By Raymond Formanek Jr.

The shelves of just about every American supermarket are lined with foods that have been genetically altered to improve the product's taste, shelf life, or resistance to insects and other pests.

Tomatoes, potatoes, squash, corn, and soybeans have been genetically altered through the emerging science of biotechnology. So have ingredients in everything from ketchup and cola to hamburger buns and cake mixes.

Most of the foods we eat today are the result of crossbreeding--a technique that relies on the laws of inheritance first described by Gregor Mendel in the 19th century--to obtain desired characteristics.

Crossbreeding is inexact. It also involves trial-and-error and lots of time. Although biotechnology is a more efficient way to introduce new traits, there are concerns. Some worry about the possibility of introducing new allergens into foods. Others worry about the potential effects that altered crop species may have on wildlife and other plants.

However, many researchers say the ability of biotechnology to isolate and introduce a specific gene or just a few genes makes outcomes more predictable, including the ability to predict risks. Supporters say that biotechnology is a tool that allows scientists and farmers to reduce damage from pesticides, boost crop yields, and improve flavor, texture and nutritional content.

FDA Oversight

The Food and Drug Administration proposed mandatory rules in January that would tighten the scrutiny of bioengineered foods. The rules would require that manufacturers of plant-derived, bioengineered foods and animal feeds notify the FDA at least 120 days before the products are marketed.

As part of the notification, the manufacturer would provide information showing that the foods or feeds are as safe as their conventional counterparts. Manufacturers have completed voluntary consultations on roughly 50 bioengineered foods using scientific guidelines published by FDA in 1992. The proposal would make the current practice of voluntary consultations mandatory and require manufacturers to submit safety and nutritional information to FDA.

"Our basic policy with respect to bioengineered foods is that there is nothing inherently different with these foods," says Joseph Levitt, director of the FDA's Center for Food Safety and Applied Nutrition (CFSAN). "We will continue to examine each product on a case-by-case basis. We'll make sure that data on things like nutritional content or natural toxicants are there. We want to be sure that all the safety bases are covered."

Levitt says the evaluation process would become "transparent" under the proposed rules. Information submitted by manufacturers, as well as FDA responses, would be posted on the CFSAN Web site at www.cfsan.fda.gov.

The FDA also has issued draft guidelines for companies that want to label their products to indicate that a food or feed has or has not been developed using bioengineering methods. Terms such as "genetically modified" (GM), "genetically modified organism" (GMO), and "modified" are not recommended under the guidelines.

On the other hand, Levitt says a manufacturer that wants to label a product as "genetically engineered" may do so "but consumer focus groups we met with suggested that they should say why."

"We want the labeling to be informative, but not misleading," he says.

Public Input

The proposed rule for notification and draft guidelines for labeling are the result of more than 18 months of discussion with consumers, manufacturers, growers and others. "We heard views across the entire spectrum," Levitt says. "We have literally thousands of comments."

The proposals can be viewed on the Internet at www.cfsan.fda.gov/~lrd/biotechm.html. FDA will issue a final rule after public comments are evaluated this spring.

No Known Dangers

Broadly speaking, growers have been selecting certain beneficial characteristics such as faster growth or sweeter fruit since our nomadic hunter ancestors began to cultivate crops thousands of years ago. Virtually every domesticated crop plant species today differs greatly from its original, wild form due to human intervention.

Companies seeking to market any bioengineered food product conduct studies to show that the new food is as safe as its conventionally crossbred counterpart. The FDA has determined that normal safety and quality control practices used by plant breeders, such as chemical analyses and taste testing, generally are important. Nutritional and other tests also are done to provide additional safety assurances. Bioengineered foods actually are regulated by three federal agencies: the FDA, the Environmental Protection Agency (EPA), and the United States Department of Agriculture (USDA).

The Federal Food, Drug, and Cosmetic Act gives FDA the authority to regulate all foods, food ingredients, and animal feeds derived from crops, including plant varieties developed through biotechnology. The USDA's Animal and Plant Health Inspection Service monitors genetically engineered plants for potential risks to the agricultural environment. The EPA regulates pesticides--including those introduced into plants through biotechnology. (See "StarLink Corn Investigation and Recall.").

Future Growth

A federally funded study by the National Research Council released in 2000 concluded, "There is no evidence suggesting that [bioengineered food] is unsafe to eat." The study also found that there is "no strict distinction" between the health and environmental risks posed by genetically engineered plants and those developed through conventional crossbreeding.

Bioengineered foods will not solve all of the world's nutritional and agricultural problems. However, the techniques used to develop them likely will play an important part in boosting food production, improving nutrition, and reducing the needs for herbicides and pesticides.

DNA: The Root of Biotechnology

The discovery that deoxyribonucleic acid (DNA) was a sort of biological "software" in the mid-1950s set the stage for today's bioengineered foods, pharmaceuticals, transgenic animals, and gene therapy.

DNA molecules contain the genetic information necessary for life. This information is contained in four chemical bases: adenine, cytosine, guanine and thymine. Specific chunks of DNA that carry the codes necessary for the production of a specific protein are called genes. These proteins contribute to the expression of a specific trait by stimulating biochemical reactions, or by acting as structural or storage units of a cell.

The fact that DNA is a genetic building block in all organisms makes it possible to insert a gene or genes into plants instead of relying on cross-pollination. The inserted gene, called a transgene, may come from an unrelated plant, or even from bacteria, viruses or animals.

For example, scientists have developed a variety of rice capable of synthesizing beta-carotene, a precursor to vitamin A, by inserting genes from a soil bacterium and two genes from a daffodil. Although it's the staple food for half the world's population, rice is a poor source of many essential nutrients and contains no vitamin A. The genetically engineered rice someday could help millions of people worldwide who suffer from vitamin A deficiency, a condition that leads to blindness in a quarter million children annually in Southeast Asia.

A Long-Running Debate

The debate over genetically engineered plants began almost as soon as scientists learned to directly alter the genes in plants in the early 1980s. Opposition to bioengineered foods has been especially strong in Europe and Japan.

Concerns include ethical issues related to potential long-term health effects of eating bioengineered foods, labeling, and potential environmental risks. The FDA has reviewed all new bioengineered foods brought to market and has found no reason to believe that they could pose any threat to health.

Grocers began selling the "Flavr Savr" tomato--the first genetically altered food product to enter the U.S. food supply--in 1994. The Flavr Savr ripened slower, could remain on the vine longer, and was expected to provide better quality than other tomatoes available in winter.

Experiments are now under way to develop tomatoes that have enhanced levels of lycopene, a plant chemical that gives tomatoes their red color. Researchers say lycopene also may offer health benefits due to its apparent antioxidant properties. Antioxidants are thought to neutralize harmful molecules in the human body called "free radicals." These substances, which result from cell metabolism and other causes, may contribute to cancer and cardiovascular disease.

Many genetic modifications have been designed to improve production. About half of the soybeans and about 25 percent of the corn grown by farmers in the United States have been bioengineered, according to the USDA. Most of these transgenic crop varieties have been designed to either better tolerate herbicides or resist insects without the need for extensive spraying of pesticides. An estimated two-thirds of the processed foods in U.S. supermarkets contain genetically engineered corn, soybeans or other crops.

Biotechnology also has the potential of creating major advances in medicine. Scientists are looking into the possibility of producing bananas that contain vaccines against cholera, hepatitis B and diarrhea. Some researchers say that food-based vaccines could be especially useful in developing countries because the costs associated with refrigeration and needle sterilization would be greatly reduced or eliminated.