Is BPA-free plastic safe? New findings with mice suggest the alternative chemical BPS could be just as harmful.
For decades, scientists have studied BPA extensively in animal models with results indicating the chemical plays a role in early pregnancy loss, placental diseases, and various negative health outcomes after birth. As these adverse health effects have become more widely known, companies have turned to using alternative chemicals to develop plastic products—namely water bottles and food containers—and often labeling them “BPA-free.”
These chemical alternatives, such as bisphenol S (BPS), still aren’t safe for people to use, warns University of Missouri scientist Cheryl Rosenfeld.
The findings, published in the Proceedings of the National Academy of Sciences, show that BPS passes from mother to offspring.
BPA-free plastic can mean BPS
In the study, Rosenfeld and her colleagues focused on the effects of BPS on a mouse’s placenta. The placenta serves as a historical record of what an unborn child faces while in the womb, she explains. It can also can transfer whatever the mother might be exposed to in her blood, such as harmful chemicals, into the developing child.
“Synthetic chemicals like BPS can penetrate through the maternal placenta, so whatever is circulating in the mother’s blood can easily be transferred to the developing child,” says Rosenfeld, a professor of biomedical sciences in the College of Veterinary Medicine, investigator in the Bond Life Sciences Center, and research faculty member for the Thompson Center for Autism and Neurobehavioral Disorders.
“This mouse model is the best model we have now to simulate the possible effects of BPS during human pregnancy, because the placenta has a similar structure in both mice and humans.”
Serotonin and fetal brains
The placenta serves as a primary source of serotonin for fetal brain development in both mice and humans, adds Rosenfeld. Serotonin, while commonly associated with the feeling of happiness, is a natural chemical that can affect a person’s functions, including their emotions and physical activities such as sleeping, eating, and digesting food.
“The placenta responds to both natural chemicals as well as synthetic chemicals that the body misinterprets as natural chemicals, but the body doesn’t have the ability to mitigate the detrimental effects of such industrial-made chemicals,” Rosenfeld says. “More importantly, these chemicals have the ability to lower the placenta’s serotonin production. Lower levels of serotonin can compromise fetal brain development because during this critical time in development the brain relies on the placenta to produce serotonin. Thus, developmental exposure to BPA or even its substitute, BPS, can lead to longstanding health consequences.”
Rosenfeld’s research is an example of an early step in translational medicine, or research that aims to improve human health by determining the relevance of animal science discoveries to people.