Food Safety Evaluation Do GMOs Mean More Allergies?

Fears are widespread: Consumers will suffer from more allergies with the arrival of genetically modified food, and new genes will turn harmless foods into serious threats. Although it isn’t easy to predict the allergenic potential of new foods, rejecting GMOs because of allergies is unjustified.

When a new gene is introduced into a plant’s genome, the principal end result is the production of a new protein. Sometimes, new proteins found in transgenic plants can be entirely new to the human diet. Therefore, we can not simply assume that these new substances are non-allergenic based on past experience.

Bt maize produces a substance that protects it against pests. Theoretically, the new protein responsible for this trait could trigger allergies. The allergenic potential of a transgenic plant can be assessed prior to its approval.     Rather than containing a new protein, the transgenic „FlavrSavr“ tomato has a deactivated gene. Concerns about allergenicity are irrelevant. (The tomato is no longer grown)

Proteins become allergens when… Proteins are large molecules composed of chains of diverse amino acids that fold into characteristic, three-dimensional structures. Countless different kinds of proteins exist, which enable organisms to perform myriad chemical and physical tasks. In theory, every protein holds the potential to trigger an allergic reaction. A protein causes an allergic reaction when certain conditions are met. The surface of the protein must present IgE antibody binding sites. Antibodies specific for certain allergens are only produced by individuals with immune systems susceptible to that allergen. Susceptibility often depends on genetic predisposition. Proteins that hold the potential to cause allergies do not always result in an allergic reaction. Such proteins only cause problems if they come into contact with a person possessing a corresponding sensitivity. Determining the allergenic potential of a protein is more difficult than just making a simple, objective assessment. Allergic reactions are complex interplays between substances and individual immune systems. Assessments of allergenic potential cannot be made with 100 percent certainty. The only certain answer is when an allergic reaction in a human actually occurs.

GMOs cause allergies? Not so fast...

The more genetically modified plants become present on the market, the more people will be consuming proteins new to the human diet. The possibility that isolated cases of allergic reactions to a new protein could arise is not out of the question. Automatically assuming that genetically modified foods cause allergic reactions, however, is not justified.

There are many ways of predicting the allergenic potential of a new protein before it reaches the market. Many simple criteria are now known that characterize known allergens. New proteins from GMOs are checked to see if they possess any of these criteria. Since GMOs tend to differ from conventional foods by only one or a few proteins, these “allergy checks” can be done quite straightforwardly. New foods such as a new exotic fruit, on the other hand, are impossible to check because the number and characteristics of the new proteins remain completely unknown.

In the last several years, knowledge on allergens has increased significantly. Databases now exist that contain extensive information on myriad allergens. In addition, tests for allergenicity have been becoming more and more accurate and reliable. Nonetheless, there is no such thing as absolute certainty.

When new genetically modified plants are being approved, their allergenic potential is reviewed.

• If a GM plant is found to contain a potential allergen, its chances of receiving approval in the EU are slim to none.

• Only GM plants containing new genes that have a very low probability of causing allergies receive a positive assessment from scientific reviewing committees.

Genetically modified, but not always a new protein

Some genetically modified plants contain no novel proteins. Sometimes, an existing gene is simply switched off by means of incorporating a reversed copy of the gene, cancelling out the existing version. An example of this is the Favr Savr tomato, in which an enzyme involved in ripening was repressed.

GMOs not the only source of new proteins in food

New or modified proteins make their way into our foods by more ways than just GMOs, which means GMOs aren’t the only source of new potential allergens.

• Developing new cultivars by conventional plant breeding and new processing methods can change the properties of proteins found in food. These common practices can increase the allergenic potential of food.

• New allergens can turn up in exotic fruits that have recently been introduced to European markets. No one can know for sure if new allergens are lurking in novel products. As was the case with kiwis, the first cases of allergic reactions come up only years after a new food’s introduction to the market.

See also on GMO-Compass:

• The Allergy Check