June 28, 2000
When an agricultural company genetically engineers a new type of soybean to be more nutritious or a new variety of corn to be more pest resistant, it may produce unintended results. One such inadvertent byproduct is the possible creation of new allergenic proteins that can cause some people to wheeze, break out in a rash or even stop breathing.
This has led to a new wrinkle in the study of food allergens. Over the past few years, Sam Lehrer, research professor of medicineclinical immunology, and his laboratory staff have been working with companies who are genetically engineering new crops to improve the risk assessment for allergy.
"We still don't know all of the properties that make a molecule allergenic," says Lehrer. "But we do know they have to be pretty hardy molecules to make it through the gauntlet of the gut. So we can do tests on these new products based on what we know about the food allergens we've already studied."
When the genetically engineered plant under study is similar to a naturally occurring plant, the researchers test to see if the new plant resulted in possible new proteins, or an increase in the known allergenic protein, by testing them with the serum of allergic individuals.
"The greater challenge is when we deal with proteins that don't have much of a history of human exposure," Lehrer says. Lehrer says the genetically engineered foods he has assessed-including a Dupont soybean altered to produce high levels of heart-healthy oleic acids-have shown no increased allergenic properties.
"We felt that this product did not post increased risk to consumers," he says. "Certainly, soy is soy and if someone is allergic to soy they will be allergic to this. But it doesn't pose any new threats or increased threats."
Scientists can also use genetic engineering to decrease the allergic properties of foods, Lehrer says. A group in Japan has significantly reduced the production of a major rice allergen, and researchers in Little Rock, Ark., have identified the allergen in peanuts and are working on ways of altering the molecule.
In his lab, Lehrer and Gerald Reese, research assistant professor of medicine, have isolated the major allergen in shrimp and are hoping to alter the molecule genetically to decrease its allergenic properties. If their research proves successful, Lehrer envisions farms with genetically-modified shrimp that people who are allergic to shellfish can eat safely.
"It's more complicated, certainly, in an animal than in a plant," he says. "But the techniques are available and it can be done."
Lehrer, who has spent his professional life studying food allergens, has been appointed to sit on the National Academy of Science's National Research Council's Standing Committee on Biotechnology, Food and Fiber Production, and the Environment. This committee identifies emerging scientific issues-such as genetically engineered foods-and evaluates biotechnology products as they affect people, agriculture and the environment.
Along with his research, Lehrer has joined the debate that surrounds genetically engineered foods. He speaks at international conferences on the allergenic properties of these foods and has heard arguments from groups that support the new technology and people who think it's unsafe.
Critics of genetically engineered foods argue that genes from the new breeds of crops may transfer to their wild relatives, perhaps resulting in a new breed with undesired characteristics, such as a weed that grows well and resists pests.
They also argue that engineering plants in the lab, perhaps crossing genes from plants that never would have bred in the wild, interferes with the balance of the ecosystem. Lehrer says these concerns are legitimate and must be considered as the field evolves.
Crops engineered to have better disease and pest resistance and improved nutritional quality, however, have benefits that justify creating new products. Developing countries in particular stand to improve substantially their food supply using these new crops, he says.
"In developing countries, food security is essential," Lehrer says. "In these countries these advances are the only way they can keep their food supply adequate for their growing populations." Above all, Lehrer says he hopes the debate on the pros and cons of genetically engineered foods can avoid becoming increasingly antagonistic.
"I'm not concerned about the fact that these products can be controversial," he says. "There is debate about them and debate is good in society and leads to better resolution of issues. What I'm concerned about is that the debate is becoming so polarized that people go beyond the point of rational discourse."
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