What do water bottles, food cans and paper money all have in common?
They all contain BPA, also known as bisphenol-A. A recent study done on rats by researchers at North Carolina State University shows that exposure to the chemical early in life can affect gene expression in the amygdala, an area of the brain known to process emotions. The study also showed that a diet rich in soy seems to mitigate the harmful effects of exposure to BPA.
About 93 percent of Americans have detectable levels of BPA in their bloodstreams. The chemical has been linked to behavior and brain alterations, alteration of infant prostate glands, breast cancer and early puberty in girls.
This particular study examined how exposure during gestation, lactation, and throughout puberty influenced the rats’ brains and behaviors. Subjects were divided into four groups, the first of which was fed only soy, the second a soy-free diet, the third fed only soy and exposed to BPA, and the fourth fed no soy and exposed to BPA.
The fourth group showed higher levels of anxiety than the others. Researchers think this was due to alterations in two genes, estrogen receptor beta and melanocortin receptor four. Both of these genes are involved in the release of oxytocin, a hormone that influences social behavior and bonding. Altered oxytocin release can cause abnormal social behavior.
The third group (rats exposed to BPA and fed with soy) did not show increased anxiety. Researchers aren’t certain how soy protects the developing brain, but they hope to find out with future research.
The study was lead by Dr. Heather Patisaul, NC State associate professor of biology, and was published in the journal PLOS ONE.
BPA is found in many products including food containers, water bottles and even epoxy resins; BPA can actually transfer from the containers to the food or drink inside. Rats and mice exposed to BPA in the study were found to have levels of the chemical comparable to what is commonly found in humans.
The study focused on the effects of BPA during early development, and did not provide information regarding the effects of a soy-rich diet in adulthood. Researchers are currently searching for ways that soy can be used to prevent and negate the effects of BPA, but consumers should practice common-sense safety and avoid products likely to contain the chemical. While not all products containing the chemical are marked, some manufacturers cater to health-conscious customers by labeling their products as BPA-free.