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Urinary excretion of equol by postmenopausal women consuming soymilk fermented by probiotic bifidobacteria

European Journal of Clinical Nutrition volume 61, pages 438–441 (2007)Cite this article

Abstract

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 μmol 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.

Sponsorship:

Australian Research Council's Strategic Partnership with Industry (Sanitarium Health Food Company) for Research and Training.

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Acknowledgements

Australian Research Council's Strategic Partnership with Industry (Sanitarium Health Food Company) for Research and Training scheme funded this research. We thank Dr John Ashton of Sanitarium Health Food Company for his support and for providing the soy germ powder required for soymilk manufacture.

Author information

Authors and Affiliations

  1. Food Safety, Authenticity & Quality Unit, School of Molecular Sciences, Victoria University, Werribee, Victoria, Australia

    D Tsangalis, N P Shah & A E J McGill

  2. Monash University Department of Medicine, Clinical Nutrition and Metabolism Unit, Monash Medical Centre, Clayton, Victoria, Australia

    G Wilcox

  3. Department of Biomedical Sciences, Victoria University, St Albans, Victoria, Australia

    L Stojanovska

Authors
  1. D Tsangalis
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  2. G Wilcox
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  3. N P Shah
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  4. A E J McGill
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  5. L Stojanovska
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Corresponding author

Correspondence to G Wilcox.

Additional information

Guarantor: D Tsangalis.

Contributors: DT, GW, NPS and LS were responsible for planning the study, preparing the application for ethics approval and writing the paper. DT, GW and LS were involved in volunteer recruitment. DT manufactured the soymilk, processed the urine specimens and carried out the laboratory testing. DT and NPS collated, calculated and statistically analysed the data. AEJM has provided critical input into the paper.

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Tsangalis, D., Wilcox, G., Shah, N. et al. Urinary excretion of equol by postmenopausal women consuming soymilk fermented by probiotic bifidobacteria. Eur J Clin Nutr 61, 438–441 (2007). https://doi.org/10.1038/sj.ejcn.1602530

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  • DOI: https://doi.org/10.1038/sj.ejcn.1602530

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