Many children, especially those with eczema, are unnecessarily avoiding foods based on incomplete information about potential food-allergies, according to researchers at National Jewish Health. The food avoidance poses a nutritional risk for these children, and is often based primarily on data from blood tests known as serum immunoassays.
Many factors, including patient and family history, physical examination, and blood and skin tests, should be used when evaluating potential food allergies. The oral food challenge, in which patients consume the suspected allergenic food, is the gold standard test.
The researchers conducted a retrospective chart review of 125 children evaluated at National Jewish Health for suspected food allergies. Depending on the reason for food avoidance, 84 percent to 93 percent of foods being avoided were restored to their diets after an oral food challenge. The researchers published their study online in The Journal of Pediatrics on Oct. 29. It will appear in a later print version of the journal. "People with known food allergies, especially those with a history of anaphylactic reactions, should by all means avoid those foods," said David Fleischer, MD, lead author of the study and Assistant Professor of Pediatrics at National Jewish Health. "However, a growing number of patients referred to our practice are being placed on strict, unproven food-elimination diets that have led to poor weight gain and malnutrition. These overly restrictive diets have been chosen for a variety of reasons, but overreliance on immunoassay tests appears to be the most common cause."
Immunoassays detect antibodies in the blood to specific foods, which can potentially cause allergic reactions. Interpretation of the results, however, can be tricky. The tests' ability to predict true food allergy has been validated for only five foods cow's milk, hen egg, fish, peanut and tree nuts.
For all other foods, the numbers derived from lab tes
|Contact: William Allstetter|
National Jewish Health