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Genetic engineering: Is this food fit to eat?

POSTED 18 MAY 2006

GM food + 10 years. How safe is genetically modified food?
As farmers register another increase in plantings of genetically engineered seeds, we've got a nagging question: Exactly how safe is genetically modified (GM) food? Most of the corn and 85 percent of the soybeans grown in the United States now contain genes moved from other species. Some contain bacterial genes for a natural pesticide.Farmer sits at the controls of a combine, harvesting dried stalks of corn Others contain a plant gene for resistance to a common herbicide. Insect-killing Bt genes (from the bacterium Bacillus thuringiensis) and herbicide resistance genes account for more than 99 percent of all GM crop plantings. A few other crops, including papaya, have had conferred on them other genes for resistance to a virus or other purposes.

The view from the combine window. Farmers have benefited from GM crops, but what about consumers? Photo: USDA

Over the horizon lurks a second generation of biotech foods. These crops may be genetically engineered to make vaccines, nutrients, drugs or industrial chemicals. Although these crops raise a whole new set of questions about food safety, we'll start by looking at the safety of crops on the market.

In judging the safety of herbicide and insect resistance genes, the biotech industry and U.S. regulators have relied on the concept of "substantial equivalence": If genetic engineering does not materially change the crop, it should be considered as safe as non-GM crops. Two plots of brilliant green, leafy soybeansProponents of GM say data proves that GM crops on the market are safe. They also point to the farmer benefits of GM crops. By moving genes among species, they claim, agriculture can feed more people with fewer environmental drawbacks.

It's easier to control weeds in soybeans that resist glyphosate (Roundup), because you can bathe the field in glyphosate, which kills pretty much everything that's green, except the special soy. Monsanto sells Roundup-resistant beans. And it sells Roundup. Photo: Monsanto

Critics charge that GM crops still have not gotten adequate testing, and that experience shows that things can go wrong with high technology. In at least two cases, they point out, unregistered biotech corn has reached the market through the grain-distribution network. Critics still want -- and industry still resists -- mandatory labels on GM food, which would allow consumers to control what they eat. Critics want mandatory Food and Drug Administration regulation, not today's "voluntary" system.

Beyond questions about human health, the political, economic, religious and cultural roots of the opposition to GM foods weave into a complicated fabric of sentiment that still matters even if it is not entirely -- or even primarily -- scientific. To take one economic and social issue, the corporate ownership of genes in crops shifts power and wealth from farmers -- whose predecessors developed food crops in the first place -- to multinationals like Monsanto and Syngenta. The seed makers, critics charge, are profiting from the unpatentable - but critically important -- plant-breeding done by generations of farmers - and then prosecuting some farmers if patented genes appear in their crops.

Bright yellow corn on the cob pokes out from drying husk on stalk
The corn plants that made these honking ears of field corn contain genes to kill corn rootworm, a major pest of a major crop. Photo: Monsanto

What's got GM?
The genetic revolution that is sweeping the world's farm fields is reflected in the food we eat. Corn, for example, is refined into numerous food ingredients that can appear all in almost any processed food. In 2002, one expert wrote, "It has been estimated that 70 percent to 85 percent of processed foods on supermarket shelves in the United States today contain one or more ingredients potentially derived from GM crops" (see "Safety Assessments..." in the bibliography). In the United States, about 125 million acres, soybeans, corn and cotton, were planted to GM crops in 2005.

Graph tracks the increasing familiarity of Americans with GMOS
While 61 percent of Americans say they are generally familiar with science and technology, 58 percent remain unaware of genetically modified foods. Forty-one percent say they have heard about genetically modified food that is sold in grocery stores. Graph: Pew Initiative on Food and Biotechnology

Yet the issue of GM foods bubbles below the surface; many Americans have no idea that they eat GM products in processed foods every day. The most recent survey by the Pew Initiative on Food and Biotechnology, found that "Most Americans continue to know relatively little about GM foods and biotechnology," says executive director Michael Fernandez. "If you ask, have you seen or read or heard about GM food in grocery stores, about 60 percent have heard little or nothing."

When the potential consumer benefits of genetically modified foods are  mentioned, Americans tend to favor GM foods. But the common GM crops benefit mainly farmers and biotech firms

As in many polls, phrasing matters. When asked a general question on GM food safety, a plurality are "skeptical, unconvinced that it's safe," Fernandez says. But if asked whether they favor genetically modified crops that would reduce insecticide use or make a healthier cooking oil, the response changes, Fernandez says. When people "think about a kind of use that may have a direct benefit for them as consumers, you tend to get a more favorable response."

What does the evidence say about GM-food safety?

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Megan Anderson, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David Tenenbaum, feature writer; Amy Toburen, content development executive

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