How Food Sensitivity Tests Work
Food sensitivity tests are fairly easy at-home blood tests (for those who aren’t squeamish, of course) that are ordered online. When the kit arrives, prick your finger, deposit drops of blood on the card, and then send your blood sample in for analysis. Results usually arrive via email within a couple of weeks. As for the science, “they use your blood to identify systemic antibodies called IgG (Immunoglobulin G) that develop when a certain food leaks out of a permeable gut or ’leaky gut’ and into the bloodstream,” says Jill Carnahan, MD, a functional medicine expert based in Colorado. “The body reacts with an inflammatory storm, which you may experience as stomach problems, joint pain, brain fog, acne, headaches, or skin issues.”
A Food Intolerance Is Not a Food Allergy
Remember, food intolerances are not the same as allergies. Allergies can result in anaphylactic reactions like hives, tongue and throat swelling, trouble breathing, and itchiness. “While an intolerance or sensitivity is uncomfortable, allergies can be life-threatening,” explains Katherine Metzelaar, MSN, RDN, CD, a Seattle-based dietitian and certified intuitive eating counselor. “When you go to a doctor specializing in allergies, you will often have a skin-prick allergy test, a blood test, or both. These will measure IgE antibodies (Immunoglobulin E) that indicate an acute immune response and a true allergy.”
The Debate Around These Tests
If you’re struggling with vague symptoms—like nagging indigestion or upset stomach, headaches, fatigue, fogginess, or skin irritation and inflammation—an at-home blood test may seem like the perfect solution for identifying the causes of your woes. But the truth is, experts are divided on the accuracy of the results.
Cons
“At home IgG food sensitivity tests are not currently recommended by the American Academy of Allergy Asthma and Immunology because the presence of the antibodies doesn’t necessarily indicate a negative reaction to a food,” says Claire Carlton, MS, RD, LD/N, a Honolulu–based registered dietitian nutritionist and digestive health expert. “These tests reflect the memory of our immune system and are often considered to actually be a marker of our tolerance—not intolerance—to these foods.” Also, if you have a history of disordered eating or anxiety around food and dieting, Metzelaar warns that these kinds of tests can do more harm than good, exacerbating and reinforcing existing issues.
Pros
That said, many swear by the accuracy of their at-home test results and have seen major lifestyle improvements by cutting out the offending foods or ingredients specified in their results. “While there haven’t been many validation studies for how accurate [food sensitivity tests] are, if you are experiencing inflammatory symptoms, it means you are not digesting certain foods properly. So these tests can be a helpful screening tool and the basis for a short-term elimination diet,” says Christina Stapke, RDN, CD, a Seattle-based integrative and functional dietician.
Healthy Tips for Managing a Food Sensitivity
Don’t Go Crazy With It
“I recommend taking 30 days off from highly reactive foods, and then reintroducing them one by one, every two to three days—or even one a week—so you’re better able to interpret how your body is reacting,” says Dr. Carnahan. “For example, if you notice headaches or stomach aches after reintroducing gluten, there’s your answer.” She adds that, as an integrative doctor, it’s beneficial for a patient to feel empowered to make their own decisions based on their symptoms.
Take Care of Your Gut
Remember, too, that the foods themselves, like gluten, dairy, chickpeas, or egg whites, aren’t the only potential issue. While a certain ingredient may be causing an inflammatory reaction, it’s likely a weakened gut that’s allowing the offending food to wreak havoc. Gut health maintenance is key. To improve your digestive health, Stapke recommends trying some daily stress relief in the form of yoga, meditation, or another form of me-time. “By reducing your cortisol levels, you give your digestive system a chance to rest, allowing your gut to produce higher secretions of the enzymes you need to break down foods, which will prevent intestinal permeability,” she says.
Eat a Variety of Foods
Stapke also recommends having variety in your diet. “If you eat the same thing every day, you’ll have a higher chance of developing a sensitivity to it. While it’s fine to make a big batch of stew to enjoy all week, you don’t want to be eating cauliflower or lentils every single day because, ultimately, your body may literally get sick of it.”
Consult a Medical Professional
Of course, if your nagging or chronic symptoms are not subsiding, or you’re having more allergic reactions when you eat certain foods, see your primary care physician or another medical professional for a full diagnosis and treatment plan.
