Consumers are becoming less and less tolerant of products containing a harmful chemical known as bisphenol-A (or BPA). But a new study suggests that replacement chemicals—like bisphenol-S (or BPS)—may be just as bad.
While most BPA studies highlight the effect of the chemical on animals, a handful of researchers are starting to explore its consequence for human health. In 2013, the FDA banned BPA use in plastic baby bottles and sippy cups out of concern that in medium to high doses, it could result in children’s developmental issues. More recently, a study showed that BPA (which mimics estrogen) may even interfere with women’s hormone production, egg production, and egg viability. BPA is found in polycarbonate plastics, which are often used in food storage containers like cans, water bottles, and even cash register receipts. As a result, BPA-free labels are becoming more common, as are BPA substitutes like BPS.
Now, a study published in the journal Environmental Health Perspectives reports that BPS caused irregular heartbeats in female lab rats (but not in male rats)—a finding that’s extremely similar to what scientists saw when they subjected BPA to female rats. The researchers concluded that both BPA and BPS disrupt proper calcium storage in heart muscle cells, making it difficult for the heart to beat normally.
Here’s Brian Clark Howard, writing for National Geographic:
The scientists removed the rats’ hearts and kept them alive and beating for some time by running a solution through them that contains oxygen, glucose, and other nutrients. Then they added BPS and monitored the effect on cells. This technique is commonly used to measure the impact of various chemicals on the heart.
Wang said the rats were exposed to doses that may be similar to the amounts that people encounter from water bottles, receipts, and other items. However, very little is known about human exposures; much more is known about BPA, which is found in the blood of virtually every person tested.
While we can’t know for sure yet BPS’s effect on humans, it’s clear that BPS is structurally similar to BPA—so it would probably have a handful of the same health impacts. In addition, other animals like zebrafish demonstrate a negative response to BPS. It may be only a matter of time until BPS-free labels begin appearing on more than just some brands of water bottles, which currently sport the disclaimer. In the near future, scientists may need to examine chemicals with similar structures to see if those need to be eliminated from products, as well.