food intolerance test

Food intolerance testing has been around for some years now and is offered by many laboratories. Since this test has become more affordable it has gained in popularity as a simple way to define what’s wrong with your diet and how to lose weight quickly.

However, in advertisements, the professional debate that revolves around this theme is not mentioned. Does the elimination of foods on the basis of food intolerance testing endanger your health? Does food intolerance testing really help in achieving health goals and losing weight?

After taking the test you usually come back with a long list of foods you should eliminate from your diet, many of which we know to be healthy.

Allergies and food intolerance symptoms

What is the connection between food intolerance testing and allergies? What are the differences between food allergies and intolerance?

If you suspect to be allergic to a food IgE antibodies are measured in your blood. If you have IgE antibodies for that particular food it means that you have a type I allergy. If no IgE antibodies are found it means your not allergic to the tested food. About 1-2% of the population have type I allergies to food. Those allergies cause acute and direct reactions within 1-60 minutes.

food allergy

Food intolerance tests don’t measure IgE antibodies but IgG antibodies in your blood. IgG antibodies are bonding to allergens and white blood cells forming large immune complexes in the blood that are deposited in organs and tissues. Those large complexes can cause inflammation and tissue damage which leads to inflammatory diseases.
Only very high values of IgG antibodies in your blood are considered as appropriate indicators for intolerance to a certain food. This kind of food intolerance is also called a type III allergy, which is characterized by delayed reactions from several hours up to 3 days.

Type III allergies can contribute to the creation of chronic health conditions.  It is estimated that about 40% of the population has this type of reaction to certain foods.

Characteristics of type I and type III allergies – allergy and food intolerance symptoms

Type I allergyType III allergy
  • Immediate acute reaction(1-60 minutes)
  • 1-2 % of the population is affected
  • IgE antibodies are formed in the blood
  • Histamine is secreted
  • Delayed reaction (several hours-3 days)
  • 40 % of the population is affected
  • IgG antibodies are formed in the blood
Symptoms type I allergy
Symptoms type III allergy
  • Rashes
  • Skin redness
  • Itching
  • Swelling of the mouth and /or throat
  • Inability breathing
  • Vomiting
  • Diarrhea
  • Allergic shock
  • Loss of appetite, bloating, vomiting, constipation or diarrhea, cramps
  • Acne, itching, rash
  • Headaches
  • Pain in the joints and/or muscles,stiffness
  • Breathing problems, worsening of asthma symptoms and the like
  • Chronic fatigue syndrome, sleep problems, tension
  • Overweight and obesity


Without scientific evidence – levels of IgG antibodies and hypersensitivity to foods

Although food intolerance testing is very popular, there are a number of official associations (Canadian Society of Allergy and Clinical Immunology (CSAC), the American Academy of Allergy Asthma and Immunology (AAAAI), European Academy of Allergy and Clinical Immunology (EAACI)) that have issued statements in order to warn consumers about food intolerance testing by measuring IgG antibodies.

In their publications is stated that there is not enough research and evidence to support the use of food intolerance testing for the diagnosis of adverse reactions to foods or to predict future consequences for your health.

Current research suggests that the presence of specific IgG antibodies to food is actually a marker of exposure and tolerance to certain foods. A positive IgG antibody result can be expected in healthy adults and children.

In other words if you for example eat a lot of tomatoes or use honey often, these foods will likely appear on the test as foods that you should be avoiding. Your IgG to these foods is higher simply because you have been eating those foods regularly.

Until now, research has been conducted only on small groups. In a study people with IBS were evaluated. Researchers compared the effect of a diet based on the presence of specific increased IgG antibodies and the elimination diet. It was concluded that elevated IgG antibodies are not reliable indicators for the diagnosis of hypersensitivity to certain foods. Such studies are rare and too small to lead to a general conclusion on IgG testing.

Is food intolerance testing dangerous?

food intolerance test

Many official allergy associations are issuing statements against food intolerance testing. The test itself is harmless, only a little blood is taken to perform the test. The test results however can lead to elimination diets which carry a risk of malnutrition. Especially because the list of foods to eliminate from your diet is typically very long, leaving you with little choice what to eat. This is especially important for children, since food intolerance testing is marketed to concerned parents.

Another concern about this test is that it is widely available, even in pharmacies, without the control and advice of doctors or nutritionists.

The good and the bad of food intolerance testing

Reports of patients, doctors and nutritionists who have used food intolerance testing to improve health problems or to lose weight show positive and negative results.

Many patients claim that the elimination of certain foods from their diet, suggested by food intolerance testing, led to improvement and relieve of certain symptoms. Patients with arthritis, bloating, diarrhea, constipation, chronic cough, rhinitis and migraine are among those who most frequently feel improvement.

On the other hand, the question is whether the improvement in these patients occurs due to the elimination of a large number of foods, including a lot of industrially processed foods. If you remove most of the refined grains, dairy products, processed breads, sugars and products with preservatives it is to be expected that you will feel better. The fact is, that food intolerance tests recommend the elimination of these foods for most patients.


Particular caution must be taken when fruits and vegetables are eliminated from your diet. Fruits and vegetables supply your body with essential vitamins and minerals for which many of us already are deficient.

Hard to follow in the long run

It is also very difficult to stick to the diet regime in the long run. It requires a radical change in eating habits as well as adopting new habits all at once. The probability that you are going to endure such radical changes is very small. For example, one common result is that your intolerant to most grains and yeast. That means that you’ll have to eat yeast free bread which is not always sold in supermarkets. That means you’ll have to bake it yourself. What is the probability that you will be able to bake bread in the long run if you’ve never done this before?

Some of the foods that you are intolerant to are reintroduced after a while, in smaller quantities, not many endure the first phase of complete elimination of many foods.
These tests can help doctors in the diagnosis and treatment of patients, but you need to be under medical supervision. Don’t just get tested and blindly follow the recommendations of the laboratory analysis by yourself.

Although very popular, such testing should be approached with caution because it is a radical change in diet that can have negative consequences for your health. Scientific evidence does not currently point to a direct link between an increased level of IgG antibodies and intolerance to certain foods.
If you decide to get tested confront laboratory assistants and doctors with the research and statements by international associations for allergies. Ask whether elevated levels of IgG antibodies indicate intolerance or just the fact that you have eaten this food. It is recommended that an analysis is done in consultation with your doctor or nutritionist.

If your looking to lose weight food intolerance testing is certainly not the best approach since you can lose weight at the beginning but regain it quickly after you stop with the elimination of foods.

Photo credit: A red bite by Wagner Cesar Munhoz