An elimination diet is used to pinpoint foods or ingredients that are responsible for adverse reactions, such as allergies, sensitivities or intolerances.

A food allergy is an adverse and potentially fatal response by a person’s immune system to a food or food component. After a susceptible person ingests a problem food, the immune system releases histamines and other hormones that trigger symptoms that can range from mild to life-threatening. About 90 percent of all food allergies have been traced to the following foods:

• Cow’s milk
• Eggs
• Peanuts
• Wheat
• Soybeans
• Fish
• Shellfish
• Tree nuts
  

Although the condition is not confirmed by the general medical community, reactions may occur when an individual consumes or comes into contact with one of many types of substances classified as a food additive—an ingredient that is not considered a part of its basic raw ingredients. Only sulfite additives have been proven to provoke an allergic reaction in some rare cases. Other additives that may trigger sensitivities include:

• Flavor enhancers
• Added nutrients, such as vitamins and minerals
• Preservatives
• Stabilizers, emulsifiers and thickeners
• Food colorings

Food intolerance involves the inability of the body to digest a substance, leading to symptoms of discomfort (e.g., stomach cramping), but usually poses little danger. Unlike a more serious food allergy, intolerance does not involve an immune system reaction. Food intolerance often allows the individual to eat small portions of a problem food without experiencing symptoms. With a food allergy, even a very small portion of a food allergen can cause an allergic reaction.

During the elimination diet, patients remove all suspected food allergens from their diet. Elimination diets are typically used for several weeks. A shorter testing period may be used in some cases, such as with young children. If symptoms disappear during this time, an allergy or intolerance to one of the excluded foods or ingredients is strongly suspected. The foods that are most frequently consumed by the patient are often the foods that cause allergic reactions.

To help confirm this diagnosis, the patient slowly resumes eating the restricted foods one at a time at intervals of three to seven days. The patient watches for and records any signs of an allergic reaction. If a reaction occurs, a food allergy diagnosis becomes more likely.

Elimination diets are not practical for patients who have allergic food reactions that result in anaphylactic shock. This condition is a life-threatening, whole-body allergic reaction that demands immediate emergency medical attention. This danger makes elimination diets too risky for individuals with a history of anaphylactic shock.

Finally, psychological and physical factors can affect test results. Patients who expect to have reactions to a food can sometimes induce symptoms, even if an allergy is not actually responsible.

It is important that a patient conscientiously follow the elimination diet without cheating. Even a small amount of cheating can ruin the diagnostic capability of the test.

An elimination diet should be performed only under the supervision of a physician. In addition to the risk for anaphylactic reaction, people who attempt an elimination diet on their own also risk nutritional deficiencies. The random removal of foods from a person’s diet can cause a lack of nutrients, leading to a number of possible health problems. Patients should not make significant changes in their diet without first discussing it with their physician. Individuals undergoing an elimination diet may benefit from consulting with a dietician. These trained professionals can help people plan a well-balanced diet while eliminating potential allergens.