How to Avoid the Obesity-Related Plastic Chemical BPA

How to Avoid the Obesity-Related Plastic Chemical BPA

September 15, 2019 56 By Ewald Bahringer


“How to Avoid the Obesity-Related
Plastic Chemical BPA” The purported link between
hormone-disrupting plastics— chemicals like BPA—and obesity was
initially based in part on observations that the rise in chemical
exposure seemed to coincide with the rise of the obesity
epidemic with graphs like these, but maybe that’s
just a coincidence. There’s lots of other changes
over the last half century, like an increase in fast food
consumption and watching TV that would seem to be
simpler explanations. But why are our pets
getting fatter, too? Fido isn’t drinking
more soda. Of course, the more we watch Seinfeld reruns,
the less we may walk the dog, but what about our cats? Well, maybe we’re giving both them
and our kids a few too many treats? That would seem
an easier explanation than some pervasive obesity-causing
chemical in the environment building up in the pet and person food
chains, but how do we explain this? A study of over 20,000 animals from
24 populations, and we’re all getting fatter. The odds that this could just happen
by chance is like 1 in 10 million. Large and sustained increases
in body weight across the board, even in animals without
access to vending machines or getting phys-ed at school. So maybe some environmental
pollutant is involved. Of course, we’re exposed to a whole cocktail
of new chemicals besides BPA, but the reason researchers
have zeroed in on it is because of experiments like this,
showing that BPA can accelerate the production of new fat cells,
in a Petri dish at least, but this was at more than a thousand
times the concentration found in most people’s bloodstream. We didn’t know if the same thing
happened at typical levels, until now. Most people have between
1 to 20 nanomoles in their blood, and even at one nanomole a significant
boost in human fat cell production. So even low levels may be a problem,
but again that’s in a Petri dish. What about in people? Why not just measure the body weights
of a population exposed to the chemical, compared to a population
not exposed to the chemical? Because there is virtually no unexposed
population; the stuff is everywhere. OK, then how about those
with higher levels compared to those with lower levels? Good thinking, which is
what researchers at NYU did, and the amount of BPA flowing through
the bodies of children and adolescents was significantly associated
with obesity. But since it was a cross-sectional
study, a snapshot in time, we don’t know which came first. Maybe the BPA levels
didn’t lead to obesity; maybe the obesity led
to high BPA levels, since the chemical is stored in fat.
Or maybe BPA is just a marker for the same kinds of processed
foods that can make you fat. What we need are prospective studies
where you measure exposure and then follow people over time,
but we never had anything like that though, until now. And indeed higher levels of BPA
and other plastics, chemicals, were significantly associated
with faster weight gain over the subsequent decade. OK. So how can we stay
away from the stuff? Though we inhale some from dust and some through our skin
touching BPA laden receipts, 90% of exposure is from our diet.
How do you tell? You have people fast and drink water
only out of glass bottles for a few days, and their BPA levels drop
as much as tenfold. Fasting isn’t very
sustainable, though. What if you did a 3-day fresh foods
intervention, where they had families switch away from canned and
processed foods for a few days? You can indeed get a significant
drop in BPA exposure. Or you can do the experiment the other way,
adding a serving of canned soup to people’s daily diet and see
a thousand percent rise in BPA levels in their urine, compared to a serving
of soup prepared with fresh ingredients. They used a ready-to-serve canned soup,
which in the largest survey of North American canned foods
has about 85% less BPA than condensed soups,
which are even worse, but the worst of the worst
appeared to be canned tuna.