Food allergy epidemiology
Food allergy has been increasing over the last two decades. Peanut allergy has even made a bigger jump, doubling from 1997 to 2002
Approximately 6% of children and 4% of adults have a food allergy (IgE mediated).
- Milk and egg are the most common food allergies, approximately 2%
- Peanut: 0.6 percent
- Tree nuts: 0.4–0.5 percent
- Fish: 0.2 percent in children and 0.5 percent in adults
- Crustacean shellfish (crab, crayfish, lobster, shrimp): 0.5 percent in children and 2.5 percent in adults
- All seafood: 0.6 percent in children and 2.8 percent in adults 
Allergies to preservatives, additive and coloring are
The most common food allergies are: milk, egg, soy, wheat, peanut, tree nuts, fish, crustaceans and sesame seed.
Food allergy definition: "Food allergens are the parts of food or ingredients within food (usually proteins) that are recognized by immune cells. When an immune cell binds to a food allergen, a reaction occurs that causes the symptoms of food allergy. "
Allergies are divided into two categories, IgE immune
mediated reactions and non-IgE immune mediated reactions.
IgE mediated: An IgE antibody that is specifically produced to recognize a specific protein recognizes and binds to the protein. This interaction starts the allergy cascade.
Non-IgE mediated: The allergen interacts with the immune system and sets off the allergic cascade with out the IgE recognition.
Most food-induced allergic reactions are IgE mediated.
Food Intolerance: The body does not tolerate what has been introduced. This intolerance does not involve the immune system. Mechanisms of the reactions include: reaction to chemical properties of the food and enzyme deficiencies. Lactose intolerance, which is a deficiency of the lactase enzyme required to digest lactose in milk, is just one of many known intolerances.
Effects of food processing on allergies to food
- Organic food has no difference in allergenicity vs non organic foods. In other words you will react to organic foods in the exact manor as non organic foods.
- Genetically modified foods can be no more/less/or more allergenic then non genetically modified foods. This all depends on if the genetic alteration increases the major allergen (protein), lowers it or a new allergen is produced.
- Heating (moist or dry), germination, fermentation, ultrafiltration all can affect the structure of the protein - In the case of milk and egg, heating alters the proteins making it so many can tolerate it. Dry roasting peanuts make them approximately 70 times more allergenic.
Is food allergy life long? In short the answer is maybe. Tolerance (the ability to be exposed to the allergen with out reaction) may be gained at some time in life
- Egg tolerance: 11% by 4yrs and 80% by teenage years 
- Milk tolerance: 19% by 4yrs and 80% by teenage years 
- Peanut tolerance: 20% by teenage years (reported episodes of recurrence) 
- Soy and wheat tolerance: approximately 60-80%
- Tree nuts, fish and shellfish tolerance:
less than 8%
1. Sichere SH, Sampson HA:Peanut Allergy: emerging concepts and approaches for an apparent epidemic. J Allergy Clin Immunol 2007, 120:491-503
3. Sathe SK, Teuber SS: Effects of food processing on the stability of food allergens. Biotechnology Advances 2005, 23:423-29
4. Nowak-Wegrzyn A, Bloom KA: Tolerance to extensively heated milk in children with cow's milk allergy. J Allergy Clin Immunol. 2008 Aug;122(2):342-7
5. Sicherer SH, HA: . . 2010 Feb;125(2 Suppl 2):S116-25