April 08: Bisphenol A
Information about Bisphenol A (BPA) on the Internet
Bisphenol A (BPA) Update (April 20, 2008)
The National Toxicology Program (NTP) Center for the Evaluation of Risks to Human Reproduction, which is part of the National Institute of Environmental Health Sciences, is conducting an evaluation of bisphenol A.
As part of the process, it released on April 15, 2008, a draft Brief on bisphenol A that contains the NTP's conclusions and the scientific basis about whether or not exposure to this chemical presents a concern for human reproduction or the development of children. The full draft can be accessed here.
Here are NTP's conclusions:
The NTP concurs with the conclusion of the CERHR Expert Panel on Bisphenol A 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 scientific evidence that supports a conclusion of some concern for exposures in fetuses, infants, and children comes from a number of laboratory animal studies reporting that “low” level exposure to bisphenol A during development can cause changes in behavior and the brain, prostate gland, mammary gland, and the age at which females attain puberty. These studies only provide limited evidence for adverse effects on development and more research is needed to better understand their implications for human health. However, because these effects in animals occur at bisphenol A exposure levels similar to those experienced by humans, the possibility that bisphenol A may alter human development cannot be dismissed.
The NTP has negligible concern that exposure of pregnant women to bisphenol A will result in fetal or neonatal mortality, birth defects or reduced birth weight and growth in their offspring.
In laboratory animals, exposure to very high levels of bisphenol A during pregnancy can cause fetal death and reduced birth weight and growth during infancy. These studies provide clear evidence for adverse effects on development, but occur at exposure levels far in excess of those experienced by humans. Two recent human studies have not associated bisphenol A exposure in pregnant women with decreased birth weight or several other measures of birth outcome. Results from several animal studies provide evidence that bisphenol A does not cause birth defects such as cleft palette, skeletal malformations, or grossly abnormal organs.
The NTP concurs with the conclusion of the CERHR Expert Panel on Bisphenol A that there is negligible concern that exposure to bisphenol A causes reproductive effects in non-occupationally exposed adults and minimal concern for workers exposed to higher levels in occupational settings.
Public comments on the draft Brief are invited. Written comments should be submitted by May 23, 2008, and oral comments can be presented at the NTP Board of Scientific Counselors meeting in Triangle Park, North Carolina, on June 11-12, 2008, Details about submitting these comments can be found in the Federal Register.
This FDA statement is posted on the Nalgene Outdoor website. (Nalgene bottles are made with BPA.)
Statement from the FDA, from a written communication dated January 29, 2008:
The Agency's current position on the presence of BPA impurities in food-contact polymers is as follows. BPA is used in the manufacture of two types of polymers used for food-contact articles (i.e., polycarbonate (PC) polymers and epoxy-based enamels and coatings) and is present at very low levels in the finished food contact materials. Typical uses of PC polymers include food processing equipment, such as popcorn makers, and water and infant baby bottles intended for repeated use. BPA-based epoxy coated cans are used in a variety of canned food and beverage applications, including cans used to hold infant formula. The Agency is aware of several reports stating that BPA has estrogen-like activity. However, there are other reports that appear to dispute any reason to expect harm at the low exposures that humans experience. A March 2007 report from a consumer group included studies showing the levels of BPA found in canned foods and migrating out of PC baby bottles and included claims that these levels are unsafe. FDA scientists have reviewed the available information from this report and have concluded that the BPA levels found in canned foods or migrating out of PC baby bottles are not significantly different than the very low levels previously found by FDA chemists and other laboratories, levels that result in a dietary exposure that is orders of magnitude below the levels known to not cause toxic effects in animals.
The agency has been actively reviewing the safety of BPA and has completed a review of the available data obtained from animal studies, and migration studies. Based on the results of the migration studies conducted by FDA chemists, we have determined that the dietary exposure to BPA is low (3.7 ppb), the level that is orders of magnitude below the levels known to cause toxic effects in animals. Considering the low dietary exposure and the fact that BPA had not demonstrated adverse effects when consumed by animals in amounts of much higher (orders of magnitude) than humans would consume, FDA sees no reason at this time to ban or otherwise restrict the uses now authorized. Our conclusion is based on our ongoing review of all available data. We will continue to monitor data on BPA to determine if its use would raise a safety concern. If such a concern exists, FDA will take the appropriate post-market regulatory action.
The National Institute of Environmental Health Sciences (NIEHS), a division of the National Institutes of Health (NIH), sponsored two expert panel reviews which released their findings in 2007.
The first panel was composed of 40 BPA researchers whose responsibility was to identify research needs for the research community. The meeting was entitled “Bisphenol A: An Examination of the Relevance of Ecological, In vitro and Laboratory Animal Studies for Assessing Risks to Human Health” and was held in Chapel Hill, NC. The meeting was attended primarily by academic investigators with expertise in the area of BPA research who were divided into several areas including in vitro, wildlife, laboratory animal models, cancer and human exposure.
The discussions led to five literature review publications in the journal Reproductive Toxicology and one consensus statement signed by the majority of the participants that also appeared in Reproductive Toxicology.
The Chapel Hill consensus panel concluded that “human exposure to BPA is within the range that is predicted to be biologically active in over 95% of people sampled. The wide range of adverse effects of low doses of BPA in laboratory animals exposed both during development and in adulthood is a great cause for concern with regard to the potential for similar adverse effects in humans.”
The second panel was convened by the NIEHS' National Toxicology Program's Center for the Evaluation of Risks to Human Reproduction (CERHR). The 12-member, independent panel of government and non-government scientists was charged with evaluating the scientific studies on the potential reproductive and developmental hazards of BPA.
This panel concluded that there is “some concern that exposure to Bisphenol A in utero causes neural and behavioral effects” in infants and children. It found “minimal” or “negligible” concern about other possible health consequences from exposure to Bisphenol. Full 396-page report.
CERHR solicited public comments on the report and is now preparing the NTP Brief on Bisphenol A. This brief will include the NTP's conclusions on the reproductive and developmental hazards associated with exposure to BPA. The brief is based on the expert panel report, public comments received on the report, and any new relevant scientific literature.The NTP-CERHR Monograph, consisting of a collection of information on bisphenol A that includes the NTP Brief, the Expert Panel Report, and the public comments on the Panel Report, will be made publicly available and transmitted to appropriate health and regulatory agencies. The NTP Monograph will likely be available in summer 2008.
The European Food Safety Authority issued its opinion on the safety of BPA in January, 2007. It established a Tolerable Daily Intake (TDI) of 0.05 mg of BPA per kilogram body weight. This is an estimate of the amount of a substance in air, food or drinking water that can be taken in daily over a lifetime without appreciable health risk. It noted that the conservative estimates of exposure were less than 30% of the TDI in all population groups considered.
Opinion of the European Food Safety Authority Scientific Panel on food additives, flavourings, processing aids and materials in contact with food (AFC) related to 2,2-BIS(4-HYDROXYPHENYL)PROPANE (2007)
The Centers for Disease Control and Prevention detected Bisphenol in the urine of 93 percent of the 2,517 people aged 6 years and older who took part in CDC's National Health and Nutrition Examination Survey (NHANES) from 2003 through 2004. CDC's scientific report.
Feb 2008 study of Bisphenol leaching from U.S. baby bottles, which found that popular brands like Avent, Disney/The First Years, Dr. Brown's, Evenflo, Gerber, and Playtex leach bisphenol A when heated. News release. Executive summary. Full 20-page report.
Feb 2008 study of Bisphenol leaching from Canadian baby bottles, which found that the most popular, easily available brands from well-known retail outlets leached BPA when heated. News release. Full 20-page report.
Environment California 2007 study of BPA leaching from baby bottles, which found that all five of the most popular brands leached BPA. Full report.
News release of 2008 Congressional investigation of Bisphenol in infant formula packaging. Congressional letters to manufacturers and industry consultants.To reduce exposure to Bisphenol, NIEHS suggests:
Plastic containers with the recycling #7 on the bottom. This is the “other” category of plastic for materials that don't qualify for numbers 1 through 6. Recycling centers cannot recycle plastic #7. Some #7 plastics contain Bisphenol and some don't. Aside from the fact that bisphenol-containing plastics are hard and shatter-proof, it's impossible to know for certain whether a #7 plastic contains Bisphenol.
No dental sealants are made with BPA, but the older versions of one brand are made with a compound that breaks down into BPA when it comes into contact with saliva, causing high but temporary elevations in blood levels of BPA. The brand is Delton from Dentsply International of York, Pennsylvania. According to a company representative, newer versions of Delton that have either the plus sign (+) or the word “plus” in their name do not contain the compound that breaks down into BPA.
Manufacturers of BPA-free infant bottles:
Eden Foods of Clinton, Michigan, uses a more expensive enamel lining made from the oil and resin extracted from plants instead of BPA to line their cans. Eden says that they believe they are the only company in the U.S. that uses this custom made BPA-free can.