Aug. 8, 2007 -- An expert panel today noted no major health risks in their review of data on a plastic chemical called bisphenol A.
Bisphenol A, or BPA, is found in polycarbonate plastic, which is used in various products including food and drink containers, as well as resins that line metal food cans.
The expert panel was convened by the Center for the Evaluation of Risks to Human Reproduction (CERHR) of the National Toxicology Program.
The 12-member panel included doctors and researchers from universities, the federal government, the American Cancer Society, and the drug companies Pfizer and Schering-Plough.
Their task was to review reams of research on bisphenol A's safety, based on lab tests on animals and studies of human exposure to bisphenol A.
The panel notes "some" concern that exposure to bisphenol A causes neural and behavioral effects in fetuses, infants, and children.
The panel notes "negligible" concerns that fetal exposure to bisphenol A produces birth defects and malformations, and "adverse reproductive effects" in adults exposed to bisphenol A. The panel's report doesn't define "adverse reproductive effects."
The CERHR will solicit public comments on its report.
Reaction to Panel's Work
The panel's conclusions are "very reassuring," Steven Hentges, PhD, tells WebMD. Hentges is the executive director of the polycarbonate-bisphenol A global group of the American Chemistry Council, an industry organization that represents firms including companies that make plastics.
The nonprofit Environmental Working Group issued a statement criticizing the panel's conclusions, claiming that the panel endorsed "an error-riddled, industry-influenced 'report' minimizing the risks that BPA poses to humans."
The panel's work comes in the wake of a statement written by 38 scientists who voice concern about bisphenol A's safety. That statement appears online in the journal Reproductive Toxicology.
About Bisphenol A
Data from lab tests and research on animals indicate that bisphenol A "may mimic the natural female sex hormone, estradiol," according to CERHR background information.
Bisphenol A leaches out of polycarbonate plastics, with more bisphenol A leaching out of heated plastics, note Ana Soto, MD, and Michele Marcus, PhD, MPH.
Soto is a professor of anatomy and cellular biology at Tufts University near Boston. Marcus is a professor of epidemiology at Emory University's Rollins School of Public Health in Atlanta.
Soto and Marcus have studied bisphenol A. They're among the 38 scientists who note concerns about bisphenol A in a consensus statement published Reproductive Toxicology.
Concerns About Bisphenol A
"The main concern is that bisphenol A is an estrogen. It mimics the action of the female hormone estradiol," Soto tells WebMD.
"My lab and other labs have found that bisphenol A causes diverse effects, and to me, the most critical ones are those that happen in fetal life where all these organs are being formed," says Soto.
Marcus agrees, noting that "the developing embryo is generally more vulnerable to the effects of exposures than adults."
Bisphenol A "has been shown to cause chromosomal abnormalities in mice and to cause early pubertal development in rodents," says Marcus.
Some research suggests that bisphenol A may have effects that span more than one generation, according to Soto and Marcus.
"It seems there is mounting evidence that bisphenol A would produce transgenerational effects," says Soto.
However, there have been "virtually no" studies of bisphenol A's direct effects in humans, says Marcus.
Bisphenol A: What to Do?
"What we know is that there a lot of harmful effects in animals and the exposure is ubiquitous. We don't know whether or not exposure is harmful to humans," says Marcus.
"However, if you would like to reduce exposure, there are a few things that you can do," Marcus notes.
Her suggestions: "You can refrain from heating foods in plastic containers and you can refrain from putting plastic containers in the dishwasher. Harsh alkaline detergents do increase the leaching of bisphenol A from polycarbonate containers."
Soto also has some ideas about reducing bisphenol A exposure.
"I think if I had a baby, I would use baby bottles that do not contain bisphenol A," Soto says. "For microwaved food, you can use ceramic dishes," she adds.
Still, people who take those steps wouldn't know the extent to which it reduces their overall exposure to bisphenol A, Soto notes.
"This is something that you cannot address only as an individual," says Soto. "I think that it is up to citizens to demand that the government pursues a policy that protects and preserves public health," she says.
Hentges says the expert panel looked at "a lot" of data on bisphenol A.
"What they found, overall, is that human exposure to bisphenol A is quite low. It's extremely low, well below levels that could be harmful," says Hentges.
"Looking at their overall conclusions, they did not find any high-level health concerns," says Hentges. "The handful of concerns that they identified were all flagged as 'minimal' or 'negligible' with one exception, which was flagged as 'some' concern, but that was primarily just an indication that they think additional research in that area might be helpful."
Hentges says that bisphenol A leaching out of polycarbonate food containers has been studied "many, many times."
"We do know quite well what kind of level could come out of those containers, and that level is extremely low," he says, adding that studies have shown no reason to be concerned about bisphenol A levels that would come out of those containers "under any typical or expected use."
As for switching to a different type of baby bottle, "the scientific conclusions don't support the need to use a different product. People have choices, though," says Hentges.