At Home Food Sensitivity Tests: How Reliable Are They?
Key Takeaways:
Food sensitivities and food allergies are two different things. Food allergies have a faster onset and more specific symptoms than food sensitivities.
Currently, ALL at home food sensitivity tests DO NOT reliably identify food sensitivities.
For IgG tests, like Everlywell, the more you eat of a specific food the higher the chance for a false positive result for that food.
Currently the Elimination Diet is the gold standard for identifying food sensitivities.
Have you ever eaten a certain food that didn’t agree with your stomach? Have you ever noticed a pattern with that food? If so, you may be a part of the 20% of the population that has a food sensitivity. (4)
What exactly is a food sensitivity?
Our mental health and physical health are closely intertwined. How we feel physically can impact our emotions and mood on a daily basis. Choosing to eat a nutritious, balanced diet is the best way to prevent disease, maintain healthy energy levels, and move easier. Food sensitivities can disrupt your system, however. Constantly feeling fatigued, in pain, drowsy, and/or irritable can and will take its toll on your mental health. Symptoms such as headaches, nausea, or digestion issues can impact your ability to get through the day. If a food sensitivity is expected, identifying and removing that trigger food helps to eliminate the symptoms and get you feeling better again.
While a food sensitivity may sound like a food allergy, there are a few key differences. Food allergies are usually an immune system response to certain foods, but they can be non-immune mediated as well. “Immune mediated” refers to conditions that are modulated by the immune system. The immune system protects the body from infections, foreign substances, and disease. Immune mediated allergies, the most common kind, occur when the body creates IgE antibodies for certain foods (such as dairy or wheat products). (2) Allergies can be serious and even deadly. Symptoms of food allergies can cause swelling of the mouth and throat, tingling in the mouth, hives, and even anaphylaxis. Symptoms usually appear almost immediately after ingesting the food allergen.
Food sensitivities, also referred to as intolerances, are non-immunologic reactions to certain foods. These occur when the body has a problem digesting or metabolizing food. It can be due to a lack of enzymes or other factors that are not associated with the immune system. (4) Symptoms of food sensitivities can be more vague than allergies, and include nausea, gas, indigestion, constipation, diarrhea, bloating, headaches, and irritability. These symptoms may occur right away or even a few days later. Food sensitivities are generally difficult to pinpoint. Because you most likely aren’t eating just one specific food at a time, it can be hard to distinguish what foods are causing the symptoms.
Food sensitivity tests:
In recent years, private companies have introduced home food sensitivity tests. These tests claim that they can identify food intolerances (over 100 on some tests) from just a blood sample, hair follicle, or skin prick. The tests cost anywhere from $50- $300 and are not covered by insurance.
These tests may be popular, but what is the science behind them? Are they worth the money? This blog will dive into 4 different tests that are available, the science behind them, and what to do with a suspected food sensitivity.
IgG Testing
IgG testing is undoubtedly the most popular home food sensitivity test on the market. A variety of companies, including EverlyWell, tout this test as an easy way to identify intolerances.
IgG (or immunoglobulin G) is an immune system component that plays an important role in immunologic memory. (4) The body makes IgG antibodies for every single food. Popular food sensitivity tests analyze the blood for certain IgG antibodies and identify a food as a trigger if the blood sample has a higher number of antibodies for that food.
Unfortunately, science does not back this notion. Research has shown that higher amounts of IgG antibodies actually indicate increased tolerance of a food, the opposite of what tests such as EverlyWell suggest. Additionally, diets based on IgG testing have not been shown to alleviate symptoms. (4) There are a couple studies that support IgG testing in regards to food intolerances, but they lack control groups, lack adequate sample sizes, and use poor or unclear measures of improvement.
White Blood Cell Testing
White blood cells (WBC) are cells of the immune system that help fight infections. A higher percentage of white blood cells indicate that the body is working to fight an infection. WBC testing analyzes and tracks the change in percentage of WBCs in a sample before and after a potential trigger food is introduced. The results are identified as normal, equivocal, or positive.1
Unfortunately, there is a lack of scientific evidence to show that a change in WBC percentage correlates accurately with food sensitivities. The ALCAT test, by Cell Science Systems, is the main company that uses this test. A review on the test stated that, “the ALCAT test system is, for the time being, relying on unproven statements that lack scientific and clinical proofs of efficacy.” (5)
Provocation- Neutralization Testing
This is a test that is generally not done at home. In this test, intradermal injections of suspected trigger foods are given to test for any symptoms. A second, different dose of the same food is given again to neutralize the first injection.
It is possible that an intradermal injection of a trigger food could promote symptoms, but it is unlikely given the small amounts that are used. It is not, however, biologically plausible that a second injection would neutralize the first injection. Double-blind studies on this method have concluded that they should not be used to make diagnostic or therapeutic decisions about food intolerances, as they are not accurate or reliable.1
Hair Analysis Testing
Allergy Test is the main company offering hair analysis tests to determine food sensitivities. They claim to test hair follicles against 500 possible food, environment and drink intolerances. The website does not describe the laboratory methods used for testing to identify food sensitivities. The only information given is that the hair samples are checked against a database to identify triggers.1
Is the evidence there?
There is little scientific evidence to back these claims as there are no published studies on this method. One small study found that hair samples from 9 individuals who did not have food sensitivities had frequent and inconsistent positive results when sent to three different labs who performed the test. Because of the lack of evidence and reproducible results, this test is not recommended.
Are food sensitivity tests worth trying?
In most cases, food sensitivity testing is not worth the time or money to have done. There is very little evidence to support the science behind a variety of tests and even less evidence that supports the notion that changing diets based on the testing alleviates symptoms. However, there is some emerging evidence that IgG testing in particular may be useful in identifying triggers in patients with IBS (irritable bowel syndrome). (3)
The use of food sensitivity testing can lead to false diagnoses and unnecessary dietary restrictions. Cutting out whole food groups without proper planning, guidance, or reason may lead to nutritional deficiencies.
Are there any other options for identifying food sensitivities?
The elimination diet is the gold standard when it comes to identifying food sensitivities, Although it isn’t as easy as a blood, skin, or hair test, it is much more accurate in identifying trigger foods! The elimination diet lasts about 10 weeks. The participant starts by eliminating a variety of potential and common trigger foods. Slowly, over the course of the diet, the participant adds foods back in, one at a time, to identify any foods that cause symptoms such as headaches, rashes, digestion issues, fatigue, etc. Food intake is tracked in a journal and symptoms are reported when they appear.
Because this diet protocol requires the participant to temporarily eliminate many foods at once, it is imperative that the participant works with a nutrition or medical professional to ensure nutrition requirements are met.
What next?
If you suspect you have a food sensitivity, speak to a nutrition or medical professional about your concerns. Modyfi offers nutrition counseling and medical guidance to help you plan out any nutrition as part of your treatment plan, reducing inflammation, and improving your mental health.
References:
Kelso, J. M. (2018). Unproven diagnostic tests for adverse reactions to foods. The Journal of Allergy and Clinical Immunology: In Practice, 6(2), 362–365. https://doi.org/10.1016/j.jaip.2017.08.021
Moore, A. (Ed.). (2022, September 28). The myth of IGG Food Panel Testing. American Academy of Allergy Asthma & Immunology. Retrieved January 13, 2022, from https://www.aaaai.org/tools-for-the-public/conditions-library/allergies/igg-food-test
Smith, E., Foxx-Orenstein, A., Marks, L. A., & Agrwal, N. (2020). Food sensitivity testing and elimination diets in the management of irritable bowel syndrome. Journal of Osteopathic Medicine, 120(1), 19–23. https://doi.org/10.7556/jaoa.2020.008
Wong, K. H., Horwitz, R., & Soffer, G. K. (2021). Immunoglobulin G Food Testing. Annals of Allergy, Asthma & Immunology, 126(6), 611–612. https://doi.org/10.1016/j.anai.2021.01.022
Wüthrich B. (2005). Unproven techniques in allergy diagnosis. Journal of investigational allergology & clinical immunology, 15(2), 86–90.
