UPDATE, February 16, 2013: Elizabeth Grossman, reporting for Environment Health News, posted today the debate among scientists over the question "Do low doses of BPA really harm people?" Her report was based on yesterday's presentation of leading toxicologists who presented their arguments at the American Association for the Advancement of Science annual meeting in Boston.
This debate, while arcane, is important because the scientific information is being used by the U.S. Environmental Protection Agency and Food and Drug Administration in deciding whether to regulate BPA in consumer products, such as canned foods. Reacting to consumer concerns, some manufacturers already have stopped using BPA in plastic baby bottles, receipts and other items....Speaking on the cautionary side, among others, was Univ. of Massachusetts Amherst biology professor R. Thomas Zoeller, above, (endocrine research focusing on BPA effects on the thyroid), who noted that the toxicological modeling is not designed to examine effects of chronic, low-dose exposure to an endocrine-disrupting chemical like BPA. Historically, these models have looked at specific cancers or fully manifested diseases. In contrast, BPA appears to produce health effects that set the stage for diseases often diagnosed many years after exposure.
“Chronic disease in human populations is not something traditional toxicology is designed to handle. It doesn’t look for risk factors,” Zoeller said.
October 5, 2012: Tia Ghose, writing for California Watch, reports:
A new UC San Diego study suggests that the byproducts of a chemical used in plastic found in the lining of cans may disrupt human hormone function more than the chemical itself.
The study, published today in PLOS ONE, may help explain why the chemical bisphenol A, or BPA, has been tied to many health problems even though the chemical doesn’t have a strong effect on cells in a Petri dish.
“We have a candidate chemical that is doing the nasty stuff, or the endocrine disruption," said study co-author and UCSD structural biologist Michael E. Baker, at left. "We know that BP analyzing the chemical that’s really doing the endocrine disruption." ...in 2003, a Japanese research team found that the body breaks down BPA into another chemical: 4-methyl-2,4-bis(p-hydroxyphenyl)pent-1-ene, called MBP for short. MBP was 500 times more powerful at mimicking estrogen than BPA.