Feds Reject Petition To Ban BPA In Food

I recently stumbled onto this article regarding bisphenol A (BPA) regulation (or lack of) while exploring the National Center for Toxicological Research (NCTR) website (http://www.npr.org/blogs/thesalt/2012/03/30/149683556/feds-to-decide-on-banning-bpa-from-food-and-other-products). The article was was posted in March 2012, but the findings have had a lasting impact on bisphenol A and other endocrine disrupting chemicals (EDC) regulation. Since learning about EDCs, I have been in favor of increasing funds for EDC research and regulation since the chemicals are associated with diabetes, immune dysfunction, subfertility, obesity, and neurobehavioral disorders in humans. A basic understanding of the endocrine system is crucial in understanding how chemicals disrupt it (skip the next two paragraphs if you want to just read about the NPR article).

The endocrine system is composed of the thyroid, pancreas, and approximately 28 other glands that use trace amount of chemical messengers, or hormones, to communicate with and regulate our bodies. The endocrine system regulates a number of bodily processes that range from female reproduction to neurological development. An endocrine disruption occurs whenever a chemical mimics, blocks, or interferes with these hormones, thereby altering bodily regulation. The three most daunting features of these chemicals are their hormonal interferences at low dosage levels, their persistence due to long half-lives, and their associated deleterious bodily and mental afflictions as wide and varied as the processes controlled by the human endocrine system.

Perhaps the most well-known EDC is dichlorodiphenyltrichloroethane, or DDT. Studies in the 1950s linked DDT exposure to harmful physiological effects in lab animals, and yet it took critical examination by Rachel Carson in Silent Spring to finally halt production of this pesticide in 1972. The most well-known EDC today is bisphenol A, which is present in the urine of 92.6% Americans and has been linked to obesity, cancer, and cardiovascular disease in laboratory animals. BPA is used in polycarbonate and epoxy production and is found in a variety of products, but predominately food and drink packaging. Some of these effects have been known since 1930, yet the Food and Drug Administration (FDA) considers BPA safe because of scientific uncertainty regarding their adverse effects. The uncertainty argument is appropriate from the skeptical perspective of science; however, scientific certainty is sufficient but not necessary for taking public policy action. In 2010, the FDA did ban BPA containing baby products, but only after retailers like Wal-Mart began removing the products from their shelves.

The NPR article discusses the refusal of the FDA to ban BPA primarily on the basis of two recent studies that were funded by the FDA. One experiment lead by Teeguarden at Pacific Northwest National Laboratory studied the amount of bioactive BPA that 20 men and women had in their urine after having a diet supposedly loaded with BPA from canned foods and juice in plastic containers (Abstract and article can be found here: http://www.ncbi.nlm.nih.gov/pubmed/21705716). The overall finding was that there were minimal BPA levels in the blood of the participants. One flaw that I immediately noticed in this study was that the initial BPA contained in the food was unknown and thus the BPA urine concentration wasn’t normalized to anything. In biochemical research, absolute values must be normalized to a control or the data doesn’t tell you much. It’s possible that the participants consumed different amounts of BPA containing food or that the measurement techniques processed the sample differently. The limited population size also limits the scope of the study. In fact Frederick S. vom Saal et al. published a critique of Teeguarden work and stated that it “contains numerous flawed assumptions, omissions, and misrepresentations of the published literature on bisphenol A (BPA) that demand our rebuttal.” I highly recommend reading it (http://toxsci.oxfordjournals.org/content/125/1/318.long#ref-19).  An article in Mother Jones labels Teeguarden as a “researcher who has collaborated with and been funded by the chemical industry, and works for an organization that also has worked with to the chemical industry.”

A second study by Dan Doerge at NCTR found that unlike mice and rat newborns who are more susceptible to BPA, newborn monkeys had no trouble inactivating the compound and only had greater BPA metabolism capabilities (Abstract and article can be found here: http://www.ncbi.nlm.nih.gov/pubmed/21983029). Other peer review studies contradict this work as well.

BPA and endocrine disruptors remain highly debated in the scientific community for numerous reasons. The primary cause of the discrepancy is that it is difficult to determine nanonmolar concentrations of EDCs and that there is no sure means to translate the impact of EDCs on experimental animals to humans. The ultimate question is how much proof do we need from the scientific community to instate regulatory policies? Data driven public health measures are the logical thing to do, but what happens when the data is ambiguous or nonexistent? A similar problem seems to be happening in Mayflower, where the Arkansas Department of Health wasn’t able to measure many toxic compounds immediately after the oil spill. According to “science” the town was not affected, but the respiratory problems and other health issues of Mayflower residents seem to tell a different story.

From a public health viewpoint, it’s likely that all populations are affected, but some are more affected than others. One would expect that low income individuals may more likely to turn to packaged foods that contain BPA and that they may be unable to receive proper medical care. It’s also possible the price of a BPA replacement in food containers could cause food cost to rise and do more harm than good. Since little is known about EDCs, the potential harmful effects could be mislabeled as another disease or chronic condition. Even if BPA is banned someday, it’s likely that another class of chemicals will take its place. In today’s modern world, we are exposed to thousands of chemicals, for better or for worse.