The Diagnostic Elimination Diet and Challenge Protocol for Management of Patients with Food Intolerance—Purpose and Development

Background: In the 1960s and 1970s, several authors reported that manipulation of diet by excluding certain additives and natural chemical substances led to apparent clinical benefit for patients with adverse food reactions involving the skin, gastrointestinal tract, respiratory tract, and central nervous system. Methods: Over the past 48 years, patients of all ages presenting to the Royal Prince Alfred Hospital Allergy Unit with adverse food reactions were offered an elimination diet low in natural salicylates, biogenic amines, and glutamate, and free of additives such as preservatives and colors, for two to six weeks. Those who became asymptomatic were offered testing with a “N-of-1” double-blind, placebo-controlled (DBPC) challenge protocol. Results: There were 14,119 patients who elected to undertake either the strict elimination diet (10,074) (71.4%), the moderate approach (2760) (19.5%), or the simple approach (1285) (9.1%). Of these, 6645 (47.1%) became asymptomatic within two to six weeks; 628 (4.4%) reported no improvement; and 6846 (48.5%) were lost to follow-up. Of those who improved, 4963 (35.2%) returned for interpretation of their challenges, and 2429 had undertaken open food challenges; 3326 had completed the DBPC capsule challenge protocol, and 1830 completed both DBPC capsule and food challenges. Although individual reactivity was idiosyncratic, a highly reproducible pattern was evident across the entire group. The proportion reacting to each of the active chemical challenges versus placebo was highly significant (p < 0.001). Conclusions: In many patients with food intolerance, idiosyncratic dietary triggers can be reliably identified with a standardized elimination diet and DBPC challenge protocol. Long-term symptom control can be achieved by appropriate dietary modification.