On April 1, 2014 Laura Vandenberg from the University of Massachusetts and colleagues published a new study in the peer-reviewed scientific journal Environmental Health, showing a method allowing for the correct analysis of BPA in human serum samples (Vandenberg et al. 2014). The article shows the results from a so called Round Robin study where four different laboratories in the US participated in a blinded analysis of the levels of free, unconjugated BPA and conjugated (or: glucuronidated) BPA (previously reported by FPF). The results from the study show that inadvertent contamination of samples can be avoided, and that spontaneous de-conjugation of BPA during sample storage or handling is not to be expected.
The study adds to one of the most debated issues surrounding BPA, namely the presence of free, unconjugated BPA in human blood samples. Recently the European Food Safety Authority (EFSA) in their 2013 draft scientific opinion on BPA assumed that measured levels of free BPA are artifacts and cannot be considered actual snapshots of human exposure to the endocrine disrupting chemical (previously reported by FPF). Instead, it has been thought that detections of free BPA, the toxicologically relevant form of the chemical, arise from measurement errors, contamination, or spontaneous de-conjugation of the chemical during sample storage. When humans ingest BPA from food, or absorb it through the skin, the chemical is believed to be completely conjugated rapidly by the body’s detoxification system. Thereby, a glucuronide group is attached to BPA, making it no longer estrogenically active. The present study offers a scientific basis for disproving these assumptions. The presence of unconjugated BPA in humans is of concern because the chemical interferes with normal estrogen signaling at low levels. Exposure to BPA is implicated with chronic diseases like breast and prostate cancer, cardiovascular disease, insulin resistance and diabetes.
FPF article “EFSA publishes draft BPA opinion, part I”
FPF article “EFSA publishes draft BPA opinion, part II”
FPF article “Free BPA detected in human serum samples”
Vandenberg, L. et al. (2014). “A round robin approach to the analysis of bisphenol A (BPA) in human blood samples.” Environmental Health, 13:15 (published online April 1, 2014).