Paper: Clarke L, McQueen J, Samild A, Swain A. The dietary management of food allergy and food intolerance in children and adults. Australian Journal of Nutrition and Dietetics. 1996;53(3):89–98.
Available from: https://www.sswahs.nsw.gov.au/rpa/allergy/research/daareview.pdf
Overview of paper: This review paper, written for dietitians, covers the definition, symptoms, and diagnosis of food allergies and (pharmacological) food intolerance. The only way to diagnose food intolerance is through an elimination diet and subsequent food challenges, and “all patients with suspected food intolerance need to be assessed by a physician to exclude any other disorder” before starting down this path.
In most patients [on an elimination diet], clinical improvement occurs gradually over a two- to four-week period. If there is no change in symptoms after four weeks of strict adherence to the elimination diet, then food intolerance is unlikely to be the main factor in causing the patient’s symptoms. A normal diet should then be resumed by reintroducing one suspect food or chemical group at a time (e.g. milk, wheat, salicylate, amines, preservatives and colours) in gradually increasing amounts, up to high doses for three to seven days to determine if symptoms are exacerbated.
Significance of quote: Even though pharmacological food intolerance reactions are often delayed, elimination diets only need to last for four weeks to rule out food intolerance.