From Today’s New York Times: “Study: Human Exposure to BPA ‘Grossly Underestimated’” (by Gayathr Vaidyanathan), here is the introduction to an article discussing an important new study (by Julia Taylor, a biologist at the University of Missouri, and her co-authors):

Americans are likely to be exposed at higher levels than previously thought to bisphenol A, a compound that mimics hormones important to human development and is found in more than 90 percent of people in the United States, according to new research.

U.S. EPA says it is OK for humans to take in up to 50 micrograms of BPA per kilogram of body weight each day. The new study, published in the journal Environmental Health Perspectives, suggests that we are exposed to at least eight times that amount every day.

“Our data raise grave concern that regulatory agencies have grossly underestimated current human exposure levels,” states the study.

The study also gives the first experimental support that some BPA is likely cleared at similar rates in mice, monkeys and humans, making it possible to extrapolate health studies in mice to humans.

Despite decades of research, questions about BPA have lingered and recently become politicized. Sen. Dianne Feinstein (D-Calif.) hopes to add an amendment to the “FDA Food Safety Modernization Act,” currently under consideration in the Senate, banning the chemical from children’s food and drink packaging. Republicans and industry representatives have been averse, saying that research has not shown conclusively that the chemical is harmful.

Hormones are essential during development and can determine, among other things, a child’s gender. BPA, since it mimics estrogen, is an “endocrine disrupter,” according to Thomas Zoeller, a biology professor at the University of Massachusetts, Amherst. And amazingly, BPA has the ability to bind to not one, but three receptors — the estrogen, the male hormone and the thyroid hormone receptors, Zoeller said.

You can read the entire Times article here.

* * *

Here are excerpts from the University of Missouri press release:

COLUMBIA, Mo. – Researchers have discovered that women, female monkeys and female mice have major similarities when it comes to how bisphenol A (BPA) is metabolized, and they have renewed their call for governmental regulation when it comes to the estrogen-like chemical found in many everyday products.

A study . . .  ties rodent data on the health effects of BPA to predictions of human health effects from BPA with the use of everyday household products. . . .

“This study provides convincing evidence that BPA is dangerous to our health at current levels of human exposure,” said Frederick vom Saal, Curators’ professor of biological sciences at the University of Missouri. “The new results clearly demonstrate that rodent data on the health effects of BPA are relevant to predictions regarding the health effects of human exposure to BPA. Further evidence of human harm should not be required for regulatory action to reduce human exposure to BPA.”

BPA is one of the world’s highest production-volume chemicals, with more than 8 billion pounds made per year. It can be found in a wide variety of consumer products, including hard plastic items such as baby bottles and food-storage containers, the plastic lining of food and beverage cans, thermal paper used for receipts, and dental sealants. The findings in the current study suggest that human exposure to BPA is much higher than some prior estimates and is likely to be from many still-unknown sources, indicating the need for governmental agencies to require the chemical industry to identify all products that contain BPA.

Several states, including Connecticut, Massachusetts, Washington, New York and Oregon, have passed bills to reduce exposure to BPA, and similar legislation is pending in the U.S. Congress.

“For years, BPA manufacturers have argued that BPA is safe and have denied the validity of more than 200 studies that showed adverse health effects in animals due to exposure to very low doses of BPA,” said Julia Taylor, lead author and associate research professor at the University of Missouri. “We know that BPA leaches out of products that contain it, and that it acts like estrogen in the body.”

“We’ve assumed we’re getting BPA from the ingestion of contaminated food and beverages,” said co-author Pat Hunt, a professor in the Washington State University School of Molecular Biosciences. “This indicates there must be a lot of other ways in which we’re exposed to this chemical and we’re probably exposed to much higher levels than we have assumed.”

* * *

You can read the abstract and download the study here or download a pdf of the study directly here. (Citation: Taylor JA, vom Saal FS, Welshons WV, Drury B, Rottinghaus G, Hunt PA, et al. 2010. Similarity of Bisphenol A Pharmacokinetics in Rhesus Monkeys and Mice: Relevance for Human Exposure. Environ Health Perspect.)

Tomorrow, I will post the portion of my interview with Drs. Carlos Sonnenschein and Ana Soto when I asked them about their pathbreaking work on BPA.


Advertisements