Elimination Diet to Diagnose Food Allergies
is a diagnostic therapy used to detect food allergies, food intolerances and other diseases which are bringing on adverse physical reactions. It is used to identify and single out the food source causing the reactions. It is an extremely important diagnostic solution in management of food allergies.
It is also referred to as the â€œTreatment Dietâ€ and was first proposed by Dr. Albert Rowe in the year 1926.
In the United States alone, it is documented that about 12 million people suffer from food allergies. It includes about 4% of adults and 6-8% of children under the age of 3. The Food and Drug Administration has come out with a list of 8 such foods which can act as a trigger for food allergies. They are milk, peanut, egg, tree nuts, fish, shell fish, wheat and soy.
Understanding what causes food allergies and intolerances will help understanding the concept of how the said allergy test works.
What are Food Allergies?
Food allergies are basically an auto immune response to certain proteins found in food. The immune system identifies the otherwise harmless protein as a threat and starts fighting it. It responds by producing antibodies known as the Immunoglobulin E (IgE). These antibodies react and bind with the mast cells found in the skin, gut and pharynx. This phenomenon causes the mast cells to react by releasing a chemical, namely, histamine. Histamine is primarily responsible for the adverse physical reactions like gastrointestinal distress, respiratory problems or other physiological reactions.
What are Food Intolerances?
Food Intolerance is a non IgE mediated response of the body. The immune system is not involved in this case. Food allergies could be caused by a trace of the allergen being ingested. However, food intolerance would require a full serving of the food containing the stimuli. Food intolerances could be congenital and are caused because the individual do not possess the necessary enzymes needed to process and metabolize the said food. In case of lactose intolerance, the absence of the enzyme lactase makes it difficult for the individual to digest lactose (a kind of sugar found in milk).
Food intolerance could be of the following types:
: Because of metabolic inconsistencies or acquired defects the individual reacts to certain foods. Examples would be lactose intolerance, gluten intolerance, diabetes mellitus, phenylketonuria etc.
: Chemical sensitivities would definitely be in this category. Reaction to low molecular weight chemicals as in salicylates, amines, glutamate etc found mostly in preservatives, food colors or taste enhancers belong to this category.
:Toxins present in food or developed in it from bacterial contamination.
: It is not a food intolerance but certain foods may evoke psychological response in individuals and manifest a physical reaction.
Mechanism of Elimination Diet
The discussed concept works through a trial and error method. The mechanism could also be explained as a â€œchallenge-dechallenge -rechallengeâ€ phenomenon. The test is administered in three steps:
: The doctor would ask you to stop eating foods which may contain a suspected allergen. It is important that you strictly avoid these foods during this phase. During this phase, the individual will stay away from processed food and avoid medication.
: After a recess period when symptoms subside, the same foods are reintroduced in diet. This stage also known as the â€œChallenge Testingâ€. It is not carried out unless all the symptoms have improved and cleared and the individual has been on the discussed diet for at least 2 weeks. This stage is risky and should be undertaken under the supervision of a physician or a registered dietician. Patients with a history of asthma and anaphylactic reactions should be hospitalized before undertaking such diagnostic procedures.
: If symptoms reappear after the reintroduction of the triggers, the cause and effect mechanism is established.
Disadvantages of the Elimination Diet
- The said allergy test is time consuming and would require ultimate discipline on the part of the patient. It could cause withdrawal symptoms because of the deprivation involved.
- It is risky as it involves teasing the immune system with the same allergens one reacts to adversely.
- It is time consuming, complicated and expensive.
- It may set in nutritional deficiency because of the restrictions imposed.
- The restrictions can also bring about social isolation.