Laws & Politics
NTP: There is some concern about toxicity of bisphenol A
By David Liu, Ph.D.
Sep 3, 2008 - 11:04:51 PM

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Thursday September 4, 2008 (foodconsumer.org) -- The National Toxicology Program today released a final report on bisphenol A, a chemical commonly used in polycarbonated plastics and epoxy resins saying that the current human exposure to this chemical is of "some concern for its effect on development of the prostate gland and brain and fetuses, infants and children.

NTP is an agency of the National Institutes of Health.  In an early draft, the NTP's voiced a soft tune about the toxicity of bisphenol A drawing criticism. Later the agency raised its voice to stress that there is some concern about this chemical.

"We are expressing this level of concern because we see developmental changes occurring in some animal studies at BPA exposure levels similar to those experienced by humans," Bucher said in a press release by the agency. But the agency is not sure whether the impact observed in animals would be applicable in humans although it expressed some concern.

New studies keep finding new toxic effects of this chemical.  

A new study published online in Environmental Health Perspectives August 14, which was reported by foodconsumer.org on Sep 1, 2008, suggests that bisphenol A could be more harmful than thought.    It has found that the chemical at the level found commonly found in humans' blood can suppress a hormone that protects people from heart attacks and type 2 disease.

The study was released on August 14, a day before the Food and Drug Administration claimed that bisphenol A is safe at current exposure levels.   The FDA commissioner Andrew C. von Eschenbach said research current available has not provided sufficient evidence to demonstrate that this chemical is harmful. The comment was published on the commissioner's web blog

Detailed opinions of the FDA were released from other officials at FDA. Dr. Norris Alderson, the FDA's associate commissioner for science early told the House Subcommittee on Commerce, Trade and Consumer Protection Committee on Energy and Commerce that the level is not high enough to cause injury.

Early studies showed that bisphenol A has a wide array of adverse effects in lab animals including reproductive problems, certain cancers and asthma.

The NTP already released its draft brief  early on April 14, which was peer-reviewed on June 11 saying that "there is some concern for neural and behavioral effects in fetuses, infants, and children at current human exposures. The NTP also has some concern for bisphenol A exposure in these populations based on effects in the prostate gland, mammary gland, and an earlier age for puberty in females."

The new study led by Nira Ben-Jonathan, an endocrinologist at the University of Cincinnati in Ohio showed the level of adiponectin, a protective hormone released by human breast fat cells decreased after exposure to bisphenol A. The effective levels of the chemical were commonly found in human blood.

In the study, the researchers exposed some human cells to estradiol, a natural human estrogen and some to bisphenol A.    Both groups of cells released reduced amounts of the protective hormone adiponectin, which protects against heart attacks and type 2 disease.

"These findings provide the molecular basis for bisphenol A being implicated in both obesity and potentially the associated disease that is now being detected in children and adolescents -- type 2 diabetes," Frederick vom Saal, a specialist in endocrine disruptors from the University of Missouri in Columbia was quoted as commenting.

Another study reported today Sep 3 by Washington Post Showed that exposure to bisphenol A was linked to problems with brain function and mood disorder in monkeys. This is believed to be the first study to show adverse effects of this chemical in primates.

The Yale University study published in the Proceedings of the National Academy of Sciences showed bisphenol A interfered with brain cell connections which are important for memory, learning and mood in monkeys after exposed to the levels of bisphenol A which the Environmental Protection Agency believes is safe.

"Our findings suggest that exposure to low-dose BPA may have widespread effects on brain structure and function," the authors were quoted as writing.   The results suggest that observed adverse effects of this chemical in animal studies may as well be applicable to humans.

Another study published in Biol. Reprod. 72 (6): 1344-51 showed that exposure to 0.025 µg of bisphenol A per kilogram of body weight per day could permanently change genital tract.

Bisphenol A, first synthesized in 1895 and found later in 1936 to be a synthetic estrogen (a female hormone) has been used in hard, polycarbonate plastics, epoxy resins used in the linings of some food and beverage containers including baby bottles and toddler sippy cups, the lining of aluminum cans for baby formulas, dental sealants and other consumer products such as sunglasses and CDs.

The Environmental Working Group (EWG), a not-for-profit environmental health advocate, issued a statement today and praised the NTP report.

"Unlike the FDA, NTP has listened to the nation’s premier scientists and has concluded that the BPA threat to the brains, bodies and behavior of our children must be taken seriously,” EWG Executive Director Richard Wiles said. “The agency’s stance is measured -- and courageous in the face of the slick, relentless publicity campaign from the chemical industry, which seems to be following the tobacco industry’s playbook.”

Wiles criticized the FDA saying “The FDA has no credibility when it comes to BPA safety."

The EWG said in its statement that “FDA ignored the nation's top public health scientists and instead lauded the benefits of a toxic hormone disruptor found in virtually every infant in America. Now that wrong has been righted."

The American Chemistry Council, a trade organization presenting the interest of the industry, has said and repeated again yesterday, quoted by the Washington Post, that "there is no direct evidence that exposure to bisphenol A adversely affects human reproduction or development."

A health observer affiliated with foodconsumer.org said there will never be direct evidence because bisphenol A cannot be tested in humans to see its toxicity.   He said whether it is toxic does not depend on how the government or the industry says about the chemical, but it will be determined by individuals.

CERHR Director Michael Shelby, Ph.D., said, "Unfortunately, it is very difficult to offer advice on how the public should respond to this information. More research is clearly needed to understand exactly how these findings relate to human health and development."

He added" "but at this point we can't dismiss the possibility that the effects we're seeing in animals may occur in humans. If parents are concerned, they can make the personal choice to reduce exposures of their infants and children to BPA."