June 6, 2011

BPA: Worse Than We Thought?

(Ivanhoe Newswire) -- A new study reveals exposure to Bisphenol A (BPA) through one's diet has been underestimated.

According to the U.S. Department of Health & Human Services, BPA is a chemical that has been used for more than 40 years in the manufacture of many hard plastic food containers such as baby bottles and reusable cups and the lining of metal food and beverage cans, including canned liquid infant formula. Trace amounts of BPA can be found in some foods packaged in these containers.

Researchers from the University of Missouri compared BPA concentrations in mice that were given a steady diet supplemented with BPA throughout the day. They continuously exposed the mice to BPA through their feed, which is considered the primary route of exposure in animals and humans. In previous studies, mice received a one-time administration of BPA.

The researchers found an increased absorption and accumulation of BPA in the blood of the mice that were exposed to BPA via their diets. Following the exposure through the diet, a significantly greater increase in the active form of BPA, which is the greatest threat as it is the form that can bind to sex steroid receptors and exert adverse effects, was absorbed and accumulated in the animals.

"People are primarily and unknowingly exposed to BPA through the diet because of the various plastic and paper containers used to store our food are formulated with BPA," Cheryl Rosenfeld, associate professor in the biomedical sciences and Bond Life Sciences investigator, was quoted as saying. "We know that the active form of BPA binds to our steroid receptors, meaning it can affect estrogen, thyroid and testosterone function. It might also cause genetic mutations. Thus, this chemical can hinder our ability to reproduce and possibly cause behavioral abnormalities that we are just beginning to understand."

According to the study, more than 8 billion pounds of BPA are produced every year, and more than 90 percent of people in the United States have measurable amounts of BPA in their bodies.

"We believe that these mouse model studies where the BPA exposure is through the diet is a more accurate representation of what happens to BPA as the human body attempts to processes this toxic substance," Rosenfeld said. "When BPA is taken through the food, the active form may remain in the body for a longer period of time than when it is provided through a single treatment, which does not reflect the continuous exposure that occurs in animal and human populations. We need to study this further to determine where the ingested BPA becomes concentrated and subsequently released back into the bloodstream to be distributed throughout the body."

SOURCE: Environmental Health Perspectives, June 6, 2011