Author: Belinda Martin, Accredited Practising Dietitian | FOOD ALLERGY
IgG testing is in vogue and is offered by several labs claiming to diagnose food sensitivities or allergies. These tests involve reporting IgG levels to multiple foods (about 90-100) and claim that removal of foods with a high IgG level can lead to improvement in symptoms. Some groups are claiming it to be a ‘cure all’ strategy saying that it helps with symptoms of cystic fibrosis, IBS and epilepsy.
Well wow! If this test diagnoses food allergies and sensitivities, tells you to remove multiple foods from your diet and cures all – it must be based on science, right? Shouldn’t we be testing everyone!?
Sounds too good to be true doesn’t it. Well the adage of ‘if it sounds to good to be true then it usually is’, most definitely applies here. This is absolute pseudoscience being promoted to the masses.
In IgG testing, the blood is tested for IgG antibodies instead of being tested for IgE antibodies (the antibodies typically associated with food allergies). The problem is that IgG antibodies just show there has been exposure to a food, NOT an allergy to a food. A normal, healthy immune system should make IgG antibodies to different proteins and a positive IgG test to a food is a sign of a normal, healthy immune system. It is NOT a sign of food allergy or intolerance and should NOT prompt you to take numerous foods out of your diet!
IgG testing is just another misleading test promoted for diagnosing allergies, in the absence of any credible evidence of reliability and science to back it up. The Australian Society of Clinical Immunology and Allergy (ASCIA) states ‘it is important to understand that this test has never been scientifically proven to be able to accomplish what it reports to do. The scientific studies that are provided to support the use of this test are often out of date, in non-reputable journals and many have not even used the IgG test in question. The presence of IgG is likely a normal response of the immune system to exposure to food. In fact, higher levels of IgG4 to foods may simply be associated with tolerance to those foods’.
In fact, due to the lack of evidence to support its use, many organisations who are leaders in allergy throughout the world (including ASCIA, the American Academy of Allergy, Asthma & Immunology, the Canadian Society of Allergy and Clinical Immunology and the European Academy of Allergy and Clinical Immunology) have recommended against using IgG testing to diagnose food allergies or food intolerances / sensitivities.
So, what should you do if you suspect you have a food allergy or intolerance? See an Allergist/Immunologist and a Dietitian who can help you get properly diagnosed and provide you with evidence-based advice. At Advanced Dietitians Group, we are all members of ASCIA and stay up to date with the latest on food allergy and intolerances. We have close working relationships with ASCIA Allergists/Immunologists. If you or your little one have a food allergy or intolerance, book into see us.
About the Author
Belinda Martin is a Perth Dietitian specialising in paediatric nutrition, food allergy, pregnancy nutrition and infant nutrition. She is the co-founder of Advanced Dietitians Group and loves working with people and families. She has been a dietitian for 20 years. She has worked as a Senior Dietitian and Paediatric Dietitian in various teaching hospitals in Western Australia and the United Kingdom. When she is not working, she is trying to tame a 4-year-old and a 2-year-old (and a 40+ year old) at home.
About Advanced Dietitians Group
Advanced Dietitians Group was founded in 2014 by Belinda Martin and Ingrid Roche, Perth dietitians with a combination of over 40 years’ experience in the industry. Both dietitians have a range of experience across the lifespan but specialise in food allergy, paediatric nutrition, pregnancy nutrition and infant nutrition. They provide up to date evidence-based nutrition advice. This coupled with their wealth of experience in dietetics ensures you get the best possible nutrition service. They get a buzz out of helping their clients and their families.
