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Bisphenol A (BPA) is a component used in clear polycarbonate plastics to make them unbreakable and shatter-proof, and in epoxy resins, liners of food cans, dental sealants, and many other household products. Some,like nursing bottles and sippy cups, are intended for use by infants and children. Plastic containers with BPA are very hard and inflexible, and often have the recycle code “7” on the bottom.
There is a big controversy about BPA in the press, in the public, and in the scientific community. BPA acts as an endocrine disruptor and has affected male reproductive development in laboratory studies using cultured cells and rodents at exceedingly small doses. Endocrine disruptors can have a feminizing effect at low doses on male wildlife species, such as making genetically male fish look female. BPA has also induced cancer in laboratory animals given higher doses2. Its effects on humans, however, are much more uncertain. The source of the controversy about BPA is whether or not it can have these and possibly other effects in levels found in humans. A recent study has implicated BPA in heart disease and diabetes3. In the most recent study by the National Health and Nutrition Examination Survey, over 96% of Americans carry some BPA in their bodies; with the highest levels of all in children.4 Levels can be almost as high as those causing effects in wildlife and comparable to the levels showing effects in laboratories5. More epidemiological studies need to be done on possible effects of BPA before firm conclusions can be drawn about its risks for humans. The U.S. National Toxicology Program issued a report on BPA in April, 2008, in which it expressed “…some concern for effects on the brain, behavior, and prostate gland in fetuses, infants, and children at current human exposures to bisphenol A.6” This concern was based on results in animal studies and the near-ubiquitous presence of BPA in our bodies. The U.S. Food and Drug Administration has been under heavy fire from scientists and the public alike for recently giving BPA a clean bill of health in spite of the NTP’s report. 7 Some states are now in the process of asking manufacturers to remove BPA from their products voluntarily. In response to this scrutiny and as part of its normal review process, the FDA is now re-considering its position on BPA8. Remember, “safety” is a relative term. One dose that may be safe in one individual or population could be harmful in another, due to gene-environment-host interactions. This is one of the basic precepts of the science of toxicology: “The dose makes the poison.” When government agencies establish standards for safe exposure to agents in the air, water, or food, these standards may not protect every individual from harm. Regardless of whether or not low doses of BPA may be harmful to adults and children, it is always wise to avoid unnecessary exposures to any potentially harmful substance. Do not drink out of plastic bottles that have been left in a car where they may get over-heated and leach BPA and other substances from the plastic into the liquid. Do not microwave food in containers with BPA. Read consumer information and the labels of containers before you buy to make informed decisions. Many Web sites and blogs keep track of which products do and do not contain BPA, so be sure to do your homework if you are concerned about BPA. So…is BPA safe or not? Err, the jury is still out. Stay tuned…
UPDATE (10/20/08): The Milwaukee Journal Sentinel reports that the Canadian government will ban the use of BPA in baby bottles. For more, read the story here.
----Some of the information in this article was taken from “HEALTH:
1. Welshons WV, Nagel SC, vom Saal FS. Large effects from small exposures. III. Endocrine mechanisms mediating effects of bisphenol A at levels of human exposure. Endocrinology. 2006 Jun;147(6 Suppl):S56-69. Epub 2006 May 11.
2. Richter CA, Birnbaum LS, Farabollini F, Newbold RR, Rubin BS, Talsness CE, Vandenbergh JG, Walser-Kuntz DR, vom Saal FS. In vivo effects of bisphenol A in laboratory rodent studies. Reprod Toxicol. 2007 Aug-Sep;24(2):199-224. Epub 2007 Jun 26.
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4. Calafat AM, Ye X, Wong LY, Reidy JA, Needham LL. Exposure of the U.S. Population to Bisphenol A and 4-tertiary-Octylphenol: 2003-2004. Environ Health Perspect 2008 Jan;116(1):39-44. 5. Vandenberg, LN, Hauser R, Marcus M, Olea N,
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9. Smith, Larry. “HEALTH:
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