Science & Technology: Biotech
Are Bio-Foods Safe?
Despite the uproar, answers are hard to find
It has been a scientific triumph. Harnessing the power of genetic engineering, scientists have been able to slip new genes into plants, creating everything from corn that kills pests to canola that produces higher-quality oil. In just the past four years, more than 40 such crops have been developed--and gene-spliced plants are being grown on an astonishing 76 million acres of U.S. farmland. To supporters of the technology, these genetically modified (GM) plants represent a new green revolution that will benefit farmers and consumers alike all over the world. But to a growing chorus of critics, it is a frightening leap into the unknown. Derisively labeling these new crops "frankenfoods," the critics charge that the plants may make people sick and wreak havoc in the environment.
The stakes for both sides are enormous. In 1999, 47% of the soybeans and 37% of the corn grown in the U.S. were genetically modified to resist herbicides or fight pests. While much of it went into animal feed, Americans now are eating small amounts of these substances in pancakes, corn flakes, and other foods. Kellogg Co. and Quaker Oats, to pick two, say they can't guarantee their products are free of genetically engineered foods. Only a few companies, such as Gerber Products Co. and H.J. Heinz Co., have sworn off GM ingredients in some or all products. If regulators have been asleep at the switch, as critics charge, and bio-foods do harbor unexpected allergens and toxins, then the dinner table becomes a scary place.
What's more, U.S. farmers are already losing $200 million a year in corn exports because of European opposition to modified foods. And international development experts fret that giants such as Monsanto Co. and Novartis have clouded the technology's future by pushing products, such as herbicide-resistant soybeans, that offer no immediately apparent benefit to consumers. If biotech foes end up blocking future biotech crops that really could make a difference, such as virus-resistant sweet potato or drought-tolerant corn, "we've done a tremendous amount of damage," warns Per Pinstrup-Andersen, director general of the International Food Policy Research Institute.OVERBLOWN. So are genetically engineered crops safe--both to people and the environment? The truth is we just don't know for certain. "It would be irresponsible to answer that question," says science policy expert and critic Erik Millstone of the University of Sussex. Even staunch biotech-food backers agree. "We don't have all the answers and to pretend we do, or to brush off concern as unfounded, is to be arrogant and reckless," said DuPont Chief Executive Charles O. Holliday Jr. in a recent speech.
Yet there are some answers, and so far, they suggest that the fears are overblown. Consider the health effects. Foes argue that foods with biotech ingredients are untested and potentially dangerous. "The same Food & Drug Administration that prides itself on keeping thalidomide off the market has turned a blind eye to the genetic engineering of our food supply," charges Representative Peter A. DeFazio (D-Ore.). The criticism puzzles FDA officials and company execs, who point out that the new crops have been through a gauntlet of tests. Take soybeans gene-altered to resist Monsanto's herbicide Roundup, a relatively benign herbicide. With those crops, farmers can use Roundup to control weeds while soybean crops are growing and avoid more dangerous chemicals.
To satisfy the FDA, Monsanto had to show that the gene-altered soybeans are no different than regular varieties. It did 1,800 analyses comparing the two types, looking at fatty acids, proteins, and hundreds of other substances. The results: The normal and genetically engineered plants are indistinguishable.NATURAL TOXINS. A second task was proving that the enzyme made by the added gene is safe to eat. Company researchers showed that its structure is identical to the natural version and that it is digested within 15 seconds in the gut. They also fed high doses of the proteins to rats, and fed gene-spliced soybeans to rats, chickens, catfish, and cows--all with no ill effects. "I don't think people appreciate how much testing we did," says Roy L. Fuchs, Monsanto's director of regulatory science. In fact, says biologist Anthony Trewavas of the University of Edinburgh, "we know more about the safety of Roundup soybeans than almost anything else we eat." After all, he says, conventional crops haven't been tested at all, even though plants naturally contain toxins--and varieties of potato and celery created by traditional breeding methods have made people sick.
The other crops on the market have passed similar tests. One reason the FDA has held hearings in November and December on modified foods is to correct the misapprehension that it isn't on the job. Even GM foes admit that, so far, safety seems high. "There is no food in the marketplace that presents any known risk," concedes Mark Silbergeld, co-director of the Washington office of GM-food-foe Consumers Union.
But he and others argue that the testing isn't answering every possible question. What if gene splicing causes subtle changes in plant substances that companies don't spot? What if health problems don't show up for years? "We can't prove these foods are safe," says Michael K. Hansen of Consumers Union.
Opponents especially worry that genetic engineering might inadvertently add allergens or toxins. They point to a controversial study conducted in Scotland and published in October in which pathologist Arpad Pusztai found lowered immune responses and damage to stomach and intestinal cells in rats fed potatoes engineered to fight pests. But such a plant would probably never make it to market. Pusztai himself says the potato he tested produces different levels of proteins, starch, and other components than the unmodified version. Thus, it doesn't meet the FDA's test of being virtually identical--or in regulatory language, "substantially equivalent."
In addition, the lectin protein in the potato made by the added gene is known to be nasty. For instance, lectin naturally found in peanuts causes changes in the colon cells of people. Despite lectin's pest-fighting potential, Monsanto nixed the idea of putting it in crops. "We had an option to use that gene, but we did not because the protein does raise safety questions," says Monsanto's Fuchs. As for the FDA's scrutiny of potential allergens, "most [conventional] products we eat wouldn't pass the tests," says Samuel B. Lehrer, research professor of medicine at Tulane University.
The bottom line is that there's no evidence that gene-altered foods threaten human health. And so far, the regulatory system seems to have worked, although FDA oversight could be strengthened. It probably will be in the wake of the controversy.ENAMORED. The degree of threat to the environment is less clear. The Agriculture Dept. oversees field-testing of biotech crops, and the Environmental Protection Agency evaluates pesticide-producing plants. But when they looked at the technology in the early 1990s, "the regulatory agencies didn't ask the very obvious questions," says biologist Guenther Stotzky of New York University. Regulators were so enamored of the potential benefits--such as sharp reductions in pesticide use because modified crops could fight insects themselves--that they too readily dismissed the potential for side effects, he says.
A case in point: Monarch butterflies. Monsanto, Novartis, and others have created corn that makes a natural pesticide called Bt. That's a boon to farmers. On Dennis Mitchell's South Dakota farm, for instance, the crop boosted yields 15% by curbing plant-devouring caterpillars. For years, scientists have known that the Bt pesticide kills non-pest caterpillars as well, such as monarchs. But EPA regulators figured that since these nontarget species aren't found in cornfields, the butterflies wouldn't be threatened. No tests were done.
Bad decision. While doing studies in cornfields, Cornell University entomologist John E. Losey noticed that milkweed--the monarch's favorite food--grows near the cornstalks, and that corn pollen falls on the milkweed leaves. In the lab, Losey showed that pollen from Bt corn can kill feeding caterpillars. His report last May helped fuel the opposition to GM crops in the U.S.
Since then, a flurry of studies have discovered that the threat to the monarch "is not as bad as it could have been," says Losey. One key finding: "The amount of pollen that actually collects on milkweed is less than expected," he says. But even if the monarch isn't in grave danger, the whole tale "shows that the regulatory process is weak," says critic Margaret G. Mellon, Director of the Agriculture and Biotechnology Program of the Union of Concerned Scientists. "They didn't do these experiments early on."
Other questions that are just now being answered include how easily added genes can spread via pollination to related plants--and what the environmental consequences might be. If herbicide- and pest-resistant genes get into a nasty weed such as the wild radish, would the result be a superweed, as GM-opponents warn?
Probably not, says ecologist C. Neal Stewart Jr. of the University of North Carolina at Greensboro. He devised a system for tracking the spread of added genes and found that the offspring of Bt canola and birdseed rape do indeed contain the Bt gene. But such mating is highly unlikely to make a bad weed much worse, he says: "An insect-resistance gene or other agronomically important genes will have some effect in a weed, but they're not going to make it kudzu." Introduced species pose a far greater threat than gene-spliced crops, says Edinburgh's Trewavas.
Moreover, Stewart says, it's possible to put new genes into "safe" spots in a crop's genetic material, where the genes are far less likely to get transferred to a weed, offering the promise of even safer biotech crops. "I don't understand the hysterical environmental groups on this," he says. "The risks are tiny compared with the risks inherent in traditional agriculture," such as the widespread use of synthetic chemicals or the threat of insect-carried fungal poisons such as aflatoxin.
Indeed, ecologists point out that biotech crops have no monopoly on worrisome environmental effects. DuPont, for instance, has created a herbicide-resistant soybean through conventional breeding, not gene-splicing, which raises the same issues as the higher-tech varieties. And overall, the environmental questions raised by GM crops have more to do with how the crops are grown than how they are created. "A lot of the critiques have credence not because of the characteristics of the technology but because of the way it is being deployed," says agricultural consultant Charles M. Benbrook.
One major worry, for instance, is that the widespread use of Bt-plants will create new strains of pesticide-resistant insects. "All of us who work in agriculture and who have seen the devastating problems of resistance are concerned," says Cornell entomologist Anthony M. Shelton. But the solution, he believes, is a ban on the crops, but rather the proper use of "refuges." Refuges are areas planted with unmodified crops where enough normal pests can thrive to nip the resistant genes in the bud.
What especially riles supporters is that critics typically overemphasize the hypothetical risks and ignore the real benefits of the new crops. Bt-cotton, which fights off budworm and bollworm pests, "has a real positive benefit in terms of the diversity of insects," says entomologist Fred Gould of North Carolina State University. Compared with normal cotton fields that are doused with chemical pesticides, the fields harbor many more beneficial bugs, such as ladybird beetles.
All of this raises a conundrum. If the risks from biotech food are so small, why are consumers wary? In Europe, much of the answer has to do with the mad cow disaster and the resulting lack of faith in regulators. Beyond that, though, a big reason is that existing products mainly benefit farmers and ag-biotech companies, not consumers.
Company execs readily admit they fumbled the ball. "If the consumer had a health benefit from these crops, I think the acceptance would have been there," says Novartis CEO Daniel Vasella. Now, Monsanto, DuPont, and others are rushing to market crops such as canola with healthier oils or corn that supplies all the proteins animals need.
The biotech wizards are even working on new methods that will allow them to identify the genes they want and slip them into economically important crops through conventional breeding techniques. So if the technology can weather today's storm, the future for biotech crops may be a little brighter.By John Carey in Washington, with Ellen Licking in New York and Amy Barrett in PhiladelphiaReturn to top