Hormone-altering effects observed in mice exposed to "safe" levels of BPA

(http://www.thedailygreen.com) According to a study published July 25, baby mice exposed in the womb to low, not high, doses of bisphenol A (BPA) were fatter and had metabolic changes linked to obesity and diabetes.

BPA is a chemical found in polycarbonate plastics, canned food liners and some thermal receipts. It was once widely found in products aimed at young children and infants, but has since been mostly removed, either voluntarily or through government regulation. BPA, which can be found in nearly everyone's body, was first developed as a synthetic estrogen and has been linked to a range of health issues including obesity and diabetes.

"What's scary is that we found effects at levels that the government not only says is safe, but that they don't bother to test," said Frederick vom Saal, a University of Missouri, Columbia, professor and senior author of the study published in the journal, Reproductive Toxicology.

When pregnant mice were fed daily doses of 5,000 micrograms or less of BPA per kilogram of body weight, the level which the Environmental Protection Agency claims produces "no effects," their offspring experienced "deranged metabolism," weight gain, increased abdominal fat and eating,impaired glucose tolerance and increased hormones that regulate glucose and appetite.

The pregnant mice were fed doses of 5, 50, 500, 5,000, and 50,000 micrograms per kilogram. The greatest effects were observed in the offspring of mice fed the 500 micrograms per kilogram dose. The number of fat cells doubled with this dosage. No effects were seen at doses higher than 5,000 micrograms per kilogram.

In a report last year, 12 scientists, including vom Saal, criticized the way that the EPA evaluates the safety of chemicals. The EPA's method for testing chemical safety typically includes giving large doses to laboratory animals and then extrapolating the derived data for the lower doses they expect humans to encounter. The report claims that this outdated strategy fails to detect health threats from low doses of hormone-like chemicals.

The EPA responded to that report last month, defending its testing. The EPA claims that its current testing of hormone-altering chemicals is adequate for detecting low-dose effects that may jeopardize health. A spokesperson for the American Chemistry Council, which represents chemical companies including DuPont, BASF, Bayer, and Merck & Co., Inc., said the findings had not been replicated and it "presents conclusions that are not supported by the findings of EPA's recent extensive review of the state of the science on low dose exposures."