Cultivating Debate

Last Editorial Review: 1/30/2005

Arguments for and against genetically altered produce.

WebMD Feature

When it comes to genetically modified foods, many Americans are saying "Thanks, but no thanks." A tomato engineered to produce its own pesticides or corn altered to resist an herbicide may sound good to farmers, but consumers have serious doubts. Are the fruits (and vegetables) of bioengineering safe to eat? Are they safe for the environment?

More than 76 million acres of the nation?s farmlands are already planted with crops that have been genetically altered, including corn, soybeans, tomatoes, and other produce. But some experts worry that there may be hidden dangers. "When you start making combinations of traits that nature hasn?t made -- especially when you start designing proteins -- you need to be very, very careful," says Margaret Mellon, director of the Agriculture and Biotechnology Program of the Union of Concerned Scientists.

Focusing on Allergies

The chief concern is that genetically altered foods could spark serious food allergies. "Since known food allergens are proteins, foods with new proteins added via genetic engineering could sometimes become newly allergenic," Environmental Defense Fund biologist Rebecca Goldburg recently said at a public hearing held by the Food and Drug Administration. Someone who has never had problems eating corn, for instance, might suddenly develop an allergic reaction. Such problems might not show up until the new items hit grocery-store shelves.

People with serious food allergies usually protect themselves by avoiding foods or substances that cause them trouble. "In the case of genetically engineered foods, however, consumers may not be able to discriminate," Goldburg says.

No one can guarantee that such problems will never arise, of course. But advocates of bioengineering insist that allergic reactions are very unlikely because genetically engineered crops undergo extensive testing. For instance, the FDA required the manufacturer of a new gene-altered soybean to do 1,800 tests, including analyses that compared its proteins, fatty acids, and other components to conventional varieties. Genetically altered varieties undergo far more testing than conventionally bred crops, which often aren?t tested at all, according to University of Edinburgh biologist Anthony Trewavas.

Dangers Down on the Farm

Even if bioengineered foods are safe for consumption, they may threaten the environment in ways that can?t easily be foreseen, critics like the Sierra Club and the Environmental Defense Fund charge. Whether engineered for insect or virus resistance, genes could escape into wild varieties, some experts worry, possibly resulting in "superweeds" that begin to run rampant, disrupting the natural balance among competing varieties.

The worries don?t end there. Not long ago the FDA approved a variety of corn engineered to create a natural pesticide that kills crop-devastating caterpillars, even though they knew that the same natural pesticide is deadly to non-pest caterpillars such as monarchs. Experts dismissed the risk because monarchs aren?t usually found in cornfields. Then Cornell University entomologist John E. Losey, PhD, discovered that corn pollen containing this pesticide, called Bt, can drift to nearby milkweed plants, which monarch caterpillars feast on. In what appeared to be an acknowledgement of potential risk, the Environmental Protection Agency in January directed biotech seed companies to ask farmers to plant traditional corn around the perimeter of Bt corn fields in order to create a buffer zone between the toxic pollen and butterflies.

Still, many biologists think the fears of environmentalists are overblown. "There?s been a lot of hype and hysteria," says ecologist C. Neal Stewart Jr., of the University of North Carolina in Greensboro, pointing out that any risks are tiny compared to those associated with the synthetic chemicals currently used to control weeds and pests.

What?s more, the furor over bioengineering has made governmental agencies more vigilant than ever. "Genetically altered plants are the most studied and most regulated crops in history," Stewart says.

Beyond Risks and Benefits: A Simple Question

Ongoing research should help answer some questions about risks and benefits. But Margaret Mellon thinks we should be asking a different question: Do we really need or want genetically manipulated foods? "What most consumers want is truly fresh and truly varied foods. We don?t need biotechnology to give us that," she says.

Before long, consumers will have a chance to cast their own vote. The FDA is expected to require labels that spell out loud and clear when a food contains genetically altered ingredients.

"No one anticipated the furor we?ve seen over gene-altered foods," says Clare Hasler, who directs the Functional Foods Program at the University of Illinois. "Right now, the future of biotechnology in agriculture depends on how Americans respond to these products. And no one?s making any predictions."

More WebMD Resources:

Food Allergies and Intolerances

Food Allergies

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