Urine and serum biomonitoring of exposure to environmental estrogens II: Soy isoflavones and zearalenone in pregnant women

• Published in: Food and chemical toxicology 2016-09, Vol.95 (C), p.19-27
• Main Authors: Fleck, Stefanie C., Churchwell, Mona I., Doerge, Daniel R., Teeguarden, Justin G.
• Format: Article
• Language: English
• Subjects: Adult; Biomonitoring; Cohort Studies; Diet; Endocrine disruptors; Environmental Exposure; Environmental Monitoring - methods; Equol - analysis; Estrogens - administration & dosage; Exposure; Female; Genistein - analysis; Glycine max - chemistry; Humans; Isoflavones - analysis; Phytoestrogens - blood; Phytoestrogens - urine; Pregnancy; Soy isoflavones; Tandem Mass Spectrometry - methods; Zearalenone; Zearalenone - analysis
• ISSN: 0278-6915; 1873-6351
• DOI: 10.1016/j.fct.2016.05.021

Urine and serum biomonitoring was used to measure internal exposure to selected dietary estrogens in a cohort of 30 pregnant women. Exposure was measured over a period comprising one-half day in the field (6 h) and one day in a clinic (24 h). Biomonitoring of the dietary phytoestrogens genistein (GEN), daidzein (DDZ) and equol (EQ), as well as the mycoestrogen, zearalenone (ZEN) and its congeners, was conducted using UPLC-MS/MS. Biomonitoring revealed evidence of internal exposure to naturally occurring dietary estrogens during pregnancy. Urinary concentrations of total GEN, DDZ and EQ were similar to levels reported for general adult U.S. population. Measurable concentrations of total (parent and metabolites) GEN, DDZ and EQ were present in 240, 207 and 2 of 270 serum samples, respectively. Six out of 30 subjects had measurable concentrations of unconjugated GEN and/or DDZ in serum between 0.6 and 7.1 nM. Urine to serum total isoflavone ratios for GEN, DDZ and EQ were 13, 47, and 180, respectively. ZEN and its reductive metabolite, α-zearalenol (α-ZEL), were present in pregnant women (11 out of 30 subjects) as conjugates at levels near the limit of quantification. The average total urinary concentration was 0.10 μg/L for ZEN and 0.11 μg/L for α-ZEL. •Concurrent urine and serum biomonitoring demonstrate pregnant women are exposed to multiple dietary estrogens.•Urinary concentrations of genistein, daidzein and equol in pregnant women reflect the exposure of the general adult U.S. population.•Aglycone levels of genistein and/or daidzein in serum were measured in 6 out of 30 subjects and ranged between 0.6 and 7.1 nM.•Zearalenone and its reductive metabolite α-zearalenol were measured in 11 out of 30 subjects’ urine with levels ranging between 0.03 and 0.29 μg/L.