|Bisphenol A Myths
Myth: BPA Accumulates in the Human Body.
Reality: Several studies on human volunteers have shown that the very small amount of bisphenol A (BPA) that may be ingested by a person during normal daily activities is efficiently converted to biologically inactive metabolites, which are eliminated from the human body within 24 hours.
Scientists use "pharmacokinetic" studies to determine what happens to a chemical in the body, including how much of the chemical is absorbed and distributed into the body, metabolized to other compounds, and eliminated or retained.
The metabolism of BPA in humans has been measured directly by exposing human volunteers to oral doses of 5 mg of BPA. A substance called glucuronide was the only metabolite detected in the subjects' urine and blood, and free BPA was not detected in either urine or blood. The glucoronide, a metabolite that has no known biological activity and, in particular, has been shown to be non-estrogenic, was cleared from the blood and excreted within the day of exposure (Völkel, W., T. Colnot, G. A. Csanády, J. G. Filser, and W. Dekant, 2002, "Metabolism and Kinetics of Bisphenol A in Humans at Low Doses Following Oral Administration," Chem. Res. Toxicol., vol. 15, no. 10, pages 1281-1287. Abstract available at: National Library of Medicine).
In contrast, similar studies on rodents, which are commonly used for toxicity studies, have demonstrated that rodents are much less efficient at eliminating BPA from the body.
Even so, a study conducted on bisphenol A in rats demonstrated that bisphenol A was rapidly metabolized to a hormonally inactive form and excreted. Metabolites of orally administered bisphenol A were undetectable in the animals' blood within 72 hours. Bisphenol A did not accumulate in body fat or sex organs of either male or female test animals (Pottenger, L.H., J.Y. Domoradzki, D.A. Markham, S.C.Hansen, S.Z. Cagen and J.M. Waechter, Jr., 2000, "The Relative Bioavailability and Metabolism of Bisphenol A in Rats is Dependent Upon the Route of Administration," Toxicological Sciences, vol. 54, pages 3-18. Abstract and full text available at: Oxford Journals Online).
Another study that compared bisphenol A metabolism in rat, mice and human liver cells showed similar metabolism across the species. The study demonstrates that the results of the pharmacokinetic study in rats also apply to humans. Consequently, bisphenol A intake from any possible human exposure would be rapidly metabolized to a hormonally inactive form and excreted from the body (Pritchett, J.J., R.K. Kuester and I.G. Sipes, 2002, "Metabolism of Bisphenol A in Primary Cultured Hepatocytes from Mice, Rats and Humans," Drug Metabolism and Disposition, vol. 30, no. 11, pages 1180-1185. Abstract and full text available at: Drug Metabolism & Disposition).
Click here to learn more about how we metabolize BPA from Steve Hentges, Ph.D., of the American Chemistry Council.
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