05-26-09 RODALE NEWS, EMMAUS, PA—Two new studies published in the journal Environmental Health Perspectives have found that bisphenol A (BPA), a hormone-disrupting chemical currently up for bans in Minnesota, California, Connecticut, and Chicago, may build up in our bodies more than previously thought.
BPA made headlines last fall when some high-profile reports pegged it as a potential health threat. The chemical is often named as harmful for babies, who can be exposed to high levels through polycarbonate baby bottles and formula cans. But it’s also bad news for adults, having been linked to heart disease, diabetes, and liver problems. Legislation currently targeted at banning the chemical focuses only on baby products, not the myriad sources from which adults get exposed every day.
THE DETAILS: In one study, researchers analyzed urine samples from 1,469 adults who participated in the Centers for Disease Control and Prevention (CDC) National Health and Nutrition Examination Survey 2003–2004. The participants fasted for 24 hours, and at various points during the fasting, their urine was tested for BPA levels. The authors noted that BPA levels declined rapidly during the first four hours of fasting, but leveled off after that. In the second study, researchers recruited 77 students at Harvard University and tested their urine at the end of one week, during which they drank from stainless steel bottles, and at the end of a second, during which they drank from polycarbonate bottles. The authors found a 69 percent increase in levels of BPA after drinking from the polycarbonate bottles.
WHAT IT MEANS: Previous research has suggested that BPA doesn’t build up in body fat, and that our bodies completely get rid of it within a few hours of exposure. However, the authors of the CDC study suggest that it may very well build up in body fat, and we seem to be continually exposed to the chemical from a number of sources we don’t expect. For instance, in addition to canned foods and polycarbonate bottles, BPA is used as a flame retardant in some types of furniture (it can bind to dust that we inhale), and some tests have detected it in PVC pipes used to carry drinking water, and in recycled-paper food packaging.
You can’t control every exposure to BPA, but here are a few that you can:
• Canned foods. Most food cans are lined with an epoxy resin that contains BPA. Highly acidic foods and some fatty foods, such as canned tomatoes and beans, tend to cause BPA to leach out in greater concentrations.
• #7 polycarbonate plastics. Polycarbonate plastic is the only plastic currently known to leach bisphenol A. However, determining which are polycarbonate plastics can be confusing, because they are marked with a “#7” in the plastic labeling system used to help recyclers separate different types of resins. The label #7 is a catchall category for any plastic invented after 1987, and it includes safer plastics that don’t leach BPA, for instance, plant-based plastics. Unless you see a “BPA-free” label next to the #7 on a plastic container, steer clear. Favor glass, ceramic, or stainless steel food and drink containers, and you’ll avoid BPA as well as chemicals that can leach out of other plastic types.
• Recycled-paper food containers. It feels good to use recycled packaging like coffee cups or takeout containers. But there is some evidence that BPA leaches out of these as well. However, some of the alternatives, such as polystyrene foam or plastic clamshells, aren’t any better; the foam can leach cancer-causing styrene, and clamshells aren’t recyclable in many areas. The solution: Bring your own containers for restaurant leftovers, and carry a reusable mug to your favorite coffee shop.