The chemical bisphenol-A, or BPA, has seized the attention of parents amid growing concerns and conflicting reports about the possible health effects of the widely used substance. The discussion has become even more heated in recent months as the National Toxicology Program, the Food and Drug Administration, and the Journal of the American Medical Association all presented new reports on the safety of BPA.
What It Is
Found in polycarbonate plastics, BPA is a synthetic estrogen used in the manufacture of most shatterproof baby bottles, sports bottles, toys, dental sealants, food cans, and microwaveable food containers. The Centers for Disease Control and Prevention say that about 93 percent of Americans have traces of bisphenol-A in their urine.
Possible Dangers
Scientists have warned of the possible harm of low doses of BPA since the late 1980s, but the first major study from an academic lab didn't come until 1997, when research done on mice found that low-level exposure to the chemical was detrimental to prostate health. Later that year, FDA tests revealed that 12 of 14 samples of liquid infant formula were contaminated with BPA, which had leached from can linings made with BPA. The Consumers Union reported that BPA leached from baby bottles when the bottles were boiled. In the past decade, nearly 100 studies, reports, and assessments from various federal agencies and independent scientists linked low exposure of BPA to prostate and breast cancer, reproductive health problems, neural and behavioral disorders, and early puberty.
Despite growing concern from the scientific community, the FDA maintained that its regulations for BPA concentration and use in food containers were adequate.
Flawed Findings
Such studies prompted the National Institutes of Health to recommend in 2003 that BPA be evaluated by the Center for the Evaluation of Risk to Human Reproduction, but by early 2007 the assessment unraveled under criticism about a conflict of interest between the contractors who conducted the evaluation and the BPA manufacturers.
In early 2008, the FDA revealed that another 2007 safety evaluation was based on two industry studies sponsored by the American Plastics Council. The scientific community expressed concern over design flaws in the first study; the second was never published in a peer-reviewed journal.
Further Study
An April 2008 report from the National Toxicology Program stated that there was "some concern" about the effects of BPA on infant health, which prompted Congress to ask that the FDA revisit their evaluation.
In mid-August, FDA scientists released their preliminary-draft reevaluation, again declaring BPA safe for use in plastic food containers. Then, in a September public hearing before a panel of six scientists appointed by the FDA, the agency again defended its position. "A margin of safety exists that is adequate to protect consumers, including infants and children, at the current levels of exposure," Laura Tarantino, head of the FDA's Office of Food Additive Safety, told the panel.
The same day, JAMA had published a report that tentatively linked BPA exposure to heart disease and diabetes. The study, based on a survey of 1,455 American adults, concluded that those with higher levels of BPA in their urine were also more likely to report that they had had heart disease or diabetes. The researchers from Britain and the University of Iowa tempered the findings, saying that their approach "may have resulted in false-positive associations" and suggested that the study be independently replicated.
Next Steps
On October 31, the FDA's Science Board is scheduled to hear conclusions from two members who reviewed the draft risk assessment. California and several other states are considering legislation and increased regulatory action to ban the chemical in baby bottles and food containers.
Meanwhile, in April Canada became the first country to move to ban BPA from use in baby bottles. Health Canada said that their assessment shows that in most instances negative health effects occur at levels much greater than those to which adults are generally exposed. However, concern over BPA-exposure for newborns and infants prompted the ban. "We have concluded that early development is sensitive to the effects of bisphenol A. Although our science tells us that exposure levels to newborns and infants are below levels that cause effects, we believe the current safety margin need to be higher," Tony Clement, the minister of health, said in a statement.
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