From the Guidelines
I strongly advise against IgG food sensitivity tests for patients due to their lack of scientific validation and potential for misleading results. These tests claim to identify food sensitivities by measuring IgG antibodies to various foods in your blood, but the presence of these antibodies is often a normal immune response to food exposure rather than an indication of sensitivity 1. Major medical organizations, including allergist and immunologist associations, do not support the use of IgG testing for diagnosing food sensitivities due to lack of evidence for their clinical utility.
Alternatives to IgG Testing
Instead, patients with suspected food sensitivities should consider an elimination diet under medical supervision, where potential trigger foods are removed and then gradually reintroduced while monitoring symptoms 1. This approach, though requiring more time and effort, provides more reliable information about individual food reactions. For true food allergies, which can be life-threatening, standardized tests like skin prick tests or specific IgE blood tests performed by allergists are appropriate.
Importance of Medical Supervision
If you're experiencing symptoms you believe are related to food, consult with a healthcare provider who can recommend evidence-based approaches to diagnosis and management. Oral food challenges, such as the double-blind placebo-controlled food challenge (DBPCFC), are considered the gold standard for diagnosing food allergies, but they should only be conducted under medical supervision due to the risk of severe allergic reactions 1.
Key Considerations
- IgG food sensitivity tests are not recommended due to their lack of scientific validation
- Elimination diets under medical supervision are a more reliable approach for identifying food sensitivities
- Standardized tests like skin prick tests or specific IgE blood tests are appropriate for diagnosing true food allergies
- Oral food challenges should only be conducted under medical supervision due to the risk of severe allergic reactions.
From the Research
Importance of IgG Food Sensitivity Tests
- IgG food sensitivity tests can be a useful guide for elimination diets, with clinical impact for a variety of diseases 2
- These tests have shown promise, with clinically meaningful results, and can be used to identify food sensitivities that may be contributing to symptoms 2
Limitations of IgG Food Sensitivity Tests
- IgG4 testing is not recommended as a diagnostic tool for food allergy, as it indicates immunological tolerance rather than hypersensitivity 3
- The presence of IgG antibodies against food allergens is associated with a normal immune response to food allergens and attests to a protracted exposure to food antigens 4
Prevalence of IgG-Mediated Food Intolerance
- A study found that 85.7% of patients with allergic symptoms lacking laboratory evidence of allergy had IgG antibodies against certain foods, with the most common being cola nut, yeast, wheat, and red kidney bean 5
- Females were found to have significantly higher food-specific IgG antibodies than males, particularly against wheat, corn, and cola nut 5
Clinical Applications
- IgG food sensitivity tests can be used to identify food sensitivities that may be contributing to symptoms, and can be a useful tool in the diagnosis and treatment of food intolerance 2, 5
- However, it is important to note that IgG testing should not be used as the sole diagnostic tool, and should be used in conjunction with other diagnostic methods and a thorough clinical evaluation 2, 6