31 March 2003
in Plastic Baby Bottles?
response to industry comments, below
Plastics Chemical Linked to Genetic Damage
31, 2003 -- A chemical used in plastic baby bottles -- and many
other food and beverage containers -- causes genetic damage in mice,
a new study suggests. But the plastics industry says there is no
cause for alarm.
damage is seen in egg cells of female mice. When these cells try
to divide, their chromosomes don't line up right. In humans this
results in spontaneous abortion, birth defects, or mental retardation,
says genetic abnormalities expert Patricia A. Hunt, PhD, of Case
Western Reserve University School of Medicine.
studies published in the April issue of the journal Current Biology,
Hunt and colleagues showed that very low doses of a common plastics
ingredient may cause these effects. They also found that dangerous
amounts of the chemical -- known as BPA -- can seep out of used
effect we saw is pretty dramatic," Hunt tells WebMD. "We
were stunned by how low a dose it took. I am becoming pretty convinced
there are significant effects [of BPA] at pretty low exposures.
I can't say how scared you should be because our studies don't say
anything about humans. But that's why we study animals. We assume
the processes are pretty well the same in humans."
chemical is known as bisphenol A or BPA. It's found in all kinds
of common products, mostly polycarbonate plastics. Nearly all plastic
baby bottles in the U.S. are made of this kind. So are many common
food containers, water storage bottles, aluminum can linings, and
even some kinds of dental sealants.
animal studies have linked BPA to low sperm count, hyperactivity,
early puberty, obesity, small testes size, and enlarged prostates.
But Hunt's is the first study to suggest that BPA can affect future
S. vom Saal, PhD, professor of biology at the University of Missouri
inColumbia, has studied BPA for many years. He says that some 40
studies show that polycarbonate plastics are dangerous. Hunt's findings
scare him most of all.
is so important about this finding is we are talking about something
that causes spontaneous abortions of babies," vom Saal tells
WebMD. "And then there is the horrifying fact that babies are
born with these chromosomal abnormities. ... This is a higher level
of concern, a major new finding of a really profound adverse effect
of this chemical in mice that were just drinking out of old baby
findings also frighten Vom Saal's colleague, reproductive endocrinologist
Wade V. Welshons, PhD.
found bad effects of fetal exposure to BPA, but that is something
a pregnant woman can avoid. When my wife was pregnant, we did try
to avoid it," Welshons tells WebMD. "But Hunt's study
shows exposure may be unavoidable. It is shocking."
didn't intend to study BPA. She was studying egg development in
mice. Suddenly, she started finding genetic defects in eggs from
mice that were supposed to be normal. Nearly a year's work was destroyed.
Finally, she found the cause. The mice were housed in polycarbonate
plastic cages. They drank from polycarbonate bottles. Both had accidentally
been washed in a floor cleaner that made them degrade faster.
Hunt's research team exposed new plastic bottles to floor cleaner,
they gave off lots of BPA. Sure enough, they found, BPA by itself
caused the genetic changes. But then they found that the bottles
gave off BPA much more easily than they'd suspected.
it doesn't take washing the bottle with floor soap," Hunt says.
"As these products get reused, they start to leach BPA. The
part that will make your hair stand on end is baby bottles. They
are made of polycarbonate plastic. People who use them say that
after just washing them in the dishwasher they see these same changes
in the bottles. When we see bottles start to turn cloudy, they are
leaching. And when they get sticky, they are giving off a lot of
plastics industry says there is nothing to be alarmed about. Large
studies of BPA show no effects on animals or on their offspring,
says Steven Hentges, PhD, executive director of the polycarbonate
business unit of the American Plastics Council. Hentges represents
the makers of polycarbonate and BPA.
says there are three things to know about the Hunt study:
from www.OurStolenFuture.org to these
industry comments can be viewed by holding
your cursor over the blue-highlighted segments below.
It doesn't actually demonstrate any health hazard. It
only looked at the genetic effects
of BPA on mice, and not at whether it caused reproductive problems
or deformed embryos.
* The techniques used in the study don't
predict actual harm in animals or humans.
* The study does not show that the effects seen are relevant
has been a lot of research on the subject of BPA," Hentges
tells WebMD. "It is very reassuring research. It give us confidence
that BPA does not cause reproductive problems. The bottom line is
when you look at the whole package of BPA studies, you don't see
any bad health outcomes. There
have been no reproductive problems of the type you might expect
from what Hunt and co-workers report."
may not be true, say vom Saal and Welshons. People are reaching
puberty earlier. Men have lower sperm counts. There's an epidemic
of obesity. Could some of this be related to the millions of tons
of BPA generated each year?
is already enough environmental exposure to lead to problems in
humans," Welshons says. "In a recent study, fetal umbilical
blood shows higher BPA levels than we generated in mice. Human exposure
levels are already high."
horrifying thing is that it looks as though these effects in the
Hunt study and other studies happen at lower doses than what is
actually found in human fetal blood -- umbilical cord blood,"
vom Saal says. "That is pretty stunning. That is an alarm.
It needs to be the basis for a very serious re-evaluation of the
potential for human harm of BPA."
points to large studies -- including one published last year by
the Research Triangle Institute -- that fail to show any effect
of BPA on animals, their organs, their genes, or their offspring.
Vom Saal and Welshons say that all such studies have been paid for
by industry sponsors and all are flawed. Hentges says it is the
smaller studies that are flawed.
Current Biology, April 2003. Lab Animal, April 2003. Patricia A.
Hunt, PhD, associate professor of genetics, Case Western Reserve
University School of Medicine, Cleveland. Steven Hentges, PhD, executive
director, polycarbonate business unit, American Plastics Council.
Frederick S. vom Saal, PhD, professor of biology, University of
Missouri, Columbia. Wade V. Welshons, PhD, associate professor of
veterinary biomedical sciences, University of Missouri, Columbia.