BOSTON – Are people exposed to doses of bisphenol A in their canned foods and other consumer products that can harm them? Or are the amounts too low to cause any harm?
This is the crux of a vehement debate that is being waged as federal officials are trying to decide whether the chemical, known as BPA, should be regulated.
A group of toxicologists, including some who work for federal agencies, is questioning the likelihood that BPA is harming human health. But biologists studying the chemical’s health effects disagree, saying that what’s been detected in people is comparable to amounts that have harmed lab animals.
BPA is arguably the most controversial chemical in consumer products. It is used to make polycarbonate plastic as well as food and beverage can liners and some paper receipts and dental sealants
What is widely agreed upon is that exposure is ubiquitous. More than 90 percent of Americans tested have traces of BPA in their bodies.
BPA acts like an estrogen, disrupting hormones In laboratory animals. it alters how their reproductive systems and brains develop, and sets the stage for breast and prostate cancer. People with higher levels of exposure have an increased risk of cardiovascular disease, obesity and diabetes, according to some studies.
Nevertheless, the potential for human effects has been highly controversial among scientists who are debating whether the amounts in people’s bodies are in fact too low to be capable of inflicting harm.
On Friday, some of the toxicologists presented their arguments at the American Association for Advancement of Science annual meeting in Boston.
Do the math. Is it harmful?
On one side of this debate are toxicologists who specialize in analyzing data with mathematical models, producing information often used to set regulatory limits on chemical exposures. Their work focuses not on physical effects observed in animals or cells but on developing models that use numbers to make predictions, in this case to describe the amount of a chemical in the human body and how it may behave.
What is widely agreed upon is that exposure to BPA is nearly ubiquitous. It has been found in more than 90 percent of the Americans tested.On the other side are scientists who study BPA’s health effects in animals and people. They include specialists in genetics, endocrinology, physiology and epidemiology from various academic institutions whose work is supported by the National Institute of Environmental Health Sciences. They have reported health effects in lab animals at very low levels of BPA exposure that they say are comparable to amounts people encounter through consumer products.
This debate, while arcane, is important because the scientific information is being used by the U.S. Environmental Protection Agency and Food and Drug Administration in deciding whether to regulate BPA in consumer products, such as canned foods. Reacting to consumer concerns, some manufacturers already have stopped using BPA in plastic baby bottles, receipts and other items.
Justin Teeguarden, senior scientist at the Pacific Northwest National Laboratory, and Daniel Doerge, research chemist at the FDA’s National Center for Toxicological Research, have produced modeling studies that cast doubt on whether levels of BPA compounds being found in people are having any effects.
At the science conference on Friday, Teeguarden contended that the levels causing effects in animal studies, particularly those caused by BPA’s interaction with estrogen receptors, are much higher than the levels his models suggest are plausible in people. He said he used several methods to examine exposure data from more than 100 studies.