Food AllergiesFood Allergies

Food Allergies
A Matter of Life or Death
September 1999 -- Nutrition Notes

By: Andrea Platzman, R.D.
Contributing Editor

  Lucretius once said, "One man's food is another man's poison." While he was not referring to food allergies, the statement is certainly apt in this situation. "It is estimated that 2% to 2.5% of the United States population, or between 6 million and 7 million people, have food allergies," says Anne Munoz-Furlong, president of the The Food Allergy Network, Fairfax, VA. "Of those affected by food allergies, approximately 2.5 million are children. Most children will outgrow their food allergies, with the exception of peanut and tree-nut allergies, which are considered life long."Source of the trouble  Peanuts are the leading cause of severe food-allergy reactions. According to Munoz-Furlong, a recent study shows that an estimated 1.1% of the United States population, or close to 3 million people, are affected by peanut or tree-nut allergies. But these are not the only culprits. "There are eight foods that cause 90% of the allergic reactions to foods - these are peanuts; tree nuts, such as almonds, cashews, walnuts, Brazil nuts and pecans; crustacea, such as crab, shrimp, lobster and crawfish; fish; cow's milk; eggs; soybeans; and wheat," says Susan Hefle, Ph.D., assistant director of The Food Allergy Research and Resource Program, University of Nebraska, Lincoln. "There are at least 160 other foods that can cause allergic reactions, but the vast majority of those are quite rare."Immune system response  At this time, it is unknown why some people develop allergies and others do not. "While food allergies are not directly inherited, genetic factors do play a role. If both parents have allergies of some kind - to dog dander, pollens, etc. - their child will have a greater chance of developing a food allergy," says Hefle.  "A food allergy is caused by the immune system's misinterpretation of a harmless food as a harmful invader. In an effort to protect the body, the immune system creates antibodies against that food. When they are released, the person experiences an allergic reaction," explains Munoz-Furlong.  According to Steve Taylor, Ph.D., et al, in an article in the January/February 1999 Nutrition Today entitled "Food Allergies and Avoidance Diets," the human body produces five classes of antibodies: IgG, IgM, IgA, IgD and IgE. These antibodies are important in fighting off infectious diseases. Of these antibodies, IgE, or immunoglobulin E, is found in higher concentrations in allergic individuals, and is extremely important in the development of the allergic response. The role, or roles, that the other antibodies have in food allergies, if any, has not yet been determined.  Susceptible individuals form allergen-specific IgE upon exposure to an allergen. The IgE then attaches itself to mast cells in various tissues of the body and to basophils in the blood during a process known as sensitization. On subsequent exposure to the same allergenic substance, the allergen cross-links two IgE molecules on the surface of the mast cell or basophil membrane. This interaction stimulates the cells to degranulate and release mediators, including histamine, prostaglandins and leukotrienes. These mediators circulate throughout the body and interact with receptors in various tissues, which can lead to the development of a wide range of symptoms, including nausea, vomiting, diarrhea, hives, eczema, swelling, asthma and even anaphylactic shock. During anaphylactic shock, breathing passages close up, blood pressure drops and the affected person loses consciousness and can even die.   With food allergies, even the smallest amount of allergen can cause a reaction. However, keep in mind that some people may not have a true food allergy, but rather a food intolerance. An intolerance often produces many of the same symptoms as an allergy, but has a different root cause. (For more information, see "The Fear of Food" and "Reality Check: The Facts Behind the Myths" in the January 1998 issue of Food Product Design.)Preventive measures  "There is no cure for a food allergy. Individuals with food allergies must read ingredient statements carefully every time they shop. Manufacturers can help by making ingredient information as complete and easy to read as possible," suggests Munoz-Furlong. "In addition, manufacturers should make every effort to notify allergic consumers when a processing, packaging or labeling mistake is made, or when ingredients change in products that have been on the market for a long time."  The key to successful allergen risk management is to develop and implement preventive programs, and more and more companies are instating HACCP plans to minimize potential problems. These programs should include at minimum:   Vendor certification. Ingredients and raw materials should only be purchased from approved suppliers.  Production control and scheduling. Cross-contamination can lead to a fatal error. Production schedules should be designed to control potential allergens.  Tracking. Every operation should be able to track a product that leaves the facility. If a problem requiring a product recall occurs, the company will be able to locate the products with ease.  Limiting rework. Rework products must be properly labeled. It is advisable to rework only like products.  Cleaning. Failure to clean properly may leave residues that could contaminate products and elicit an allergic response in susceptible individuals.   Labeling. Wrong labels, switched ingredients and formulation mistakes can be hazardous. It is important to make sure that labels are up to date and that the proper packages are used.  Hefle observes that the more specific the information a company gives the food-allergic consumer, the better. "Until there is a cure for a food allergies, consumers and food manufacturers must work together," states Munoz-Furlong.  Andrea D. Platzman is a registered dietitian who is a consultant to the food industry, and regularly writes for nutrition publications. She earned a master's degree in nutrition from New York University, and has a culinary and business background.Back to top