Often food sensitivity testing is ordered simply due to patient demand for this service. However, the fact of the matter is that food sensitivity testing has a great deal of usefulness in clinical practice.
Functional medicine practitioners have used it effectively to unearth the root cause of health problems, pinpoint the reasons behind what exacerbates a given health concern, and even determine which dietary supplements can do more harm than good.
And therefore, a food sensitivity panel can help practitioners customize their treatment program to each individual – an approach which leads to more successful outcomes. In fact, food sensitivities may be the reason why a particular protocol isn’t working in a specific patient.
Many clinicians use food sensitivity testing to springboard into a 5R protocol for gut healing (Remove, Replace, Reinoculate, Repair, and Rebalance). By removing offending foods, the patient responds more quickly and appropriately to other dietary and lifestyle changes.
What Are Food Sensitivities and Food Intolerances?
Food sensitivities and food intolerances are different than food allergies. Each of them falls into the category of food reactivities, but in the end they’re not the same thing.
- Food allergies are IgE-mediated. They often cause immediate, severe, anaphylactic reactions. Hives, swelling, itching, trouble breathing, and wheezing are common symptoms. Food allergy tests measure immunoglobulin E (IgE) reactions to foods.
- Food intolerances are often due to lack of a particular enzyme. A good example of a food intolerance is lactose intolerance, the inability to digest lactose, the sugar found in dairy. These patients have a deficiency of the lactase enzyme.
- Food sensitivities are immune-mediated reactions to foods, usually involving IgA, IgM, or IgG antibodies. Food sensitivities can cause reactions that are more subtle and that may be delayed by hours or even days after eating an offending food. Symptoms may be gastrointestinal or they may be camouflaged as other problems that seemingly have nothing to do with GI health such as sinus problems, acne, or mood issues. IgG food sensitivity panels are among the top five most commonly ordered functional medicine lab tests at Rupa Health (see the labs available through Rupa at the end of this article).
Labs may differ in the way they test for food sensitivities. Some labs measure IgG antibodies to commonly consumed food antigens. Other labs measure both IgA and IgG, while others measure IgG and IgG4. Many labs combine IgE and IgG testing into one panel to measure both food sensitivities and frank food allergies. Some labs include complement testing, which measures the inflammatory cascade triggered by certain foods.
Food sensitivity tests often require a blood draw or a blood spot specimen.
The Clinical Usefulness of IgG, IgG4, IgA, and Complement
- Complement is an important part of the immune system. In high levels, it results in an inflammatory cascade that is associated with IBS, IBD, eczema, migraines, autism, anxiety, depression, and obesity. Many forms of IgG, with the exception of IgG4, activate complement and lead to inflammation.
- IgG makes up the majority of the total antibodies in the blood. IgG food sensitivity testing is clinically useful because it can be very challenging for a patient to pinpoint their reactive foods since symptoms may appear up to days after an exposure.
- IgG4 is clinically useful in a number of contexts such as weight gain, eosinophilic esophagitis, autism, and irritable bowel syndrome. It’s also used to monitor allergen specific immunotherapy. Here are some pieces of evidence from the literature:
- Autism spectrum disorders (ASD), which are associated with increased IgG4 levels. This is thought to be caused by an altered immune response that occurs in this group of children. Some studies have found a relationship between high levels of IgG4 in children with ASD and behavioral symptoms.
- Irritable bowel syndrome. This group of patients has elevated IgG4 levels to certain foods including wheat, beef, pork, milk, eggs and lamb. After eliminating these foods, the patients experienced significant improvement after three months in pain severity and frequency, bloating severity, satisfaction with bowel habits, and quality of life.
- IgA is the second most abundant immunoglobulin antibody in circulation after IgG. Anti-gliadin IgA can be measured in blood as part of a standard celiac test. IgA antibody levels in blood may suggest intestinal permeability. IgA is also found on mucosal surfaces where it is known as secretory IgA. There, it protects against exposure to environmental antigens, pathogens, and toxins. Because of its role at mucosal surfaces, some sIgA food antibodies, especially anti-gliadin, are measured in saliva or blood.
Food Sensitivity Symptoms
- May exacerbate Autism symptoms
- Congestion or runny nose
- Diarrhea or loose stools
- Gas or bloating
- Headaches or migraines
- Immune system impairment
- Inflammatory bowel disease
- Irritable bowel syndrome
- Joint pain or inflammation
- Malabsorption of vitamins and minerals
- Rashes, eczema, or swelling
- Sinus infections
- Weight gain
Are Food Sensitivities a Real Barrier to Healing?
The existence of food sensitivities is often a controversial issue and conventional doctors often don’t recognize their existence as a contributing factor in health conditions. However, reports in the medical literature as well as clinical practice point to the identification and treatment of food sensitivities as an effective strategy to relieve symptoms of chronic illness.
In a case study of two patients published in Global Advances in Health and Medicine, both patients experienced improvement in their asthma symptoms after eliminating the foods to which they reacted on an IgG antibody test.
In a double-blind, randomized, crossover trial, 30 patients with migraines had an IgG antibody test against 266 food antigens. For six weeks, the patients were then randomized to either an elimination diet based on the results of the test or a diet that included the food to which they reacted.
After two weeks off of either diet, the patients were then switched to the opposite diet. While the subjects were on the elimination diet, there was a significant reduction in the number of days they had headaches, as well as a reduction in migraine attacks.
A larger study of 77 patients with diarrhea-predominant IBS (IBS-D) and 26 healthy controls tested the subjects for IgG antibodies in the serum against 14 common food antigens. Researchers identified food-specific IgG antibodies in 39 (50.65%) of the IBS-D patients and only 4 (15.38%) of controls.
After four weeks of eating an elimination diet, all symptoms including abdominal pain, diarrhea frequency, bloating, abdominal distension, and general feelings of distress, significantly declined compared to baseline.
Reasons to Test for Food Sensitivities
There are a number of reasons why functional medicine practitioners should consider using food sensitivity testing. Here are four of the most important.
Reason #1: Figure Out Why Your Patient Isn’t Getting Better
If your patient has hidden food sensitivities, it can hold back their progress. As long as problematic foods continue to assault your patient’s immune system and harm tissues, it will be hard to reap the benefits of even the most well-designed protocol.
There are various types of diets that practitioners like to employ in their patients’ treatment regiments. A healthy diet plan can be undermined by a hidden food reaction. For example, most keto recipes include almond flour as an ingredient. However, if a patient reacts to almonds, this would not be the best choice. Instead, coconut flour would be a more suitable substitute.
Another example is a patient on a gluten-free diet who is doing a lot of “healthy” baking with gluten-free flour mixtures that contain rice flour. If that patient reacts to rice on a food sensitivity panel, this type of eating will hold back progress, no matter how effective the treatment protocol is otherwise.
Reason #2: Pinpoint Intestinal Permeability
Food sensitivity testing doubles as intestinal permeability testing. People who show immune reactivity to many foods may be experiencing intestinal permeability. As the gut lining is breached, large food peptides can enter circulation where they don’t belong. The immune system treats them as foreign, creating a food antibody and initiating inflammation. Antigen-antibody complexes can deposit in tissues, triggering ill health. Intestinal permeability has been proposed as a major underlying cause of autoimmune diseases such as inflammatory bowel disease, celiac disease, autoimmune hepatitis, type 1 diabetes, multiple sclerosis, and systemic lupus erythematosus.
Reason #3: Avoid Supplementation Faux Pas
Food sensitivity testing can stop practitioners from recommending dietary supplements to which a patient may react.
For example, many clinicians use oregano in patients with small-intestinal bacterial overgrowth (SIBO). However, some patients may react to oregano. Not only would they not benefit from that botanical, but it may actually make them feel worse.
The same is true for other spices like turmeric, garlic, and ginger, and even seemingly innocuous foods like hemp.
Reason #4: Identify Foods that Contribute to Depression and Poor Mental Health
There is growing evidence of a strong connection between the gut and the brain. Due to the recognized presence of a gut-brain axis, it should not be surprising that an emerging link has been established between leaky gut, food sensitivities, and mental disorders.
The wheat protein gliadin can trigger the overproduction of zonulin, which leads to loosening of the tight junction barrier in the intestines and increased permeability of the gut wall (“leaky gut”). This in turn leads to larger molecules that would normally remain in the gut to escape into the bloodstream, which triggers IgG-mediated food sensitivities. This results in an increased immune response and the release of proinflammatory cytokines, which may lead to the development of depression.
According to one group of researchers, “It seems advisable to assess the intestinal permeability using as a marker, for example, zonulin and specific IgG concentrations against selected nutritional components in patients with depression.”
Similarly, researchers have found an increased prevalence of hypersensitivity to food antigens, specifically gluten and casein from cow’s milk, in patients with schizophrenia. When these patients were put on a gluten-free diet, their mental state improved.
Treatments Based Upon Food Sensitivity Testing
- Elimination and Rotation Diet – Elimination diet is the gold standard for identifying food allergies and it is a widely used treatment for patients with food sensitivities. It involves eliminating the offending foods from the diet. This diet may be used for one to three months or much longer. As the clinician determines, the patient can add the food back into their diet to see how they react. The rotation diet involves eating an offending food only once every three days.
- Eat a Gut-Healthy Diet – Eliminate sugar and refined carbs. Include more fiber-rich, colorful, whole foods into the diet while excluding the foods to which a patient reacts.
- Probiotics and Prebiotics – These are used to heal the gut from previous damage and to encourage the growth of beneficial microbiota.
- Digestion Support – Add a good digestive enzyme or stomach acid supplement when needed as well as chewing food thoroughly and relaxing at mealtimes.
- Gut-healing Products – The amino acid L-glutamine is well-known for its ability to heal the gut lining. Formulas that combine L-glutamine together with other gut-healing substances like slippery elm are useful.
- Anti-Inflammatory Medical Foods – Compromised gut function can lead to impaired nutrient uptake. Supplementing with a nutritional formula can make up for deficiencies and calm inflammation in the gut lining. It is important to make certain the formula chosen doesn’t contain any of the foods or botanicals to which the patient reacts.
- Plant Sterols – These can promote a balanced immune response, which in turn can make patients less reactive to food.
Food Sensitivity Testing Leads To More Successful Outcomes
Ordering a food sensitivity test can lead to a more customized treatment approach and better patient outcomes. It is a critical tool in functional medicine and can help guide your 5R protocol or other gut healing treatment plans. Using this test together with an elimination diet and appropriate nutritional supplementation can address the root causes of gastrointestinal and immunological disturbances without medications. It can bring about dramatic clinical improvements. Your patients will thank you!
Rupa Health helps practitioners take the guesswork out of the labwork experience. Clinicians can order, track, and get access to 20+ lab companies in one place, at no extra cost. Choose from a variety of food sensitivity laboratories, including:
Alletess Medical Laboratory
Cell Science Systems
ELISA / ACT Biotechnologies
Great Plains Laboratory
Infinite Allergy Labs