Most reactions to food do not involve this classic antigen-antibody reaction and therefore many traditional allergists do not believe that food creates health problems for many individuals. The allergists believe that only a few people have food allergies. For them there is a short list of foods which cause only a few possible symptoms. These symptoms include urticaria, anaphylaxis, rhinitis and stomach problems. Over 30 million people in the United States suffer at some time from known allergies, ranging from mild to severe.
Allergies are one of the most prevalent causes of illness in the Unites States.
The number of substances to which people are exposed to has gone up dramatically in the last few decades. Some of the foods we consume all the time are foreign to us, at least in terms of our genetic backgrounds. For example, soy and corn were not eaten in Europe where the majority of Americans have their genetic roots. Intolerances can affect any organ system of the body. They may include rhinitis, breathing problems, digestive problems, itching skin, hives, eczema, rash, headaches, insomnia, hyperirritability, anxiety, depression, and concentration problems.