A number of
studies have focused on bisphenol A's (BPA) effect on human
reproduction. Now, a new study has added to the data, suggesting
the widespread chemical causes lower fertility in mice. The study
was presented over the weekend at the 93rd annual Endocrine Society meeting in
Boston.
BPA is a chemical used in many food industry containers. It
provides rigidity to plastics, such as water and soft drink
bottles. It's also used in the plastic liners of food cans.
Lower sperm count
Researchers at Banaras Hindu University in Varanasi, India,
injected BPA daily into a group of mice. After two months, they
said the mice had lower sperm counts than a control group that
received injections of a saline solution without BPA. Compared with
untreated controls, mice exposed to BPA produced litters that were
50 percent smaller.
The researchers say the same effects may be showing up in the
human population.
“We are being exposed to BPA in our daily lives at a level
much higher than the safe recommended exposure,” said the
study’s principal author, Surya Singh, PhD, associate
professor in the university’s biochemistry department.
“In this study, we are trying to explore what the outcome can
be if we are continuously exposed to BPA in our routine
life.”
BPA-exposed mice received a dose that was twice the daily upper
limit of safe exposure recommended by the U.S. Food and Drug Administration (FDA) and the
Environmental Protection Agency
(EPA). The mice in the experiment were considered
“subfertile” after two months of exposure, but Singh
speculates that exposure for more than two months might lead to
complete infertility.
“Even short-term exposure to BPA could be dangerous to
fertility, but we are still investigating this possibility,”
he said.
Adds to evidence
These new research findings add to a growing body of scientific
evidence that links exposure to BPA, an endocrine (hormone)
disrupter, with numerous adverse health effects, including on
reproductive function.
How do humans get BPA in their bodies? A 2009 study by
researchers at the Harvard School of Public Health found that study
participants who drank for a week from polycarbonate bottles, the
hard plastic drinking bottles and baby bottles, showed a two-thirds
increase in their urine of BPA. The study was the first to show
that drinking from polycarbonate bottles increased the level of
urinary BPA, and thus suggests that drinking containers made with
BPA release the chemical into the liquid that people drink in
sufficient amounts to increase the level of BPA excreted in human
urine.
While the food industry has vigorously defended against attempts
to ban or regulate BPA, Wal-Mart announced in 2008 that it would
stop selling plastic baby bottles that contain BPA and many other
retailers have followed suit.
Indian researchers say they have found evidence that bisphenol A (BPA) reduces fertility in mice....