Plastics are ubiquitous in our daily lives. Chemically, plastics are referred to as polymers – they are made up of repeating subunits or building blocks bonded to each other much like beads on a string. Recently Bisphenol A (BPA) has come under increasing scrutiny by the Environmental Protection Agency (EPA) for its possible harmful effects on human health.
BPA is used to make polycarbonate plastic and epoxy resins for use in digital media, electronic equipment, automobiles, sports safety equipment, reusable food and drink containers, circuit boards composites, paints and adhesives and numerous other products. In terms of the scale of production, approximately 2.8 million tons of BPA was produced in 2002. Concern for the safety of this compound has been heightened because of the recent finding that plastic caps of infant feeding bottles that have been scratched or cracked can leach BPA into infant formula even in the cold. BPA is so prevalent that it has been estimated that 90% of Americans have it in their urine.
BPA belongs to a class of compounds known as xenoestrogens – foreign man-made substances that mimic estrogen, the female sex hormone. Because of its structural similarity, BPA can bind to tissues in the body that are biologically designed to interact with estrogen. Since estrogen exerts such a wide ranging impact on human body, it would be reasonable to assume that BPA could, therefore, interfere with normal estrogen-related activity and have a deleterious impact on human health.
This hypothesis seems to be supported by extensive scientific data. A 2007 review of the literature determined that low doses of BPA during development exert a significant impact on brain structure, function and concomitant behavior in rats and mice. Furthermore, a study by the Yale School of Medicine conducted in 2008 demonstrated that neurological effects occurred in non-human primates when regularly exposed to doses of BPA that were equal to the EPA-determined maximum safe dose. And most importantly, a major study of the health effects of exposure to BPA, conducted by Iain Lang and his associates, was reported in the prestigious Journal of the American Medical Association (JAMA). The data collected from a study of 1500 participants showed a significant association of exposure with heart disease, diabetes and abnormal liver function. Although these data did not show an unambiguous cause and effect relationship, the preponderance of data from animal studies strongly support such a relationship.