Safety of Genetically Engineered Foods : Part 3

by Food and Drug Administration (FDA)

(Page 4 of 4)

A Look Into the Biotech Laboratory

Scientists are developing new varieties of crops that can withstand harsh growing conditions.

Ray Wu, Ph.D., a genetic engineering pioneer and molecular biologist at Cornell University in Ithaca, N.Y., has added two genes from the E. coli bacteria to rice plants, making them tolerant to drought, cold temperatures and salty soil. The genes produce trehalose, a naturally occurring sugar found in a variety of organisms, including bacteria, that protects them from environmental stresses.

The rice plants grew successfully in the greenhouse and are ready for field testing, says Wu. He predicts that in about five years, the plants can be growing in farmers' fields.

Wu explains that the two E. coli genes in the rice will not harm consumers. "E. coli contains thousands of genes," says Wu. "We are only taking two particular genes that we know will not produce toxic products." As an added precaution, Wu used a "promoter" to control the expression of the E. coli genes to direct the plant to make trehalose in specific parts, such as the non-edible leaf. Also tested was a second promoter, which serves as an "on-off switch" so that trehalose is made only in response to an environmental stress.

Although rice is a relatively minor crop in the United States, it is a staple in many developing parts of the world, says Wu. And scientists can use the same procedure of inserting genes and a promoter to create biotech wheat, corn and other cereal plants that can withstand harsh conditions. "The world population continues to increase at an explosive rate, our arable land is deteriorating, fresh water is becoming scarce, and increasing environmental stresses will pose ever more serious threats to global agricultural production and food security in future years," says Wu. "Anything we can do to help crop plants cope with environmental stresses will also raise the quality and quantity of food for those who need it most."

One concern about genetic engineering is that scientists might unknowingly create or enhance a food allergen. But researchers are hoping that this powerful technology can be used to eliminate or reduce allergens, such as those found in peanuts, wheat and soy.

Experts estimate that 8 percent of children 6 years old and younger and 1 to 2 percent of adults have food allergies, which can cause severe, and sometimes life-threatening, reactions.

Early attempts to eliminate a food allergen have yielded promising results. In 2002, researchers genetically engineered soy to eliminate expression of a common soy protein. Soy allergies are particularly common in infants and young children, according to the National Institute of Allergy and Infectious Diseases. It's difficult to avoid eating soy because of its wide use in many processed foods, including infant formula, cereals, and salad dressings.

Using a "gene silencing" technique, researchers were able to "knock out" a gene that makes a protein called P34, which is thought to trigger most allergic reactions to soy. Tests on blood from people allergic to soy showed no antibody response to the plant with the knocked-out gene, indicating that the allergen could not be detected. The plant's characteristics were also analyzed. "We see no change in the pattern of growth, productivity, or protein composition," says Eliot Herman, Ph.D., lead researcher on this project and molecular biologist at the U.S. Department of Agriculture's Agricultural Research Service.

The work is not done yet, cautions Herman. "There are up to 15 different proteins in soybeans that people are allergic to," he says. "The major one, P34, is responsible for 75 percent of the allergic reactions. How much do you have to get rid of to not trigger an allergic response at all? This is what we need to find out."

Herman sees the benefit of genetically engineered soy in both human food and animal feed. "Baby pigs are similar to baby humans in their reaction to soybeans," he says. "They have gastric distress too." Herman's team is studying the reaction of piglets to the genetically engineered soy, and these studies may pave the way to human clinical trials.

'Pharm' Factories of the Future

Plants may become miniature "factories" for pharmaceuticals through genetic engineering. Scientists are growing plants that produce antibodies to help fight cancer, heart disease and tooth decay. And researchers are experimenting with growing fruits and vegetables that contain vaccines for measles, hepatitis B, Norwalk virus, diarrhea, cholera and more.

These edible vaccines could be pureed into an applesauce-like consistency and fed to children and adults alike. They could be produced in larger quantities and at less expense than current vaccines, although they will have to be grown and handled under strict conditions imposed by the U.S. Department of Agriculture (USDA) aimed at ensuring that they do not inadvertently enter the food supply.

The Food and Drug Administration regulates pharmaceuticals, whether they are manufactured in traditional factories or in crops in the field, to ensure their safety, purity and potency. The FDA and the USDA have jointly published draft guidance specifically addressing the use of bioengineered plants to produce pharmaceutical products.

The FDA is also part of a White House National Economic Council working group that is addressing the regulation of genetically engineered crops to ensure there are no gaps in protecting human health and the environment.

About the Author

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.