Allergy and Intolerance - Different Problems

Food Allergies - Rare but Risky

True food allergies affect a relatively small percentage of people - experts estimate that only 2 percent of adults, and from 2 to 8 percent of children, are truly allergic to certain foods. Food allergy is different from food intolerance.

The difference between an allergy and an intolerance is how the body handles the offending food.

In a true food allergy, the body's immune system recognizes a reaction-provoking substance, or allergen, in the food - usually a protein - as foreign and produces antibodies to halt the invasion. As the battle rages, symptoms appear throughout the body. The most common sites are:

• The mouth - swelling of the lips.
• The digestive tract - stomach cramps, vomiting, diarrhea.
• The skin - hives, rashes or eczema.
• The airways - wheezing or breathing problems.

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 immunologic immaturity and, to some extent, intestinal immaturity. Children sometimes outgrow the allergies they had as infants, but an early peanut allergy may be lifelong. Adults are usually most affected by tree nuts, fish, shellfish, and peanuts. People with allergies must avoid the offending foods altogether.

Food Intolerance

Food intolerance is a much more common problem than allergy. The problem is not with the body's immune system, but, rather, with its metabolism. The body cannot adequately digest a portion of the offending food, usually because of some chemical deficiency. For example, persons who have difficulty digesting milk (lactose intolerance) often are deficient in the intestinal enzyme lactase, which is needed to digest milk sugar (lactose). The deficiency can cause cramps and diarrhea if milk is consumed.

Estimates are that about 80 percent of African-Americans have lactose intolerance, as do many people of Mediterranean or Hispanic origin. It is quite different from the true allergic reaction some have to the proteins in milk. Unlike allergies, intolerances generally intensify with age.

Source from: U. S. Food and Drug Administration

TRUE ALLERGIES

Heredity may cause a predisposition to have allergies of any type, and repeated exposure to allergens starts sensitizing those who are susceptible.

Some experts believe that, rarely, a specific allergy can be passed on from parent to child.

Several studies have indicated that exclusive breast-feeding, especially with maternal avoidance of major food allergens, may deter some food allergies in infants and young children.

Smoking during pregnancy can also result in the increased possibility that the baby will have allergies.

Most patients who have true food allergies have other types of allergies, such as dust or pollen, and children with both food allergies and asthma are at increased risk for more severe reactions.