Food allergies are relatively common in the United States and are reported to be on the rise. Up to 8% of children and 2% of adults in the United States are estimated to have food allergies. Food allergies occur when the immune system mistakes an element of food for a foreign invader and mounts an immune response against it. This can lead to symptoms such as an itching sensation in your mouth, vomiting, diarrhea, throat tightness, trouble breathing, and in rare cases, a potentially deadly reaction called anaphylaxis.

Not all foods can cause food allergies. For unknown reasons a short list of only eight foods is responsible for more than 90% of all food allergies in the U.S. Food allergies are related to how common a particular food is in the diet and as a result, tend to be cultural: rice allergies are common in Japan and codfish appears on the list in Scandinavia. Below is a list of the most common foods that cause food allergies, along with a discussion of their prevalence in adults and children.

The top foods that cause food allergies are:

• Cow’s Milk
  The most common food allergy in children, milk allergy affects 2-3% of infants in developed countries. Up to 90% of these children grow out of the allergy by the time they reach 4 years of age. Note that an allergy to cow’s milk is not the same thing as lactose intolerance. The former is a true allergy and causes symptoms such as hives and breathing problems as well as stomach problems, while the latter is not an allergy but a food “intolerance” and causes only digestive problems.


• Eggs
  Eggs are another very common food allergy among children and this allergy persists into adulthood for some. Most kids will outgrow an egg allergy by age 5. Something to be aware of if you or your child has egg allergies is that some vaccines, including the flu vaccine, contain egg proteins which may provoke a serious reaction in allergic individuals.


• Peanuts
  Peanut allergies are common in both children and adults with about 1% of each group affected. Only about one-quarter of children with peanut allergies outgrow them. Peanut proteins in seem especially adept at provoking the immune system into a lethal attack on the body, and indeed peanut allergies are the leading cause of food-related death. However, these deaths are still quite rare.


• Tree nuts
  Tree nut allergies are more common in children than adults but a fair amount of adults are affected as well. Tree nuts include most familiar nuts except peanuts, including almonds, walnuts, cashews, Brazil nuts, pecans, macadamia nuts, and others.


• Wheat
  Wheat allergies are quite common in adults, accounting for as much as one-quarter of all food allergies. Many children also have wheat allergies. There is a related problem called celiac disease, in which the immune system attacks the small intestine whenever the protein gluten is ingested. Gluten is present is large amount in wheat, rye, and barley. For people with either celiac disease or wheat allergies, a wheat-free diet is essential.


• Soy
  Soy allergies are more common in children than adults. Think babies don’t eat soy? Actually, many infant formulas contain soy protein and soy allergy often starts with a reaction to a soy-based infant formula. Although most children outgrow soy allergy by age 3, soy allergy may persist and is becoming more common in adults. Other foods that contain soy include tofu and many bread products, which may contain soy flour.


• Fish
  Seafood allergies, which include allergies to fish and shellfish, are the most common cause of food allergy. Seafood can be a powerful allergen for certain people, causing life-threatening reactions. Seafood allergies are life-long, but don’t affect children as much as adults because kids don’t eat as much seafood. Most people who are allergic to fish are not allergic to shellfish and vice versa, but it is not a good idea to test that for yourself unless under the supervision of a doctor.


• Shellfish (i.e. crustaceans and mollusks)
  As with fish, shellfish allergies are very common, especially among adults. Interestingly, people tend to be allergic to either crustaceans (e.g. crabs, lobsters, and shrimp) or mollusks (e.g. squid, clams, mussels, oysters, and scallops); only 14% of seafood allergy sufferers are allergic to both.

For more information about food allergies, see the Healia Health Guide on Allergies. To share stories and tips about how to live with a food allergy, join the Healia Health Community for Food Allergy

_{Sources: Ameican Academy of Allergy, Asthma, and Immunology, TIps to Remember: Food Allergy. http://www.aaaai.org/patients/publicedmat/tips/foodallergy.stm; Seafood Allergy, Allergy and Asthma Advocate, Winter 2006. http://www.aaaai.org/patients/advocate/2006/winter/seafood.asp}

_{Photo: wEnDaLicious, Flickr, Creative Commons}