Dr Sarah Wells – Thyme GP
In the realms of dietary health, the quest for understanding our reactions to food is becoming high in demand, with an ever rising prevalence of IBS-type symptoms.
From gluten sensitivity to lactose intolerance, there’s a myriad of ways in which our bodies can react to the foods we consume. In recent years, IgG food intolerance blood testing has emerged as a popular method for identifying potential food sensitivities. But what exactly is it, and how reliable is it?
Understanding IgG Food Intolerance Testing
IgG is a type of antibody produced by the immune system in response to foreign substances entering the body, such as bacteria, viruses, or food antigens. IgG food intolerance testing aims to identify IgG antibodies specific to certain foods in an individual’s bloodstream. The theory behind this testing is that elevated levels of IgG antibodies to particular foods may indicate a sensitivity or intolerance to those foods.
Often IgG antibodies form in a response to microscopic particles of food that enter the bloodstream, if the integrity of the gut is compromised- from chronic stress, medication use, an inflammatory diet or lifestyle. This is the pathophysiology behind IBS-type symptoms, where then exposure to certain foods exacerbate symptoms further. The type of sensitising food or drink differs amongst individuals, however commonly triggering foods include dairy, gluten, fried foods, processed food, alcohol, caffeine; due to their inflammatory nature.
When there is confusion around which things trigger symptoms, IgG food intolerance testing can be helpful.
The Testing Process
The process typically involves a simple blood test, where a small sample of blood is taken and analysed for IgG antibodies. The sample is then tested against a panel of various foods & drinks to determine the presence and levels of IgG antibodies specific to each food. Once the results are obtained, they are usually presented in a report outlining which foods, if any, have elevated IgG antibody levels. The levels of IgG are tiered into red (high likelihood of reaction), amber (medium), and green (low).
Interpreting the Results
Interpreting the results of IgG food intolerance testing is not always straightforward; whilst elevated IgG levels to certain foods can point to the likely triggers of digestive symptoms, they do not necessarily indicate a clinical allergy or intolerance. A different blood test- IgE testing is used to identify true anaphylactoid allergies, where the reaction is more severe.
Sometimes circulating IgG levels for a certain food can be raised if it is consumed on a regular basis, allowing for some false positive results.
Despite this, some individuals report feeling better after eliminating foods identified through IgG testing, as it allows for a more personalised diet tailored to their individual needs and sensitivities.
Conclusion
IgG food intolerance testing is a tool that some individuals use to identify potential food sensitivities. However, it’s essential to approach it with careful interpretation, with the help of a healthcare professional. While it may provide insights into possible dietary triggers for certain symptoms, it is not a definitive diagnostic tool.
If you suspect you have a food intolerance or sensitivity, it’s advisable to consult with a healthcare professional who can help guide you through appropriate diagnostic testing and personalised dietary recommendations. In the quest for optimal health and wellbeing, understanding your body’s unique needs and responses to food is key, and IgG food intolerance testing may be one piece of the puzzle for some people.
At Thyme we have a range of options for allergy testing. For help and advice contact the team.


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