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Common Food Allergies

A food allergy is basically an immune system response to a particular food, or foods, that the body mistakenly believes is harmful. An individual may be allergic to any food, such as vegetables, fruits, and meats there are eight particular foods which account for the majority of all food allergic reactions. These particular foods are milk, peanut, fish, egg, tree nut, shellfish, soy, and wheat. Allergic reactions to certain foods typically begin within minutes to a few hours after eating the food. The frequency and severity of symptoms may vary widely from one person to another. When symptoms first appear, it is important to differentiate between a real food allergy and another potential cause. Often the cause may be something other than a food allergy, most commonly simple food intolerance.

The most common symptoms of food allergies involve the skin and intestines. Intestinal symptoms may include nausea, vomiting, stomach cramps, diarrhea, and indigestion. Skin rashes typically include hives and eczema. Other symptoms caused by food allergies include asthma, with coughing and wheezing, rhinitis, and occasionally anaphylaxis. Anaphylaxis is a severe allergic reaction that may become life threatening. Peanut allergies affect more than one million people in the United States alone. As the most common cause of life threatening allergic reactions, peanut allergies account for 80 percent of fatal or near fatal allergic reactions every year.

A food allergy is the result of the body's immune system overreacting to food proteins. Not all adverse reactions to food are due to allergy. Some reactions to milk may be related to a deficiency of an enzyme that normally breaks down a sugar in milk. When individuals with lactase deficiency drink cow's milk or eat other dairy products, they may experience intestinal symptoms, typically misinterpreted as a food allergy. Almost any food can cause an allergic reaction and some individuals are only allergic to one food, while others may be allergic to several types of food. Cow's milk is the leading cause of allergic reactions in very young children. Milk allergy affects about 2 percent to 3 percent of infants worldwide, and its signs and symptoms can be serious enough to cause distress for both the allergic child, but also for the child's family. Most children do outgrow a milk allergy by age 2 or 3.

Some people have an allergic reaction to a food that is triggered by exercise. As the body is stimulated by exercise, a person with an exercise induced food allergy may feel itchy and lightheaded. In more severe cases, reactions such as hives or anaphylaxis may occur. Not eating for a few hours prior to exercising may help prevent this problem. Some fresh fruits and vegetables may also trigger a mild allergic reaction that causes the mouth to tingle or itch. This is called cross-reactivity in which the proteins in fruits and vegetables cause the reaction because they are similar to allergy causing proteins found in certain pollens. Most cooked fruits and vegetables generally do not cause cross-reactive oral allergy symptoms.