"Why BPA Hasn't Been Banned"
The number of new chemicals is increasing exponentially.
We're talking 12,000 new substances a day.
Yet data aren't available on the hazards
of even some of the high volume chemicals.
BPA is one of the highest volume chemicals
with billions of pounds produced each year.
And studies have raised concerns about its possible implication
in the cause of certain chronic diseases
such as diabetes, obesity, reproductive disorders, cardiovascular diseases,
birth defects, chronic respiratory and kidney diseases, and breast cancer.
A new study on the health implications of BPA comes out nearly every week.
BPA was first developed over a hundred years ago as a synthetic estrogen,
but it wasn't until the '50s that industry realized it could be used
to make polycarbonate plastic,
and it rapidly became one of the most used chemicals worldwide,
even though it was recognized to have hormonal effects.
About a billion pounds are also used to line food and beverage cans,
especially, it seems, in tuna and condensed soups.
And now we basically all have BPA in our bodies, and our children's bodies.
But not to worry, the government says up to 50 µg a day is safe —
50 micrograms per kilogram.
And even those working in Chinese BPA factories don't get exposed
to more than like 70 times lower than that safety limit.
OK, then why did exposure seem to affect the male workers' sperm counts?
In the U.S., the general population only gets less than like
a thousand times lower than the safety limit.
Yet still we seem to be seeing adverse effects on thyroid function,
weight control, blood sugar control, cardiovascular disease, liver function,
and immune function, even at those incredibly low doses.
So the fact that there are significant adverse effects in populations
exposed to BPA at concentrations thousands of times lower
than the official tolerable daily limit indicates that the safe exposure
to BPA may be much lower than previously thought in humans;
yet the limit hasn't been changed.
It's been banned from baby bottles and sippy cups,
but nearly unlimited doses are still apparently OK for everyone else.
What's the disconnect here?
It has to do with the fascinating world of low dose effects
of hormone-disrupting chemicals.
For decades, these chemicals
"have challenged traditional concepts in toxicology,"
particularly the old adage that it's "the dose makes the poison,"
the concept that lower exposures to a hazardous compound
will therefore always generate lower risks."
That's the core assumption underlying our system of chemical-safety testing.
They start dosing lab animals with a super-high amounts,
and then keep lowering the dose until whatever adverse effects disappear,
then add a safety buffer and assume everything below that dose should be OK,
assuming the curve looks like this: the higher the dose, the higher the effect.
But hormone-disrupting chemicals can have all sorts of curious curves.
Wait a second.
How could something have more of an effect at a lower dose?
Think about a hormone and its receptors in a body.
At low levels of the hormone, like going from 0 to 1,
the receptors can fill up quickly,
but once they're almost all filled up, going from 4 to 5,
adding really high doses may not change things much.
Let's use an actual BPA example.
This was a study to see if BPA suppressed an obesity protective hormone
in fat samples taken from breast reduction and tummy tuck patients.
As you can see, at 100 nanomoles of BPA —
I feel like a weather man here, but—
at a 100 nanomoles of BPA, you can see hormone levels
are no lower than they are at 0 BPA.
And since most people have levels between like 1 and 20,
then BPA must be safe.
But here's the actual graph.
So, no suppression at 0, and no suppression at 100,
but right where levels are in people's bodies,
BPA appears to cut hormone release nearly in half.
As the world's oldest, largest, and most active organization
devoted to research on hormones concluded:
even infinitesimally low doses of exposure—
indeed, any level of exposure at all—may cause problems,
nearly three billion dollars' worth of problems every year, just counting
the estimated effects of BPA on childhood obesity and heart disease alone.
Now there are alternatives that the industry could use.
The problem though is that they may cost 2 cents more.