Possible Cancer Chemical Varies in Foods

Wednesday   Dec 4, 2002

By LAURAN NEERGAARD, AP Medical Writer

Popular U.S. brands of potato chips and french fries contain highly variable levels of a possible cancer-causing substance — amounts that fluctuate from bag to bag and seem to depend partly on how long foods are cooked — according to federal research released Wednesday.

The substance, called acrylamide, made headlines last spring when Swedish scientists discovered it in snacks and other high-carbohydrate foods that are fried or baked at high temperatures.

Several other European countries confirmed Sweden's discovery — and now preliminary testing by the U.S. Food and Drug Administration is providing the first examination of how levels in some American brands compare.

The only surprise: How much acrylamide levels varied, even within the same brand of food. For example, FDA scientists bought french fries at four different Popeye's restaurants and found a threefold difference between the batches with the highest and lowest acrylamide levels. In tests of 25 bags of Lay's Classic Potato Chips, only two bags came back with the exact same level.

Testing is far from complete — hundreds more brands remains to be examined — and consumers should not use these preliminary results to change what foods they eat, stressed FDA food safety chief Janice Oliver.

While high doses of acrylamide cause cancer in test animals, no one knows if it also harms people and, if so, what levels would be dangerous.

Moreover, acrylamide forms during traditional cooking methods — it's not just in processed foods, but forms during home cooking, too — said FDA senior scientist Dr. Bernard Schwetz.

"This is something that's been going on a long time," he said of people's dietary exposure.

So instead of worrying about acrylamide in their favorite snack brand, Americans should make sure they "eat a balanced diet with a variety of foods that are rich in high-fiber grains and fruits and vegetables," Oliver said.

But the big variability does suggest it may be possible to reduce levels of acrylamide in foods, FDA scientists told a panel of independent scientists convened Wednesday to advise the agency on how best to research the worrisome chemical.

Why would levels differ so markedly?

Scientists suspect an amino acid called asparagine is the culprit. When asparagine is heated with certain sugars such as glucose, a chemical reaction forms the acrylamide. Potatoes are especially rich in both asparagine and glucose, although the amino acid is in numerous carbohydrates and grains. So a different batch of potatoes could yield different acrylamide levels once they're fried.

There even are signs that the longer certain foods are cooked — the browner the fries get, or turning bread into toast — the more acrylamide forms.

The food and restaurant industries stressed that FDA's preliminary research showed no danger to consumers. But food manufacturers are working with the government to figure out why acrylamide levels are so variable — and how to lower them.

That may be a big challenge, because both cooking and a naturally occurring amino acid play a role, said Henry Chin of the National Food Processors Association. How much asparagine is in potatoes — and numerous other foods — depends on environmental factors and how long the uncooked foods are stored, factors hard to alter, he said.

Plus, lower cooking temperatures too much and get a soggy potato chip.

"The challenge ... is not to change what people expect from the taste of food," Chin said.

Acrylamide is used to produce plastics and dyes and to purify drinking water. Although traces have long been found in water, no one expected high levels to be in basic foods. In announcing their discovery last April, Swedish scientists said the levels in some foods are high enough that acrylamide might be responsible for several hundred cases of cancer in that country each year.

Here, the FDA cautions that no one even knows if acrylamide can cause cancer in people, but it has made determining just what risk the chemical poses a top priority

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