Diagnosing and Managing Your Allergies

A food allergy or food hypersensitivity is defined as an abnormal immunologic response to certain foods, characterized by a variety of symptoms. Food allergies are commonly confused with food intolerances because they share similar symptoms. Unlike food allergies, however, food intolerances (lactose intolerance, for example) do not involve the immune system, and the allergic individual can usually tolerate small amounts of the offending food without a reaction.

About 1.5 percent of adults and five to eight percent of children under three years old in the United States have a true food allergy.1 In pediatrics, milk allergy is found in 0.3 to 7.5 percent of the population while soy allergy is found in 0.5 percent or less of the population. 1 Children usually present with a soy or milk allergy by three months of age and may experience diarrhea, vomiting, irritability, atopic dermatitis, rhinitis, asthma,1 or poor growth.2 Infants born to parents with a history of atopic disease are at an increased risk for developing food allergies.3 Children with soy, milk, and egg allergies frequently outgrow them,4 especially when strictly avoided for a period of time. A physician diagnoses a food allergy by reviewing the patient’s food diary for foods and symptoms, from a physical exam, and through lab tests. The most common test methods are: the elimination diet and food challenge (see article on page 3 of this issue), skin test (involving pricking the skin with a needle containing a small amount of liquid extract from the potential allergen), and radioallergosorbent (RAST) test or enzyme-linked immunosorbent (ELISA) blood test (tests that measure the presence of food-specific IgE antibodies in the blood). A fourth test, the double-blind, placebo-controlled food challenge (DBPCFC), is considered the gold standard for food allergy diagnosis but cannot be used on individuals with a history of anaphylactic reactions.5 Regular retesting by a physician is important to avoid unnecessary life-long restriction from an allergy that may have been outgrown.

The only treatment for a food allergy is strict avoidance of the allergen as even a miniscule amount of the offending food can be fatal to the particularly sensitive. Label reading is crucial because an allergen can be listed in different ways, such as its technical or scientific name (such as textured vegetable proteinTM). Ingredients on labels may change frequently. Contact the manufacturer with questions about a particular ingredient. The Food Allergy and Anaphylaxis Network (www.foodallergy.org) has recipes, and tips on label reading to help people with soy and other food allergies stay healthy.

Soy-allergic individuals can substitute rice milk, cow’s milk, almond milk, or other nut milks in place of soy, provided they are well tolerated. Infants with soy allergies can be fed with formulas, such as Similac or Alimentum, which contain protein-free soy oil, fortified rice milk, or hypoallergenic specialty formulas, such as Nutramigen. Vegetarians who rely on soy as a protein source may consider dairy or eggs, if tolerated; vegans can choose from nuts, seeds, peas/legumes and beans. Legumes and beans should be eaten in moderation; however, as they may cross-react (people sensitive to soy may develop sensitivity to members of the bean and legume families, and vice versa.4 Your doctor, dietitian and allergist can suggest healthy alternative foods and supplements to provide for overall nutritional adequacy.

When dining out, carefully question the wait staff and/or chef about ingredients before you order. Become aware of any substitutions that might be made in a dish if a particular soy-based ingredient runs short. Consider carrying a wallet- sized card that lists your food restrictions and safe substitutions. When in doubt about a food item, avoid it.

Learn about food processing, preparation and service to help reduce accidental exposure to allergens. Cross contamination can come from cutting boards, pots, pans and utensils used to prepare foods or from salad bar containers or bulk storage bins in grocery stores that previously held an allergen and have not been properly cleaned. With vigilant label reading skills and the confidence to ask questions when in doubt, one can dramatically reduce the risk of accidental exposure to an allergen.

Melinda Dennis, M.S., R.D., L.D.N., is an outpatient dietitian in the Medical Nutrition Therapy Clinic at Beth Israel Deaconess Medical Center in Boston, Massachusetts. She sees many patients with food allergies. Melinda received her master’s degree in nutrition and health promotion from Simmons College, Boston.

REFERENCES
1. Sampson HA. Food allergy. Curr. Opin. Immunol. 1990; 2:542-47.
2. Christie L, Hine J, Parker J, Burks W. Food allergies in children affect nutrient intake and growth. J Am Diet Assoc. 2002;102:1648-1651.
3. Zeiger R, Heller S. The development and prediction of atopy in high risk children: Follow-up at age seven years in a prospective randomized study of combined maternal and infant food allergen avoidance. J Allergy Clin Immunol. 1995;95:1179- 1190.
4. Food avoidance and alternatives to common foods. In: Brostoff J, Gamlin L. Food Allergies and Food Intolerance: The Complete Guide to Their Identification and Treatment. Rochester,VT: Healing Arts Press; 2000:382-413.
5. Christie L. Food hypersensitivities. In: Samour PQ, Helm KK, Lang CE, eds. Handbook of Pediatric Nutrition. 2nd ed. Gaithersburg, MD: Aspen Publication; 1999:149-172. Elimination Diet, Food Challenge Tools For Patients With Allergies