Bisphenol-A (BPA)

Fifteen years ago, toxicologists would have scoffed because the resulting exposures are so low.  Now thousands of scientists around the world are studying the impact of exposure to man-made sex hormones that leach out of everyday household products and toys. 

Humans are exposed to bisphenol-A (BPA), an estrogenic compound that leaches from dental materials and plastic food and beverage containers.  Baby bottles made of polycarbonate plastic can release traces of BPA into liquids they contain.

 A 1995 study found that the liquid in some cans of tinned vegetables have been found to contain both BPA and the related chemical dimethyl.   A chemical that leaches out of plastic baby and sports bottles and from the lining of tin cans is a serious threat to human health. 

BPA has been shown to have developmental toxicity, carcinogenic effects, and possible neurotoxicity.  Just one to three servings of foods with concentrations of these could expose a woman or child to BPA at levels that caused serious adverse effects in animal tests.

The potential for BPA to cause birth defects and reproductive harm is being evaluated by a federal advisory panel at the Center for Evaluation of Risks to Human Reproduction, a division of the National Institutes of Health. 

Low doses of BPA lead to a range of health problems.  Despite the growing evidence of risk to human health, there are no limits on the amount of BPA allowed in canned food.

In animal experiments, university scientists have now linked early bisphenol A exposure not only to prostate cancer and breast cancer in adulthood, but also  to attention disorders, changes in behavior, elimination of brain differences between males and females, disruption of insulin regulation (which leads to diabetes) and an increase in body weight, chromosomal damage in the eggs of female babies (which usually means their embryos are miscarried), reduced sperm count and infertility. 

Several studies have linked BPA to the chemical altering of the mammary glands of female mice.  They grow in a way that makes them more likely to develop breast cancer and also to respond unusually to estrogen. 

When a prostate gland is developing in the male fetus, it is very sensitive to estrogen, and scientists have theorized that prostate cancer incidence may be increasing because of exposure to the xeno-estrogens before they are born.  They discovered that exposure to the chemical caused a permanent alteration of the gene structure in the prostate cells. 

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