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Urinary excretion of equol by postmenopausal women consuming soymilk fermented by probiotic bifidobacteria
D Tsangalis1, G Wilcox, N P Shah
1Food Safety, Authenticity & Quality Unit, School of Molecular Sciences, Victoria University, Werribee, Victoria, Australia.
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.
Design:
Double-blind crossover pilot study comprising three 14-day supplementation periods separated by a washout.
Setting:
Victoria University, Melbourne, Australia.
Subjects:
Sixteen postmenopausal women.
Intervention:
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.
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