Jury Still Out on BPA/Plastics Risk
What to Do While Scientists Study Risk From Plastic Baby Bottles, Other Sources
WebMD News Archive
Aug. 24, 2007 -- The jury is still out on whether there's a health risk from
bisphenol A (BPA), a chemical that leaches from plastic baby bottles,
food/beverage cans, and many other products.
Industry uses more than 6 billion pounds of BPA every year to make the
resins that line food cans and the polycarbonate plastics used to make baby
bottles and many, many other products. The CDC says that 95% of us carry
measurable amounts of BPA in our blood.
Some scientists say there's reason to worry. They note that BPA acts like
the sex hormone estrogen -- indeed, BPA was originally developed as a chemical
estrogen. These researchers worry that BPA is behind hormone-linked trends in
human health such as increased abnormal penis development in males, earlier
sexual development in females, increases in neurodevelopmental diseases such as
ADHD and autism, increased child obesity, decreased sperm count, and more
breast and prostate cancers.
The plastics industry says there's nothing to worry about. Industry-funded
studies by the Harvard Center for Risk Analysis and the Gradient Corporation
say there's not cause for alarm.
A scientific panel asked by the National Toxicology Program to settle the
issue says there's "some" concern about neural and behavioral effects
from BPA exposure in fetuses, infants, and children.
The panel found no major health risks. But there are serious questions about
the panel's report -- and about its independence from industry (the contractor
that prepared the panel's draft report was fired for apparent conflict of
This fall, the National Toxicology Program is expected to issue a ruling on
whether BPA is toxic. Until then, here's a summary of what is known -- and what
you can do if you feel you're at risk.
Is BPA Really Risky?
There's no argument that at some level of exposure, BPA is toxic. BPA has a
half-life in the human body of about six hours. But because we're continually
exposed, nearly all of us have measurable blood levels of BPA.
Whether these levels are dangerous isn't known for sure. One problem is that
BPA acts like a hormone. This means that low doses may have effects not seen at
higher doses. This is a problem for traditional toxicology studies, which
usually try to find a high-dose effect and lower the dose until that effect
Currently, the EPA says that the "safe" level of BPA is set at
50 micrograms per kilogram of body weight per day. But animal studies suggest
that this level of BPA has harmful effects, including genetic
damage. Exactly how to translate these animal findings into human effects
is a bone of contention between academic and industry scientists.
Nevertheless, BPA can flip the estrogen switches on cells at
part-per-trillion concentrations -- lower concentrations than those common in
the blood of human infants, children, and adults.