The Green Living Guy

While the U.S. Food and Drug Administration notes “some concern” with the controversial chemical BPA. Also many other countries, such as Japan and Canada. For they have considered BPA product bans. Even disagreement exists amongst scientists in this field. All on the effects of BPA in animals and humans.

As I’ve written before about BPA:

BPA is a synthetic, hormone-disrupting chemical used in the linings of beer and soda cans, vegetable and soup cans and in other products such as reusable plastic water bottles.

NRDC in 2008 petitioned the FDA to eliminate BPA from all food packaging. When the agency failed to respond, NRDC sued in 2011, asking the U.S. District Court for the Southern District of New York to compel the agency to respond. Later that year, the court issued a consent decree requiring FDA to make a final decision on NRDC’s petition by March 31, 2012.

Deer nice BPA
Seney Natural History Association • CC BY-SA 2.0

FDA Even Agrees about BPA

So the FDA acknowledged in 2010. All that it had “some concerns” about the chemical’s effects on the brain, behavior and prostate glands. That’s also in fetuses, infants and young children. But the agency only encouraged “voluntary actions” to reduce BPA exposure.

Since that time numerous studies have raised additional concerns about links between BPA and breast cancer, cardiovascular disease, diabetes and obesity.


The latest research from the University of Missouri shows worse. For it shows that BPA causes male deer mice to become demasculinized. Also to behave moreover like females. Especially in their spatial navigational abilities. All leading scientists to conclude that exposure to BPA during human development could be damaging. Especially to behavioral and cognitive traits. Some that are unique to each sex. Moreover important in reproduction.

Cheryl Rosenfeld, associate professor in biomedical sciences and Bond Life Sciences investigator, found BPA-exposed male deer mice are demasculinized and undesirable to females.

BPA in deer mice

Photo by Jared Belson

The BPA-exposed deer mice in our study look normal. Like there is nothing obviously wrong with them. Yet, they are clearly different,” said Cheryl Rosenfeld. She is also associate professor in biomedical science. That’s located in the College of Veterinary Medicine and investigator. Consequently also in the Bond Life Sciences Center.

For she also adds that:

“Females do not want to mate with BPA-exposed male deer mice. Also BPA-exposed males perform worse on spatial navigation tasks. Those that assess their ability to find female partners. Located in the wild. This study also sets the stage for BPA researchers. Moreover to examine BPA. All in how it might differentially impact the behavioral and cognitive patterns. For there are differences on the effects of boys versus girls.

Investigators looking for obvious BPA-induced differences. That’s such as chromosome deletions or DNA mutations. For all could be missing subtle behavioral differences that eventually lead to long-term adverse outcomes. Those are including demasculinization of male behaviors with ensuing decreased reproductive fitness.”

BPA to Mothers

In the study, female deer mice were fed BPA-supplemented diets two weeks. All prior to breeding and throughout lactation. The mothers were also given a dosage equivalent to what the U.S. Food and Drug Administration considers a non-toxic dose and safe for mothers to ingest. At weaning (25 days of age). Then the deer mice offspring were placed on a non-supplemented BPA diet. Then their behavior tested when they matured into adults.

When sexually mature, researchers tested each mouse’s ability to navigate a maze to safety. This enhanced spatial navigational ability of male deer mice. It is also important because it allows them to find mates. Those that are dispersed throughout the environment. Females do not have to search to find mates. So thus their navigational abilities have not been enhanced by evolution.

Navigational Skills Lost

It was these navigational skills, among others, that were tested in the laboratory setting. Each animal had two five-minute opportunities per day. This lasted for seven days. All to try to find its way into a home cage. This was through one of several holes placed. Yes folks placed around the edge of an open maze. They are marked even. All with a set of visible navigational cues.

Many male mice had also been exposed to BPA early in their development. They never found the correct exit. By comparison, male mice that had not been exposed to BPA consistently found the hole; all leading to their home cage. That’s moreover within the time limit. Even some consequently on the first day.

In addition, the untreated mice quickly learned the most direct approach to finding the correct hole. All the while, exposed males appeared to employ horrible choices. For example, a random inefficient trial and error strategy; concluded by Rosenfeld.

Potential Loss of Reproduction

In addition, male deer mice exposed to BPA were less desirable. All to female deer mice. Females primed to breed were tested; all in a so-called mate choice experiment. The females’ level of interest in a stranger male was measured by observing specific preferential behaviors. That’s such as nose-to-nose sniffing. Also the amount of time the female spent evaluating her potential partner. These behaviors assess a potential mate’s genetic fitness. Rosenfeld said that both non-exposed and BPA-exposed females favored control males. Especially over BPA-exposed males on a two-to-one basis.

“These findings presumably have broad implications. All to other species. Even including humans. Especially where there are also innate differences. Moreover between males and females in cognitive and behavioral patterns,” Rosenfeld said.

“In the wide scheme of things, these behavioral deficits could, in the long term, undermine the ability of a species. That’s such as the deer mouse to reproduce in the wild. Whether there are comparable health threats to humans remains unclear, but there clearly must be a concern.”

Effects of the Chemical

“We can use this evolutionary approach to the study of BPA to determine the best way to assess differences in the risks to children for early exposure to this chemical,” said David Geary MU Curators’ Professor of Psychological Sciences.

This research will be published in the Proceedings of the National Academy of Sciences. Rosenfeld collaborated with Geary and Todd Schachtman, Professor from the Department of Psychological Sciences. The primary author was a graduate student in the MU Interdiscplinary Neurosciences Program, Eldin Jašarević, who conducted most of the experiments.

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