"Transgenic" food update.

Genetic engineering has created much controversy in recent years, especially in the medical field. By altering the genetic structure of plant cells, scientists have been able to produce new varieties of older fruits and vegetables with more favorable characteristics--more resistant to disease, more nutritious, etc. Now medical scientists are examining the genetic aspects of many diseases in the hope of finding faulty genes and eventually restructuring them in the sperm or ova of affected parents to prevent transmission of such diseases to their offspring. The possibility that such manipulation could eventually be used to produce a strain of "superior" humans raises legitimate concern.

Of more immediate concern, however, is the question of safety in food biotechnology--in particular the possible negative consequences of transferring allergenic proteins from donor organisms into the food supply. Allergies to proteins in food are very common. In the process of genetically transferring a particular protein from a source rich in that protein to a food lacking the protein, the recipient "transgenic" food product could now become allergenic. Persons who were previously able to tolerate that product could now be allergic to it without being aware of it.

The Food and Drug Administration (FDA) addressed this issue in 1992, when it devised a policy requiring premarketing safety testing of transgenic plant foods. Unless the developer of a new plant variety could show that the introduced protein could not cause allergic reactions in susceptible persons, the food must be labeled to alert consumers to the fact that it contained a potential allergenic protein. However, the FDA regulations apply only to foods with genes transferred from the ten or so most commonly allergenic foods--and public interest groups have pointed out that this is not enough to protect persons against lesser-known transgenic allergens.

The issue recently came to a head when researchers at the University of Nebraska and the University of Wisconsin jointly tested a new variety of soybean on persons known to be allergic to Brazil nuts--the source of the gene used to produce the transgenic soybean. Soybean protein is deficient in the amino acid methionine, so genes from methionine-rich Brazil nuts were introduced into transgenic soybeans. Because allergies to nuts are among the most common food allergies, the researchers tested the new variety of soybean on people known to be allergic to Brazil nuts--with positive results.

The results of the study, published in the March 14 issue of the New England Journal of Medicine (NEJM), would have required the developer of the soybeans to label them accordingly. Although they were developed for use in animal feed, there was no way to assure that these soybeans would not find their way into the human market, so the developer discontinued its plans to market them, rather than having to label them under FDA regulations.

In this case, the public benefited from the developer's decision, but there is concern that the next time such a problem arises in a transgenic food product, the results might not be as ideal. As an editorial in the NEJM noted, "It is in everyone's best interest to develop regulatory policies for transgenic foods that include premarketing notification and labeling. Industry benefits when the public is convinced that transgenic foods are safe, and stronger federal regulations would encourage such public confidence."