Bioavailability and urinary excretion of isoflavones in humans: Effects of soy-based supplements formulation and equol production
Journal of Pharmaceutical and Biomedical Analysis. 2007-03-01; 43(4): 1488-1494
DOI: 10.1016/j.jpba.2006.10.006
Lire sur PubMed
1. J Pharm Biomed Anal. 2007 Mar 12;43(4):1488-94. doi:
10.1016/j.jpba.2006.10.006. Epub 2006 Nov 15.
Bioavailability and urinary excretion of isoflavones in humans: effects of
soy-based supplements formulation and equol production.
Vergne S(1), Titier K, Bernard V, Asselineau J, Durand M, Lamothe V, Potier M,
Perez P, Demotes-Mainard J, Chantre P, Moore N, Bennetau-Pelissero C, Sauvant P.
Author information:
(1)ENITA, Unité Micronutriments, Reproduction, Santé, Bordeaux, France.
Soy isoflavones (IF) are of particular interest for their possible estrogenic
effects on the symptoms of menopause. The bioavailability of IF is clearly a
factor influencing their biological activity. The first aim of this study was to
elucidate the impact of the matrix process and especially the formulation of
soy-based capsules on IF bioavailability. Twelve healthy volunteers were
recruited for a randomized, double-blind, two-way crossover trial and received a
single dose of the two soy-based formulations, one containing a pure soy
standardized extract of IF, and the other containing soy flour in addition to
the standardized extract of IF. Using a new and validated ELISA method, we
measured the plasma and urinary concentrations of genistein, daidzein and its
metabolite equol. Based on European Medicine Evaluation Agency recommendations,
the main pharmacokinetic parameters allowed us to demonstrate the bioequivalence
of the two formulations, indicating that the presence or absence of soy flour
did not alter either the absorption or the elimination of daidzein and
genistein. As bioequivalence was demonstrated, we pooled data collected during
the two study-periods to address another original issue: Did the ability to
produce equol affect the bioavailability of daidzein? We demonstrated that
daidzein excretion was significantly lower in equol producers compared with
equol non producers over the entire elimination period of the soy IF. This
difference disappeared when equol excretion was added to daidzein excretion in
equol producers. Our results indicated that the production of equol could partly
explain the difference in daidzein bioavailability after IF ingestion.
DOI: 10.1016/j.jpba.2006.10.006
PMID: 17110073 [Indexed for MEDLINE]