All About Genetically Modified Foods

Farmers, ranchers and vintners have been modifying and improving crops, livestock and wine for thousands of years, through cross-fertilization and selective breeding.

Recent advances in genetics, however, have made this process smoother and faster. Today's agricultural and food industries are using genetic engineering to develop new and better foods and food-related products.

Modifying foods by deleting or inserting certain genes into a plant is not vastly different from cross-fertilization, a process that has produced scores of varieties of apples, as well as hybrid corn and the tangelo, a hybrid of the tangerine and the grapefruit.

When cross-fertilization and other traditional modification methods are used, thousands of genes from several plants are mixed in the offspring. It can take many attempts over many years to weed out the unwanted traits that occur. Genetic engineering allows scientists to move only the desired genes. This makes the process more precise, predictable--and faster. By controlling the insertion of one or two genes into a plant, scientists can give it a specific new characteristic without transferring undesirable traits.

The first genetically modified (GM) food product for human consumption was a tomato, which went on the market in 1994. It had a longer "shelf life" than other tomatoes. Since then, potatoes, squash, corn, potatoes and sugar beets have joined the ranks of GM foods, and many more foods contain engineered ingredients. Up to 75 percent of all processed foods sold in grocery stores today may have GM ingredients, according to the Grocery Manufacturers of America.

Benefits and risks

The Food and Drug Administration (FDA), the Department of Agriculture (USDA) and the Environmental Protection Agency (EPA) all oversee GM food production. The FDA determines that foods made with GM plants are safe to eat; the USDA makes sure the GM plants are safe to grow, and the EPA regulates the pesticides used on GM plants.

GM foods are generally regarded as safe. The safety of each new GM food will have to be judged individually, however.

There are many advantages to GM foods. By selectively breeding for desired traits, farmers and scientists have produced plants and animals that are more resistant to disease, drought and pests (so less pesticides and water have to be used); have improved taste and nutritional value; produce more food; and grow faster. 

GM foods could help in areas of the world where malnutrition is a problem. They can be bioengineered to contain certain nutrients. "Golden rice," for instance, has been developed to contain beta-carotene, a precursor of vitamin A. A deficiency in vitamin A is common in certain developing countries that depend on rice; vitamin A deficiency can cause blindness and a weakened immune system.

Although no reports of illness or injury from GM foods have been reported, there may be risks that have not yet been observed. Environmental concerns have been voiced about GM plants and animals: Could these modified plants or animals interbreed with their unmodified cousins, ultimately leading to extinction of the original plant or animal? Could plants developed to be resistant to certain pests turn out to be vulnerable to other pests? Could GM plants transfer a gene to a weed, which might then grow out of control, becoming a "super weed"? Could modified plants cause unexpected allergic reactions?

Other concerns hinge on social and political issues: Will countries that develop GM crops make them available to poorer countries? Will those that develop GM crops make sure they are safe?

Future of genetically modified foods

The first GM plants were not consumed directly by people, but were developed to make it easier for farmers to grow animal feed or crops that were processed into oils. These "first generation" crops were able to resist certain pests and diseases or tolerate herbicides that got rid of weeds. Ongoing research is developing GM crops that are more tolerant to cold, heat, drought or salt.

A "second generation" of GM crops is aimed directly at consumers. These include fruits and vegetables -- like that first tomato -- that have a longer shelf life and better taste, as well as crops with added nutrients. Ongoing research is developing GM foods such as less bitter citrus fruits and less gassy beans.

A "third generation" of GM crops is exploring ways to use plants to create edible vaccines and antibiotics, as well as substances such as anticoagulants, blood substitutes and hormones. Other GM ideas: plants that can absorb and trap toxic substances, and trees that withstand disease.

Labeling of genetically modified foods

You may not be able to tell when you're buying GM foods, because the FDA generally doesn't require manufacturers and producers to label them as such. That's because GM foods are considered no different in quality or safety from conventionally produced foods. A label mention would be required only if the GM food were obviously or significantly different -- if, for instance, the food contained different nutrients or possible allergens, the FDA says.