Whether its politics, religion, the environment, or health, extremists are likely to bend the facts to their own purposes. The issue of chemicals that disrupt human endocrine function is an emerging topic. BPA (Bisphenol A) has recently been in the limelight. It is used as a building block for plastics, as a coating in metal cans to prevent the metal from contact with food contents, as the plastic in food containers, refrigerator shelving, baby bottles, water bottles, returnable containers for juice, milk and water, micro-wave ovenware and eating utensils. A recent article in JAMA (Journal of the American Medical Association, September 17, 2008—Vol 300, No. 11 1303) relating to BPA and chronic diseases (including diabetes) raises concerns. The authors evaluated “BPA concentrations and health status in the general adult population of the United States, using data from the National Health and Nutrition Examination Survey 2003-2004. Participants were 1455 adults aged 18 through 74 years.” The results: “Higher urinary BPA concentrations were associated with cardiovascular diagnoses [heart disease and stroke]. Higher BPA concentrations were also associated with DIABETES.” Emphasis added.
How does BPA affect human biology? It is important to note at the outset that we are just scratching the surface on this subject. There are few human studies in this regard and none to relate specifically to BPA definitely causing human disease. On the one extreme one can read the industry position sponsored by the American Chemistry Council, PlasticsEurope, and the Japan Chemical Industry Association (http://www.bisphenol-a.org/) or the environmentalists view at http://www.ourstolenfuture.org/NewScience/oncompounds/bisphenola/bpauses.htm. Bisphenol A is a wide spread chemical used in polycarbonate and polyvinyl chloride plastics and epoxy resins and found in the urine of > 90% of Americans. According to an editorial in the issue of JAMA mentioned above, BPA mimics estrogen in lab animals. It stimulates the release of insulin and increases insulin resistance. “BPA and estradiol have equal potency and efficacy. BPA and estradiol are also equipotent at inhibiting adiponectin release from human adipocytes at 1 nM, further implicating BPA at current human exposure levels in insulin resistance and the metabolic syndrome.” These parameters are known defects in type 2 diabetes. Again, there is no evidence that this occurs in humans. Those old enough to remember the lung cancer/tobacco debates will recall similar positions.
Is there real reason for concern? I think so. The Endocrine Society issued the following statement: “In this first Scientific Statement of The Endocrine Society, we present the evidence that endocrine disruptors [e.g. BPA] have effects on male and female reproduction, breast development and cancer, prostate cancer, neuroendocrinology, thyroid, metabolism and obesity, and cardiovascular endocrinology.”
What is one to do? It a good policy to avoid as much BPA as possible. However, one cannot completely avoid it, without living in a bubble, also plastic. BPA is everywhere, including some paper used in credit card receipts. Some firm plastic containers contain BPA. One should certainly avoid reusable water bottles unless certified BPA free. Plastics possibly containing BPA can be identified by the recycling codes, types 1 through 7. According to Wikipedia some type 7 plastics are made from BPA. Type 3 (PVC) may contain BPA.
Types 1 (PET), 2 (HDPE), 4 (LDPE), 5 (polypropylene), and 6 (polystyrene) do not use bisphenol A [BPA] during polymerization or package forming.
My Dasani® water bottle being used as I write this has the symbolPETE
Charles H. Raine, III, M.D.
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