by Chiara Ganzer

Created on: September 15, 2007

Most people have food allergy that can cause severe symptoms so it's important to clear up the confusion surrounding food allergy and intolerance.

Food allergy is sometimes confused with a food intolerance or food poisoning, which do not involve severe allergic reaction, it's rarely dangerous. Certain foods cause heartburn, bloating, diarrhea, or other intestinal symptoms.

While allergic reaction to food can start within minutes or an hour or two after eating the food and causes a systemic reaction. The immune system responds to foreign substances by producing proteins called antibodies and we have the first symptom of an allergic reaction to food. Antibodies like immunoglobulin E (IgE)attached to special cells called mast cells, a type of cell that is found in the body. The next time you eat that food mast cells respond by releasing chemicals - such as histamine- to protect your body.
This struggle produces allergic reactions such as hives -also known as urticaria- rashes, anaphylaxis and other minor diseases.

Anaphylactic shock is the most severe allergic reaction which can involve respiratory or cardiovascular symptoms, may cause a person to lose consciousness and stop breathing. Each year, about 150 people in the United States die of food-related anaphylaxis. Epinephrine is a injectable drug avaiable at pharmacies with a doctor's prescription, which can stop an anaphylactic reaction.
You get it diagnosed by a doctor, so that you can avoid it and prevent further allergic reactions in fact you are more likely to react to other foods. The cross-reactivity can occur when we are sensitised to more than one allergen. If you are allergic to prawns, other shellfish may affect you. Allergic symptoms caused by similar proteins advise to avoid exposure to the associated allergens.
But, can additives cause allergic reactions?
Many studies have shown that additives such as monosodium glutamate (MSG), aspartame and food dyes do not cause allergic reactions. Although food additives can cause an adverse reaction in sensitive people.

Methods of testing for food allergies are the RAST (radioallergeosorbent) test, skin test and food challenge. Rast measures food-specific IgE in a blood sample but is more expensive and less immediate than the skin prick test which- on the other hand- are useful in detecting food allergies but detect only the presence of antibodies. Well, food challenge test is a safe method to diagnose food allergy: a small amount of the food will be given to the patient under strict supervision, to see if a reaction occurs. During the double-blind procedure- another way to perform the food challenge- neither the allergist nor the patient is aware of which capsule, or food, contains the suspected allergen. This placebo-controlled test avoid the possibility of a psychological reaction.

There is currently no cure for food allergy but treatment such as injectable epinephrine and antihistamines can be used to alleviate symptoms resulting from accidental exposures.

Learn more about this author, Chiara Ganzer.
Click here to send this author comments or questions.