In the latest of a series of findings involving health risks associated with plastic additive bisphenol A, a team of MU scientists has determined that women, female monkeys and female mice all metabolize the chemical in similar ways—a result that reinforces the idea that animal models are a legitimate means of predicting bisphenol A’s effects on human beings.
The new study is co-authored by MU’s Frederick vom Saal, a curators’ professor of biological sciences, and Julia Taylor, an assistant research professor. Researchers from the University’s departments of biological and biomedical sciences, the MU Veterinary Medical Diagnostic Lab, Washington State University and the University of California-Davis also participated. The study appeared in the September 20 edition of the National Institutes of Health journal, Environmental Health Perspectives.
“This study provides convincing evidence that BPA is dangerous to our health at current levels of human exposure,” says vom Saal. “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.”
Pioneering work by vom Saal has in the past shown that exposures to even very small amounts of BPA produce an “estrogen effect” that could harm the development of fetuses and lead to brain and reproductive abnormalities in adults. The chemical is used in hundreds of common household products.
Vom Saal’s research and tireless efforts to inform the public, regulators and legislators about the research has led several states to pass laws requiring plastics manufacturers to limit the public’s exposure to BPA. Similar federal legislation is pending before Congress.
In addition to confirming the efficacy of animal models, the new findings suggest human exposure to BPA may be much higher than prior estimates. The scientists say these higher exposure levels raise concerns that there may be more bisphenol A in the environment than previously supposed.
“We’ve assumed we’re getting BPA from the ingestion of contaminated food and beverages,” study co-author Pat Hunt, a professor in Washington State’s School of Molecular Biosciences, told the MU News Bureau earlier this fall. “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.”
In January, the U.S. Department of Health and Human Services and the Food and Drug Administration announced that they did not have the authority to regulate BPA or over 60,000 other “grandfathered” chemicals that were declared safe without review when the Toxic Substance Control Act was passed in the 1970s.
The agencies instead provided written guidance for women wishing to limit infants’ exposure to the chemical, called for more research into its effects, and new laws to provide the FDA with the authority to determine what products may contain BPA.
Organizations representing manufacturers who use BPA have consistently argued that the chemical is safe. One of the most prominent of these organizations is the Arlington, Va.-based American Chemistry Council. The ACC applauded the agencies for not imposing new rules, but criticized their lack of a more forceful endorsement.
“ACC and our members are committed to the safety of our products, and we will continue to support laws and regulations that protect consumer safety,” the group wrote in a January 15 statement. “While ACC recognizes that HHS and FDA are attempting to address public confusion about BPA, we are disappointed that some of the recommendations are likely to worry consumers and are not well-founded.
“Plastics made with BPA contribute safety and convenience to our daily lives because of their durability, clarity and shatter-resistance. Can liners and food-storage containers made with BPA are essential components to helping protect the safety of packaged foods and preserving products from spoilage and contamination. ACC remains committed to consumer safety, and will continue to review new scientific studies concerning the safety of BPA.”
Might this new study provide enough evidence to change their minds? Not likely, says Taylor, the MU study’s lead author.
“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,” says Taylor. “We know that BPA leaches out of products that contain it and that it acts like estrogen in the body.”
Vom Saal, too, is unequivocal on this point: “If the standard is that there has to be absolute proof of human harm prior to regulating a chemical that every American is exposed to, which would require doing an unethical experiment with people, this approach would represent a failure of the regulatory system to protect the health of all Americans,” he says.