BPA 11 times higher in newborns than adults - infants lack enzyme to metabolize this EDC
- BPA may pose greater threat to newborns
Toxic substance that mimics estrogen may linger longer in babies than in
adults, researchers find
>From Tuesday's Globe and MailFebruary 24, 2009 at 9:42 AM EST
Bisphenol A, the controversial chemical used to make plastic, lingers
far longer in the bodies of babies who ingest it than in adults because
they lack a crucial liver enzyme needed to break it down, according to
researchers at the University of Guelph.
The finding prompted one of the researchers to recommend that parents
try to make sure their babies have no exposure to bisphenol A, and that
pregnant women minimize what they ingest to protect their developing
Len Ritter, professor at the university's department of environmental
biology and the study's lead author, said infants "do appear to have
significantly greater levels ... up to 11 times higher [than adults].
That's not trivial."
The study, published in Environmental Health Perspectives, is likely to
put further pressure on Health Canada to step up its efforts to control
bisphenol A (also known as BPA), a synthetic compound that has raised
concerns because it mimics estrogen.
Bisphenol A is used to make polycarbonate and the linings of most food
and beverage cans. It is also an additive in many types of plastic.
Because it is not tightly bound in consumer packaging, trace amounts can
leach into food and drinks.
Last year, the federal agency added the chemical to Canada's
toxic-substances list and announced a ban on plastic baby bottles made
from it, the first country in the world to take such actions.
Health Canada also said it wanted infant formula makers to minimize the
amounts seeping out of can linings, but neither the companies nor the
government have finalized control measures.
Health Canada said in a statement in response to questions from The
Globe and Mail that it met last month with the U.S. Food and Drug
Administration, infant formula makers and canning companies to develop a
North American approach to the reduction of BPA in food products.
Health Canada believes pregnant women don't need to reduce their
exposure, but said in the statement that pregnant or breastfeeding women
with concerns can reduce exposure by using non-polycarbonate plastic
containers to heat foods or using alternatives such as glass or
Many researchers are worried that through exposure to BPA, people are
getting what amounts to an extra dose of estrogen. Animal experiments
have found the chemical is associated with hormonal conditions, such as
earlier onset of sexual maturity in females, and breast cancer,
particularly when exposure occurs during fetal or neonatal periods.
In the new study, Dr. Ritter used models based on animal and human
experiments to estimate how long it would take babies to clear the
chemical from their bodies, compared with adults, when both were given
equivalent doses, adjusted for their differing body weights.
Adults have a well-developed capacity to metabolize BPA into a harmless
form that is quickly excreted in urine. Dr. Ritter said this capacity
isn't fully developed in newborns, allowing BPA to build up in their
blood to 11 times what an adult would have.
Infants gradually gain the ability to detoxify BPA, and by three months
would still have about double adult levels of the chemical, he said.
Researchers don't know precisely when infants gain a fully developed
capacity to metabolize BPA.
PCBs alter rat hormones, organs in two generations.
27 February 2009
A PCB mix altered reproductive hormones and organ growth in two
generations of female rats that were never directly exposed to the
chemicals themselves. The abnormalities worsened in the
granddaughters when compared to the daughters. The worst effects
were seen at the mid -- not the highest or lowest -- level tested.
Levels were within the range of human exposure.
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