A new study has found ‘compelling’ evidence that the plastic
additive bisphenol A (BPA) may negatively impact women’s reproductive
systems and cause chromosome damage, birth defects and miscarriages.
Researchers from Washington State University and the University of
California, Davis, found that rhesus monkeys exposed to similar levels
of BPA that humans are exposed to suffered serious reproductive
abnormalities that increased their risk of giving birth to offspring
with Down syndrome or other birth defects – or even having a
miscarriage.
Prior studies done in worms and rodents have shown similar effects,
but because rhesus monkeys have the most human-like reproductive system,
this study “hits much closer to home,” Dr. Patricia Hunt, a geneticist
and professor of molecular biosciences at Washington State University,
told FoxNews.com.
BPA is a low-grade estrogen that until recently was found in certain
plastic bottles—typically marked with the number ‘7’ inside a recycling
symbol. It is still found in the linings of aluminum cans and
heat-activated cash register receipts.
A 2003-2004 National Health and Nutrition Examination Survey (NHANES)
found BPA exposure is “nearly ubiquitous” in the U.S. population, with
92.6 percent of people over the age of 6 having detectable levels of BPA
in their urine.
The chemical has also been associated with obesity, cardiovascular
disease, diabetes, breast cancer, prostate cancer and neurological
disorders. While the U.S. Food and Drug Administration recently banned
BPA from sippy cups and baby bottles, it did not extend the ban to other
products.
This latest WSU study found when pregnant monkeys were given either a
single daily dose of BPA or low-level continuous doses – meant to mimic
exposure levels in humans – it led to changes in the cells that would
become eggs in the developing fetus.
Therefore, once the offspring were ready to reproduce themselves, the
egg cells were not able to divide properly, meaning the fertilized egg
had the wrong number of chromosomes. This can cause various birth
defects, including Down syndrome, and can even lead to miscarriage.
“The really stunning thing about the effect is we're dosing grandma,”
Hunt said in a released statement. “It's crossing the placenta and
hitting her developing fetus, and if that fetus is a female, it's
changing the likelihood that that female is going to ovulate normal
eggs.”
Furthermore, in the monkeys that were continually exposed to BPA, the
researchers found the fetal eggs were not packaged the right way in
follicles, which is where they develop. Eggs must be packaged properly
in order to grow, develop and mature, according to the researchers.
“This means [the monkeys] will probably end up with a lot fewer eggs
to work with, because a female is born with all the eggs she’s going to
have,” Hunt said. “Her reproductive lifespan may be shorter.”
While the experiment’s results are worrisome, Hunt said it is nearly
impossible to set up a study establishing a concrete cause-and-effect
relationship between BPA and reproductive issues in humans, and even
correlational findings would take a while to become evident.
“The problem for both of these effects is we would have to wait a
generation to see results of fetal exposure in utero. What happens when
they grow up and make babies?” she said.
However, she added that it was “compelling evidence” that three
different experimental models in worms, mice and monkeys all showed
similar effects.
In response the study findings, Steven Hentges, of the American
Chemical Society’s Polycarbonate/BPA Global Group released a statement
critiquing the study's small sample size and said it was "of unclear
relevance to humans."
"In the second test protocol, the monkeys were injected with BPA
under the skin, which is of very little relevance to the minute BPA
exposures that occur in humans through the diet," he added, "...Because
of the way BPA is processed in the body, it is very unlikely that BPA
could cause health effects at any realistic exposure level."
The study was published Monday in the
Proceedings of the National Academy of Sciences.
الثلاثاء فبراير 13, 2024 10:56 am من طرف nadaroyal
موضوع: Study links BPA to birth defects, miscarriage 
