Peanuts can leave you breathless. Cat dander can lead to itchy eyes, a stuffy nose, coughing and sneezing. And most of us have suffered through those seasonal allergies with horrible pollen counts. Learn more...
Food allergies represent an important medical condition that ranges in severity from mild skin and intestinal irritation to anaphylactic shock that can result in death. Food allergies may be present in up to 2 of adults and 8 of children, with surveyed results of perceived allergic reactions being as high as 22 for the population.1 The vast majority of foods allergens are proteins and, as a whole, are represented by more than 1500 reported amino acid sequences, with more sequences being characterized for their allergenicity every year.2 The eight most commonly reported allergic reactions are to peanuts, tree nuts, cows' milk, hens' eggs, fish, Crustacea, wheat, and soybeans.3 Moreover, adverse reactions to plant-derived foods are very common in birch pollen allergic subjects.4 Typical birch pollen-related food allergies include apple, stone fruit such as peach, apricot and cherry, hazelnut, carrot, celery, and soybeans. Although the majority of observed reactions to those foods are...
There are several areas of public concern with regard to potential human health risks of GM foods. These relate to understanding the potential of proteins and or other molecules in GM foods to cause allergic reactions, to act as toxins or carcinogens and or to cause food-intolerance reactions among the population. Methods of testing and evaluating these types of risks have been established for food and these are being applied to GM foods so as to detect any increased risks associated with particular foods (Lehrer, 2000).
Genetic engineering need not make a food inherently different from its conventional counterpart. The technology itself is unlikely to increase the food's probability of containing an allergen. Concern about food allergies, however, is frequently cited as a major consumer issue with GM foods. Fortunately, much is known about foods that trigger allergic reactions for example, 90 of all food allergies in the United States are caused by a very small number of foods cow's milk, eggs, fish and shellfish, tree nuts, wheat, peanuts, and legumes.
Acute and chronic urticaria and angioedema can result from exposure to a number of agricultural products. They may be caused by immunologic and nonimmunologic histamine releasers. Immunologic mechanisms involve type I (immunoglobulin G IgG -mediated), type II (cytotoxic antibody-mediated), or type III (immune complex-mediated) reactions. Nonimmunologic mechanisms usually involve substances such as aspirin that directly incite the release of histamine and other mediators from mast cells. Medications, foods, food additives, and the bites of insects and snakes have been implicated. Common food allergies include shellfish, fish, eggs, nuts, chocolate, berries, tomatoes, cheese, and milk (27).
The primary goal of the protein allergenicity assessment process is characterization of transgenic proteins prior to their inclusion in foods so that risk of allergenic protein exposure remains low. An excellent example of the success of this process was the proposed transfer of a Brazil nut 2S albumin encoding gene into soybean in an attempt to improve nutritional quality.68 Because the Brazil nut was a known allergenic food, the 2S albumin was assessed for its potential allergenicity. Using the assessment process, this protein was found to be allergenic and the GM product never reached the consumer market place. With regard to potential alterations to the allergenicity of proteins, there is to date no evidence from marketing surveys or other studies that a nonallergenic, transgenic protein expressed in food has become altered to affect human allergy.69-71
The potential risks of biotechnology on human health may include toxic reactions, increased cancer risks, food allergies, food contamination, and antibiotic resistance (Table 4.1). There is also concern that GMOs in animal feed might present a health risk for consumers, or for the animal itself. Consumers are also concerned about the long-term health effects of genetically modified foods. 3. Food allergies. In 1996, a Brazil nut gene spliced into soybean was reported to induce potentially fatal allergies in people sensitive to Brazil nuts.
The International Life Sciences Institute (ILSI) has developed a decision tree that provides a framework for risk assessment in foods (Lehrer, 2000). It uses the following criteria, that an introduced protein in a food is not a concern if (i) there is no history of common allergenicity (ii) there is no amino acid sequence similar to those of known allergens (iii) there is rapid digestion of the protein and (iv) the protein is expressed at low levels. For example, these risk assessment techniques were used to test the safety of increasing the protein content in soybean by introducing a protein from Brazil nut. However, food allergy tests showed that this transferred a potential allergen to soybean. Hence, further development of this GM high-protein soybean ceased.