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Food sensitivity test is unreliable, says Canadian expert

3 commentsBy Caroline Scott-Thomas , 22-Mar-2012
Last updated on 22-Mar-2012 at 14:10 GMT

An increasingly popular food sensitivity test may lead individuals to eliminate foods from their diets that are not harmful to them, according to a paper published in the Canadian Medical Association Journal.

Dr. Elana Lavine, from the Department of Pediatrics at Humber River Regional Hospital in Toronto, wrote that both traditional and complementary practitioners may offer blood testing to identify foods that could play a role in a patient's illnesses. However, the differences between food allergy - a specific immune response that occurs with exposure to a particular food - food intolerance, such as lactose intolerance, and food sensitivity, may not be clear to many patients.

"Food sensitivity is a nonspecific term that can include any symptom perceived to be related to food and thus may be subject to a wide range of usage and interpretation," she wrote.

In particular, Dr. Lavine writes that immunoglobin G (IgG) antibody testing and IgG4 testing may be misleading - and results of IgG4 testing may be misinterpreted to indicate food sensitivity or intolerance, even though IgG4 is thought to be a marker of exposure to a food, or even of tolerance.

The test is also available online and at pharmacies, and checks IgG levels in response to a wide range of foods, "many of which are ubiquitous, difficult to avoid or very rarely documented as food allergens".

IgG is released in response to foods, but is not a reliable marker for allergy or sensitivity tests, she said.

"Physicians should caution patients about the controversy surrounding testing for food sensitivity," Lavine wrote, adding that doctors may find it useful to explain the "paucity of evidence for using these tests to diagnose food allergy or guide elimination diets".

The American Academy of Allergy, Asthma, and Immunology also takes the position that measurement of specific IgG antibodies to foods is unproven as a diagnostic tool.

Earlier this month, researchers writing in the Annals of Internal Medicine argued that increasing diagnosis of non-celiac gluten sensitivity may also lead to needless dietary limitations.

Source: Canadian Medical Association Journal

CMAJ 2012. DOI:10.1503/cmaj.11002

"Blood testing for sensitivity, allergy or intolerance to food"

Author: Elana Lavine

3 comments (Comments are now closed)

IgG Food test helped me control acid reflux symptoms

I was diagnosed with GERD and took PPI's for six months under MD's supervision. While taking the PPI's I was continually losing weight. Due to chronic pain of acid reflux, I was eating just to survive, and trying to figure out with a food journal what foods I could tolerate. Even after substantial weight loss, lifetyle modifications, and eventually stopping PPI, symptoms continued. Then I started seeing a ND who worked on healing digestion. While under the care of ND. I read about the IgG blood test, although expensive, I thought it might be worth a try. The results of the IgG 200+ proved beneficial for me in getting acid reflux symptoms under control, and I am grateful that such a test was available.

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Posted by Marie Lubbe
28 March 2012 | 22h12

More research needed...!

I'm an ND practicing in Victoria BC and consider myself to be an evidence-based practitioner. IgG food allergy testing IS a useful tool, and DOES have "scientific evidence to support it's use". Example http://www.ncbi.nlm.nih.gov/pubmed/22429360

After all, any evidence-based practitioner should recognize that studies carry more weight than medical opinion!

Through studying immunology, doctors learn about various types of antibodies, many of which are involved in different types/severity of allergic reactions. Years ago IgE immediate-onset reactions (Type 1) were seen as being the only "true" allergy, but now we are seeing various hypersensitivity reactions responding to a myriad of antibodies... such as Celiac disease reacting to IgA, an autoimmune Type 4 hypersensitivity reaction. IgG mediates Type 3 hypersensitivity reactions, these are DELAYED ONSET, very different from IgE/histamine reactions.

I hope this news reaches Dr. Lavine as it was clearly missed in med school!

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Posted by DrAtkinsND
22 March 2012 | 23h42

Gluten Intolerance Symptoms

Gluten Intolerance Symptoms http://www.aboutgrain.com/

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Posted by Don
22 March 2012 | 21h57