BPA causes reproductive
health defects at levels currently considered safe – study
of Article: http://www.foodproductiondaily.com/Quality-Safety/BPA-causes-reproductive-health-defects-at-levels-currently-considered-safe-study
By Rory Harrington, 19-Jun-2009
Bisphenol A (BPA) causes significant
reproductive health effects at levels equivalent to or below the dose that
that has been thought not to produce any adverse results, new research has
The study from North Carolina State University and the National
Institute of Environmental Health Sciences (NIEHS) found that exposure to
levels of BPA
that US authorities have currently judged to be harmless over the course of
a lifetime triggered reproductive problems in female rats.
BPA is a chemical found in baby bottles, water bottles, canned foods
and an array of other consumer products. Its use is the subject of intense
debate. A number of US states have banned its use in containers for infants
and the Food and Drug Administration is currently reviewing its opinion
that the substance poses no threat to human health.
The research group discovered that female rats exposed to a
50-microgram/kilogramme of body weight (µg/kg) dose of the chemical in
their first four days of life experienced the early onset of puberty. Those
exposed to 50 milligrams per kilogramme (mg/kg) during the same four-day
period “developed significant ovarian malformations and premature loss of
their estrus cycle”, said a statement from the group.
Exposing female rats during the first four days of life is
significant because this is a “sensitive developmental window for the
animals, similar to a sensitive developmental stage that takes place for
humans when they are still in the womb”, explained the NC/NIEHS.
Dr. Heather Patisaul, lead researcher and assistant professor of
biology at NC State, said: "The 50 mg/kg level is important because
it is equivalent to the U.S. Environmental Protection Agency's 'Lowest
Observable Adverse Effect Level' for BPA. So, by definition, we should not
have seen significant effects at or below this level, but we did."
Patisaul also said the 50 µg/kg is significant because this is the
EPA’s listed reference dose for BPA. This means it is the level the EPA
says a person can be exposed to on a daily basis without any expectation of
adverse effects following a lifetime of exposure.
The research group acknowledged the fact that because the
experiments were carried out on rats, this makes it “difficult"
to determine its applicability to humans. However, Patisaul stressed that
it added to “a growing body of evidence that exposure to low doses of BPA
during development can impact female reproductive health."
But the American
Chemistry Council (ACC) has dismissed the study as being of
“very limited relevance to human health”.
Dr Steven Hentges, of the ACC, said “It is a continuing
disappointment to see that researchers conduct studies that involve
injection of laboratory animals with BPA. This experimental technique has
recently been acknowledged by the NIEHS to have very limited value for
assessing human health effects since people are orally exposed to BPA, not
by injection. It is well-known that BPA is efficiently metabolized and
rapidly eliminated from the body after oral exposure.”
Hentges said the researchers were wrong to suggest the study is
significant because it used a quantity equal to the EPA reference dose for
BPA because this level is applicable to oral doses only and not to