Food Elimination Diets and Testing: What You Need to Know

Are you experiencing chronic symptoms? You may be dealing with food sensitivities or food intolerances. Food sensitivities and food tolerances can lead to digestive issues, chronic inflammation, and chronic symptoms. 

Symptoms may be delayed, and recognizing food as a culprit can be tricky. Testing for food allergies and food sensitivities and trying an elimination diet to spot food sensitivities, food intolerance, or histamine intolerance, may help to find the foods causing your chronic symptoms.

What Are Food Allergies, Food Sensitivities, and Food Intolerances

Food allergies, food sensitivities, and food intolerances can have similar symptoms. But they are not the same.

Food Allergies

Food allergies are driven by something called an Immunoglobulin E (IgE) reaction. Thus we may refer to them as IgE allergies. IgE reactions cause an immediate response to a foreign substance your body encounters. (1, 2).  

For example, if you are allergic to peanuts, if you eat even a tiny amount of peanut butter, your body will react to it. How does this happen? Your body will recognize the peanut butter as something harmful. It will start producing IgE antibodies immediately, which will attach to your mast cells, causing the release of histamine and other chemicals. 

From your first allergic reaction on, every time you eat peanuts or peanut butter, these IgE antibodies will prompt your mast cells to send histamine and other chemicals to cause an allergic reaction. Symptoms will be immediate, and they may be severe or even life-threatening, in the case of an anaphylactic shock,  without treatment 

Symptoms of food allergies may include:

• Hives
• Swelling
• Rashes
• Itching
• Difficulty breathing
• Throat closing
• Anaphylactic shock

Food Sensitivities

Food sensitivities cause Immunoglobulin G (IgG) reactions. IgG causes a more prolonged reaction than IgE with a subtle delayed reaction to a foreign substance (3).

For example, if you have a food sensitivity to gluten, you won’t notice any immediate reaction. Your reactions likely won’t be severe either. Instead, you will experience delayed and more subtle reactions hours or days later. 

How does this happen? When your body encounters a food sensitivity, it will make IgG antibodies, which will trigger inflammatory processes in your body. These processes work slower, thus this may only cause symptoms hours or usually days after exposure. 

Since symptoms are delayed, most people don’t realize that their symptoms are due to food sensitivities. As a result, they may consume the foods they are sensitive to on a regular or even daily basis. This can lead to a constant flow of IgG reactions, inflammation, and chronic symptoms without understanding the real problem (4, 5).

Symptoms of food sensitivities may include:

• Migraines and headaches
• Skin rashes, eczema, or swelling
• Fatigue and sleep issues
• Gas, bloating, diarrhea, constipation, acid reflux, and other digestive issues
• Joint pain and muscle aches
• Brain fog, memory problems, and other cognitive issues
• Depression, anxiety, irritability, and mood disturbances
• Congestion, runny nose, or other sinus issues
• Poor immune function, getting sick often
• Malabsorption of vitamins and minerals

Food Intolerances

Many people use food sensitivities and food intolerances interchangeably. However, they are not the same.

Unlike food sensitivities and food allergies, food intolerances are non-immunologic reactions to food. Your body doesn’t make immunoglobulins (IgEs or IgGs) when encountering a problematic food. Instead, they usually develop because of a deficiency of an enzyme you need to digest a specific food. 

Lactose intolerance is one of the most common food intolerances. You may develop lactose intolerance if your body is unable to produce enough of the lactose enzyme needed to break down lactose in cow’s milk. If you have casein intolerance, it means your body doesn’t make enough enzymes to break down the protein in cow’s milk, called casein (6, 7).

Symptoms of food intolerances may include:

• Abdominal cramps, gas, bloating, diarrhea, nausea, and other digestive issues
• Fatigue 
• Headaches or migraines
• Rashes or other skin problems
• Runny nose or congestion
• Joint pain or muscle aches
• Irritability or nervousness

Histamine Intolerance

Histamine is a chemical in your body that serves many functions. When you encounter an allergen, your body releases histamine to remove it. It also serves as a neurotransmitter supporting your brain function. It also triggers stomach acid release for healthy digestion.

Histamine only becomes a problem if you have too much of it. Histamine intolerance means that you have too much histamine, and your body cannot break down and metabolize it all. If you have histamine intolerance, you may not have enough DAO or HNMT enzymes to break down excess histamine. This may cause a histamine build-up and histamine-related symptoms. Eating too many high-histamine foods and other lifestyle factors may increase the risk of histamine intolerance. Other factors, including mast cell activation syndrome, chronic stress, gut health issues, environmental toxins, and certain medications, may also trigger histamine intolerance. Histamine intolerance can affect your entire body and lead to a long list of symptoms.

Symptoms of histamine intolerance may include:

• Headaches or migraines
• Eczema, dermatitis, rashes, or other skin issues
• Hives
• Flushing
• Allergic reactions
• Asthma attacks
• Congestion or runny nose
• Bloating, diarrhea, nausea, or other digestive issues
• Abnormal menstrual cycle or PMS
• Fatigue
• Dizziness or vertigo
• High blood pressure or low blood pressure
• Irregular heartbeat
• Anxiety

Testing for Food Allergies and Food Sensitivities

Your first step to better health is testing for food allergies and food sensitivities. When it comes to food allergies, skin pricking is still the standard. However, skin pricking tests for food allergies, not food sensitivities.

IgG blood tests are a common way to test for food sensitivities. These tests are looking at IgG reactions to certain foods. They are not completely accurate but can be a good start.

Another option is the Patented Mediator Release or MRT test. This test offers a functional measurement of diet-related sensitivity pathways to common food sensitivity triggers and chemicals. What’s interesting about this test is that it not only identifies inflammation-inducing foods, but also gives us insights into the best foods for the patient. This can help us create a dietary plan to reduce inflammation, decrease symptoms, and improve health.

I now prefer MRT over IgG testing because it targets more of what I look for and the issues I see with my patients. For example, with the MRT we can look at foods that may aggregate an immune response of the immune cells, including mast cells, that are capable of releasing chemical mediators like histamine. MRT may be a great tool if you have histamine intolerance or mast cell issues, while IgG testing may be less helpful in that regard. Also, unlike with the IgG, the MRT has immune memory so that re-introducing a problematic food is not necessary to run the test.  I should note that I just started recommending the MRT the past 3 months for patients that warrant it after a full assessment and discussion of options.

Looking at blood tests is not enough. Always listening to my patients’ symptoms and health history is a critical part of my practice. When spotting food sensitivities, simply removing the problematic foods is just a beginning. We need to address underlying gut microbiome imbalances, leaky gut, and other health issues. Making dietary and lifestyle adjustments to improve root issues is critical. When we address these underlying problems, food sensitivities may improve or disappear completely.

Elimination Diet for Food Sensitivities and Food Intolerances

Testing for food sensitivities is a guide but may not be enough. Food sensitivity tests simply don’t include all the foods on the planet. It’s possible that some of your favorites are missing, or you are sensitive to a less common culprit. Even with the best tests out there, false results can happen too. And when it comes to histamine intolerance or some other food intolerances, there are no tests to spot them.

This is when an elimination diet comes into the picture.

What Is an Elimination Diet?

An elimination diet is a nutrition plan that involves removing specific foods from your diet for a certain period of time. These are foods that you suspect may be behind your symptoms, perhaps with one of the aforementioned tests as a guide. After an elimination period, you will reintroduce these foods, one at a time, while checking in with your body to see if you experience any negative reactions. 

The elimination diet generally lasts anywhere between 5 to 8 weeks total, depending on the number of foods you are removing during the elimination phase. Results can inform you what foods you should remove from your diet or need to be careful with. The results of your elimination diet may help to alleviate chronic symptoms.

Types of Elimination Diet

You may use an elimination diet for various food-related issues:

• Elimination diet for food sensitivities: In this case, you are removing any common and suspected foods that may cause food sensitivities.
• For histamine intolerance: During this elimination diet, you are removing high-histamine foods from your diet.
• Elimination diet for other food intolerances: You can try an elimination diet for just about any other food intolerance. For example, you may remove casein from your diet to see if you have casein intolerance. You may remove high-oxalate foods to see if you have issues with oxalates.

How to Do an Elimination Diet

Are you ready to figure out the food culprits behind your chronic symptoms? Let’s get into how to do an elimination diet.

Phase 0: Planning for an Elimination Diet

• Figure out what kind of elimination diet you are doing. Are you looking at food sensitivities? Histamine intolerance? Other food intolerances?
• Make a list of all the foods that you are eliminating. 
  • If you are testing for food sensitivities, I recommend removing all common food sensitivities, as well as, any foods you suspect to be an issue or anything that has shown up on a food sensitivity test. Common foods recommended to remove during an elimination diet for food sensitivities include:
    • Nightshades, including tomatoes, eggplant, pepper, potatoes, paprika, and cayenne pepper, etc
    • Citrus, including lemon, oranges, and grapefruits, etc
    • Nuts and seeds
    • Legumes, including lentils, soy, and beans
    • Gluten and starchy foods, including wheat, spelt, rye, oats, and corn
    • Certain meats, including processed meat, cold cuts, and canned meat
    • Seafood, including fish and shellfish
    • Dairy, including milk, cheese, and yogurt
    • Fats, including hydrogenated oils, margarine, butter, and refined oil
    • Spices and condiments, including mustard, relish, salad dressings, and other sauces
    • Certain drinks, including alcohol, soda, and caffeine
    • Refined sugar, including white and brown sugar, high-fructose corn syrup, corn syrup, candy, chocolate, and other desserts.
• Plan for any healthy substitutions. For example, if you are removing peanuts during the elimination phase but not almonds or sunflowers, almond butter or sunflower butter may be great substitutes for peanut butter. Coconut milk, hemp milk, or almond milk may be great options instead of cow’s milk.
• Plan some elimination-diet-friendly meals and recipes. Make a shopping list and go grocery shopping for the week. Remember to choose organic whole food options. 
• Get your food journal ready! During the elimination and re-introduction, you want to write down everything you eat and note any symptoms.
• Plan on some strategies that will support you emotionally. Removing foods that you are used to can be emotionally challenging. Have a toolbox you can reach for when things get tough. Journaling may be a good idea to release frustration. Going for a walk, spending time in nature, or exercising may help too. Positive affirmations and reminding yourself of the importance of this experiment may help. Talking with supportive friends and family, cuddling with your pets, playing with your kids, or distracting yourself with a book, music, crafts, or even your favorite TV show may be helpful too.

Phase 1: Elimination Phase

• This phase lasts for about 2 to 3 weeks.
• During this phase, remove all the foods you planned on. Follow a healthy, nutrient-dense, whole foods diet: no refined sugar, refined oils, additives, junk food, or overly processed foods!
• You need to remove these foods completely. No cheating! Having just a bite of a problematic food can bring back your symptoms and throw off the experiment. Remember, the elimination phase is not that long. You can do it!
• Track all your meals and pay attention to your symptoms. Your symptoms should improve gradually by week 2 or 3. 
• If you don’t notice any improvements, it’s possible that you have some other health issues besides food triggers. However, I still recommend following the reintroduction phase carefully. Even if you have other underlying health issues, you may spot some food sensitivities or intolerances during that phase.

Phase 2: Reintroduction Phase

• The length of this phase depends on the number of foods you eliminated during phase 1. 
• Start reintroducing foods one by one. 
• Since symptoms can be delayed, I recommend waiting 5 days between each reintroduction. For example, you may start by reintroducing peanut butter on day 1. Wait for 5 days. Don’t reintroduce anything on day 2 -5. On day 6, you are ready for another introduction. Let’s say, it’s tomatoes. Again, wait for five days, until day 12 to reintroduce anything new.
• If you are not noticing any symptoms after reintroduction, it likely means that you are not sensitive to this food. You may incorporate it back into your diet. First, only in small quantities. Sensitivities may have different levels. You may do well with a certain food if you are only consuming it once or a few times a week, but not 3 times a week. A gradual reintroduction can check for this.
• If you are experiencing symptoms with a certain food, there is a chance you have a food sensitivity or food intolerance. Remove this food again. You may try to reintroduce it again to double-check it wasn’t just a fluke. If you are continuing to have issues, I recommend removing this food for now.

Phase 3: Post-Elimination Diet?

So you spotted some food issues. Great! But you may be wondering if you have to remove these foods from your diet forever. The answer is: It depends.  At this stage, the identified food is removed for a 3 month minimum before gently trying again.

Food sensitivities may change over time. You may develop food sensitivities due to microbiome imbalance, other gut health issues, chronic inflammation, and other factors. If you successfully address your gut health issues and other underlying health problems, you may be able to overcome your food sensitivities and eat these foods again.

On the flip side, you may develop new food sensitivities over time due to gut problems and other factors. If you start developing new chronic symptoms, it’s always a good idea to check in with your diet, especially if you haven’t done an elimination diet in a while. You may benefit from an elimination diet every few years or any time you are experiencing new chronic symptoms.

When it comes to histamine intolerance, if you reduce your overall histamine bucket and reduce other factors that may contribute to histamine intolerance, including stress, toxins, mold, gut infections, and medications, you may be able to eat high-histamine foods again. It may depend on the food as well. You may be able to tolerate one high-histamine food well, but not another one. Most people can eat at least some high-histamine foods again, while others may not.

Next Steps

If you are experiencing symptoms of food sensitivities or food intolerances, you may benefit from trying an elimination diet. Furthermore, if you are dealing with symptoms of food sensitivities or food intolerances, I invite you to schedule a consultation with me here to see if you can benefit from the strategies listed in this article. 

If you are dealing with any chronic health issues, for advice on how to improve your nutrition and health, I welcome you to start a functional medicine consultation with me for further personalized guidance. You may book your consultation here. 

Check out my Histamine Intolerance Course here. Learn on your own time, from anywhere. Get an inside look at the most helpful functional medicine tests for pinpointing imbalances, ways to identify and manage the most common (and sometimes surprising) mast cell triggers, and learn what to eat, what to avoid, and why.