BPA exposure in US-approved levels may alter insulin response in non-diabetic adults

"Bisphenol A is an endocrine disrupting chemical that is used to manufacture thermal paper receipts, plastics and a wide range of consumer products," said Frederick vom Saal, an endocrinologist and Curators' Professor in the Division of Biological Sciences in the MU College of Arts and Science, and a co-author on the study. "Experiments with human and mouse pancreatic cells have revealed that low-dose exposure to BPA, in the presence of glucose, triggers an insulin response. We wanted to test the potential effects of BPA in humans to see whether it held true."

In both of the studies, subjects were orally administered a safe dose of BPA, which led to the same amount of BPA in their blood that customers might encounter by handling a cash register receipt; or, the same subjects received a placebo exposure for comparison. Insulin responses were then assessed through an oral glucose tolerance test in the first experiment or a hyperglycemic clamp in the second experiment. Results of both studies showed that BPA altered insulin release relative to the placebo exposure in the subjects. In animal studies repeated BPA exposure resulted in insulin resistance.

"This exploratory study needs to be replicated because it suggests that BPA exposure at a dose considered safe by U.S. regulators could alter glucose-stimulated insulin responses in humans," vom Saal said. "Our study is an initial step toward investigating whether exposure to endocrine disrupting chemicals, such as BPA, contributes to insulin resistance and eventually Type 2 diabetes."