Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Food-allergy fears drive overly restrictive diets

05.11.2010
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 testing are suggestive but not definitive. Low test values suggest that a child's immune system is sensitized to the food, but not necessarily to the extent that it will cause an allergic reaction. Higher values suggest an increasingly likelihood of true food allergy. None of the tests are 100 percent accurate, however, in predicting clinical food allergy on their own.

National Jewish Health physicians use blood tests as one piece of evidence in their comprehensive evaluation of food allergy. They also carefully evaluate a patient's history, including any previous reactions to food, the type of reaction, the patient's age, and the result of skin testing for food allergy. They generally perform an oral food challenge when the evidence is mixed and they want a definitive answer to the food allergy question.

Children in the study were avoiding 177 different foods based primarily on previous blood test results. In many cases, especially those with high test results for egg, milk, shellfish, peanut and tree nut, National Jewish Health elected not to perform oral food challenges. They did perform oral food challenges for 71 foods or about 40 percent of the cases where the clinical allergy was equivocal and it was important to determine whether or not the patient had food allergy. In 86 percent of those cases, the child passed the food challenge and the food was restored to the child's diet. Overall, 66 of the 177 foods avoided because of blood tests were restored to children's diets. For the entire study, 325 foods were restored to the diets of 125 children.

"When you are able to restore foods such as dairy products, egg, peanut, wheat, and vegetables to a child's diet, it improves their nutrition, reduces the need for expensive substitute foods and makes meal time easier for families," said Donald Leung, MD, PhD, senior author and Edelstein Chair of Pediatric Allergy and Clinical Immunology at National Jewish Health.

The problem can be especially acute among patients with eczema, also known as atopic dermatitis. Research suggests that specific foods can cause flare-ups in about one third of eczema patients. They commonly have high immunoassay tests to a variety of foods, many of which are not truly allergenic. As a result, many mistakenly avoid foods they believe are causing flare-ups, but neglect basic skin care that is vital to improving the eczema. One hundred and twenty of the 125 children in the study had eczema.

National Jewish Health is a world leader in food-allergy treatment and research. Patients interests in participating in food-allergy research at National Jewish Health can call 303-270-2222.

William Allstetter | EurekAlert!
Further information:
http://www.njhealth.org

More articles from Studies and Analyses:

nachricht The importance of biodiversity in forests could increase due to climate change
17.11.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

nachricht Win-win strategies for climate and food security
02.10.2017 | International Institute for Applied Systems Analysis (IIASA)

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Corporate coworking as a driver of innovation

22.11.2017 | Business and Finance

PPPL scientists deliver new high-resolution diagnostic to national laser facility

22.11.2017 | Physics and Astronomy

Quantum optics allows us to abandon expensive lasers in spectroscopy

22.11.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>