Food Sensitivity Testing: The Fictions Behind the Fad
October 21, 2024
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Social media would have us believe that food sensitivity tests and fad diets are the fix for chronic conditions. But the science says otherwise.
If you searched social media for every symptom you have, you’d likely find lots of suggestions to take a food sensitivity test. Stomach issues? Take a test. Fatigue? Test yourself. Skin issues? You guessed it, time for a test.
These days, food sensitivity testing is one of the most widely recommended methods for understanding why one’s body is behaving in unpleasant or unpredictable ways.
This isn’t entirely surprising: After all, everyone eats. Food is one of the first culprits you might consider when something feels off in your body. This is especially true if you’re having gastrointestinal symptoms, like diarrhea, constipation, or bloating.
And wouldn’t it be simple if all your symptoms could go away just by removing one ingredient or food group, like dairy, gluten, or soy? But let’s be real. The truth is that chronic health conditions are rooted in a complex interplay of stress, genetics, environment, and more, and there’s no simple fix.
A maze of misinformation
Before I had a clear diagnosis, I had a slew of gastrointestinal symptoms that led me, in frustration, to a nutritionist. What I didn’t know at the time was that “nutritionist,” in many states, is an unregulated title, and the advice I received from those professionals didn’t meet the same scientific standards as what I would get from a medical doctor or dietitian.
What ensued was expensive food sensitivity testing that informed me I was intolerant to — well, pretty much everything I ate on a daily basis. (Spoiler alert: This is almost always the result of these tests. I’ll tell you why later.)
Next came months of a very restrictive diet that damaged my mental health and made me lose a dangerous amount of weight.
The whole process caused me to question the science behind food sensitivity testing — as well as some popular fad diets (gluten-free, dairy-free, and soy-free) that people often try as a result of these tests, upending their lives to accommodate them. And I’m not the only one.
Is food sensitivity testing valid?
The short answer is that food sensitivity testing is not scientifically valid. You could even call it a scam. Or complete BS.
According to the American Academy of Allergy, Asthma & Immunology (AAAAI), immunoglobulin G (IgG) food sensitivity testing has never been scientifically proven, and the studies that do claim its benefits are outdated or the companies are not reputable.
For these reasons, both the AAAAI and the Canadian Society of Allergy and Clinical Immunology recommend against using food sensitivity testing for any situation. The results of these tests can lead people to unnecessarily make severe dietary restrictions and lifestyle changes.
An important distinction is that food sensitivities are different from food allergies, and their testing is also different. A food allergy is a dangerous, and sometimes life threatening, inappropriate immune response. In contrast, a food sensitivity or intolerance is when you have difficulty digesting a certain food and experience symptoms as a result.
You may know that people with food allergies undergo testing. Food allergies are tested by Immunoglobulin E (IgE) blood tests, skin prick tests, or oral challenges. Food sensitivities, on the other hand, are tested with an IgG blood test.
The important difference here? IgE and IgG are both antibodies, but only IgE is associated with an allergic reaction.
Instead, the presence of IgG is actually a normal immune response when you’re exposed to a food, so it actually may indicate tolerance rather than intolerance.
As mentioned above, this explains why all the foods I reacted to on my food sensitivity test were those I ate on a regular basis. The antibody the test looks for indicates that your body is familiar with a food, not that there is a problem with that food.
Fad diets as a fix
Despite the fact that food sensitivity testing results hold no scientific merit, many people adopt diets that eliminate gluten, dairy, or soy based on such test results — or based on social media recommendations.
These diets may be beneficial for some people but not for everyone. Below, we discuss three frequently shared diets and the research surrounding them.
Gluten-free diet
These days, most people have heard of the gluten-free diet.
The diet involves removing foods that contain the protein gluten, aka anything with wheat, barley, or rye, or ingredients sourced from those grains (for example, soy sauce, which contains wheat).
While the diet may be trendy, it’s medically necessary for people with celiac disease. This is a genetic autoimmune condition in which a person’s small intestine undergoes damage when they consume gluten.
The only treatment for it is a strict lifelong gluten-free diet.
That said, only 1% of people in the United States have celiac disease, yet an estimated 25% are on a gluten-free diet. Why is that?
Many people adopt a gluten-free diet in hopes of improving conditions such as inflammatory bowel disease (IBD), multiple sclerosis (MS), migraine, and more.
The evidence supporting a gluten-free diet for these conditions is sparse and controversial. For example, the International Organization for the Study of Inflammatory Bowel Diseases (IOIBD) recommends against a gluten-free diet for IBD, and the National MS Society states there is an unclear relationship between gluten and MS.
In addition, the GF diet comes with downsides, like cost, challenges when dining out, and a potential lack of fiber and important vitamins and minerals.
Ultimately, it’s important to discuss the potential risks and benefits of a gluten-free diet with a medical professional before you try it — most importantly, so you can get an accurate test for celiac disease first.
Dairy-free diet
The dairy-free diet is also popular, which you may already know based on the number of alternative milks available today.
This diet isn’t completely without its evidence, but it’s important to be aware of some caveats.
Lactose intolerant people lack the enzyme lactase, which helps break down the lactose protein. Lactose intolerance is not an allergy, but it is one of the most well-documented intolerances, and an estimated 65% of the worldwide population has it.
A healthcare professional can diagnose this condition with a hydrogen breath test, stool acidity test, and other means.
However, people with lactose intolerance can still consume dairy. Different dairy products contain different amounts of lactose. For example, ice cream is high in lactose, whereas aged cheese is low.
In addition, the lactase enzyme is available in pill form, to help make dairy more tolerable. Lactose-free versions of many dairy products are also available. Just because you’re lactose intolerant doesn’t mean you have to follow a dairy-free diet.
Fact check
Social media influencers often say that dairy is inflammatory. But is this true?
A 2024 study found that dairy processing may affect its inflammatory status; pasteurized milk was found to be anti-inflammatory, whereas both UHT homogenized milk and raw milk were pro-inflammatory.
Yogurt also has been shown to be anti-inflammatory, and researchers believe this may be due to the probiotics it contains.
Dairy is a large group of many different foods, so generalizing whether dairy is harmful is difficult.
By eliminating all dairy from your diet, you may do more harm than good. Dairy provides vitamin D, calcium, protein, and fat, which are all important components of a healthy diet. Be sure to discuss a dairy-free diet with your dietitian or doctor before trying it.
Soy-free diet
Another common recommendation is to go soy-free, although this is difficult because soy is present in so many processed foods in the form of soy protein isolate, soy lecithin, and similar products.
There’s a persistent myth that soy’s plant-based estrogens can cause disease among people with hormonally mediated conditions, such as breast cancer, polycystic ovarian syndrome (PCOS), endometriosis, or prostate cancer.
While it’s true that soy contains phytoestrogens these don’t affect the body in the same way that estrogen produced by the human body does.
Claims that soy causes breast cancer, thyroid problems, or dementia are not proven. In contrast, evidence in humans suggests that soy could even protect against breast cancer.
Research from 2010 suggested that soy stimulates breast cancer cells in rats and in petri dishes, but this hasn’t been shown in humans because we process soy’s isoflavones differently.
Soy is a source of fiber, potassium, magnesium, protein, and B vitamins. All of these are healthy additions to a person’s diet, particularly for vegetarians and vegans who don’t get these nutrients from meat. Removing soy from your diet, if you don’t have a soy allergy, can deprive you of necessary nutrients.
The takeaway
There’s a lot of misinformation out there when it comes to food sensitivities, testing, and various diets. If you’re sick, it’s completely understandable that you want a simple answer to start feeling better, and removing one or more foods may seem like an easy and sensible approach.
The reality is a bit more complicated than social media or unregistered health professionals may have you believe. Your best bet is to visit a licensed doctor or dietitian to discuss your concerns before significantly changing your diet.
Medically reviewed on October 21, 2024
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