There’s been a lot of recent press regarding plastics and their possible effects on health. Many parents know about the 2007-8 recalls of baby bottles made of polycarbonate plastic Bisphenol A (BPA). This was mostly in response to newer studies, including a review in JAMA, showing an association (but not causation) between BPA exposure and increased risk in heart disease and diabetes, among other diseases. And the well-regarded editorialist Nicholas D. Kristof of the New York Times has published a couple columns bringing up this issue. He mostly focuses on a powerful position paper last year by the Endocrine Society which reviews the literature on “endocrine-disrupting chemicals”, which include plastics and other chemicals. Here’s a bit of their summary:

The evidence for adverse reproductive outcomes (infertility,
cancers, malformations) from exposure to endocrine disrupt-
ing chemicals is strong, and there is mounting evidence for
effects on other endocrine systems, including thyroid, neu-
roendocrine, obesity and metabolism, and insulin and glu-
cose homeostasis.

The chief concern is that these endocrine-disrupting chemicals may be a major cause of the worldwide increase in infertility, as well as contributing to cancers, diabetes, obesity and other diseases. And one very concerning suggestion is that damage can be done to a woman’s unborn child due to her exposure. The Endocrine Society does admit that as of yet the evidence isn’t conclusive, but is concerning enough to raise this issue. Kristof, in his articles, describes the issues well and also puts it in a personal manner, by asking a group of endocrinologists what they are personally doing:

I asked these doctors what they do in their own homes to reduce risks. They said that they avoid microwaving food in plastic or putting plastics in the dishwasher, because heat may cause chemicals to leach out. And the symposium handed out a reminder card listing “safer plastics” as those marked (usually at the bottom of a container) 1, 2, 4 or 5.

It suggests that the “plastics to avoid” are those numbered 3, 6 and 7 (unless they are also marked “BPA-free”). Yes, the evidence is uncertain, but my weekend project is to go through containers in our house and toss out 3’s, 6’s and 7’s.

Are we overreacting?

I must admit that after reading the Endocrine Society’s report, among other sources, that I am personally much more cautious now. Specifically, I’ve decided not to use any plastic containers at home and have now switched to Lock&Lock glass containers. I’m also extremely wary of microwaving any take-out plastic ware for leftovers; I am also very particular about getting good, reputable brands of plastic wrap (cling wrap), especially ones that say “PVC- or BPA free”. Other things people should consider:

• Don’t let your plastic cling wrap touch the surface of foods.
• Cover your dish in the microwave with a paper towel instead of cling wrap
• Try to avoid plastic numbers 3, 6, and 7
• Try to avoid canned foods, which usually have plastic linings

Are we being too hasty? Well, I think these suggestions certainly do no harm, which is doctor rule #1. And yes, I do feel there is enough evidence to be wary. This situation is a classic example of what public health experts call the precautionary principle:

The precautionary principle states that if an action or policy has suspected risk of causing harm to the public or to the environment, in the absence of a scientific consensus that harm would not ensue, the burden of proof falls on those who would advocate taking the action. Effectively, this principle allows policy makers to make discretionary decisions in situations where there is evidence of potential harm in the absence of complete scientific proof. The principle implies that there is a responsibility to intervene and protect the public from exposure to harm where scientific investigation discovers a plausible risk in the course of having screened for other suspected causes.

In fact, the Endocrine Society specifically mentions this principle as a major reason for publishing their statement:

In the absence of direct information regarding cause and effect, the precautionary principle is critical to enhancing reproductive and endocrine health. As endocrinologists, we suggest that The Endocrine Society actively engages in lobbying for regulation seeking todecrease human exposure to the many endocrine-disrupting agents. Scientific societies should also partner to pool their intellectual resources and to increase the ranks ofexperts with knowledge about EDCs who can communicate to other researchers, clinicians, community advocates, and politicians.