Bisphenol A (BPA), a controversial chemical used to make polycarbonate plastic and epoxy resins found in water bottles, cans and other food packaging, continues to add to its wrap sheet of health risks. Human studies have linked BPA with an increased risk of heart disease, asthma, kidney damage, and breast and prostate cancers.
The latest animal study finds that low-dose prenatal BPA exposure can have long-lasting effects on brain function and behavior in offspring.
Researchers treated pregnant female mice daily with various concentrations of BPA, including doses below the level considered “safe” for humans, looking at not only behavioral outcomes in male and female offspring, but also post-natal maternal care.
Most of the animal studies on BPA have been at exposure rates far higher than human exposure levels, so trying to get to real-world dosing was crucial to the study, says co-author Frances Champagne, PhD, an assistant professor in the department of psychology at Columbia University.
“Something is being laid down early in development to this in-utero exposure to bisphenol A. And it’s really becoming integrated into the way our DNA functions and is activated,” says Dr. Champagne; specifically, the process of DNA methylation, which alters the expression of genes in cells as they divide and differentiate themselves from stem cells into specific tissues. Some of the modifications that occur during DNA methylation become imprinted on our genes and therefore, inherited later.
It is during this process where exposure to BPA might have the most influence to future development. The study found at the lowest doses administered there was a profound effect on DNA methylation, gene expression, as well as anxiety-like behavior, but not at the highest dosages, as scientists expected. Consistent with other studies, the doses affected male and female offspring differently.
“We don’t know what the implications for the next generation are,” says Champagne. She acknowledges that studies like these, though adding to the body of knowledge, also add to the confusion of whether BPA has long-term effects and it doesn’t help that the FDA will not ban the chemical, citing insufficient evidence of harm.
“There’s a wealth of data on BPA that it is a toxic chemical,” says Frederica Perera, MPH, DrPH, professor of environmental health sciences at Columbia University, and a colleague of Champagne’s at the Columbia Center for Children’s Environmental Health. “There is a wide consensus, and public understanding, that this is a chemical to which exposure should be prevented.”
In her research on children, Dr. Perera has also found significant behavioral changes linked to prenatal BPA exposure. “The fetal brain is very susceptible to damage from chemicals that can disrupt the epigenetic programming. And we see this in this latest study,” says Perera.
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