Saturday, June 30, 2012

Bisphenol A

Published in the Sun June 30, 2012


Wouldn’t it be great if experts could agree on which toxic chemicals don’t belong in our food supply?  Instead, one group of environmental scientists will warn that a certain chemical is turning all the little boy fishes into little girl fishes, and then another group of scientists, usually the ones paid by the makers of the maligned chemical, claim that it is safe enough to put into baby bottles.  The federal government will eventually wade into the controversy, form a huge committee, and proclaim that more studies are needed.



I am referring specifically to bisphenol-A (BPA), widely used these days in hard plastics and epoxy resins.  Ninety-three percent of Americans have measurable BPA in their urine, according to a study by the Centers for Disease Control.  Although our bodies can get rid of BPA if the exposure stops, we are constantly re-exposed.  Our main exposure comes from the epoxy resin used to line the majority of food and beverage cans.   Tiny quantities of BPA leach into our vegetable soup or canned green beans or whatever we threw on the stove for a 5-minute supper, so the more canned food you eat, the more BPA you get.



We are also exposed to BPA by drinking from polycarbonate bottles, the hard plastic ones that usually have a number 7 on the bottom.  A study of Harvard students found that students who drank most of their beverages from polycarbonate bottles for one week increased the level of BPA in their urine by 69%.  In the past, baby bottles were made with BPA, which is especially hazardous because parents tend to warm bottles in the microwave.  Heat dramatically increases the amount of BPA that migrates into the milk or formula.



Nobody disputes that we are exposed to BPA.  The question is, “Does it matter?”  The dose makes the poison, and the quantities in our bodies are very small, far lower than the level the EPA says is safe for a chronic exposure.  However, there are researchers who believe the EPA is looking at the wrong endpoints.  BPA is an endocrine disruptor; meaning that tiny quantities could have important hormonal effects on sensitive cells, especially in a fetus or newborn baby.



BPA was first used as a pharmaceutical agent in the 1930s to promote growth in cattle and poultry, and later as a synthetic hormone in pregnant women.  It was eventually abandoned as a drug and taken over by the plastics industry as a hardener for clear plastic.



In 1989 Dr. Ana Soto at Tufts University School of Medicine found that her experiments exposing cells to hormones went haywire when her test tube company started providing her with new impact-resistant test tubes.  Sure enough, the new tubes contained a plastic hardener similar to BPA that was causing her experimental cells to act as if they were being exposed to estrogen, a female sex hormone.  This discovery led Dr. Soto to begin animal experiments with several plastic additives, including BPA.  She discovered that at doses comparable to what people receive in their daily lives, BPA could cause reproductive effects, obesity, behavioral changes, and breast cancer in animals.



Over the following 20 years many trees were cut down to publish the scientific papers linking tiny doses of BPA to hormone-related disorders such as abnormal sperm development, heart disease, prostate cancer, diabetes, and even obesity.  Not too surprisingly the plastic industry vigorously maintains that BPA is safe at the levels to which we are exposed.



Despite the controversy, the European Union, Canada, France, Denmark, Malaysia, Turkey, United Arab Emirates, and China have all banned BPA from being used in baby bottles, reasoning that while the experts continue to argue, it is better to be safe than sorry.



The US Food and Drug Administration, on their website devoted to BPA, states unequivocally that they are “pursuing additional studies.”  They concede that since infants may be a sensitive population for BPA, they are “supporting the industry’s actions to stop producing BPA-containing bottles and infant feeding cups for the US market” and “facilitating the development of alternatives to BPA for the linings of infant formula cans.”  In other words, if consumers want plastics without BPA, we should stop buying BPA plastics.  That would be a fine strategy if the majority of consumers were well-informed about BPA, but endocrine disruption is not high on the worry list for most people.  Dr. David Ramsey, a Georgetown pediatrician, says that he has never, ever had a parent bring up the topic of BPA in baby bottles.



If you go shopping, you may find some products or canned goods that say “BPA-Free”, but you won’t find any that say “This product contains BPA” because what company would put that on your canned food or plastic cup if they don’t have to?  In 2009, Walmart voluntarily stopped selling baby bottles made with BPA.  Jen Sherwood, an assistant manager at the Georgetown Walmart, also showed me the Cool Gear BPA-Free plastic water bottles for adults which come in a wild assortment of styles and colors.  She has three of them herself.  Isn’t it interesting that Walmart would be more concerned with consumer protection than the FDA?



I asked Dr. Joshua Long, Environmental Studies professor at Southwestern, for his opinion on the controversy surrounding BPA.  He thinks there is enough evidence from animal testing to support the toxicity of BPA.  He personally avoids BPA and avoids giving it to his family.



If you want to take a few prudent steps to cut down your BPA exposure, here are some suggestions.



1.  Limit canned foods unless the cans are BPA-free.  Use frozen or fresh.



2.  Use glass and ceramic dishes for storing (and microwaving) food.



3.  Don’t put plastics in the microwave.  Even if containers are “safe” for the microwave, hot liquids dramatically increase leaching of BPA (and other chemicals) into your food.



4.  Throw away your polycarbonate water bottles (marked #7) and get some reusable metal bottles that don’t have a BPA lining.  Or just drink out of a glass.


                                          Items from my kitchen that probably contain BPA

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