HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wiseman, H. Articles by Clarke, D. B Search for Related Content PubMed PubMed Citation Articles by Wiseman, H. Articles by Clarke, D. B Agricola Articles by Wiseman, H. Articles by Clarke, D. B

Influence of 10 wk of soy consumption on plasma concentrations and excretion of isoflavonoids and on gut microflora metabolism in healthy adults^1,2,3,4

¹ From the Nutrition, Food and Health Research Centre, the Department of Nutrition and Dietetics, King's College London (HW, KC, and RD); TNO-BIBRA International, Surrey, United Kingdom (EAB and MD); the Northern Ireland Centre for Diet and Health, University of Ulster, Coleraine, United Kingdom (IRR); and the DEFRA Central Science Laboratory, York, United Kingdom (ASL, AM, RT, and DBC)

Background: Little information is currently available on the role of the gut microflora in modulating isoflavone bioavailability or on sex differences in isoflavone metabolism and bioavailability.

Objective: We sought to determine whether chronic soy consumption influences isoflavone bioavailability as judged by plasma isoflavone concentrations and modified gut microflora activities [ß-glucoside hydrolysis and equol and O-desmethylangolensin (O-DMA) production]. We also examined whether sex differences in isoflavone metabolism exist.

Design: A randomized, parallel, controlled study design was used to compare a high-soy diet (104 ± 24 mg total isoflavones/d) with a low-soy diet (0.54 ± 0.58 mg total isoflavones/d) in 76 healthy young adults for 10 wk.

Results: Concentrations of isoflavones and their gut microflora metabolites in the plasma, urine, and feces were significantly higher in the subjects who consumed the high-soy diet than in those who consumed the low-soy diet. Concentrations of O-DMA in plasma and urine were higher in the men than in the women. Fecal bacteria from subjects consuming both diets could convert daidzein to equol ex vivo. Fecal ß-glucosidase activity was significantly higher in the subjects who consumed the high-soy diet than in those who consumed the low-soy diet.

Conclusions: Although interindividual variation in isoflavone metabolism was high, intraindividual variation was low. Only concentrations of O-DMA in plasma and urine appeared to be influenced by sex. Chronic soy consumption does not appear to induce many significant changes to the gut metabolism of isoflavones other than higher ß-glucosidase activity.

Key Words: Soy • isoflavone • bioavailability • metabolism • gut microflora • equol

This article has been cited by other articles:

				C. Atkinson, K. M Newton, E. J A. Bowles, M. Yong, and J. W Lampe Demographic, anthropometric, and lifestyle factors and dietary intakes in relation to daidzein-metabolizing phenotypes among premenopausal women in the United States Am. J. Clinical Nutrition, March 1, 2008; 87(3): 679 - 687. [Abstract] [Full Text] [PDF]

				J. W. Erdman Jr., D. Balentine, L. Arab, G. Beecher, J. T. Dwyer, J. Folts, J. Harnly, P. Hollman, C. L. Keen, G. Mazza, et al. Flavonoids and Heart Health: Proceedings of the ILSI North America Flavonoids Workshop, May 31-June 1, 2005, Washington, DC J. Nutr., March 1, 2007; 137(3): 718S - 737S. [Abstract] [Full Text] [PDF]

				M. Messina, W. McCaskill-Stevens, and J. W. Lampe Addressing the soy and breast cancer relationship: review, commentary, and workshop proceedings. J Natl Cancer Inst, September 20, 2006; 98(18): 1275 - 1284. [Abstract] [Full Text] [PDF]

				O. Mezei, Y. Li, E. Mullen, J. S. Ross-Viola, and N. F. Shay Dietary isoflavone supplementation modulates lipid metabolism via PPAR{alpha}-dependent and -independent mechanisms Physiol Genomics, September 14, 2006; 26(1): 8 - 14. [Abstract] [Full Text] [PDF]

				M. Kano, T. Takayanagi, K. Harada, S. Sawada, and F. Ishikawa Bioavailability of Isoflavones after Ingestion of Soy Beverages in Healthy Adults J. Nutr., September 1, 2006; 136(9): 2291 - 2296. [Abstract] [Full Text] [PDF]

				A. A Franke, B. M Halm, L. J Custer, Y. Tatsumura, and S. Hebshi Isoflavones in breastfed infants after mothers consume soy. Am. J. Clinical Nutrition, August 1, 2006; 84(2): 406 - 413. [Abstract] [Full Text] [PDF]

				L. Gu, S. E. House, R. L. Prior, N. Fang, M. J. J. Ronis, T. B. Clarkson, M. E. Wilson, and T. M. Badger Metabolic Phenotype of Isoflavones Differ among Female Rats, Pigs, Monkeys, and Women J. Nutr., May 1, 2006; 136(5): 1215 - 1221. [Abstract] [Full Text] [PDF]

				K. Decroos, E. Eeckhaut, S. Possemiers, and W. Verstraete Administration of Equol-Producing Bacteria Alters the Equol Production Status in the Simulator of the Gastrointestinal Microbial Ecosystem (SHIME) J. Nutr., April 1, 2006; 136(4): 946 - 952. [Abstract] [Full Text] [PDF]

				M. J Gibney, M. Walsh, L. Brennan, H. M Roche, B. German, and B. van Ommen Metabolomics in human nutrition: opportunities and challenges Am. J. Clinical Nutrition, September 1, 2005; 82(3): 497 - 503. [Abstract] [Full Text] [PDF]

				D. M. Harris, E. Besselink, S. M. Henning, V. L. W. Go, and D. Heber Phytoestrogens Induce Differential Estrogen Receptor Alpha- or Beta-Mediated Responses in Transfected Breast Cancer Cells Experimental Biology and Medicine, September 1, 2005; 230(8): 558 - 568. [Abstract] [Full Text] [PDF]