America's most demonized food-packaging chemical, nationally debated and being considered for a federal ban under an amendment of the food safety bill, S. 510, may be even worse than anyone imagined, a new peer-reviewed study finds. This chemical is bisphenol A (BPA), a compound found in plastic bottles, cans, containers, dental sealants, and even on receipts.
Research published on September 20 in Environmental Health Perspectives concludes that the potentially hazardous chemical can enter the human body via multiple routes and is far harder for our bodies to metabolize than previously believed. The new study examined both mice and rhesus monkeys, the latter selected because they are good predictors of how the human body absorbs this type of chemical. Eighteen hours after exposure, the monkeys' blood still contained active BPA—a finding that suggests we have "grossly underestimated current human exposure levels."
BPA is everywhere, with the CDC concluding that more than 90 percent of Americans are chronically exposed. Such pervasiveness is, in the words of one of the study's seven authors, Dr. Frederick vom Saal, "nothing short of insanity." The University of Missouri endocrinologist also does not hesitate to use the word "scary," comparing today's use of BPA to the use of lead in paint a century ago.
Despite national debates over whether BPA harms humans—debates mired in politics, marketing, and industry lobbying—vom Saal has no doubt of the chemical's risks.
The risks of plastic have defined much of his life for the last 13 years. In the late '90s, vom Saal and his colleagues in the University of Missouri's Endocrine Disruptor Group were the first to show BPA's possible danger. BPA acts like estrogen, something scientists have known since 1936, but no one knew its potential harm until 1997. Vom Saal and his fellow researchers discovered how the chemical warped the reproductive systems of mice, enlarging prostates and reducing sperm counts.
Those initial studies slowly caused an international furor, and the studies multiplied. Vom Saal published more than 30 papers on BPA himself, and he became a spokesman for the plastic's dangers, traveling across the country to testify before legislatures and talk to national media. This September, he won a Heinz Award, worth $100,000, for his contributions to the BPA debate.
The velocity of the debate sped up during the last two years. The National Toxicology Program found "some concern" with the chemical in September 2008 (PDF of the report here), a concern mirrored by the FDA this January 2010 and the EPA in March. The scientific progress has been "astounding," vom Saal says, and has helped usher in a new paradigm of toxicology, one that works with endocrinologists in entirely new ways. The "total disconnect" between toxicology and endocrinology was, vom Saal explains, how BPA was misclassified as safe. Animal studies have linked BPA to health problems including unusual brain chemistry, obesity, attention disorders, breast cancer, prostate cancer, and premature puberty. A 2008 cross-sectional study with 1,500 humans found a significant correlation between BPA levels in urine and heart disease.
Courtesy of the University of Missouri
The most recent study indicates that past rodent data may, in fact, be a compelling predictor of how BPA harms humans, now that the effects of BPA have also been observed in rhesus monkeys and shown to harmonize with prior data. If the study's conclusions are valid, then the effects of BPA may actually be far more serious than anything we feared in the past. It also removes another shred of doubt about BPA's safety in a debate conflicted with varying methodologies, a great deal of money, and heated emotions.
"At the NIH," vom Saal says, "you don't have debates about whether bisphenol A is causing harm. ... This is not a chemical you want floating around in your body at the levels you're seeing."
And why does a debate persist? Partly because we've yet to definitively prove that BPA harms humans. Several publications, including The New Yorker and The New York Times, have investigated the methodology of the research behind BPA in recent months. But vom Saal advocates the same precautionary principle that NYU nutritionist Marion Nestle supported last month on the Atlantic Food Channel. "If you set the bar at proof of harm to humans," vom Saal says, "you have failed to protect the public health." Vom Saal supports a green chemistry solution, blending the sensibilities of public health and chemistry to ensure any replacement for BPA is safe. He points to Japan, which successfully phased out BPA a decade ago with little trouble.
With 8 billion pounds of BPA produced annually, industry has had a profound impact on the debate, which has stalled the passage of the national food safety bill throughout 2010. Yet vom Saal seems certain that there will be a day of reckoning. The companies know the hazards, he believes, and eventually court cases will confirm this. We also need to know what products contain BPA, he says—information we currently lack.
"The American Chemistry Council is winning the battle with money," vom Saal says. "When you have that much money, our Congress doesn't work. They are throwing money around like drunks. And it's pocket change to them."
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