Beverage and food manufacturers who package their products in plastic bottles or cans with a plastic lining made with the chemical bisphenol A (B.P.A.) have found themselves embroiled in a dispute about its safety. The result has left food manufacturers in a quandary as a variety of scientific bodies ranging from the Food and Drug Administration, the National Institute of Health’s National Toxicology Program and Health Canada, that country’s version of the F.D.A., sort through the science in an effort to determine what risk, if any, the chemical poses for consumers, most notably newborns and infants.
In early September, the N.T.P. finalized its report on B.P.A., which is a componentof some plastic products used to make shatter-proof bottles and the plastic that lines the inside of metal cans, and said there is "some concern" for the effects on the development of the prostate gland and brain and for behavioral effects in fetuses, infants and children. The conclusions of the N.T.P. report are primarily based on research involving laboratory animal studies.
The N.T.P. bases its findings on a five-point scale, with "some concern" representing the mid-point. The other four categories include "serious concern," the highest level, "concern," "minimal concern," and "negligible concern." The likelihood of a negative effect is expressed as a level of concern by the N.T.P.
The N.T.P. report also noted there is "minimal concern" that B.P.A. exposure will accelerate puberty in females. The group said there was also "negligible concern" exposure of pregnant women to B.P.A. will result in fetal or neonatal mortality, birth defects or reduced birth weight and growth in offspring.
"There remains considerable uncertainty whether the changes seen in the animal studies are directly applicable to humans and whether they would result in clear adverse health effects," said Dr. John Bucher, associate director of the N.T.P. "But we have concluded that the possibility that B.P.A. may affect human development cannot be dismissed.
"We are expressing this level of concern because we see developmental changes occurring in some animal studies at B.P.A. exposure levels similar to those experienced by humans."
An issue that has driven concern about B.P.A. is the primary source of exposure to the compound for most people is through diet. While air, dust and water are other possible sources of exposure, B.P.A. in food and beverages accounts for the majority of daily human exposure.
The chemical may leach into food from the lining of canned foods and from consumer products like water bottles, baby bottles or plastic food storage containers. The degree to which B.P.A. leaches from bottles into liquid may depend more on the temperature of the liquid or bottle, than the age of the container.
"Unfortunately, it is very difficult to offer advice on how the public should respond to this information," said Dr. Michael Shelby, director of the N.T.P.’s Center for the Evaluation of Risks to Human Reproduction. "More research is clearly needed to understand exactly how these findings relate to human health and development, 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 B.P.A."
Concern about the potential health effects of B.P.A. date back to the 1930s, but the component did not draw prominent attention until April of this year when Health Canada announced it was considering banning the import, sale or advertising of plastic bottles that contain B.P.A. Health Canada researchers conducted a risk assessment focused on B.P.A.’s impact on newborn children and infants up to 18 months, but noted the health risks for consumers of all ages also were considered.
The agency determined the main source of exposure for newborns and infants was through the use of plastic baby bottles containing B.P.A. when they are exposed to high temperature as well as migration from cans into baby formula. Health Canada scientists concluded in the assessment that B.P.A. exposure to infants is below levels that may pose a risk, but that the gap between exposure and effect was not large enough. As a result, the
Canadian government proposed reducing the exposure of B.P.A. in newborns and infants.
The comment period on the proposal was 60 days and ended in June, but a spokesman for Health Canada said the agency is still considering the comments and will announce its final rule on or before Oct. 16.
The reaction to Health Canada’s risk assessment was immediate. Citing consumer concern, Wal-Mart Canada, Mississauga, said it was ceasing the sale of baby bottles, water bottles and food containers identified as containing B.P.A.
Shortly after Health Canada made its announcement, the F.D.A. asked its science board subcommittee to review the research available on B.P.A. The results of the review were made public in mid-August, with the agency saying it believed there is a large body of evidence that indicates F.D.A.-regulated products containing B.P.A. currently on the market are safe and exposure levels to B.P.A. from food contact materials, including for infants and children, are below those that may cause health effects.
"However, we will continue to consider new research and information as they become available," the agency said.
It also was noted by the F.D.A. that the agency’s position was consistent with two risk assessments for B.P.A. conducted by the European Food Safety Authority and the Japanese National Institute of Advanced Industrial Science and Technology. Each of the risk assessments considered the question of a possible low-dose effect and concluded that no current health risk exists for B.P.A. at the current exposure level.
"B.P.A. has been safely used in food contact applications for 50 years and plays an essential role in keeping foods safe and fresh," said Dr. Robert Brackett, chief science and regulatory affairs officer for the Grocery Manufacturers Association, Washington. "Based on the entire body of scientific evidence, and the findings of the F.D.A. and numerous health authorities and researchers, consumers can continue to safely enjoy foods and beverages in the many forms of packaging provided, including those that contain B.P.A., without changing their purchasing or eating patterns."
Researchers link B.P.A. to metabolic syndrome in humans
CINCINNATI — Research from the University of Cincinnati (U.C.) has linked bisphenol A (B.P.A.) as a risk factor for metabolic syndrome, a combination of risk factors that may lead to coronary heart disease. The research was published in the Aug. 14 on-line edition of the journal Environmental Health Perspectives.
In a laboratory study, using fresh human fat tissues, the U.C. researchers found B.P.A. suppresses a key hormone, adiponectin, which is responsible for regulating insulin sensitivity in the body and puts people at a substantially higher risk for metabolic syndrome. Dr. Nira Ben-Jonathan and her team claim to be the first to report scientific evidence on the health effects of B.P.A. at environmentally relevant doses equal to "average" human exposure. Previous studies primarily have focused on animal studies and high doses of B.P.A.
"People have serious concerns about the potential health effects of B.P.A.," Ms. Ben-Jonathan said. "As the scientific evidence continues to mount against the chemical, it should be given serious attention to minimize future harm."
The U.C. study was designed to mimic a realistic human exposure to B.P.A. (between 0.1 and 10 nanomolar) so a more direct correlation between human exposure and health effects may be drawn. To conduct the study, the U.C. researchers collected fresh fat tissue from Cincinnati patients undergoing several types of breast or abdominal surgery.
The researchers found that exposing human tissues to B.P.A. levels within the range of common human exposure resulted in suppression of a hormone that protects people from metabolic syndrome.
"These results are especially powerful because we didn’t use a single patient, a single tissue source or a single occurrence," Ms. Ben-Jonathan said. "We used different fat tissues from multiple patients and got the same negative response to B.P.A."
This article can also be found in the digital edition of Food Business News, September 16, 2008, starting on Page 1. Click