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The latest skirmish in the battle over bisphenol A (BPA) - the synthetic chemical used to make polycarbonate plastics, to make the epoxy resins that line food and beverage cans, and as developers in thermal receipt papers - came last week when the Breast Cancer Fund, an Oakland-based non-profit, released the results of its testing for BPA in canned food marketed to children (PDF). The report found BPA in Campbell's Disney Princess Cool Shapes, Toy Story Fun Shapes Pasta in chicken broth, Spaghettios With Meatballs, Earth's Best Organic Elmo Noodlemania Soup, Chef Boyardee Whole Grain Pasta Mini ABCs &123s With Meatballs, and Annie's Homegrown Organic Cheesy Ravioli at levels that ranged between 13 and 114 parts per billion, levels that have been shown to be biologically active, meaning they're high enough to interact with and affect our cells.
In response, the North American Metal Packaging Alliance (NAMPA), a trade association representing the food-and-beverage metal-packaging industry, fired off a press release citing a study ostensibly showing that there's no health risk from BPA exposure through canned food.
"This comprehensive, first-of-its-kind clinical exposure study, funded entirely by the U.S. Environmental Protection Agency (EPA), offers definitive evidence that even the highest exposure levels of BPA from canned foods and beverages did not lead to detectable amounts in the human blood stream," said NAMPA. "The EPA-funded study emphatically showed there is not a health risk from BPA exposure in canned foods because of how the body processes and eliminates the compound from the body, in children as well as adults," said NAMPA chairman Dr. John M. Rost in the press release.
Trouble is, this study - by Teeguarden et al. - which was indeed funded by the EPA and conducted by the Pacific Northwest National Laboratory and published in the September issue of Toxicological Sciences, shows nothing of the kind. No children were included in the study, and researchers did not measure how much BPA was in the food the subjects ate so there's no way to tell if the BPA in their systems came from that food. But why should we care?
BPA, which has long been identified as an endocrine-disrupting chemical, has been linked in numerous studies to health effects that include adverse impacts on developmental, metabolic, reproductive, neurological, cardiovascular, and other systems. Childhood exposure is a particular concern because early life exposure to endocrine-disrupting chemicals can set the stage for later life health disorders, including diabetes, obesity, and certain cancers.
Concern over these effects have led ten U.S. states and several local governments to bar BPA from children's reusable food and beverage containers, and prompted major manufacturers of baby bottles and toddlers' sippy-cups to switch to alternate materials. Canada has added BPA to its list of toxic substances, Japan took BPA out of can linings and receipt papers in the 1990s, and China and Malaysia have now instituted bans on BPA in baby bottles, but the U.S. federal government does not bar the use of BPA in such products. Environmental Protection Agency (EPA) and Food and Drug Administration (FDA) policies have been inching in that direction, though.
In 2010, after having been sent back to the drawing board by its science advisory board in 2008, the FDA issued a policy statement that supports a shift toward stronger regulation of BPA and that supports efforts to find safe alternatives to BPA for infant formula and other food and beverage can liners. Meanwhile, the EPA has issued an "action plan" for BPA that could lead to more oversight on its use.
The chemical industry, NAMPA, and other industry groups have consistently defended the safety of BPA - and lobbied extensively against its regulation. But that such a flawed study would be published and its findings so misrepresented has outraged prominent members of the scientific community. "Its conclusions are preposterous," says Fred vom Saal, professor of biological sciences at the University of Missouri-Columbia whose research on endocrine hormones dates back to the 1970s. "How could a federal agency be associated with this? It is profoundly bad."
NAMPA said the Teeguarden et al. study showed BPA in cans presented no health risks to adults or children, and called it "a large clinical study," but it included only 20 adult subjects. The study's major flaw, however, is that it did not measure how much BPA was in the food the subjects ate (and says so clearly: "Measurement of BPA levels in the foods was outside the scope of the current study for logistical and financial reasons"), so it is impossible to tell how much of the BPA measured in subjects' blood and urine actually came from meals consumed during the study.
"The study design is fundamentally flawed as a toxicokinetic study as the authors did not measure inputs - how much BPA the subjects consumed - so should not be used to draw any conclusions about metabolism of BPA in humans from dietary exposure," says Dr. Ted Schettler, science director of the Science Environmental Health Network, a non-profit that promotes the use of science in public and ecosystem health protection.
The Teeguarden et al. study is listed as "significant laboratory study" by the American Chemistry Council's Polycarbonate/BPA Global Group. In 2010, the American Chemistry Council spent millions of dollars on lobbying to defeat legislation that would restrict the use of BPA. The study has also gone out via the NAMPA press release on a number of industry online newsletters, and been touted in a Forbes column by Trevor Butterworth, editor-at-large of STATS, a non-profit affiliated with George Mason University, known for its defense of the chemical industry.
In criticizing the Breast Cancer Fund study, NAMPA also said the levels of BPA found in the kids' canned food tested - an average of 13 to 114 parts per billion - "are well within the safety recommendations of government agencies." But such levels of BPA, which is known to be biologically active at very low levels of exposure, according to vom Saal, are sufficient "to prompt an entire range of effects."
This is not the first time a study published by Toxicological Sciences has drawn fire from other scientists. Last year the journal published a letter signed by 24 biological scientists pointing to design flaws in another BPA study the journal published in 2009 that - like the Teeguarden et al. study - concluded no harm from the BPA exposure measured. A letter from vom Saal and a colleague responding to the Teeguarden study is forthcoming in a future issue of Toxicological Sciences as is a response from the study's lead authors.
"From my perspective this is very sad as it diminishes the credibility of science, and the consequences of that are profound," says vom Saal.
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