Allergies and Food Sensitivities

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.


A food allergy is the result of the bodys 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 cows 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. Cows 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 childs 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.

Your Mileage May Vary

Food allergy reactions can vary from person to person. Some reactions can be very mild and only involve one part of the body. Other reactions may be more severe and involve more than one part of the body. Reactions can occur within a few minutes or up to a few hours after contact with the food. A serious allergic reaction with widespread effects on the body is known as anaphylaxis.

This sudden and potentially life threatening allergic reaction involves two or more body areas. In addition, there may also be swelling of the airway, serious difficulty with breathing, a drop in blood pressure, loss of consciousness, and in some cases, even death.

The primary caregiver will look for any other condition that could cause the symptoms. If the doctor suspects a food allergy, the patient will likely be referred to an allergy specialist, who will ask in depth questions, perform a physical exam, and perform tests to help make a diagnosis.