A couple of new studies warrant serious consideration by the federal government. They support a growing body of research that shows risks to human health from bisphenol A (BPA), a common ingredient in many plastic bottles and tin cans.
Back in June, I discussed how environmental toxins -- like BPA -- may be changing our epigenome and what that can mean for our health. And in a video post on sustainable food shopping I pointed out some foodstuffs you might avoid if you are concerned about BPA. You may recall from those posts that BPA is a component of polycarbonate plastic that shows up in many household products such as the lining in food tins and rigid plastics like those used in water bottles. If you use these products, you almost certainly have ingested some BPA.
There are now a host of studies that suggest that there is a link between BPA and human disease. As a result of this body of work, the National Toxicology Program (which is part of the National Institutes of Health) issued a synthesis report indicating "'some concern' for effects on development of the prostate gland and brain and for behavioral effects in fetuses, infants, and children." But a direct cause and effect has yet to be shown in any of these studies. That, at least in part, is why a draft report [pdf] by the Food and Drug Administration (FDA) published last month concluded that BPA doesn't pose a risk at the levels to which people are exposed to every day, and why the FDA has not yet regulated its use. By comparison the European Union's equivalent to our FDA has established a tolerable daily intake (TDI) rate for BPA.
Nevertheless, for many of us the results of the studies suggesting a link are worrisome, and the two new studies don't provide any reassurance.
One study published in the Journal of the American Medical Association (JAMA) found that Americans with elevated levels of BPA had higher rates of heart disease and diabetes. This is the first, large, population-based study to examine the effects of BPA in our everyday lives.
The other study reported in Proceedings of the National Academy of Sciences (PNAS) is the first to show BPA having an adverse effect on nonhuman primate brains. Here BPA was found to negatively affect mood and brain function at levels deemed safe by EPA.
What is different about these studies when compared to previous work is that they both looked at the impacts of low doses of BPA or those considered safe by EPA. Critics argue that the statistical association between BPA and disease cited in the JAMA study still does not establish a cause-and-effect link, and the PNAS study used primates and therefore may not apply to humans. These criticisms are technically correct, but should not in my opinion prevent the FDA from seriously reconsidering the conclusion of its draft report and its regulatory stance on BPA.
Dr. Bill Chameides is a member of the National Academy of Sciences and the dean of Duke University's Nicholas School of the Environment. He blogs regularly at www.thegreengrok.com.