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 A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg

nachricht Urbanization to convert 300,000 km2 of prime croplands
27.12.2016 | Mercator Research Institute on Global Commons and Climate Change (MCC) gGmbH

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: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Multiregional brain on a chip

16.01.2017 | Power and Electrical Engineering

New technology enables 5-D imaging in live animals, humans

16.01.2017 | Information Technology

Researchers develop environmentally friendly soy air filter

16.01.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>