It's in plastic baby bottles, water jugs, dental sealants, food packaging, canned goods, cell phones, CDs and DVDs, and countless other household products. In 2005 alone, manufacturers worldwide produced approximately 3.5 million tons of the industrial chemical Bisphenol A—primarily for use in manufacturing polycarbonate (PC) plastic and epoxy resins. Although past studies have shown conflicting results, and some have deemed the chemical safe, new research adds to the evidence that Bisphenol A, or BPA, may pose a significant health threat.

Conducted at the University of Cincinnati, the research concluded that even low doses and short exposure to BPA can inhibit brain development. Published in Endocrinology, this latest study measured BPA's effect on rats in stages of development equivalent to the third trimester through the first few years of human life (2005, vol. 146, no. 12). Experiments revealed that "surprisingly low" doses (0.23 parts per trillion) slowed neuron growth after only minutes of exposure. BPA acts as an artificial estrogen, potentially interfering with the hormone's normal role in developing neurons.

Previous studies have linked BPA to reproductive problems, developmental disorders, and increased breast and prostate cancer cell growth. "The presence of large quantities of [BPA] in the environment may not only have long-lasting effects on human health but may also impact the well-being of a diverse array of ecosystems," says Scott Belcher, PhD, an associate professor at UC College of Medicine and the study's lead author. Given estrogen's critical role in brain development, as well as in the normal functioning of adult brains, Belcher and his colleagues hope the findings will encourage regulatory agencies to reevaluate the chemical's use more seriously, especially in materials that come into contact with foods.