Allergic responses are not uncommon. These fall into clearly defined categories, associated with the protein portion of the food. IgE mediated reactions occur in response to cow's milk, soy, peanut and egg, and less frequently to other nuts, fish, shellfish and poultry. The meaning of combination being the sum of food allergy and intolerance 10 . Each of these has been criticized as being non-specific and unrelated to food intake.
Prick tests are only valid to determine IgE mediated food allergies.
Acute allergic reactions may be detected by RAST or prick tests. Celiac disease is a very specific form of immunologic reaction to gluten, and can often be validated by detection of circulating IgA antibodies to gliadin. A small bowel biopsy is the only way to accurately confirm that dysfunction. These include a number of systemic inabilities to digest, metabolize or tolerate foods. Several are well known, others are relatively obscure.