11. The Potential For Allergic reactions

In the United States, a quarter of all people report that they have an adverse reaction to one or more foods.(1)

All  foods contain proteins, the basic building materials of a cell. For people who are unable to tolerate proteins found in certain foods, eating even trace amounts of these foods causes allergic reactions ranging from minor discomfort to a serious illness or even death.

In genetic engineering, genes are transferred from one organism to another. This gene transfer results in the production of new proteins. If a new protein happens to be one that causes an allergic reaction, food that was previously safe for a person could thus become dangerous for him or her to eat.

A seed company called Pioneer Hi-Bred International engineered soybeans with a gene from a brazil nut in the hope that it would improve the soybean's protein content. Researchers at the University of Nebraska tested these soybeans on samples of blood serum taken from people who were allergic to brazil nuts. The tests indicated that if these people had eaten the soybeans, they would have suffered an allergic reaction that could have been fatal.(2)

"In the special case of transgenic [GE] 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be allergenic, serum samples from persons allergic to the donor species were available for testing and the product was withdrawn. The next case could be less ideal, and the public less fortunate."

Because most genes being introduced into GE plants come from sources which have never been part of the human diet, such as bacteria, insects and viruses, there is no way of knowing whether or not the products of these genes will cause allergic reactions. Some people could develop a sensitivity to a GE food gradually after being exposed to it over time; others might have an acute allergic reaction after eating a minute amount. Unfortunately, the lack of labelling effectively undermines any attempt to monitor GE foods. If allergies do develop, it will be extremely difficult to trace them to their source.
 

References

1. Sloan A., Powers M. (1986) A perspective on popular perspections of adverse reactions to foods. Journal of Allergy and Clinical Immunology, 78: 127-133.
2. Nordlee J., Taylor S., Townsend J., Thomas L., Bush R. (1996). Identification of a brazil-nut allergen in transgenic soybeans. The New England Journal of Medicine, 334(11): 688-692
Melo V. et al. (1994) Allergenicity and tolerance to proteins from Brazil nut (Bertholletia excelsa H.B.K.). Food Agric Immunol 6, 185-195.
3. Nestle M. (1996) Allergies to transgenic foods: Questions of policy. The New England Journal of Medicine, 334(11): 726-727.
 

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