If Food’s in Plastic, What’s in the Food?
Bisphenol-A, a common chemical used in plastic, had been proven to pass into foods
In a study published last year in the journal Environmental Health
Perspectives, researchers put five San Francisco families on a three-day
diet of food that hadn’t been in contact with plastic. When they
compared urine samples before and after the diet, the scientists were
stunned to see what a difference a few days could make: The
participants’ levels of bisphenol A (BPA), which is used to harden
polycarbonate plastic, plunged – by two-thirds, on average – while those
of the phthalate DEHP, which imparts flexibility to plastics, dropped
by more than half.
The findings seemed to confirm what many experts suspected: Plastic
food packaging is a major source of these potentially harmful chemicals,
which most Americans harbor in their bodies. Other studies have shown
phthalates (pronounced THAL-ates) passing into food from processing
equipment and food-prep gloves, gaskets and seals on non-plastic
containers, inks used on labels – which can permeate packaging – and
even the plastic film used in agriculture.
The government has long known that tiny amounts of chemicals used to
make plastics can sometimes migrate into food. The Food and Drug
Administration regulates these migrants as “indirect food additives” and
has approved more than 3,000 such chemicals for use in food-contact
applications since 1958. It judges safety based on models that estimate
how much of a given substance might end up on someone’s dinner plate. If
the concentration is low enough (and when these substances occur in
food, it is almost always in trace amounts), further safety testing
isn’t required.
Meanwhile, however, scientists are beginning to piece together data
about the ubiquity of chemicals in the food supply and the cumulative
impact of chemicals at minute doses. What they’re finding has some
health advocates worried.
This is “a huge issue, and no [regulator] is paying attention,” says
Janet Nudelman, program and policy director at the Breast Cancer Fund, a
nonprofit that focuses on the environmental causes of the disease. “It
doesn’t make sense to regulate the safety of food and then put the food
in an unsafe package.”
A complicated issue
How common are these chemicals? Researchers have found traces of
styrene, a likely carcinogen, in instant noodles sold in polystyrene
cups. They’ve detected nonylphenol – an estrogen-mimicking chemical
produced by the breakdown of antioxidants used in plastics – in apple
juice and baby formula. They’ve found traces of other hormone-disrupting
chemicals in various foods: fire retardants in butter, Teflon
components in microwave popcorn, and dibutyltin – a heat stabilizer for
polyvinyl chloride – in beer, margarine, mayonnaise, processed cheese
and wine. They’ve found unidentified estrogenic substances leaching from
plastic water bottles.
Finding out which chemicals might have seeped into your groceries is
nearly impossible, given the limited information collected and disclosed
by regulators, the scientific challenges of this research and the
secrecy of the food and packaging industries, which view their
components as proprietary information. Although scientists are learning
more about the pathways of these substances – and their potential effect
on health – there is an enormous debate among scientists, policymakers
and industry experts about what levels are safe.
The issue is complicated by questions about cumulative exposure, as
Americans come into contact with multiple chemical-leaching products
every day. Those questions are still unresolved, says Linda Birnbaum,
director of the National Institute of Environmental Health Science, part
of the National Institutes of Health. Still, she said, “we do know that
if chemicals act by the same pathway that they will act in an additive
manner” – meaning that a variety of chemicals ingested separately in
very small doses may act on certain organ systems or tissues as if they
were a single cumulative dose.
The American Chemistry Council says there is no cause for concern.
“All materials intended for contact with food must meet stringent FDA
safety requirements before they are allowed on the market,” says
spokeswoman Kathryn Murray St. John. “Scientific experts review the full
weight of all the evidence when making such safety determinations.”
Hard to measure
When it comes to food packaging and processing, among the most
frequently studied agents are phthalates, a family of chemicals used in
lubricants and solvents and to make polyvinyl chloride pliable. (PVC is
used throughout the food processing and packaging industries for such
things as tubing, conveyor belts, food-prep gloves and packaging.)
Because they are not chemically bonded to the plastic, phthalates can
escape fairly easily. Some appear to do little harm, but animal studies
and human epidemiological studies suggest that one phthalate, called
DEHP, can interfere with testosterone during development. Studies have
associated low-dose exposure to the chemical with male reproductive
disorders, thyroid dysfunction and subtle behavioral changes.
But measuring the amount of phthalates that end up in food is
notoriously difficult. Because these chemicals are ubiquitous, they
contaminate equipment in even purportedly sterile labs.
In the first study of its kind in the United States, Kurunthachalam
Kannan, a chemist at the New York State Department of Health, and Arnold
Schecter, an environmental health specialist at the University of Texas
Health Science Center, have devised a protocol to analyze 72 different
grocery items for phthalates. Schecter won’t reveal the results before
they’re published – later this year, he hopes – except to say he found
DEHP in many of the samples tested.
Perhaps the most controversial chemical in food packaging is BPA,
which is chiefly found in the epoxy lining of food cans and which mimics
natural estrogen in the body. Many researchers have correlated low-dose
exposures to BPA with later problems such as breast cancer, heart
disease and diabetes. But other studies have found no association.
Canada declared BPA toxic in October 2010, but industry and regulators
in the United States and in other countries maintain that health
concerns are overblown.
Last month, the FDA denied a petition to ban the chemical, saying in a
statement that while “some studies have raised questions as to whether
BPA may be associated with a variety of health effects, there remain
serious questions about these studies, particularly as they relate to
humans and the public health impact.”
The fact that a plastic bottle or bag or tub can leach chemicals
doesn’t necessarily make it a hazard to human health. Indeed, to the
FDA, the key issue isn’t whether a chemical can migrate into food, but
how much of that substance consumers might ingest.
If simulations and modeling studies predict that a serving contains
less than 0.5 parts of a suspect chemical per billion – equivalent to
half a grain of salt in an Olympic-size swimming pool – FDA’s guidance
does not call for any further safety testing. On the premise that the
dose makes the poison, the agency has approved a number of potentially
hazardous substances for food-contact uses, including phosphoric acid,
vinyl chloride and formaldehyde.
Emerging science
But critics now question that logic. For one thing, it doesn’t take
into account the emerging science on chemicals that interfere with
natural hormones and might be harmful at much lower doses than has been
thought to cause health problems. Animal studies have found that
exposing fetuses to doses of BPA below the FDA’s safety threshold can
affect breast and prostate cells, brain structure and chemistry, and
even later behavior.
According to Jane Muncke, a Swiss researcher who has reviewed
decades’ worth of literature on chemicals used in packaging, at least 50
compounds with known or suspected endocrine-disrupting activity have
been approved as food-contact materials.
“Some of those chemicals were approved back in the 1960s, and I think
we’ve learned a few things about health since then,” says Thomas
Neltner, director of a Pew Charitable Trusts project that examines how
the FDA regulates food additives. “Unless someone in the FDA goes back
and looks at those decisions in light of the scientific developments in
the past 30 years, it’s pretty hard to say what is and isn’t safe in the
food supply.”
FDA spokesman Doug Karas in an e-mail interview said that before
approving new food-contact materials, the agency investigates the
potential for hormonal disruption “when estimated exposures suggest a
need.” But FDA officials don’t think the data on low-dose exposures
prove a need to revise that 0.5 ppb exposure threshold or reassess
substances that have already been approved.
Another criticism is that the FDA doesn’t consider cumulative dietary
exposure. “The risk assessments have been done only one chemical at a
time, and yet that’s not how we eat,” Schecter notes. (Karas counters
that “there currently are no good methods to assess these types of
effects.”)
“The whole system is stacked in favor of the food and packaging
companies and against the protecting of public health,” Nudelman, of the
Breast Cancer Fund, says. She and others are concerned that the FDA
relies on manufacturers to provide migration data and preliminary safety
information, and that the agency protects its findings as confidential.
So consumers have no way of knowing what chemicals, and in what
amounts, they are putting on the table every day.
It’s not just consumers who lack information. The companies that make
the food in the packages can face the same black box. Brand owners
often do not know the complete chemical contents of their packaging,
which typically comes through a long line of suppliers.
What’s more, they might have trouble getting answers if they ask.
Nancy Hirshberg, vice president of natural resources at Stonyfield Farm,
describes how in 2010, the organic yogurt producer decided to launch a
multipack yogurt for children in a container made of PLA, a corn-based
plastic. Because children are particularly vulnerable to the effects of
hormone disrupters and other chemicals, the company wanted to ensure
that no harmful chemicals would migrate into the food.
Stonyfield was able to figure out all but 3 percent of the
ingredients in the new packaging. But when asked to identify that 3
percent, the plastic supplier balked at revealing what it considered a
trade secret. To break the impasse, Stonyfield hired a consultant who
put together a list of 2,600 chemicals that the dairy didn’t want in its
packaging. The supplier confirmed that none were in the yogurt cups,
and a third party verified the information.
Originally published by the Washington Post
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