Dietary aspects of adverse reactions to foods in adults.

Dietary considerations play an important role in the diagnosis, treatment and management of immunologic and nonimmunologic reactions to foods. Food diaries and trial elimination diets may prove helpful in identifying the responsible foods. Elimination diets must be monitored carefully for nutritional adequacy and should be used no longer than absolutely necessary; in some instances appropriate vitamin and mineral supplementation may be necessary. Ideally the identification of foods that provoke symptoms should be confirmed by means of double-blind challenge testing. Avoidance of some problem foods is unlikely to cause nutritional problems, but the practical and nutritional implications of allergies to staple foods such as cow's milk, eggs and wheat are far greater. Nonimmunologic adverse reactions that may mimic food allergic reactions include gastrointestinal disorders, sensitivity to food additives and psychologically based adverse reactions. There may be some degree of tolerance in metabolic disorders, which makes dietary management easier. Sensitivity to food additives necessitates careful scrutiny of food labels. In psychologic adverse reactions to foods, several foods are often involved, which increases the risk of nutritional problems.