Important Health Topics
Engineering: The Future of Foods?
Hawaiian farmers were in trouble. In the mid-1990s, an insect-borne
virus--the papaya ring spot virus (PRSV)--threatened to decimate
Hawaii's second-largest fruit crop. Plant breeders scrambled to
produce a virus-resistant papaya. When traditional plant breeding
methods failed, researchers turned to genetic engineering.
Years of research were finally met with success, and by spring
of 1998, Hawaiian farmers were planting the seeds of PRSV-resistant
"The results were dramatic," says Dennis Gonsalves,
Ph.D., a Cornell University plant pathologist who led the researchers'
efforts to save the tropical delicacy and the livelihood of Hawaii's
growers. "It was not a matter of increasing the yield, but
a matter of whether they could grow it or not grow it."
Gonsalves' team of researchers from academia, industry, and
government had isolated and copied a virus gene, then used a device
called a gene gun to "shoot" the gene into the cells
of the papaya plant. The virus gene in the plant works somewhat
like immunization, but the mechanism of resistance is different,
says Gonsalves, now director of the U.S. Department of Agriculture's
Pacific Basin Agricultural Research Center in Hilo, Hawaii. "By
integrating this virus gene into the chromosomes of the papaya,
this made the papaya and subsequent generations resistant to the
The rescue of the Hawaiian papaya industry is "a really
satisfying story," says Gonsalves, and one that shows the
difference that genetic engineering can make in people's lives.
But not all share Gonsalves' enthusiasm for genetically engineered
foods. Although the newness of these foods may be wearing off,
public concern about the safety and environmental impact of genetically
engineered foods remains.
Some consumers and advocacy groups urge mandatory labeling that
discloses the use of genetic engineering. Others advocate more
stringent testing of these products before marketing. Still others
want a ban on all genetically engineered foods.
"The Food and Drug Administration is confident that the
genetically engineered food products on the U.S. market today
are as safe as their conventionally bred counterparts, and the
agency is prepared to meet the safety and regulatory challenges
presented by new products as they emerge from the laboratory,"
says Commissioner of Food and Drugs Mark B. McClellan, M.D., Ph.D.
"Genetically engineered foods must adhere to the same high
standards of safety under the Federal Food, Drug, and Cosmetic
Act that apply to more traditional food products," McClellan
What Are Genetically Engineered Foods?
Genetically engineered foods are produced from crops whose genetic
makeup has been altered through a process called recombinant DNA,
or gene splicing, to give the plant a desirable trait. Genetically
engineered foods are also known as biotech, bioengineered, and
genetically modified, although "genetically modified"
can also refer to foods from plants altered through other breeding
methods, says James Maryanski, Ph.D., the FDA's food biotechnology
coordinator. "Scientists and farmers have been genetically
modifying plants for hundreds of years," he says. Hybrid
corn and tangelos (hybrid of a tangerine and grapefruit), for
example, are the result of genetic modification through traditional
methods of plant breeding. And the many varieties of apples we
eat today were produced through genetic modification.
Using traditional genetic modification methods, such as cross-fertilization,
scientists can produce a desired trait, such as a hardier plant.
But in doing so, they mix thousands of genes from several plants,
requiring many attempts over many years to weed out the unwanted
traits that occur.
Newer methods of genetic modification, in the form of genetic
engineering, are more precise and 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
The first genetically engineered whole product--a tomato--went
on the market in 1994. The FDA determined that the new tomato,
which could be shipped vine-ripened without rotting rapidly, was
as safe as other commercial tomatoes. Since then, more than 50
other genetically engineered foods have been determined by the
agency to be as safe as their conventional counterparts.
The Grocery Manufacturers of America estimates that between
70 percent and 75 percent of all processed foods available in
U.S. grocery stores may contain ingredients from genetically engineered
plants. Breads, cereal, frozen pizzas, hot dogs and soda are just
a few of them.
Soybean oil, cottonseed oil and corn syrup are ingredients used
extensively in processed foods. Soybeans, cotton and corn dominate
the 100 million acres of genetically engineered crops that were
planted in the United States in 2003, according to the U.S. Department
of Agriculture (USDA). Through genetic engineering, these plants
have been made to ward off pests and to tolerate herbicides used
to kill weeds. Other crops, such as squash, potatoes, and papaya,
have been engineered to resist plant diseases.
Safety of Genetically Engineered Foods
Genetically engineered plants are regulated by three government
agencies: the FDA, the USDA, and the Environmental Protection
Agency (EPA). The FDA ensures that foods made from these plants
are safe for humans and animals to eat, the USDA makes sure the
plants are safe to grow, and the EPA ensures that pesticides introduced
into the plants are safe for human and animal consumption and
for the environment. While these agencies act independently, they
have a close working relationship since many products come under
the review of all three.
The Federal Food, Drug, and Cosmetic Act (FD&C Act) gives
the FDA authority to regulate foods for humans and animals, including
foods derived from bioengineered plants. Under the act, companies
have a legal obligation to ensure that any food they sell meets
the safety standards of the law. The safety standards apply equally
to conventional food and genetically engineered food. If a food
does not meet the safety standards, the FDA has the authority
to take it off the market.
More than 50 biotech food products have been evaluated by
the FDA and found to be as safe as conventional foods, including:
- Canola oil
- Cottonseed oil
- Sugar beets
- Sweet corn
Sources: Council for Biotechnology Information,
Food and Drug Administration
Bioengineered foods do not pose any risks for consumers that
are different from conventional foods, says Maryanski. "We
make sure there are no hazards, such as an unexpected allergen
or poisonous substance in the food, or that the food is not changed
in some way that would affect its nutritional value."
The FDA's efforts to ensure the safety of bioengineered foods
include publishing rigorous safety testing guidelines, establishing
a consultation process with industry, and seeking the expertise
of scientists outside the agency.
In 1992, the FDA published a policy statement and testing guidelines
for foods developed using all methods of plant breeding, including
the use of genetic engineering. These guidelines explain the types
of food safety questions that developers should address in evaluating
the safety of all plant-derived foods.
In 1994, the FDA set up a consultation process to assist developers
in meeting the safety standards set forth in its guidelines. FDA
scientists advise companies on the tests needed to assess the
safety of new foods. After testing is completed, companies send
safety and nutritional information to the FDA for the agency's
Although consultation is voluntary on the part of developers,
the legal requirements that the foods have to meet are not. Some
consumer advocates and scientists have urged the FDA to make the
consultation process mandatory, but the agency believes that companies
are cooperating within the voluntary system.
"This current process is working very well and fully protects
public health," says McClellan. "To the best of our
knowledge, all bioengineered foods on the market have been evaluated
by FDA through the current consultation process." This includes
genetically engineered foods produced by companies outside the
United States and marketed here.
In July 2003, the Codex Alimentarius Commission adopted international
guidelines for biotech food safety that are consistent with the
FDA's approach. Codex, an entity established by the World Health
Organization and the Food and Agriculture Organization of the
United Nations, is the highest international body on food standards.
Several private and government organizations have studied the
safety of genetically engineered foods. In a study released in
2000, a committee of the National Academy of Sciences (NAS) concluded,
"The committee is not aware of any evidence that foods on
the market are unsafe to eat as a result of genetic modification."
This conclusion was echoed in a report published by the Government
Accounting Office in 2002. On the animal side, the international
Organization for Economic Cooperation and Development published
a consensus document in 2003. It noted that there is no evidence
to date from animal feeding studies with bioengineered plants
that the performance of animals differed in any respect from those
fed the non-bioengineered counterpart.
The FDA has received many inquiries about the labeling of genetically
engineered foods. Some consumer advocates and organizations, such
as the Union of Concerned Scientists, urge the FDA to require
labeling to identify which foods are genetically engineered.
Under the FD&C Act, Congress has provided the FDA a limited
basis on which to require labeling. Generally, there must be something
tangibly different about the food product--not the process by
which it's made--for the FDA to require labeling.
"The FDA has no information that the use of biotechnology
creates a class of food that is different in quality, safety or
any other attribute from food developed using conventional breeding
techniques," says Maryanski. He adds that disclosure of genetic
engineering techniques is not required on the label, just as identification
of conventional breeding techniques is not required--for example,
"hybrid corn" can just be called "corn."
Any significant differences between the bioengineered food and
its conventional counterpart do have to be disclosed in labeling.
These would include differences in nutritional properties, the
presence of an allergen that consumers would not expect in the
food, or any property that would require different handling, storage,
cooking or preservation. For example, when a manufacturer produced
a line of soybeans whose oil had higher levels of oleic acid than
found in conventional soybean oil, the FDA agreed to naming the
product "high-oleic soybean oil" to distinguish it from
traditional soybean oil. The high-oleic oil can be used in frying
without the need for the chemical process of hydrogenation, which
produces trans fat.
Food processors may voluntarily label either the presence or
absence of a genetically engineered food in their products as
long as the information is truthful and not misleading to consumers.
The FDA has produced guidance to the industry for this type of
Future Foods and Regulatory Challenges
The first generation of genetically engineered crops was developed
primarily to benefit the growers. Plants were created to resist
pests and diseases and to tolerate herbicides used to kill weeds.
Scientists see the next generation of genetically engineered products
benefiting consumers directly. They are adding nutrients to foods
to help prevent diseases, reducing allergens and toxins, and making
Using the tools of biotechnology, researchers are working to
reduce the bitterness in citrus fruits, reduce saturated fats
in cooking oils, produce more flavorful tomatoes, and even lessen
the gassiness caused by beans. Grains, fruits and vegetables that
contain more nutrients and potatoes that absorb less oil when
made into chips and french fries are also in the development pipeline.
As the tools and techniques used in biotechnology become more
complex and a broader range of plants are researched for a wider
variety of uses, the FDA must prepare for the safety and regulatory
challenges that novel genetically engineered foods may present.
One of these challenges is evaluating food for its potential
to cause allergic reactions. People who have food allergies are
usually allergic to specific proteins in foods.
FDA biochemical engineer Tong-Jen Fu, Ph.D., is analyzing methods
currently used by scientists to determine the allergenic potential
of new proteins that may be introduced in food. "The only
way people can avoid allergic reactions to food is to avoid eating
those offending foods," says Fu. "But we know that there
is some possibility that a new protein in food may be an allergen
for some individuals. So it is important to have sound scientific
methods for assessing whether a new protein will be an allergen."
Fu is analyzing a current test that assumes a correlation between
digestive stability and allergenic potential. Using simulated
gastric and intestinal fluids, she has found that this correlation
isn't always present. Fu's work is improving the FDA's knowledge
about proteins and their likelihood of being allergens, which
ultimately will help agency regulators determine if a food is
To further assure that the FDA has the best scientific knowledge
available to assess the safety of genetically engineered foods,
the agency has increased the number of staff experts in plant
genetics, molecular biology, immunology, and agricultural biotechnology.
In addition to its own scientists who evaluate safety data,
the FDA looks to outside experts, such as the NAS, for advice
on food safety assessments. In response to public concerns about
the unknown long-term effects of consuming genetically engineered
foods, the FDA, USDA and EPA requested assistance from the NAS.
The NAS is currently conducting a study to assess the potential
for unintended health effects resulting from genetically engineered
"We have no reason to believe there are any adverse effects
from the long-term use of these foods," says Maryanski, "but
we've asked the NAS to look into it as part of our continuing
effort to make sure that our decisions are based on the best science
The FDA has added members with agricultural biotech expertise
to its advisory committees that address scientific questions related
to bioengineered foods and animal feeds. These committees also
include consumer representatives.
"The FDA will continue to reach out to the public to help
consumers understand the scientific issues and the agency's policies
regarding genetically engineered food," says McClellan. "FDA,
in cooperation with USDA and EPA, will continue its oversight
of new and emerging food biotechnology products and will be vigilant
in ensuring the safety and integrity of the food supply."
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
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
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
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
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.
For More Information
FDA's food biotechnology Web site
List of bioengineered foods that have completed FDA consultation