Oral Antibiotics Decrease Urinary Isoflavonoid Excretion in Children After Soy Consumption

Abstract

How oral antibiotics (OABX) alter isoflavones (IFLs) in soy-consuming children is unknown. We evaluated OABX effects on urinary IFL excretion rates (UIERs) in 17 children, ages 4 to 17 yr, who provided 2 urine collections in pairs of a baseline urine and an overnight urine collection after consuming a body-weight-adjusted dose of soy nuts. The first collection was during OABX treatment for a bacterial infection and the second when healthy and off antibiotics. IFL food levels and UIERs were measured for nonmetabolites (NM), namely, daidzein, genistein (GE), and glycitein, and the metabolites (M) dihydrodaidzein, dihydrogenistein, equol, and O-desmethylangolensin (DMA), by liquid chromatography mass spectrometry. Urinary IFLs were hypothesized to change after OABX due to intestinal microflora alterations. A total of 11 children completed the study correctly. During OABX use, UIER (nmol/h/kg) for GE (6.4 ± 1.0 vs. 10.1 ± 1.6), all NM (27.5 ± 4.8 vs. 36.2 ± 4.7), and total IFLs (all NM + all M; 29.4 ± 5.0 vs. 38.8 ± 4.8) was reduced (P < 0.05) vs. when healthy. In contrast, a trend toward more DMA production during OABX was observed (1.2 ± 0.6 vs. 0.4 ± 0.3, P = 0.13). The reduction in urinary IFL appearance could be due to the changes of intestinal bacteria by OABX and/or due to processes related to the infection.

ACKNOWLEDGMENTS

Supported by the Revival Company, by the National Cancer Institute (CCSG No. CA71789) and by the National Center for Research Resources (No. S10 RR020890; there are no conflicts of interest). We are very grateful to the diligent participation by the children and their parents and thank them genuinely for their time and efforts. Support from Revival Company for this research is acknowledged. We thank Samantha Chen for assistance in study coordination, Christian Caberto for assistance in statistical analyses, and Laurie J. Custer for performance of the chemical analyses. Brunhild M. Halm assisted in the design and overall performance of the study, recruited study subjects, supervised personnel, conducted data interpretations, and provided major contributions in writing the manuscript. Adrian A. Franke, the principal investigator of this study, was responsible for the design and overall performance of the study; he carried out data interpretation and statistical analyses and wrote the manuscript. Leslie A. Ashburn and Sandra M. Hebshi were study coordinators and assisted in manuscript preparation as well as matters related to the institutional review board. Lynne R. Wilkens performed data analysis. No authors have a conflict of interest.

Notes

^a 11 subjects, 2 repeat therapies.

^b Repeated treatment of Subject 4 in the sequence shown.

^c Repeated treatment of Subject 9 in the sequence shown.

^a Abbreviations are as follows: DE, daidzein; GE, genistein; GLYE, glycitein; EQ, equol; DMA, desmethylangolensin; DHDE, dihydrodaidzein; DHGE, dihydrogenistein; NM, nonmetabolite; M, metabolite; IFL, isoflavonoids.

^b Student's paired t-test using absolute data.