Food intolerances are the cause of a large number of disease symptoms that initially occur without any apparent cause. The spectrum of symptoms ranges from flatulence and abdominal pain to diarrhoea, skin rashes, itching and other discomforts. Intolerances to substances contained in the food supplied cause the problems.
The most well-known food intolerances are related to fruit sugar (fructose) and milk sugar (lactose). But also gluten-containing food can cause complaints in the context of simple intolerance and should not be consumed under any circumstances in the case of a certain disease – coeliac disease. The role of the substance histamine is still being discussed in science.
From a medical point of view, intolerance is distinguished from an allergy, but is usually milder than in the case of complete intolerance. In the case of an allergy, the human immune system reacts to food ingredients and fights them like a pathogen. In the case of food intolerance, the immune system plays no role.
In Germany, only a few people are actually affected by food intolerance. While 3 to 4% have corresponding problems, pollen allergy sufferers make up a significantly higher proportion, at 15 to 20%. The impression that there are many people with intolerance reactions is only spread by the media and the food industry.
More and more products are appearing that do not contain lactose or gluten. Indeed, it is questionable whether such behavior does not strengthen the development of intolerances. With food incompatibilities, a distinction is made between toxic (poisonous) and non-toxic reactions.
Everyone should be aware of the fact that discomfort develops when spoiled food is consumed. If there is no poisoning, there is a non-toxic reaction, i.e. an intolerance in the true sense. In this case, the symptoms are caused by a limited or missing function of enzymes – at least in the case of fructose and lactose intolerance.
On the one hand, the substance gluten can lead to food intolerances, which, however, should not automatically be associated with the disease coeliac disease. Celiac disease is a serious illness in which the immune system attacks the intestinal mucosa when it comes into contact with gluten. A strict gluten diet is the only possible therapy and therefore brings with it many limitations and often malnutrition.
Food intolerance is usually diagnosed by the treating doctor. For this purpose, the doctor must exclude all possible options and conduct a detailed patient interview (anamnesis). In advance, the person concerned can perform a self-test.
For this purpose, a diary can be created in which all the food consumed and any complaints that arise are documented. After 2 to 4 weeks, an evaluation can then be made by checking whether certain foods are related to the symptoms noted over time. If there is not only a food intolerance but also an intolerance or food allergy, further testing can be done.
The prick test represents the diagnostic standard for allergy testing. This is a skin test in which tiny amounts of the substances to be tested are injected into the skin and a reaction is waited for. If the patient has an allergy, at best there is local redness and swelling of the skin.
However, since the solutions administered are not standardized, as is the case when testing for pollen allergies, false results may be obtained. Therefore, blood testing plays an important role in the diagnosis of food allergies. During a blood test, various parameters of the immune system can be checked, which show conspicuous values in allergies.
The most important tests are the Radio-Allergo-Sorbent-Test (RAST) and the Enzyme-Linked-Immuno-Sorbent Assay (ELISA). In these methods, the test allergen – the substance that triggers the allergic reaction – is bound to a carrier and added to the patient’s blood. If the patient has already formed so-called antibodies (defense cells) against the substance, complex formation occurs.
This can be detected and measured. In this way, the blood can be tested for reactions with countless foods, from apples to chicken.However, it is important to note that a positive test result does not necessarily require treatment: the test is only relevant if the patient reacts clinically to the allergens. In addition to the described test procedures, which can be performed as a multi-test for many or specifically for one substance, the total concentration of immunoglobulins E should also be checked. Immunoglobulins are the antibodies that trigger the defense reaction. The subgroup E of immunoglobulins can be elevated in various clinical pictures – also in case of an existing allergy.
