Food Intolerance TEST
Recently, the laboratory tests aimed at detecting intolerance that people may have to certain foods have been brought up to date.
We must differentiate between two different concepts and therefore two clinical manifestations that are also different.
On the one hand, there are food allergies. This is a very well-known subject which has been extensively studied, a classic in the pathology of the allergy. In this case, an allergen – in general, a specific protein in foods – is capable of triggering an allergic reaction, the clinical manifestation of which may be oedemas, diarrhoea, urticaria, eczema, asthma, with a classic clinical set of allergic symptoms.
Allergy is a complex immunological process mediated by specific IgE (immunoglobulin E) when the protein from the food is found. It can be precisely detected in the laboratory by determining the levels in blood serum of specific IgEs from foods which are suspected of producing the allergy. In the case of an allergy there is a very rapid cause-effect reaction, so that the allergic reaction is manifested within a few hours of having ingested the food which triggers the reaction and the manifestations are generally clinically evident.
There is another group of processes, less simple to detect, without a rapid cause and effect, as in the case of an allergy, whose pathological manifestations are generally less clear, more insidious and sometimes difficult to detect. We are referring to so-called Food Intolerance, which means that a particular person may show a “sensitivity” – not an allergy – to certain foods.
The food antigens which may give rise to adverse reactions are proteins and glyco-proteins of low molecular weight, resistant to the acid hydrolysis of the stomach and to the action of digestive proteases as well as to denaturalisation by heat. These molecules are captured by the M cells of the epithelium which covers the Peyer patches, where they are absorbed by the macrophages which make the subsequent antigenic presentation to the lymphocytes. In most cases, this process does not arise as the organism does not react to the food proteins as if they were foreign bodies, but in certain cases there is an immunological sensitisation, with the formation of antibodies but not of the IgE type (which would trigger an allergic process) but a first stage of IgA type and after multiple stimuli,, the formation of IgGs (immunoglobulins G). These IgGs are of the same nature as those that are produced in the presence of proteins of micro-organisms, and which confer acquired immunity. Their stimulation and permanent production is the scientific basis for the action of vaccines.
We are therefore looking at situations in which certain foods can produce specific IgGs in the presence of any of its characteristic proteins, as an immunological mechanism, and respond to fresh consumption of an abnormal form which can, ,in certain cases be evident, diarrhoea or digestive disorders, but in many cases the manifestations are insidious and difficult to relate with the food, precisely because this is a moderate pathology of a chronic type.
The clinical conditions which it has been possible to relate to food intolerance and which, after suppressing the food or foods, in more than two thirds of cases, have produced evident improvements, are the following, with data from a range of publications:
• Gastro-intestinal disorders (50%): Abdominal pains, constipation, diarrhoea, swelling, irritable bowel syndrome. This is the pathology which most leads to thinking of a food allergy. It can give rise to anything from abdominal pain, diarrhoea or vomiting, to constipation, with the result that it might be advisable to carry out the biochemical test for IgG in the presence of foods with an etiologically little-defined digestive pathology.
• Dermatological processes (16%): Acne, eczema, psoriasis, rashes, urticaria, itching.
• Neurological disturbances (10%): headache, migraine, dizziness, vertigo
• Respiratory disturbances (10%): Asthma, rhinitis, difficulty in breathing. In these cases, there may be overlapping with an allergic process.
• Psychological disorders (11%): Anxiety, lethargy, depression, fatigue, nausea, hyperactivity (mainly in children).
• Others: Arthritis, fibromyalgia, inflamed joints.
Food intolerance and obesity
In obese persons who do not respond to ordinary slimming treatments losses of weight have been seen when eliminating from the diet those foods to which there was a high degree of sensitivity. The explanation for this relationship may be the process that we set out below.
The antibodies to the proteins of certain foods which have created an intolerance, will be joined to the specific antigens after ingestion of the food, forming immune-complexes which may form networks of the so-called “circulating immune-complexes”. If the ingestion of the food, to which an intolerance has developed, is frequent, other elements of the immune system are activated, causing a local tissue inflammation, which in serious cases can even cause symptoms of vasculitis. The persistence of these circulating immune-complexes in quantity can increase coloidosmotic pressure of the blood plasma, at the level of the glomerular capillaries of the nephrons, reducing the glomerular filtration, which causes retention of liquids, which can give rise to oedemas, particularly in the extra-cellular compartment, although in grave cases, it can also arise at the intra-cellular level.
This process of water retention, due to food intolerance, can lead to an increase in weight, which does not respond to hipocaloric diets, which is aggravated because in many cases the diets are associated with an increase in water consumption, which makes the situation worse regarding retention of liquids, caused by the food intolerance, if the food or foods which cause it are not excluded from the diet.
It is for this reason that the Food Intolerance Test is recommended for screening to be included in the ordinary clinical examinations, prior to the establishment of a diet aimed at treating obesity.
Reviewing all the groups of pathologies that we have described, which may be triggered by food intolerance, and reviewing data from the scientific literature and from our own records, giving a very general overview, we can say that evident improvements have been found in between half and two thirds of the cases which have fulfilled the diet established by their doctor, suppressing the foods which have been shown to be least recommended by the analyses. In general, the improvement perceived by the patient occurs between 20 and 60 days after having started the proper diet.
We believe that the determination of levels of IgG in response to different foods (in our laboratory we carry out a screening of 217 foodstuffs), and establishing, through the doctor, a suitable diet which suppresses those foods to which there is a high degree of intolerance, is a significant option to be borne in mind in the group of pathologies described, which can be improved by simply suppressing their cause.