What is the difference between the two and how are they accurately diagnosed?
A food allergy is an immune system response to a food protein that the body mistakenly believes is harmful. The severity of a reaction can range from mild to severe, resulting in the breaking out in hives, swelling of the face, breathing difficulties and in the most severe cases anaphylaxis which can be life-threatening.
Almost any food can cause an allergic reaction, however, the most common triggers are cow's milk (dairy), peanut, tree nuts, sesame, soy, wheat, and seafood. Consuming just small amounts of a trigger food is enough to elicit an allergic reaction meaning the only method of treatment is the complete avoidance of the triggered food.
Unlike allergies, food intolerances do not involve the body’s immune system and are often not life-threatening. They occur when the body is unable to digest or absorb a particular food or when a particular food irritates the digestive system. Symptoms often include bloating, gas, diarrhea, nausea or abdominal pain.
Food intolerances can be triggered by naturally occurring food chemicals such as salicylates (found in fruits and vegetables), amines (found in ripened fruits and vegetables), glutamates (found in protein-containing foods) or preservatives, artificial colours and flavourings.
Unlike food allergies which involve the strict elimination of the trigger food, most intolerances are dose-dependent. This means that individuals with intolerances are still able to consume their trigger foods in small quantities without suffering from any symptoms. This, of course, varies based on the individual and the severity of their sensitivity.
Validated diagnosis tools
You may have heard of various diagnostic tools that have been marketed to diagnose food allergies and intolerances but what does the science actually show?
Food allergies are diagnosed either via a skin prick test or a blood test for allergen-specific Immunoglobulin E (antibodies) that help to identify potential food allergy triggers.
On the other hand, food intolerances can be difficult to diagnose as no blood tests or skin prick testing can help diagnose food intolerances. The only reliable method of diagnosis is via a temporary elimination diet under the supervision of a dietitian and medical practitioner.
Tests such as Cytotoxic Food Testing, Vega Testing, Kinesiology, Iridology, Pulse Testing, Alcat Testing, Rinkel's Intradermal Skin Testing, Reflexology, and Hair Analysis have been shown to be inaccurate and unreliable in published studies.
Risk of developing nutritional deficiencies
Food allergies and food intolerances may result in the elimination or restriction of certain food groups. This can lead to nutritional deficiencies and intern negative health outcomes if not well supplemented or accounted for. In saying this, if you suspect you may have a food allergy or intolerance it is important that you seek a general practitioner or an accredited dietitian.
By Annalise Farah, Accredited Practicing Dietitian (APD) - BMedSc & MND