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Synthesis/Regeneration 18   (Winter 1999)

Why We Need Labeling of Genetically Engineered Food

by Michael Hansen, Ph.D. & Jean Halloran, Consumer Policy Institute/Consumers Union

Food is fundamentally different from other consumer products. As something we literally take inside ourselves, that is necessary on a daily basis for growth and life, and that is bound up in our cultures and traditions, we care about it intensely. Consumers feel they have a fundamental right to know what they are eating, and that it is safe. Most developed countries have adopted laws that reflect this view, requiring ingredient labeling, labeling as to any processing (e.g., frozen, homogenized, irradiated), conformance to standards of identity (e.g. peanut butter must be made from peanuts), and indicating presence of any additives (e.g. sulfites, preservatives). Some countries require labeling as to the fat, protein, carbohydrate and vitamin content of food as well.

Consumers want to know what they are eating both as a pure matter of taste and preference, and for many health-related reasons. They may want to eat fish to improve their chances of avoiding heart disease, or avoid fish because they are concerned about depletion of certain species in the oceans or about mercury contamination. Body builders may seek out red meat, vegetarians will avoid it, and Muslims will avoid pork but not lamb. Mothers may look for apple juice for their children because it is a natural drink, or avoid it because it gives their child a stomach ache. Every day, millions of consumers worldwide read millions of food labels and make millions of decisions like this for themselves and their families.

The countries of the European Union have recognized this, and have instituted regulations requiring labeling of all genetically engineered food, although many consumer and environmental groups think the labeling requirements do not go far enough. In the United States, where genetically engineered corn, soybeans and potatoes are being grown commercially, repeated public opinion surveys show consumers overwhelmingly want labeling, but thus far the government has failed to require it. Most countries have not considered the issue yet. Of the large chemical/biotechnology companies that are developing these foods, some, like Novartis, support labeling, but most, like Monsanto and other major developers, oppose it.

Consumers feel they have a fundamental right to know what they are eating, and that it is safe.

The Codex Alimentarius, an agency of the United Nations World Health Organization and Food and Agriculture Organization, is considering whether to adopt a guideline recommending that all countries require labeling of genetically engineered food. Codex guidelines are not binding, but are often adopted by developing countries and can be used to settle trade disputes (if a country adopts a Codex standard, that standard cannot be challenged as protectionist).

Consumers want and have a right to labeling of all genetically engineered food, because it is not "substantially equivalent" to conventional food, because some individuals can have unpredictable mild to severe allergic reactions, because it can have unanticipated toxic effects, because it can change the nutrition in food, because it can cause dramatic environmental effects and because consumers presently use food labeling to express a wide variety of religious, ethical and environmental preferences.

Genetically Engineered Food is Different

Some people-mostly scientists and corporations involved in the development of genetically engineered food-argue that the strawberry with the foreign genes is not really different-it is "substantially equivalent" in the language Codex and international regulation, and therefore needs no label. Consumers, however, through their organizations, through comments to regulators, and through opinion surveys, have repeatedly expressed the view that this strawberry, and all other genetically engineered foods, are not "substantially equivalent," but are sufficiently different that, like irradiated foods, and foods containing additives, they should be labeled. Since labeling laws are created to meet consumer needs, it is consumer opinion which should be relevant in this regard.

A range of consumer and other civil society organizations worldwide argue that any plant or animal food to which genes have been added from a source other than the species to which the food belongs, should be required to be labeled as genetically engineered, because it is different from conventional food; in the language of Codex, it is not "substantially equivalent" to unengineered food.

Genetically Engineered Food Can Cause Toxic Effects

The fact that genetic engineering can go seriously wrong was shown by one of the very first products introduced into the market. An amino acid called tryptophan was sold in a number of countries including the United States as a dietary supplement. In the late 1980s, the Showa Denko company of Japan began making tryptophan by a new process, using genetically engineered bacteria, and selling it in the United States. Within a period of months, thousands of people who had taken the supplement began to suffer from eosinophilia myalgia syndrome, which included neurological problems. Eventually at least 1500 people were permanently disabled and 37 died (Mayeno & Gleich, 1994).

As doctors encountered this syndrome, they gradually noticed that it seemed linked to patients taking tryptophan produced by Showa Denko. However, it took months before it was taken off the market. Had it been labeled as genetically engineered, it might have accelerated the identification of the source of the problem.

Showa Denko refused to cooperate in any US government efforts to investigate the cause of the problem. However, the Showa Denko tryptophan that caused the problem was determined to contain a toxic contaminant which appears to have been a byproduct of the increased tryptophan production of the genetically engineered bacteria (Mayeno & Gleich, 1994).

There are many ways besides this in which genetic engineering could go awry and result in hazardous toxins in food. Many common plant foods such as tomatoes and potatoes produce highly toxic chemicals in their leaves, for example. Any responsible company working with such plants would check for any changes in toxin levels. But not all companies are equally responsible, as the Showa Denko example shows, and a serious hazard can be missed.

Government agencies also cannot be counted on to prevent unexpected problems. Worldwide, government premarket safety reviews of genetically engineered products currently ranges from relatively thorough in the European Union, to no review at all in much of the world. In the United States, the government only conducts premarket safety reviews if requested to by the company.

Allergens can be transferred from foods to which people know they are allergic, to food that they think is safe, via genetic engineering.

We can expect that in the future genetically engineered food will be developed and grown in many countries, many of them with no premarket safety reviews. Consumers want labeling of genetically engineered food because unless all such products are labeled, it will be extremely difficult to determine the source of any toxin problems originating in such food.

Genetically Engineered Food Can Cause Allergic Reactions

In the United States, about a quarter of all people say they have an adverse reaction to some food (Sloan & Powers, 1986). Studies have shown that 2% of adults and 8% of children have true food allergies, mediated by immunoglobin E (IgE) (Bock, 1987; Sampson et al., 1992). People with IgE mediated allergies have an immediate reaction to certain proteins that ranges from itching to potentially fatal anaphylactic shock. The most common allergies are to peanuts, other nuts and shellfish.

...for virtually every food, allergists will tell you, there is someone allergic to it.

Allergens can be transferred from foods to which people know they are allergic, to food that they think is safe, via genetic engineering. In March 1996, researchers at the University of Nebraska in the United States confirmed that an allergen from Brazil nuts had been transferred into soybeans. The Pioneer Hi-Bred International seed company had put a Brazil nut gene that codes for a seed protein into soybeans to improve their protein content for animal feed. In an in-vitro and a skin prick test, the engineered soybeans reacted with the IgE of individuals with a Brazil nut allergy in a way that indicated that the individuals would have had an adverse, potentially fatal reaction to the soybeans (Nordlee et al., 1996).

This case had a happy ending. As Marion Nestle, the head of the Nutrition Department at New York University, summarized in an editorial in the respected New England Journal of Medicine, "In the special case of transgenic soybeans, the donor species was known to be allergenic, serum samples from persons allergic to the donor species were available for testing and the product was withdrawn." (Nestle, 1996: 726) However, for virtually every food, allergists will tell you, there is someone allergic to it. Proteins are what cause allergic reactions, and virtually every gene transfer in crops results in some protein production. Genetic engineering will bring proteins into food crops not just from known sources of common allergens, like peanuts, shellfish and dairy, but from plants of all kinds, bacteria and viruses, whose potential allergenicity is largely uncommon or unknown. Furthermore, there are no fool-proof ways to determine whether a given protein will be an allergen, short of tests involving serum from individuals allergic to the given protein. This point is strongly driven home in the the case of the transgenic soybean containing a Brazil nut gene, where animal tests had suggested that the transfered Brazil nut seed storage protein was not an allergen (Nordlee et al., 1996). Had the results of the animal tests been relied on and the soybeans approved, the results could have been disastrous.

However, most biotechnology companies increasingly use microorganisms rather then food plants as gene donors or are designing proteins themselves, even though the allergenic potential of these proteins is unpredictable and untestable. Consequently, Nestle continues, "The next case could be less ideal, and the public less fortunate. It is in everyone's best interest to develop regulatory policies for transgenic foods that include premarketing notification and labeling." (Nestle, 1996: 727)

To adequately protect consumer health from the effects of unrecognized or uncommon allergens, all genetically engineered food must be labeled. Otherwise there will be no way for sensitive individuals to distinguish foods that cause them problems from ones that do not. This need is particularly urgent, since one of the potential consequences is sudden death, and the most affected population is children.

To adequately protect consumer health from the effects of unrecognized or uncommon allergens, all genetically engineered food must be labeled.

Genetic Engineering Can Increase Antibiotic Resistance

Genetic engineering, despite the precise sound of its name, is actually a very messy process, and most attempts end in failure. While the gene to be transferred can be identified fairly precisely, the process of inserting it in the new host is often very imprecise. Genes are often moved with something that is the molecular equivalent of a shotgun. Scientists coat tiny particles with genetic material and then "shoot" these gene into thousands of cells in a petri dish before they get one where the desired trait "takes" and is expressed. Because the transferred trait, such as ability to produce an insecticide in the leaves of the plant, is often not immediately apparent, scientists generally also must insert a "marker gene" along with the desired gene into the new plant. The most commonly used marker gene is a bacterial gene for antibiotic resistance. Most genetically engineered plant food contains such a gene.

Widespread use of antibiotic resistance marker genes could contribute to the problem of antibiotic resistance. Antibiotic resistance genes may move from a crop into bacteria in the environment. Since bacteria readily exchange antibiotic resistance genes, such genes could eventually move into disease-causing bacteria and make them resistant to a given antibiotic and therefore harder to control. It is already known that naked DNA can be taken up by bacteria in a suitable environment, so antibiotic resistance genes could theoretically be transferred in the digestive tract to bacteria. A genetically engineered Bt maize plant from Novartis includes an ampicillin-resistance gene. Ampicillin is a valuable antibiotic used to treat a variety of infections in people and animals. A number of European countries, including Britain, have refused to permit the Novartis Bt corn to be grown, over health concern that the ampicillin resistance gene could move from the corn into bacteria in the food chain, making ampicillin a far less effective weapon against bacterial infections. The fact that the ampicillin resistance gene is connected to a bacterial promoter (a genetic "on" switch) rather than a plant promoter in the Novartis Bt corn could improve the chances that it if the gene moved into bacteria it could be readily expressed. In September, 1998, the British Royal Society put out a report on genetic engineering that called for the ending the use of antibiotic resistance marker genes in engineered food products (Anonymous, 1998).

Some consumers may wish to avoid plants with antibiotic resistance marker genes.

Genetic Engineering Can Alter Nutritional Value

Genetic engineering can alter nutritional value of foods in positive ways. For example, canola oil has been engineered to have a different profile of fatty acids, which means that they contain less of the fat molecules that tend to build up in people's arteries and give them heart attacks. Scientists are also working on increasing the vitamin C content in some foods.

It is also possible that nutritional content could be reduced as an unexpected side effect of some other genetic engineering effort. Consumers need labeling of genetically engineered food so that they can educate themselves about any nutritional changes in the product.

Since bacteria readily exchange antibiotic resistance genes, such genes could eventually move into disease-causing bacteria and make them resistant to a given antibiotic and therefore harder to control.


Anonymous. (1998). Call for UK genetic food watchdog. Nature online service. Sept. 3

Bock, S.A. (1987). Prospective appraial of complaints of adverse reactions to foods in children during the first three years of life. Pediatrics, 79: 683-688.

Mayeno, A.N. & Gleich, G.J. (1994). Eosinophilia myalgia syndrome and tryptophan production: a cautionary tale. TIBTECH, 12:346-352.

Nestle, M. (1996). Allergies to transgenic foods-Questions of policy. The New England Journal of Medicine , 334(11): 726-727.

Nordlee, J.A., Taylor, S.L., Townsend, J.A., Thomas, L.A. & Bush, R.K. (1996). Identification of a brazil-nut allergen in transgenic soybeans. The New England Journal of Medicine , 334(11): 688-692.

Sampson, H.A., Mendelson, L. and J.P. Rosen. 1992. Fatal and near-fatal anaphylactic reactions to food in children and adolescents. The New England Journal of Medicine , 327: 380-384.

Sloan, A.E. & Powers, M.E. (1986). A perspective on popular perspections of adverse reactions to foods. Journal of Allergy and Clinical Immunology, 78: 127-133.

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