Environmental activists are always endorsing
the view that reducing risk is always for the best. Now
they want to warn consumers about the presence of acrylamide,
a known carcinogen, in French fries and potato chips.
Taking a more pragmatic approach are food scientists.
They say that acrylamide has been discovered in many foods
— black olives, coffee, bread, breakfast cereal
— and that humans have been eating the chemical
for years with few, if any, ill effects.
As the two sides square off, two
questions frame their debate: At what level does acrylamide
pose a threat to humans? And how much risk is acceptable?
Though acrylamide has long been recognized as a rodent
carcinogen and human neurotoxin, no one ever suspected
to find it in food. It was believed to be the exclusive
product of industrial waste.
Then came the discovery in 2002 that acrylamide is almost
everywhere in our diet. The tasteless, invisible byproduct
of cooking is formed when foods — particularly high-carbohydrate
foods such as potatoes — are fried or baked at high
temperatures.
Acrylamide turns up in a wide variety of foods; the chemical
is present in 40% of our daily calories. But French fries
and potato chips contain the highest concentrations, and
because we consume so much of them, acrylamide fears have
focused around these products.
The chemical's sheer ubiquity has led some scientists
to question the California attorney general's rationale
in filing suit in August against McDonald's, Wendy's,
Burger King, KFC and several potato chip manufacturers,
including Cape Cod Potato Chips and Kettle Foods.
The suit says the companies are required, under California's
Proposition 65, to warn the public that their potato chips
and French fries contain a toxic chemical.
Many scientists — including the author of the only
published epidemiological studies on acrylamide —
argue that there simply isn't enough data to justify a
warning.
"I think a lot of people were pretty surprised" at the
lawsuit, says Lorelei Mucci, a researcher at Harvard University's
School of Public Health and lead author of two published
epidemiological studies on acrylamide. "It's prevalent
in so many foods that to just target these manufacturers
is not fair."
Mucci's studies suggest that the amount of acrylamide
consumed through diet is insufficient to raise the risk
for colon, rectal, kidney, bladder and breast cancers,
all cancers caused in high-dose acrylamide testing on
laboratory animals.
"More research needs to be done," says Mucci. "But the
preliminary evidence is somewhat reassuring."
Other experts, including government scientists, contend
that — with definitive evidence lacking —
California should do what it can to reduce the risk. They
emphasize that though acrylamide does exist in a wide
variety of foods, its high levels in fries and chips lend
special concern.
"We definitely believe acrylamide is a chemical to be
concerned about," says George Alexeeff, deputy director
for scientific affairs at the state Office of Environmental
Health Hazard Assessment, the office that oversees implementation
of Proposition 65. "Our general presumption is that unless
there's some other evidence, we assume that if something
causes cancer in animals, it causes cancer in humans."
The Environmental Protection Agency considers acrylamide
potentially so dangerous that it has fixed the safe level
for human consumption at almost zero, with a maximum permissible
level in drinking water of 0.5 parts per billion.
By comparison, a 2.4-ounce serving of French fries, a
small portion at McDonald's, contains about 401 parts
per billion, a small, vending-machine-sized bag of potato
chips 466 parts per billion.
According to published studies, the average American consumes
40 micrograms of acrylamide a day — much of it in
coffee, a cup of which has 7 parts per billion.
Swedish researchers discovered its presence in food almost
by accident while testing workers exposed to acrylamide
during railroad construction. When the scientists set
up a control group, they were stunned to find high levels
across the board.
"They got alarmed, brought it up to the World Health Organization
and a series of meetings were convened fairly quickly
to look at this issue," says Carl Winter, director of
the FoodSafe Program at UC Davis, where he researches
naturally occurring toxins in food.
From his viewpoint as a food toxicologist, such fear may
not be warranted.
"It's the levels of exposure that determine the risks,"
he says. "We don't need to take a green light-red light
approach to foods. If we eat foods in moderation, we can
have very healthy diets."
When it comes to toxicology, the argument goes, the size
of the dose makes the poison.
"Dose is the key," says Lois Swirsky Gold, senior scientist
and director of the Carcinogenic Potency Project at UC
Berkeley, who says that scientists don't yet know that
the chemical is hazardous in the doses people get through
their diet.
"The epidemiology doesn't show anything, and even if you
ignored the epidemiology — which I don't think you
should — I would say that just because a chemical
is positive in a rat test doesn't give us the information
we need to call it a human carcinogen," Gold says.
No one denies that acrylamide causes cancer, but neither
is anyone sure just how much of the chemical is dangerous.
Animal studies conducted in the late 1980s exposed rats
to 100,000 times the amounts humans have received in occupational
exposures.
"You're dealing here with very low levels of a potentially
toxic compound," says Michael Pariza, a food toxicologist
at the University of Wisconsin. "We know that rats and
mice are not humans, but we use these tests simply because
we don't have any alternative. It has some rough predictive
marks you can follow, but no one believes these models
extrapolate with any predictive experience."
The argument has pitted food industry scientists against
government regulators.
"If they understand the chemical properties of acrylamide,
they should be concerned about its mutagenicity, toxicity
and carcinogenicity," says Ronald Melnick, a toxicologist
at the National Institute for Environmental Health Sciences.
"Is there uncertainty? Yes. But do we know that it's a
carcinogen? Absolutely. This isn't one of [those]
chemicals you just pooh-pooh because you don't like the
animal data."
Some hope it may be possible to control acrylamide in
food, since the levels vary between brands — even
brands within the same company.
James Wheaton, director of the Oakland-based Environmental
Law Foundation, which works to enforce environmental laws,
says he is encouraged that may be the case.
He cites the fact that some oils contribute to higher
acrylamide levels than others. Other variables seem to
include the kind of potatoes used, how they are stored
and length of cooking time.
The Environmental Law Foundation is one of three nonprofit
organizations that sued the giant potato chip makers before
the state filed its own lawsuit under Proposition 65,
the 1986 ballot initiative requiring "clear and reasonable"
warnings for known carcinogens.
It did so, says Edward G. Weil, assistant attorney general
leading the case against the food makers, only because
the FDA has declined to act.
"They've been studying the problem for three years now,
and they have no schedule or timetable for doing anything,"
Weil says. "Given the fact that we have this law in the
state for dealing with chemicals in the food, it was time
to do something."
Though the FDA opposes labeling food for acrylamides,
Terry Troxell, director of the Office of Plant and Dairy
Foods and Beverages, says the agency may eventually call
for new recommendations for home and industrial cooking.
"But before we go out and make major changes to the food
supply, we need to understand the risk," Troxell says.
"People agree, we need to reduce the levels. But how do
you get there? How can we reduce the levels and still
have a food supply that still has taste and flavors and
colors we still enjoy."
In California, an acrylamide warning might be communicated
by labels, signs in stores (as currently exist for mercury
levels in fish markets), newspaper ads.
The point, says Weil, is to allow consumers to make their
own informed choices.
"Your attorney general has singled out French fries and
potato chips, which reveals that something else is going
on here," says Elizabeth M. Whelan, president of the American
Council on Science and Health, a consumer advocacy group
that receives funding from the food industry.
"There's a huge list of foods containing acrylamide, including
bread and olives. Maybe he decided he didn't want people
to eat these so-called junk foods."
Weil denies any hidden agenda. "It's a convenient rationalization
to say that it's an anti-junk food crusade, but it just
isn't the case," he says. "We're picking the biggest hazard
the way you do in most safety issues."
