BPA (bisphenol-A), is and estrogen-like chemical compound that is widely used (3 million tons annually) in the production of plastic food containers, the resins that line food cans, dental sealants, baby bottles, and toys.
The highest levels of the chemical were found in cans of peas. It has also been food in the liquid contained in cans of beans, artichokes, mixed vegetables, corn, and mushrooms.
Research has now repeatedly shown that BPA leaches out of products and may be absorbed into the body at low concentrations. Those low doses, however, appear to be sufficient to pose numerous (quite serious) health risks as a result of multiple animal studies published this year.
In addition more than 100 studies published in peer-reviewed journals have shown the detrimental effects of BPA. The most recent ones have been as follows:
January 2005 – BPA Shown to Increase the Growth of Prostate Cancer Cells:
A study conducted by a research team at University of Cincinnati and published in the January 2005 issue of the journal Cancer Research reported that BPA increased the growth of some prostate cancer cells.
May 2005 – Researchers Find Link between BPA and Breast Cancer:
An animal study suggests that even at extremely low concentrations, BPA exposure in the womb may be harmful. Moreover, the study uncovered evidence that BPA may be a breast cancer risk factor because of its potential effect on the development of vulnerable and sensitive breast tissue.
June 2005 – Japanese Study Links BPA to Recurrent Miscarriages:
BPA (already implicated as a possible cause of breast cancer) was linked to recurrent miscarriages in a study at Nagoya City University Medical School published in Human Reproduction Magazine.
The researchers, led by Dr. Mayumi Sugiura-Ogasawara of the OBGYN department, examined 77 women. Of that group, 45 had suffered three or more consecutive miscarriages and 32 had a history of successful pregnancies.
The women in the miscarriage group were found to have average BPA levels approximately three times higher than those who had not miscarried. Because of the small size of the study, further research is needed into the precise nature of the effect BPA has on human reproduction.
December 2005 BPA Found to Disrupt Brain Development
A University of Cincinnati (UC) research team, now reports in two articles in the December edition of the journal Endocrinology that BPA shows negative effects in brain tissue "at surprisingly low doses." Although best known for its function as a female sex hormone, estrogen also has very important roles in the developing brain of both males and females.
According to team leader, Dr. Scott Belcher: "These new studies are also the first to show that estrogen’s rapid signaling mechanisms are active in the developing and maturing brain in regions not thought to be involved with sexual differences or reproductive functions."
Dr. Belcher is an associate professor in the pharmacology and cell biophysics department at UC College of Medicine. He stated that: "BPA molecules are linked into polymers used to create polycarbonate plastics and epoxy resins that are widely used in many products. While plastics are typically thought of as being stable, scientists have known for many years that the chemical linkage between BPA molecules was unstable, and that BPA leaches into food or beverages in contact with the plastics."
This most recent study utilized rats at a period in their development equivalent to the third trimester of human fetal development through to the first few years of childhood.
In the absence of estrogen, BPA alone was found to mimic the actions of estrogen in developing neurons. Very low doses of BPA completely inhibited the activity of estrogen.
Since estrogen normally increases the growth of neurons and regulates their viability during development, these results support the theory that BPA may harm developing brain cells.
The most startling and disturbing finding, however, was that near-maximal effects of BPA on rat brain neurons occurred "at surprisingly low" doses of only 0.23 parts per trillion and happened in a matter of minutes.
These low-dose results indicate that BPA may be inflicting maximal damage at levels found in developing fetuses and typical human exposure thereby raising the possibility that detection is being missed by standard approaches used in measuring chemical exposure.
According to Dr. Belcher: "Estrogen’s actions on these neurons appear to be a double-edged sword. During certain periods of development estrogen can kill specific subsets of neurons, but at a later developmental stage it actually appears to increase their viability."
Any disruption of either of these actions of estrogen could be considered potentially harmful, Dr. Belcher added. "We have now shown that environmental estrogens like BPA appear to alter, in a very complicated fashion, the normal way estrogen communicates with immature nerve cells. The developmental effects that we studied are known to be important for brain development and also for normal function of the adult brain."
Despite the fact that plastics free of BPA and other toxic chemicals are already available, the chemical industry and every federal agency charged with regulating such compounds have resisted all efforts to have BPA banned.