Food antigens

Allergy is derived from the Greek word for ‘other’. An antigen is a small part of a larger molecule that is capable of provoking an immune response.

Food allergy or protein intolerance is an immunologic reaction to a dietary protein component considered foreign, or ‘other than oneself’.

Certain food antigens are especially likely to lead to sensitization, such as egg, cow’s milk and peanut.

There are many potential paths from mouth to target organ for food antigens to follow. Every tissue of the body can manifest a food allergic response. Some activity is noticed in minutes; the onset of other activity is delayed hours to days.

During viral or bacterial infections of the digestive tracts, intestinal permeability to food antigens generally increases, due to epithelial damage induced by the infectious agents and to the inflammatory reaction.

Few studies have reported a clear link between increased uptake of food antigens and the development of food allergy. It has often been suggested that infection, by disrupting the epithelial barrier and increasing antigen absorption, would lead to intestinal dysfunction and persistent diarrhea.

Typically antigens responsible for food allergies are 10 to 40 kd glycoprotein or acid proteins resistant to enzyme and heat denaturation. Allergic reactions to cow’s milk protein are the most significant in infancy.

In most people, food antigens are destroyed in the gastro-intestinal tract.
Food antigens