Urinary isoflavone phytoestrogens in German children and adolescents – A longitudinal examination in the DONALD cohort
Article first published online: 11 OCT 2010
Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Molecular Nutrition & Food Research
Volume 55, Issue 3, pages 359–367, March 2011
How to Cite
Degen, G. H., Blaszkewicz, M., Shi, L., Buyken, A. E. and Remer, T. (2011), Urinary isoflavone phytoestrogens in German children and adolescents – A longitudinal examination in the DONALD cohort. Mol. Nutr. Food Res., 55: 359–367. doi: 10.1002/mnfr.201000325
- Issue published online: 2 MAR 2011
- Article first published online: 11 OCT 2010
- Manuscript Accepted: 30 AUG 2010
- Manuscript Revised: 26 AUG 2010
- Manuscript Received: 13 JUL 2010
- Long-range Research Initiative (LRI) of the European Chemical Industry Council (Cefic)
- Ministry of Innovation, Science and Research of North Rhine Westphalia, Germany
Scope: In light of concerns about hormonally active agents, it is important to assess human exposure to such compounds, especially in children as a susceptible subgroup. Estrogenic plant constituents are present in the human diet in varying levels, in particular the isoflavones daidzein (DAI) and genistein (GEN). We aimed to examine age-dependent and secular trends in phytoestrogen exposures and to investigate equol (EQ) excretion of German children using biomarker analysis in 24-h urine samples from a longitudinally designed study.
Methods and results: The concentrations of DAI, its metabolite EQ and GEN were determined by GC-MS analysis in 24-h urines (510 samples) collected between 1985 and 2000 in 90 (47 boys) German children (6–18 years old), who are participants in the Dortmund Nutritional and Anthropometric Longitudinally Designed study. The results from the urinary biomarker analysis indicate isoflavone exposures at quite variable levels in German children: Analyte concentrations in over 500 urine samples cover the range reported previously in adults on typical German diet and with soy intake. EQ, the DAI metabolite produced by the gastrointestinal microflora, was detected in a high fraction of all samples, with 28/90 children (31%) excreting EQ in all their urines, and 62/90 children (68%) in at least one sample. Interestingly, when multiple urines obtained from individuals at different ages (6–18 years) were analyzed, EQ formation did not appear to be a constant trait over time. When stratified by sex, DAI, EQ and GEN concentrations (ng/mL) in urines and excretion rates (μg/day) were similar in boys and girls. Total isoflavone excretion rates (μg/day) increased during childhood (6–12 years) (p=0.02) and were constant during adolescence (13–18 years) (p=0.6). No clear trend for changes in dietary isoflavone exposure over the total study period was seen (p=0.7).
Conclusions: In conclusion, biomarkers in urine of German children and adolescents indicate a frequent, but widely variable dietary isoflavone intake and suggest no secular increase (1985–2000) in the exposure to isoflavone phytoestrogens among German children and adolescents.