Bisphenol A (BPA) is a chemical used during the production of polycarbonate plastics and epoxy resins. BPA is classified as an endocrine disruptor because it can mimic naturally-occurring hormones in the body such as estrogens, androgens, and thyroid hormones, potentially altering normal hormonal signals. Several chronic diseases are associated with BPA exposure, including hypertension, central obesity, hyperlipidemia, and cancer. Findings from a new study indicate that the FDA’s current methods for gauging BPA exposure levels in humans may be inadequate.
Following oral ingestion of BPA, the body breaks down the chemical into several metabolites, which are then excreted in the urine. Current methods for measuring urinary BPA, which rely on indirect measures, may not accurately estimate human exposure, however. The authors of this study developed a technique that relied on direct measures of BPA and its metabolites in human urine. They found that the indirect assay grossly underestimated actual human levels of BPA exposure. In pregnant women, in particular, urinary BPA levels were 44 times higher than indirect measures reflected.
BPA exposure is widespread due to extensive use of plastics and other BPA-containing products, with an estimated 9 million tons of the chemical produced every year. Food and water, which are commonly packaged in plastic, are common vehicles for BPA exposure. Previous research suggests that the tolerable daily intake of BPA established by the FDA is as much as 20,000 times higher than the levels at which adverse effects have been observed. The findings from this study highlight the need for more accurate measures of human BPA exposure and more research to determine safe levels of exposure.
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