By London Nutritionist Sylvia Hensher
Different Types Of Food Reactions
Type 1 Immune Reactions
The best known and well-studied form of food allergies is called a Type 1 immune reaction, also known as a classical food allergy. Type 1 food allergies occur in approximately only 2-5% of the population, mostly in children and are less frequent in adults. The reaction is immediate, usually appearing 15 – 30 minutes from the time of exposure to the offending food substance. Usually occurring in people who are genetically predisposed, the immune system begins creating a specific type of antibody called Immunoglobulin E (IgE) to certain foods. One side of the IgE antibody will recognise and bind to the allergic food. The other side of the antibody is attached to a specialised immune cell called a mast cell which is packed with histamine. Histamine is one of the chemicals that is released in the body as part of an allergic reaction, and which causes the itching, sneezing, wheezing, and swelling typical of allergic symptoms. Primed for action, the IgE antibody now patiently waits for re-exposure to food allergens.
So, when you eat the allergic food the next time, IgE antibodies hungrily latch onto the food. Instantaneously, histamine and other allergy-related chemicals are released from the mast cell, quickly bringing on the unwelcome symptoms of stomach cramping, diarrhoea, skin rashes, hives, swelling, wheezing or the most dreaded of all Type 1 reactions, anaphylaxis. Anaphylaxis is a severe, potentially life-threatening allergic reaction which causes your blood pressure to drop suddenly and your airways to narrow, blocking normal breathing. It requires immediate emergency medical attention.
Clinical approach: In Type 1 food reactions, offending foods are completely avoided and nutritional immune and digestive support provided.
Type 3 immune reactions
Type 3 immune reactions are much more commonly involved in food sensitivities than Type 1 reactions. In fact, 45-60% of the population has been reported as having delayed food allergies. A delayed food sensitivity also involves the immune system and occurs when your immune system creates an overabundance of antibody Immunoglobulin G (IgG) to a specific food. The IgG antibodies, instead of attaching to Mast cells, like IgE antibodies in Type 1 allergies, bind directly to the food as it enters the bloodstream, forming food allergens bound to antibodies circulating in the bloodstream. The allergic symptoms in Type 3 immune reactions are delayed in onset – appearing anywhere from a couple of hours to several days after consuming allergic foods. This delayed onset makes pinpointing the culprit food difficult. In this instance, laboratory testing may be useful.
Delayed food reactions may occur in any organ or tissue in the body and have been linked to over 100 allergic symptoms and well over 150 different medical diseases.
Clinical approach: In Type 3 immune reactions, it is important to identify food triggers, either through food exclusion tests or laboratory testing (more on this below).Depending on the symptoms, these foods are then excluded for a period of time, and then reintroduced on a rotational diet to avoid retriggering symptoms. In addition, nutritional immune and digestive support is provided.
Why Has the Incidence of Food Sensitivities Risen? (more…)