Canada deserves a big pat on the back: On Wednesday, our northerly neighbor added bisphenol A (BPA) to its list of known toxic substances. Canada still has to iron out how it will regulate the chemical, but this is definitely a step in the right direction. (Bryan Walsh over at Time just posted a great piece about this, too—among other things he explains why BPA is “a litmus test for environmental health and for risk tolerance.”)
Let me use this news as an excuse to talk some more about my (least) favorite chemical. (You knew it would happen.) We’ve known for a while where BPA hides—canned goods, polycarbonate bottles, and receipts, among other things. But how do these each contribute to our overall body BPA burden?
A study published in March in the Journal of Exposure Science and Environmental Epidemiology strived to answer just this question. Researchers at the University of Maryland and Penn State College of Medicine analyzed data from the 2005-2006 National Health and Nutrition Examination Survey and found that people who had the most BPA in their bodies also happened to consume the most soda, school lunches, and meals prepared outside the home—suggesting that these items might well be big culprits. Bottled water did not make a big difference (which makes sense: purchased bottled waters aren’t made from polycarbonate—it’s the hard re-usable bottles that are.)
School lunches and restaurant food make total sense to me: I’m guessing both rely on canned products to conserve cost. Last time I went to a Middle Eastern restaurant, for instance, I saw huge tins of canned chick peas lining the walls. It made me think twice about eating their hummus (but in the end, I did anyway—who can turn that stuff down?).
As for soda: I feel dumb, but I’ve never really thought of it as a BPA culprit. When I think of the “canned goods” that contain BPA, I tend to think about canned peaches and canned beans, not Coke or Sprite! But of course: BPA lines these cans, too, and Americans drink so damned much of the stuff, it’s bound to be a big contributor. Indeed, a study published by Canadian researchers in August in the Journal of Food Protection found BPA in every single sample of soda they collected from cans (and none in soda collected from bottles). Interestingly, they also found BPA in canned beer: yet another problem I hadn’t even thought about. Budweiser, you’re bad for us for so many reasons.
LaKind, J., & Naiman, D. (2010). Daily intake of bisphenol A and potential sources of exposure: 2005–2006 National Health and Nutrition Examination Survey Journal of Exposure Science and Environmental Epidemiology DOI: 10.1038/jes.2010.9
Cao XL, Corriveau J, & Popovic S (2010). Sources of low concentrations of bisphenol A in canned beverage products. Journal of food protection, 73 (8), 1548-51 PMID: 20819371