Food Allergic Patient Evaluation - Elimination Diets

Elimination diets are used in both the diagnosis and treatment of patients suffering from adverse reactions to foods, regardless of the mechanism involved. During the diagnostic phase suspected foods are eliminated from the diet while the patient’s clinical course is carefully monitored for a reduction in or resolution of symptoms.

A lack of significant improvement prompts a search for additional offending foods or potential causes other than foods. During the treatment phase, an elimination diet is constructed that removes all offending foods from the diet while meeting the patient’s nutritional requirements and taste preferences.

Elimination diets should be carefully constructed, as the overzealous elimination of foods unnecessarily from the diet has been associated with adverse physical and psychologic consequences. Different versions of elimination diets, which vary in regard to the number of foods removed, are used.

Limited elimination diets involve the removal of only those foods for which there is a high level of suspicion, based either upon the history or the results of testing. These are the simplest to prepare and use when a single food not widely found in the diet is suspected, and become more difficult to design as more foods or those pervasive in the diet come under suspicion.

Oligoantigenic diets are constructed using only a few foods classically considered to rarely be allergenic. Elemental diets consist of an elemental formula, with or without the addition of a few foods considered to be safe. Oligoantigenic and elemental diets are used when there is uncertainty about which foods cause symptoms or when a large number of foods are suspected.

Elemental diets are useful in young infants not yet on solids, but adherence to these diets is often difficult to maintain beyond infancy. One food-associated disorder in which the use of elemental diets has been shown to be of particular benefit is eosinophilic esophagitis, where improvement in 98% of patients placed on elemental diets has been reported.

When oligoantigenic and elemental diets are used, foods are added back to the diet individually at selected intervals, accompanied by symptom monitoring. Tolerated foods are left in the diet, while those associated with a return of symptoms are removed.

When elimination diets are instituted for extended periods, care must be taken to ensure that the patient’s nutritional requirements are met. Children on dairy-free diets have been shown to have difficulty meeting their requirements for calcium, vitamin D, and phosphorous.

Consultation with a registered dietician to provide a nutritional assessment and patient education regarding label reading, food preparation, hidden sources of food allergens, and alternative nutrient sources is encouraged.