Bisphenol A (BPA) is an industrial chemical found in polycarbonate plastics, epoxy resins, dental sealants and thermal paper used in receipts and other substances. BPA is one of the highest volume chemicals produced worldwide and is found pervasively in the environment worldwide.
Human exposure to BPA occurs primarily through food consumption and through skin contact with thermal paper. Over the past 10 to 15 years there has been high concern about the health effects of BPA, although it has been known to be an endocrine disrupting chemical since 1936.
BPA can act as an endocrine disrupting chemical by binding to estrogen receptors and androgen receptors to have both agonistic and antagonistic effects on estrogen production, as well as through nonclassical estrogen pathways. Exposure to BPA has been associated with significantly increased mammographic density — a known risk factor for breast cancer — in postmenopausal women as well as increased mammary growth and lesions in rodents.
Polybrominated Diphenyl Ethers
Polybrominated diphenyl ethers (PBDEs) are a class of over 200 chemicals known as organohalogenated compounds. Organohalogenated compounds are organic compounds which contain a halogen bonded to carbon.
PBDEs are widely used as flame retardants due to their chemical properties. PBDEs are found in foams, textiles, plastics, electronic devices, building materials, furnishings, airplanes, motor vehicles and more.
Due to their widespread use as flame retardants in a broad spectrum of materials over the past 30 years, PBDEs are now found almost universally in the environment. In fact, PBDEs are now one of the most ubiquitous environmental pollutants.
PBDEs are endocrine disrupting chemicals which interfere with the body’s normal endocrine processes. PBDEs disrupt the endocrine system in various ways. PBDEs can act as both agonists and antagonists in the endocrine system and are capable of binding to androgen receptors, progesterone receptors and estrogen receptors.
Certain PBDEs, known as lower brominated PBDEs, contain fewer bromine atoms per molecule and bioaccumulate more efficiently, thus posing a greater risk. Lower brominated PDBEs have been shown to promote the production of estrogen by acting as estrogen receptor agonists and have also been reported to affect the activity of aromatase, an enzyme which helps produce estrogen.