Exposure to bisphenol A (BPA), the estrogen-mimicking chemical that has been at the center of controversy in recent months has now been found to alter brain function, impairing the ability to learn and remember, according to a new Canadian-United States study. The study was conducted on monkeys, whose brain development is similar to that of humans and points to the likelihood that disorders such as depression, Alzheimer’s disease, and schizophrenia may be linked to BPA.
As we have long been reporting, BPA is a ubiquitous and toxic plastic-hardening chemical found in many consumer products. Studies confirm BPA is chemically similar to diethylstilbestrol, a synthetic estrogen linked to the development of vaginal cancer in the daughters of women who took DES in the 1950-60s to prevent miscarriage. Most experts agree BPA disrupts the body’s hormonal system; scientists disagree over what dosage is harmful. Over six billion pounds of BPA are produced in the US annually by Dow Chemical, BASF, Bayer, and others and BPA is now found in the urine of about 93 percent of Americans, confirming that most people living in industrialized societies are exposed to BPA and that BPA is one of the highest volume synthetic chemicals. Despite this, the American Chemistry Council—a group which represents plastics manufacturers—“stressed that studies from animals provide ‘limited and inconclusive evidence,’” said the AP. That group has worked over the past year defending BPA over concerns about the chemical’s risks to children.
In this study, researchers from the University of Guelph in Ontario and Yale University in Connecticut, found low-level BPA exposure blocked formation of some types of brain synapses, which can impair remembering thoughts and experiences; such impairments are common in those with depression and brain-related ailments. The study represents a significant advance over previous rodent-based. “If bisphenol A at these kind of low doses is able to interfere with [monkey synapses] then there has to be concern that continuous exposure to bisphenol A is probably not a good thing,” said Neil MacLusky, a biomedical science professor at the University of Guelph and a study author.
The researchers found harmful effects were present with a daily dose of 50 micrograms per kilogram of body weight—the human-exposure limit considered safe by the U.S. Environmental Protection Agency (EPA); one microgram is one millionth of a gram. Health Canada’s limit is half that; Dr. MacLusky said standards in both countries are too lax and should be reduced, “If we’re getting a complete blockage of the effect” at the U.S. standard, then Canada’s standard “is probably not safe.” Steve Hentges, a spokesman for the American Chemistry Council, which represents BPA manufacturers and has long criticized the overwhelming evidence pointing to BPA’s growing list of hazards, criticized the study.
Last month, researchers at the University of Cincinnati linked BPA to heart attacks and adult onset diabetes. BPA suppresses the production in human fat tissue of a key hormone that protects people against such conditions. Also, the National Toxicology Program, part of the U.S. Department of Health and Human Services, just raised concerns BPA may be able to alter the prostate gland and the brain, and cause behavioral changes, particularly in during fetal development and childhood.
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