Endocrine Disruptors Everywhere

“Does not contain” has become a prime advertising slogan.  “No cholesterol.”  “No saturated fat.”  “No sugar.”  “No salt.”  “No nitrites.”  “No MSG.”  “No GMOs.”  And the ultimately absurd, “no chemicals.”  Within the last few years another “no” has joined the alliance.  “No BPA.”  Most people would be hard pressed to identify what the letters stand for, but they are likely to have heard enough about this substance to conclude that they don’t want in their food or in their water and certainly not in their body.  BPA stands for Bisphenol A, a chemical used to formulate polycarbonate plastics, epoxy glues, the resins that line the inside of food cans as well as the white dental fillings that are increasingly replacing amalgam. 

BPA has long been mired in controversy because of its hormone-like effects.  Although it is rapidly eliminated in the urine, the trace amounts that circulate in the bloodstream have raised concern because such levels have been linked with developmental problems, obesity and disease in test animals.  Although regulatory agencies around the world agree that the amounts to which we are exposed are unlikely to cause any significant effect, the precautionary principle suggests that we should err on the side of caution and take whatever measures are needed to minimize exposure to “environmental estrogens.”  It isn’t surprising then that plastic items that feature the “no BPA” catchphrase have become hot sellers.  There are even movements afoot to ban BPA totally, a totally unrealistic goal.  The perception is that ridding our life of this chemical will decrease the risk of obesity, heart disease, cancer and almost any other ailment one can think of.  This is a very simple-minded view, as demonstrated by a study recently reported in the peer-reviewed journal, Environmental Health Perspectives.  The paper has the startling title “Most Plastic Products Release Estrogenic Chemicals,” but it does come with a soothing subtitle, “A Potential Health Problem That Can Be Solved.”

Most of the interest, at least as far as the public is concerned, has focused on BPA leaching out of polycarbonate food or beverage containers.  This is reasonable, given that BPA is one of the building blocks of the polymer that makes up this plastic.  But plastics are actually complex mixtures that are formulated with a variety of antioxidants, dyes, ultraviolet light absorbers, clarifying agents and chemicals that allow easy release from the molds that are used to give the plastic its final form in addition to their main polymer component.  The authors of the afore mentioned publication wondered if some of these additives might have estrogenic effects and accordingly decided to test a large array of plastics using a standard assay for estrogenic activity.  The test involves exposing a type of cancer cell, known as the MCH-7 cell, to the chemical in question, and comparing the rate of multiplication of the cells to that produced by exposure to beta-estradiol, the body’s naturally occurring estrogen.  The results were unexpected. 

Practically all commercial plastics leached chemicals that had detectable estrogenic activity, and most surprisingly, some BPA free products showed greater estrogen activity than BPA-containing products!  Obviously the portrayal of BPA as a chemical fiend that has to be expunged from the face of the earth is misguided.  Estrogen-like chemicals are everywhere.  And, not only in plastics.  Soy, flax, sesame seeds, peanuts, meat and dairy all have compounds that give a positive reaction in tests for estrogens.  We cannot eliminate exposure to such substances, and there is no reason to be neurotic about exposure to them. 

As mentioned, the testing revealed that most plastics released some components with estrogenic activity, but it was also clear that not all did.  This allowed the researchers to identify and publicize which plastics released chemicals with estrogenic activity and which did not.  The study highlighted the possibility of producing plastics unencumbered by the baggage of endocrine disruptors.  It is, however, pertinent to point out that four of the five researchers who carried out the study work either for CertiChem Inc, the company that tests chemicals for estrogenic activity, or for PlastiPure, a company that specializes in plastics that are guaranteed to be free of such activity.  This of course does not invalidate the results, but does raise the question of whether the putative negative effects of bisphenol A are being overemphasized in order to boost sales of plastics approved by PlastiPure.  There is no question, though, that the data sheds new light on our exposure to estrogenic compounds and points out the folly of blaming one specific compound for the ills of society.

It is useful to know that plastics can be formulated without the concern of leaching estrogenic compounds.  As it turns out, polyethylene, polypropylene and their copolymers don’t release estrogens, but unlike polycarbonate, cannot be formulated into a clear, hard plastic.  However, a relatively new plastic made with “cyclic olefin copolymer” can be used instead of polycarbonate.  I expect that soon we will be seeing a new claim on labels.  “Contains no chemicals with estrogen activity.”  Will it make a difference to our health?  Very doubtful.  Will it make a difference to the bottom line of PlastiPure?  Probably.

Print | posted on Friday, February 24, 2012 6:36 PM

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