Agricultural Biotechnology Support Project II

Supporting agricultural development through biotechnology

Health Issues

Food Allergies and Bio-engineered Foods

A novel bio-engineered food may have the potential to cause new allergic reactions if it contains proteins that the conventional food doesn't have. Of particular concern are GE foods engineered to contain a protein from a food already known to cause allergic reactions. If the protein in the GE food happens to have been an allergen in the original allergenic food, then it is possible that the GE food will also cause allergies. For example, people who are allergic to Brazil nuts may also be allergic to a GE soybean containing a Brazil nut protein.

In addition, that a protein is non-allergenic in one organism does not necessarily mean the protein will still be non-allergenic in the new GE organism. If a bacterial protein is moved into a plant, the plant may make alterations to the protein that bacteria don't make (called "post-translational modifications") which could affect its allergy-causing potential. At least one common plant protein alteration-- glycosylation, the adornment of a protein with long sugar-based chains-- has been demonstrated to have a large affect on the allergenicity of a protein. Furthermore, the quantity of protein produced may have an affect on allergenicity (although most transgenic proteins in GE plants are produced at very low levels relative to common allergens). On the other hand, some GE plants do not make a new protein at all; they pose no new allergy risk.

How are genetically engineered foods tested for allergenicity?

Internationally regulatory bodies (FAO/WHO, OECD, EU, and ILSI) have agreed on the design of food safety evaluation strategies for transgenic food crops. The corner stone of the safety assessment is a comparative approach, i.e. if a new food is found to be comparable with an existing traditional product which is considered to be safe on the basis of long term experience and history of use (concept of substantial equivalency) it can be considered as safe as the counterpart(s) (Regulation EC/258/97).

For more information, go to the European Union portal.

The principle of substantial equivalency is also applied in the US. Since 1992, the U.S. Food and Drug Administration has also recommended (but not required) the developers of genetically engineered foods to assess their potential allergenicity, particularly if the food contains a protein from another food known to be allergenic. Although this assessment is not a legal requirement, so far all developers have submitted their products to the recommended allergy assessment. The US Food and Drug Administration suggests that if there is insufficient evidence of a lack of allergenicity, the new product must be labeled or kept off the market entirely.

Potential to Reduce Allergenicity Through Genetic Engineering

Genetic engineering may actually have some potential to create "hypoallergenic" foods. Researchers in Japan have developed an experimental variety of GE rice that produces lower levels of rice allergens. Although the GE variety did have dramatically reduced levels of the allergens, it is not yet known whether this reduction in allergenicity is sufficient to allow normally rice-allergic persons to consume safely the new "hypoallergenic" rice as a part of their daily diets.

In a Nutshell

Some genetically engineered foods could have the potential to cause new allergic reactions if they produce a protein not normally present in the conventional food. This is particularly true if the GE food contains a protein taken from another food known to be allergenic (although there are none like this presently on the market). On the other hand, some GE plants do not produce a new protein at all, and therefore pose no new allergy risk.

Many experts feel that the likelihood of GE-induced allergies is very small, but agree that it is difficult, if not impossible, to predict the allergenicity of proteins in any new food (including new conventional foods) using current technologies. Proponents of GE-labeling argue that a lack of labeling prevents consumers from identifying and avoiding an allergenic food if an allergy develops, however rare.

Finally, genetic engineering may have the potential someday to reduce the allergenicity of commonly allergenic foods.