunteers who were classified as non-equol producers on day 1 did not acquire the ability to produce equol after 1-month exposure.<br />Conclusions: Chronic exposure to isoflavones in postmenopausal women resulted in plasma concentrations as high as 2.5-5 micromol/l of each isoflavone, but did not induce the ability to produce equol.<br /> (Published online 15 February 2006.)
- Subjects :
- Administration, Oral
Aged
Area Under Curve
Biological Availability
Dietary Supplements
Equol
Female
Genistein blood
Genistein urine
Humans
Isoflavones administration & dosage
Isoflavones biosynthesis
Isoflavones blood
Isoflavones urine
Middle Aged
Postmenopause blood
Postmenopause urine
Time Factors
Isoflavones pharmacokinetics
Postmenopause drug effects
Glycine max chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 0954-3007
- Volume :
- 60
- Issue :
- 9
- Database :
- MEDLINE
- Journal :
- European journal of clinical nutrition
- Publication Type :
- Academic Journal
- Accession number :
- 16482068
- Full Text :
- https://doi.org/10.1038/sj.ejcn.1602415