Bisphenol A (BPA) and
phthalates
are what's known as "endocrine disruptors"—that is, at very small doses
they interfere with our hormonal systems, giving rise to all manner of
health trouble.
In peer-reviewed research, BPA has been linked to
asthma,
anxiety,
obesity,
kidney and heart disease, and
more. The rap sheet for phthalates, meanwhile, includes
lower hormones in men,
brain development problems,
diabetes,
asthma,
obesity, and, possibly,
breast cancer.
So, ingesting these industrial chemicals is a bad idea, especially if
you're a kid or a pregnant woman. But avoiding them is very difficult,
since they're widely used in plastics, and are ubiquitous in the food
supply.
The federal government has not seen fit to ban them
generally—although the FDA
did outlaw BPA from baby bottles last year (only after the
industry had voluntarily removed them) and Congress
pushed phthalates out of kids' toys back in 2008. Otherwise, consumers are on their own to figure out how to avoid ingesting them.
Unfortunately, that's a really hard task—and eating fresh, local, and organic might not be sufficient, as
new research (abstract), published in the peer-reviewed
Journal of Exposure Science and Environmental Epidemiology, shows.
A team led by Sheela Sathyanarayana of University of Washington's
Seattle Children's Research Institute performed a "dietary intervention"
on two sets of five local families.
After using urine tests to
establish baseline BPA and phthalate levels for each group, they
subjected one set of families to five days of eating meals from a
catering company that avoids plastics and uses fresh and, when possible,
local and organic ingredients.
The other set was given "handouts
describing best practice recommendations to reduce phthalate and BPA
exposures" and asked to follow them as well as possible as they prepared
their meals over the course of the five days. Levels of the chemicals
were then again measured after the five-day period.
"I'm a pediatrician, and people are always asking me, 'What can we do
in the home to reduce our exposure to these chemicals?'" Sathyanarayana
told me.
The idea was to figure out whether merely giving people common
sense tips—reduce consumption of canned foods, avoid contact between
food and heated plastic, etc.—was sufficient for achieving significant
exposure reductions.
They assumed that the catered diet, with its fresh,
plastic-free foods, would see their levels of these chemicals drop, and
that the families merely following good-practices guidelines wouldn't
see much of a change.
The takeaway would be: The guidelines aren't
enough, and we need to do more to protect people from these chemicals,
because switching to completely scratch-cooked meals isn't an option for
most families.
But what they discovered, Sathyanarayana said, was "completely
unexpected": The handout-receiving group indeed showed no change, but
for the catered local and organic diet group, BPA levels doubled and
levels of the highly toxic phthalate DEHP jumped a stunning 2,377
percent.
In other words, the researchers were right that following
guidelines wouldn't do much to decrease exposure, but were surprised to
find that eating mainly fresh, local, organic food, cooked and stored
without plastics, seemed to dramatically boost levels of these endocrine
disruptors.
The researchers were surprised for good reason. Sathyanarayana told
me that the team went to great lengths to ensure that the food prepared
for the catered-diet group had no exposure to plastic in preparation,
cooking, or storage of the ingredients used, to the point that the
caterer asked its local farm suppliers to deliver produce in crates
instead of plastic bags.
And in a
2011 study, published in
Environmental Health Perspectives,
a different set of researchers had subjected five families to a similar
catered diet, and got the expected result: BPA levels fell by 66
percent and levels of DEHP dropped by 53 percent to 56 percent.
DEHP is a phthalate. Note the dairy products at the top of the chart, and the spices, especially coriander, toward the bottom. Study by Sathyanarayana, et al, 2013.
Stunned by their outlier results, Sathyanarayana and her team went
back to the caterer and tested a range of ingredients for phthalates
(they didn't test the food for BPA).
The researchers found high levels
of DEHP in two kinds of foods: dairy, which had come in glass bottles
from a local farm, and spices, which were certified organic but
imported. All of the rest of the ingredients showed very low levels.
(See table, right).
Sathyanarayana said that phthalate levels for
children in the study spiked even higher than those of the
adults—probably because they may have consumed more dairy products than
the adults, and because of their lower body weights.
Sathyanarayana told me that spices and dairy are well established as carriers of phthalates. She pointed me to
this 2006 European study
(PDF) on a range of foods (see table IV) that also found high levels in
those foodstuffs.
She added that the levels found in the milk and
spices used by the caterer were much higher than levels found in
previous studies.
I asked Sathyanarayana how phthalates could be getting into
glass-bottled milk from a Washington dairy that sells into the Seattle
market. She stressed that the group had no specific information on the
dairy itself and had only tested its retail milk, cream, and butter.
But
she pointed out that that even in relatively small commercial dairies,
milk is collected by from cows' udders through soft, flexible plastic
tubing—the very kind that often contains phthalates, which are used to
make plastic flexible. "It's warm milk going through soft plastic, and
we know that when phthalates in plastic are heated, there's leaching,"
Sathyanarayana said. She stressed that her analysis of possible pathways
for exposure was purely conjectural.
As for the organic spices—check out ground coriander in the chart
above—she noted that organic standards say nothing about chemicals that
might leach into foods through processing. Virtually all spices consumed
in the United States are imported, and it's extremely difficult to get
information on processing practices, which might be where endocrine
disruptors are sneaking in.
I should note, as the study itself does, that these results require
much more research before firm conclusions can be made about, say, dairy
and spices. The sample size is extremely small, and the results could
stem from a problem at a particular dairy or a spice processor. It would
be foolhardy to draw conclusion about the BPA or phthalate levels of
any particular food, organic, local, or not, from this study alone.
But the findings illustrate a larger point: Independent of choices we
make as consumers—whether we buy milk in glass bottles or microwave
food in plastic containers—processing is taking place beyond our view
that can contaminate our food with endocrine-disrupting chemicals.
I ran
the study by Kim Harley, associate director for health effects at
University of California-Berkeley's Center for Environmental Research
and Children's Health, who has done epidemiological studies on BPA and
other endocrine disruptors.
"The lesson is that you can try to reduce
exposure, but there are unknown sources of phthalates that could be very
large lurking in the food chain," she said. She added that if the best
efforts of well-resourced scientists can't always come up with food
that's untainted by these chemicals, then consumers acting on their own
are in a tight spot.
In my view, when individual consumers can't protect themselves
through reasonable means, collective action—i.e., regulation—is the only
remedy. These results add to a weight of evidence that should push the
FDA to take action on the role of plastic conditioners in food
processing and packaging.
I asked Sathyanarayana how she is advising families to minimize
exposure to BPA and phthalates. "I'm advising that they not use plastic
in cooking storage, and preparation, and to focus on fresh foods and
low-fat foods," she said. If only that were enough.
