Expert Q&A: Toxicologist Linda Birnbaum on BPA
[Via – ConsumerReports]
At the same time that the Food and Drug Administration announced a significant shift in its view on the potential health risks posed by Bisphenol A, the Department of Health and Human Services said that it is investing $30 million in human and animal studies over the next two years to yield further information about BPA’s health effects. BPA is a chemical used in the linings of most food and beverage cans as well as in many clear plastic containers.
Shepherding this crucial research effort is Linda Birnbaum, director of the National Institute of Environmental Health Sciences (NIEHS), a federal research center based in North Carolina. The center’s mission, as defined on its Web site, is “… understanding how the environment influences the development and progression of human disease.” Birnbaum, an award-winning microbiologist and toxicologist, has served as a federal scientist for nearly three decades. During that time, her research has focused on the health effects of environmental pollutants such as dioxin, which like BPA is thought to be an endocrine-disrupting chemical.
I interviewed Dr. Birnbaum just a few days before the FDA’s policy change was announced. Excerpts from that interview in the Q&A below address the challenges that lie ahead in assessing the safety of one of the highest-volume chemicals in the world: At least 7 billion pounds of BPA are produced annually for use in products ranging from dental sealants to medical equipment to coatings on cash-register receipts, as well as food containers and packaging.—Andrea Rock
Q: What do you think the most important unanswered questions are? In this $30 million of research what would be at the top of your list?
A: I think there are a couple that are really important. We really have to understand the severity of effects that can be caused. How important really are the effects that are being reported at very low levels of BPA? And there’s a multitude of effects. Some of the analyses or the evaluations have focused, for example, on the effects on the developing reproductive system or the developing nervous system. Well, there’s evidence that it also affects the immune system . There is evidence that it affects the cardiovascular system . And I think it’s very important that we have a better understanding of the overall nature of the effects.
The other thing we really have to understand is how much of the BPA is needed to cause these effects? And what are the critical times of exposure in people? Are the critical windows in utereo? Are the critical windows in infants? What about puberty? There are now several new studies that have come out showing effects in adults. When you do cross-sectional studies, which are what these new studies are, and you look at a single point of time in people, you don’t really know if the effects you are seeing are caused by the current exposure to BPA or whether it was the history of exposure that led to that effect. Those are still some major questions
Major issues that I think other groups are looking at are trying to get a better handle on where is BPA in our environment. It’s not just in linings of cans, it’s not just in the polycarbonate bottles. Many of those sources are now being removed from the market. Industry has responded very responsibly and said we’re looking for alternatives. But where else is the BPA and how are we really being exposed? Is some of the BPA in the indoor air, is some of the BPA in dust, where it’s coming out of different consumer products? So we don’t understand. You really need to understand how we’re really being exposed eventually if we want to prevent exposure from happening.
Q: Do you believe there is enough uncertainty about BPA’s safety to caution people to avoid it in all food contact items?
A: I think we don’t really know where it is in many cases. Your study, Concern over canned foods, very clearly showed that in two cans of the same brand, some had a lot of BPA and some had very little.
Q: But I’d read that you did say that was your belief, that there was enough uncertainty to caution consumers to avoid BPA in food contact items?
A: I think people have to do what makes sense to them and follow their own conscience and what they think and if people find that there’s something that they have concerns about and they have alternatives, then it’s their decision to choose.
Q: In your personal life have you made those kind of decisions?
A: Let’s just say I’m a pragmatist and I do things that make sense to me.
Q: Like cutting back on canned food use and not microwaving in plastic containers?
A: I’ve never been a canned food user. I buy fresh vegetables as much as possible and I’ve done that for years. And I will say I stopped microwaving in plastic about 15 years ago, not because of concerns for BPA but just because of the lack of necessity to do that.
Q: Do you advocate our government following the precautionary principle?
A: I’m a believer in the precautionary principle. It doesn’t say that you act when you have no information, but you act in the presence of concerning information even if you don’t have certainty. Science is rarely 100 percent certain. So if you follow the precautionary principle, you look at all the evidence and you say maybe we don’t know everything, but there’s enough to suggest that we might want to be cautious. That’s the appropriate use of the precautionary principle.