Food Sensitivities & the IgG Test

Did you know that many of us may be eating foods that we are sensitive to daily? And a lot of times these symptoms and reactions can show up hours or even days after we eat them, making it difficult to connect the discomfort to a particular food. If we continue to eat these certain foods, our bodies will have long term inflammatory reactions which may manifest in a variety of conditions.  Such as chronic pain, digestive disorders, migraines, fatigue, skin reactions and the list goes on. This is what a food sensitivity is. Hard to identify, and pinpoint . Unlike food allergies where the symptoms can be more severe and instant. But you and I know that sensitivities can negatively impact our health and daily life , therefore we should take them seriously.

Since I was a little girl, I  have lived with both food intolerance and sensitivities. For many years I did not know I even had sensitivities, I just knew I was lactose intolerant. But it was more than just dairy, often times I did not feel well after eating certain types of foods such as eggs and wheat. As a kid, I remember getting ultrasounds on my stomach because I was in so much stomach pain – it was chronic. There were concerns from the doctor as to what was going on, but when results came back the only feedback my doctor gave me was that I had lots of gas!

So, about 10 years ago I decided to take action and try to get to the root of it. I decided to go see a Naturopathic doctor where she  decided to put me on the Elimination Diet. (At that time the IgG test was $600, so I didn’t want to spend the money.) The elimination diet is basically removing the foods you think may be the culprit and keep a diet diary to see how you feel removing them. Then you reintroduce them later on and log your symptoms. After we had some discoveries here, I decided to go for it and pay for the IgG test . Turns out the same foods discovered on the elimination diet were on the test result and several more (since it is measured against hundreds of foods!) To be honest, this was life changing for me. I had been suffering with stomach discomfort daily such as gas, bloating, pain, constipation and much more. Having pin -pointed which foods were the main culprits allowed me to reduce or avoid them completely. The symptoms that I was experiencing daily such as constipation, gas, bloating, pain and skin reactions greatly diminished and my quality of life improved.

The most common food sensitivities (and allergies)

It is important to note here, that I am not recommending doing the IgG test alone -it is best to do it with the elimination diet for the most comprehensive approach.

Now let’s dig a bit deeper.

First, I want to break down the differences between food sensitivity, food intolerances and food allergies.

  1. FOOD SENSITIVITY(IgG Test) : typically takes months to develop and is triggered by IgG antibodies. The release of IgG antibodies to specific foods is considered normal, as is the formation of antigen-antibody complexes (which form when a food antigen meets an IgG antibody and they bind together. Cells called macrophages typically remove these complexes; however, when many antigen-antibody complexes are present, macrophages may not be able to remove them all. The complexes that are left behind deposit in tissue and release substances that promote inflammation. Inflammation is much more likely to occur if the reactive food remains a regular part of the diet since more immune complexes will form, and in turn may trigger inflammation and contribute to a variety of symptoms.


  1. FOOD INTOLERANCE – A food intolerance is the inability to digest or absorb certain foods. For example, someone with lactose intolerance does not have enough of the enzyme lactase to break down the sugar (lactose) found in dairy products. You may experience intestinal gas, painful abdominal cramping or diarrhea, as well as potentially serious long-term health consequences. While the symptoms of a food intolerance or sensitivity may cause extreme discomfort, they are confined to the gastrointestinal tract and are generally, not life-threatening.


  1. FOOD ALLERGY(IgE test): is a potentially serious health condition triggered by the release of IgE antibodies to a specific food. Food allergy symptoms typically appear very soon after eating a problem food (e.g. peanuts). Reactions may include a condition called anaphylaxis, which can be life-threatening; hives (red swollen patches on skin); breathing difficulties and other symptoms. Although it is possible to measure IgE antibodies in the blood, having IgE antibodies to a particular food shows a reaction is likely, but doesn’t reveal how serious the reaction might be.
Example of the IgG Test Results

What is the IgG Test?

The IgG test is an anti-body-based food sensitivity test that measures your production of immunoglobin G antibodies to foods.  It picks up the antigen-antibody complexes ,which form when a food antigen meets an IgG antibody and they bind together. Doing this test can help you identify which are causing inflammation and your symptoms/discomfort.

It works by a simple prick to the skin creating a drip of blood, this is a completely safe process . The blood sample is then sent to a lab to measure  IgG antibodies against hundreds of foods. Foods that have an elevated number of antibodies circulating through your bloodstream are indicated as your food sensitivities. Within a week you should get your results, where there is a list of foods and an indicator of LOW/MED/HIGH .These show your level of sensitivity to that particular food. HIGH being the most sensitive. (Click here to see a sample test report from ROCKY MOUNTAIN ANALYTICAL)

Where should I do the test?

It is best to do the test through a Naturopathic Doctor or Nutritionist, so they can also review the test results with you in detail. They will come up with a plan on how to make healthy replacements and modifications to your diet to ensure you are still getting all your essential vitamins and nutrients. Follow ups are also critical to ensure progress in your health from eliminating these foods. I personally would recommend to re-do the test every few years, since sensitivities can change or these tests (like any other testing) can have false positive results. The cost of this test has dramatically reduced compared to 10 years ago when I took it and range between $150-$400. And if you have a benefit plan you might just be able to have it covered.

Why the controversy?

  1. The first reason allergists or doctors may not like this test, is because some people confuse ALLERGY with SENSITIVITY. If the individual does not understand the difference they can end up in anaphylaxis and life threating symptoms if the sensitivity is in fact an allergy and not properly investigated or diagnosed as an allergy .
  2. There are many individuals that do the IgG test and do not work alongside a professional. Therefore, they eliminate all these foods, without understanding how to properly replace them with nutrient dense alternatives to ensure they get the daily intake of vitamins and nutrients they need. Therefore, it is important to work with health professionals like naturopathic doctors or nutritionists.
  3. Some allergists believe that the IgG immune complexes that accumulate are not inflammatory, however, there is a lot of case studies that have been done to show improvements in those completing the IgG test and elimination of those foods. In fact, most IgG antibodies (95%) form complexes with antigens (like food) that trigger inflammation and provide no benefit against IgE food reactions. Highest results being improvements in mind and digestion .I know I personally have had great success with it and a lot of others that I know. Feeling better and relieving my chronic symptoms is enough science for me !


I have done both the elimination diet and the IgG test. Completing food sensitivity testing alongside an Elimination Diet provides for the most comprehensive approach to identify your food sensitivities.  I would recommend doing the IgG test first, then eliminate the foods recommended for a period of 4- 6 weeks to see if symptoms cease. If they do cease, then continue to avoid them for up to 4 months – 1 year. After that point you can try to reintroduce to see how you feel . I remove them completely because I just feel better without them. I then re-do the test every 3 -4 years to see if anything has changed and tweak from there.

There is A LOT of confusing information out there on sensitivities and what you should and should not eat based on the news, social media and friends/family. Doing the IgG test , you will be able to better evaluate your own bodies reactions to certain foods and possibly pinpoint where your symptoms are coming from. Working alongside a professional will help you navigate through your results, eliminations and food choices. Ultimately improving your digestive health and everyday well-being.

Until Next Time,

MellyFit xo

Here’s a pretty chart from www.healthline.com to help break it down:

Food allergy
Food sensitivity Food intolerance
Immune system involved? Yes (IgE antibodies) Yes (IgG and other antibodies, white blood cells and other immune system molecules) No (Digestive enzyme deficiency, poor absorption of certain carbs)
Examples of foods involved Top 8 most common: milk, egg, peanut, tree nuts, wheat, soy, fish and crustacean shellfish. Varies from person to person and may include foods you eat often. Fermentable carbs (FODMAPS): milk (lactose), legumes and certain vegetables, fruits, grains and sweeteners.
Onset of symptoms after eating the food Rapid, often within minutes. Within a few hours but may be delayed up to a few days. Within 30 minutes to 48 hours after eating.
Examples of symptoms Trouble swallowing or breathing, nausea, vomiting, hives. Can result in anaphylaxis. Headaches, joint pain, digestive issues, skin issues, an overall feeling of being unwell. Most common are digestive issues: bloating, excess gas, gut pain, diarrhea, constipation.
Amount of food needed to cause symptoms Tiny. Varies depending on your degree of sensitivity. Generally worse with larger amounts of problem foods.
How it’s tested Skin prick tests or blood tests of IgE levels to specific foods. Many tests are available, but their validity is uncertain. Breath tests may identify fermentable carb intolerances (lactose, fructose).
Age of diagnosis Commonly in infants and young children, but adults can also develop them. Can appear at any age. Varies, but lactose intolerance is most likely in adults.
Prevalence 1–3% of adults; 5–10% of children. Uncertain but suspected to be common. 15–20% of the population.
Can you get rid of it? Kids may outgrow milk, egg, soy and wheat allergies. Peanut and tree nut allergies tend to continue into adulthood. May be able to consume a food again without symptoms after you avoid it for several months and address any underlying issues. Can minimize symptoms by limiting or avoiding problem foods in the long term. Antibiotic treatment for small intestinal bacterial overgrowth may also help.


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  1. Pingback: Should I Avoid Dairy? - MellyFit.com - Holistic Nutrition and Digestive Health in Toronto

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