An elimination diet is the systematic elimination of foods or group of foods from the diet suspected in causing a food allergy. It is used as a means to diagnose an allergic reaction to foods.
While people of all ages can develop an allergic sensitivity to certain foods, such allergies are especially common among children. In the United States, one child in six develops an allergic reaction to certain substances, and foods are among the prime offenders. (Many food allergies are outgrown during adolescence.) Food elimination is considered only when no other cause can be found for the symptoms the child is experiencing. Common symptoms of food allergies include hives , angioedema (swelling), rashes , respiratory congestion, and gastrointestinal problems such as constipation , diarrhea , and/or gas. Food allergies are also known to play a secondary role in many chronic conditions, such as asthma , acne , ear infections, eczema, headaches, and hay fever. The most effective means of treating food allergies is to avoid the foods that produce allergic reactions.
There are two main ways of diagnosing food allergies by the elimination method. A casual approach involves eliminating, one at a time, foods from the diet suspected of causing allergic reactions and observing the person to see if there is a reduction in symptoms in the absence of particular foods. This method is often recommended for children, as it is easier to follow than the standard elimination diet. The more rigorous method (which is a true elimination diet) reverses this strategy by eliminating many foods at the outset and then reintroducing suspected allergens (allergy-producing substances) one at a time. Elimination diets often include a rotation component, by which even the limited foods allowed at the beginning are allocated in such a way that no single food is eaten more than once within a three-day period. This feature has two purposes. First, it alleviates the monotony of a limited diet. Second, it allows for the possibility that some persons may even be allergic to the relatively safe foods allowed initially. If there is an allergic reaction at this stage, rotating foods makes it possible to identify the cause of the problem.
An elimination diet is divided into two parts: the elimination phase and the reintroduction (or food challenge) phase. During the elimination phase, which generally lasts between one and two weeks, as many known allergy-producing foods as possible are eliminated from the diet. Foods commonly known to cause allergies include: citrus fruits, strawberries, corn, peas, tomatoes, peanuts, nuts, legumes, soy products, wheat, oats, chicken, shellfish, eggs, dairy products, cow's milk, vinegar and other products of fermentation, coffee and tea, cane sugar, chocolate, and food additives. The elimination diet can be very strict or more liberalized depending on the severity of the symptoms. It is important to personalize the diet whenever possible.
During the elimination phase of the diet, which clears the body of allergens, ingredient labels for all processed foods should be carefully scrutinized to make sure that none of the proscribed foods makes its way into the diet. Different diets handle the reintroduction phase differently. In some cases, the "test" foods are introduced at three-day intervals while in others, a new food is reintroduced every day for 15 days. Foods should be reintroduced in as pure a form as possible (for example, cream of wheat rather than bread) for maximum certainty that the resulting effects are produced by the substance in question rather than by some other ingredient added during the manufacturing process.
A strict elimination diet should not be undertaken without the supervision of a physician and/or dietitian.
Another way to identify food allergies is to keep a food diary, recording everything eaten for a period of three or four weeks and noting any allergic reactions during that period.
The elimination phase of the diet should not last more than two weeks, since this restricted regimen will lack some essential nutrients. Also, a child's growth may be affected if placed on an elimination diet for an extended period. For example, a child with a cow's milk allergy must obtain his calcium, vitamin D, and other essential nutrients found in milk from other sources. Children with food allergies need to be followed by a physician and or dietitian to ensure they are not at risk for growth problems or inadequate intake of nutrients.
Persons with chronic food allergies should see their symptoms subside during the elimination period. Sometimes they may experience withdrawal, an episode in which symptoms may actually worsen before they subside. These include: bloating, food cravings, headache , fatigue, and general aches and pains. This condition may last for a few days. Upon reintroduction of the offending food, these symptoms should return and are often worse than previously reported.
In order to effectively eliminate the offending foods, a parent should be educated on label reading, cross-contact, and selecting alternate foods for an allergic child.
Kleinman, Ronald E., and the American Academy of Pediatrics Committee on Nutrition. Pediatric Nutrition Handbook , 5th ed. Elk Grove Village, IL: American Academy of Pediatrics, 2003.
Mahan, L. Kathleen, and Sylvia Escott-Stump. Krause's Food, Nutrition, & Diet Therapy , 10th ed. Philadelphia: Saunders, 2000.
Physicians Committee for Responsible Medicine. Healthy Eating for Life for Children. Hoboken, NJ: Wiley, 2002.
Willett, Walter C., and P. J. Skerrett. Eat, Drink, and Be Healthy: The Harvard Medical School Guide to Healthy Eating. New York: Simon & Schuster Source, 2002.
Christie, Lynn, et al. "Food Allergies in Children Affect Nutrient Intake and Growth." Journal of the American Dietetic Association 102, no. 11 (November 2002): 1648–51.
Mofidi, Shideh. "Nutritional Management of Pediatric Food Hypersensitivity." Pediatrics 111, no. 6 (June 2003): 1645–53.
Schiltz, Barbara. "Elimination Diet: Food Challenge Tools for Patients with Allergies." Journal of the American Dietetic Association 103, no. 4 (April 2003).
American Academy of Pediatrics. 141 Northwest Point Blvd., Elk Grove Village, IL 60007–1098. Web site: http://www.aap.org.
American Dietetic Association. 120 South Riverside Plaza, Suite 2000, Chicago, IL 60606–6995. (Web site: http://www.eatright.org.
Laura Kim Saltel Allan, R.D.