The symptoms of a food intolerance can be vague
They can be easily confused with other medical conditions, as symptoms include gastrointestinal problems, nausea and indigestion, eczema or asthma.
Diagnosis of a food intolerance is determined by using the elimination diet and oral challenge test. Any or all foods suspected of causing an issue are removed from the diet for one to three weeks. After this period of time small amounts of the food are slowly reintroduced. If there is more than one food suspected of causing an issue then these foods are reintroduced separately to determine which one is responsible for the reaction. If the symptoms reappear, then food intolerance is confirmed.
This test must be undertaken by an experienced doctor, allergy specialist or Registered Dietitian. If there is a risk of a severe reaction, foods should never be reintroduced without first consulting a health professional, especially in children.
The majority of food intolerances are dose-dependent. This means that you may be able to consume a certain amount of the food causing the intolerance before symptoms appear. However gluten intolerance differs from other food intolerances in that gluten must be strictly avoided.