Food sensitivities are everywhere these days – at least, that’s what it seems like when you scroll through social media or visit the wellness aisle of your local pharmacy. Testing kits promise to reveal the mysterious foods causing your bloating, fatigue, or brain fog. But here’s the thing: many of these tests aren’t as clear-cut (or as helpful!) as they appear.
As a registered dietitian, I work with many clients who come to me feeling frustrated and confused after getting their food sensitivity test results. If you’ve ever found yourself wondering whether you should eliminate half your diet based on a test, this article will help you cut through the noise. And if you’re wanting more support, book a call to work with me!
What Are Food Sensitivity Tests, Really?
Food sensitivity tests often measure levels of something called IgG antibodies in your blood. These antibodies form whenever you eat a food – it’s part of your immune system learning what you’ve been exposed to.
Here’s the catch: having IgG antibodies is not a sign of harm. In fact, research shows that IgG antibodies are often a marker of tolerance, meaning your body recognizes that food as familiar, not something to fight against.
So when a test flags multiple foods as “high reactivity,” it’s often just showing what you’ve eaten recently or regularly, not necessarily what’s causing your symptoms.
Setting the Record Straight: Allergy, Intolerance, or Sensitivity?
These terms get mixed up a lot, but they don’t all mean the same thing. And understanding the difference can save you unnecessary food rules and restriction.
- Food allergies involve the immune system and can be immediate (like hives or swelling after eating peanuts – this is an IgE reaction!) or delayed (hours to days later, as in some non-IgE reactions).
- Food intolerances are different: they don’t involve your immune system at all. An example of this is lactose intolerance, which is where your body lacks the enzyme to break down lactose, causing gas, bloating, or diarrhea.
- Food sensitivity, as commonly used, is more of a gray area. There’s no clear medical definition or validated test for it. Many people use this term when they feel unwell after eating certain foods but don’t meet the criteria for an allergy or intolerance.
Why IgG Food Sensitivity Tests Fall Short
#1 Lack of Scientific Evidence
Health authorities, including the Canadian Society of Allergy and Clinical Immunology (CSACI), have stated that IgG testing is not a reliable tool for diagnosing food reactions. In fact, the presence of IgG antibodies often reflects exposure and tolerance rather than an intolerance or allergy.
#2 Risk of Unnecessary Food Elimination
When someone receives a long list of “reactive” foods, it can feel overwhelming. I’ve worked with many clients who cut out dozens of foods only to find their symptoms didn’t improve and their relationship with food became much more stressful. Over-restriction can also lead to nutrient gaps and increase the risk of disordered eating.
#3 Symptoms May Have Other Causes
Digestive symptoms like bloating, fatigue, or brain fog can stem from many factors such as stress, irregular eating patterns, hormonal changes, or even gut microbiome shifts. Pinning them all on one or two foods based on a questionable test can lead you down the wrong path.
What to Do If You Suspect a Food is Bothering You
Instead of relying on unproven tests, here’s what I’d recommend as a few suggestions to support you:
- Track your symptoms, gently. A food and symptom journal (not one that’s hyper-detailed or obsessive – think general notes about meals & snacks) can be helpful to notice any patterns of themes.
- Work with a qualified professional. A Registered Dietitian or Allergist can help you identify possible triggers without unnecessary restriction.
- Consider a short-term, structured elimination trial—if appropriate. In some cases, removing and reintroducing a specific food under guidance can give you more reliable information than any at-home kit.
The Bottom Line
Food sensitivity tests can be tempting because they promise quick answers to frustrating symptoms. But the truth is, most of these tests measure something that’s not strongly linked to food intolerance—and can sometimes cause more harm than good.
If you’re navigating ongoing digestive issues, fatigue, or other symptoms, know that you don’t have to do it alone. And you don’t need to eliminate foods out of fear. There are evidence-based ways to explore your symptoms while keeping food freedom (and your health – both physical AND mental!) intact.
References:
American Academy of Allergy Asthma & Immunology. (2018). The myth of IgG food panel testing | AAAAI. Retrieved from https://www.aaaai.org/conditions-and-treatments/library/allergy-library/IgG-food-test
Carr, S., Chan, E., Lavine, E., & Moote, W. (2012). CSACI Position statement on the testing of food-specific IgG. Allergy, Asthma & Clinical Immunology, 8(1), 12.
Food Allergy Canada. (2018). FPIES. Retrieved from https://foodallergycanada.ca/about-allergies/related-conditions/fpies
Gocki, J., & Bartuzi, Z. (2016). Role of immunoglobulin G antibodies in diagnosis of food allergy. Advances in Dermatology and Allergology/Postȩpy Dermatologii i Alergologii, 33(4), 253.
Nordqvist, C. (2017, December 20). Food Intolerance: Causes, types, symptoms, and diagnosis. Retrieved from https://www.medicalnewstoday.com/articles/263965.php
Spergel, J. M. (2006). Nonimmunoglobulin e-mediated immune reactions to foods. Allergy, Asthma & Clinical Immunology, 2(2), 78.
0 Comments