Food intolerances and food allergies: food intolerance test

Begoña Aubá Guedea, Pharmaceutical, Dietitian and Nutritionist, health nutrition consultant and and food specialist at the Cook & Chef Institute, explains the difference between allergy and food intolerance.

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The difference between an allergy and an intolerance is that the allergy is usually mediated by immunoglobulin E (IgE) and it has a more rapid and verifiable clinical manifestations than intolerance (mediated by IgG). Intolerance occurs with more diffusely in time which sometimes makes it difficult to relate food with the symptom in question.

Food intolerance tests measure the quantity of IgG compared with over 50, 100, 200 and even 500 foods, after the exposure of a blood sample from the patient. It is known that between 20 and 35% of the population suffers from some form of food intolerance whose symptoms can be as diverse as diarrhea, headache, fluid retention, gastritis...

The test is done by using a blood sample and the result is expressed with an easily interpretable code of colors.

Let’s take an example: The lactose. The classical test to determine intolerance to lactose passes through ingesting an oral overload of lactose and at a determinate time, to measure it by an acid breath. From the result it can be deduced if the subject has enough lactase (the enzyme that helps to digest this sugar) or if instead lactose reaches the last parts of "intact" intestine without being digested. In this case the fermentation of sugar can causes bloating, gas, diarrhea, halitosis...

It may happen that the results of this test are negative, leading the individual to continue to consume dairy products; however in this case, a food intolerance test could also measure other particles presents in dairy products such as casein, alpha lactalbumin, beta-lactoglobulin ... And it’s maybe because of these other substances that the patient is complaining about being sick after eating certain dairy products.

I believe that the food intolerance test is a very useful tool to understand some symptoms of our patients and I believe that it can guide us when it comes to make a diet plan that best suits your needs and welfare.


Begoña Aubá Guedea

Farmacéutica. Nº Col. 2487

Dietista - Nutricionista. Nº Col. ARA 00092