Although any food can potentially trigger an allergy, 90 percent of the life-threatening reactions are caused by eight foods: peanuts, eggs, milk, wheat, tree nuts, soy, fish and shellfish, according to the American Federal Drug Administration.
In highly allergic people even minute amounts of a food allergen (for example, 1/44,000 of a peanut kernel) can prompt an allergic reaction.
In a true food allergy, the body's immune system recognizes an allergen in the food - usually a protein - as alien and reacts by making antibodies to halt the invasion. The ensuing battle causes a multitude of symptoms, from swelling of the lips, stomach cramps, vomiting, diarrhoea, hives, rashes and eczema, to wheezing and severe breathing problems and even death.
Cow's milk, eggs, wheat and soy are the most common sources of food allergies in children. Allergists believe that infant allergies are the result of young immune systems and, to some extent, immature intestinal tracts. Children sometimes outgrow the allergies, but an early peanut allergy may last a lifetime. Adults are usually most affected by tree nuts, peanuts, fish and shellfish.
- (HealthDayNews, updated July 2008)