Urinary excretion of equol by postmenopausal women consuming soymilk fermented by probiotic bifidobacteria.
OBJECTIVE
To study the effects of consuming isoflavone aglycone-enriched soymilk fermented by bifidobacteria on urinary excretion of equol with respect to fermentation, daidzein dose, supplementation duration and background diet.


METHODS
Double-blind crossover pilot study comprising three 14-day supplementation periods separated by a washout.


METHODS
Victoria University, Melbourne, Australia.


METHODS
Sixteen postmenopausal women.


METHODS
SUBJECTS randomized into two groups consuming either fermented (FS) or non-fermented soymilk (NFS), ingested three daily dosages of daidzein via soymilk and collected pooled urine specimens. Daidzein and equol were quantified using high-performance liquid chromatography.


RESULTS
After 14-days supplementation six women (38%) excreted equol (>1 micromol equol/day), including four from the FS group, two of whom were classified as non-producers at day 4. Bifidobacteria ingestion, composition of daidzein and its glucosides, and carbohydrate intake appeared to influence equol formation among equol producers.


CONCLUSIONS
Pilot-study group mean urinary equol excretion results provided insufficient evidence (P>0.05) that FS consumption instigates equol production in women predetermined as non-producers.
Tsangalis
D
D
Food Safety, Authenticity & Quality Unit, School of Molecular Sciences, Victoria University, Werribee, Victoria, Australia.
Wilcox
G
G
Shah
N P
NP
McGill
A E J
AE
Stojanovska
L
L
D001644:Bifidobacterium / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D060754:Equol; D005260:Female; D005285:Fermentation; D005511:Food Handling / Q000379:methods*; D006801:Humans; D007529:Isoflavones / Q000378:metabolism / Q000652:urine*; D008875:Middle Aged; D048789:Phytoestrogens / Q000378:metabolism / Q000652:urine*; D010865:Pilot Projects; D017698:Postmenopause / Q000652:urine; D019936:Probiotics; D041942:Soy Milk / Q000008:administration & dosage* / Q000737:chemistry
C007610:4',7-dihydroxy-3,4-dihydroisoflavone; D007529:Isoflavones; D048789:Phytoestrogens; D060754:Equol; C004742:daidzein