The 'boom' of food intolerance tests: they neither have medical endorsement nor do they have an impact on better health

A quick Google search is enough to find the first bargain. On a website they promise us that for only 290 euros, in 10 days, we will know if we are “intolerant” to any of the 200 foods on the list. From beef to tomato, including spices such as thyme. On the following website they offer us the same, but with a discount of 80%.

Are these tests really useful for anything?

The reality is that, despite being so widespread, these food intolerance or sensitivity tests do not have scientific evidence. In fact, they are not used as a tool within the public health system and are discouraged by numerous scientific societies.. Among them are the Canadian Society for Allergy and Clinical Immunology (CSACI) and the American Academy of Allergy, Asthma and Immunology (AAAAI) who have strongly criticized these tests for their lack of evidence.

What is the difference between an allergy and an intolerance?

It is common for these terms to be spoken of interchangeably and there is some confusion when in reality they are very different concepts from each other.. In the event that a person is allergic to a food, an immune response is generated. This can be really dangerous and even cause death..

Intolerances, however, occur when the body does not process or digest food properly, causing discomfort of varying severity.. A classic example is lactose intolerance, which causes abdominal distension, stomach pain, gas, diarrhea in patients…. Although “you don't die” from intolerance, it can significantly worsen the quality of life of those who suffer from it.

Some people feel similar symptoms for reasons that have nothing to do with a food intolerance and this encourages them to try these tests in search of an answer.

What do these food intolerance tests measure?

In these intolerance or sensitivity tests, serum IgG antibodies are determined against proteins from different foods in the diet.. The problem is that IgG tests lack specificity for food intolerance and do not measure any clinically valid markers..

This test has never been scientifically proven to be able to achieve what it promises. In fact, it is believed that the presence of IgG is probably a normal immune system response to food exposure.

What are the problems that the use of these tests can cause?

These tests have a high enough price to be considered “good” but without ceasing to be relatively affordable (although the “slash” they hit you goes by neighborhoods). Therefore, the patient asks himself, what can I lose? (apart from money, of course). The reality is that trusting the results of these tests can lead us to establish an erroneous diagnosis and modify lifestyle and diet without having a justification for it..

For example, if there is no reason to eliminate gluten or dairy, the fact of eliminating them from the diet in an uncontrolled way can cause nutritional deficit.

The next twist is that there are those who confuse speed with bacon and stop consuming the foods that they have been told to suppress the test because they think they “make them fat”.. Stop eating lettuce or tomato because “tomatoes make me fat” can not only lead to nutritional deficiencies but to more important behavioral disorders.

Why are they still selling if they are not effective?

Because we are willing to look for ways to feel better… but we like shortcuts. Because the human being still wants to believe in magic. And because, above all else, we need systems and laws that protect us from the legal loopholes that some find in order to put misleading tests on the market.