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Food Intolerance: “Interdisciplinary Collaboration Is Very Important“
Professor Martin Raithel;
Goose legs with red cabbage, fish curry, French fries with ketchup and mayonnaise, chocolate cake, ice-cream – the list of scrumptious dishes could practically be endless. Meals and the foods they are made off make up a large part of our life and our culture. Ultimately, we need to eat to stay healthy and strong.
But what happens if food makes you sick? MEDICA.de spoke with Professor Martin Raithel of the University Hospital Erlangen in Germany about this issue.
MEDICA.de: Professor Raithel, what is the difference between food intolerance and a food allergy?
Martin Raithel: Allergies and food intolerances are in fact often mixed up. A food allergy is a disease of the immune system. This is a specific disease of the immune system which particularly relates to one, two or more allergens. In contrast, food intolerance is an affection which does not specifically involve the immune system. It is for instance due to an enzyme deficiency or an intolerance to biogenic amines – but there is no specific immune reaction behind it. That’s the difference.
Both have a relatively similar effect on the patients. In both instances they feel discomfort and in most cases think it’s a food allergy. However, many of these responses are in fact
“just“ intolerances. We call these ‘non-immunological intolerance reactions‘. With an occurrence rate of totaling 10 to 15 percent of the population, the aforementioned appear far more often than a food allergy at a rate of 3 to 5 percent.
MEDICA.de: What are the symptoms of possible food intolerance?
Raithel: It needs to be said that the symptoms of an allergy and those of intolerance resemble each other. This makes it difficult for doctors as well as for patients to distinguish between them. For instance in the case of an allergy as well as intolerance asthma attacks and diarrhea may occur. Cutaneous reactions like itching, wheals or headaches and blood pressure changes also appear in both cases, so that these symptoms alone cannot justify a definite distinction.
MEDICA.de: What happens in the body if these different symptoms occur?
Raithel: With an allergy for example, due to a specific immune response IgE antibodies are being produced against a certain food. After contact of the food with this IgE antibody, it leads to the release of allergens, particularly histamine, which in turn provokes an allergic inflammatory reaction. Newer immunomediators that we know are for instance Interleukin-1 and TNF-alpha, but also arachidonic acid products such as Leukotriene and Prostaglandin, which then provoke the various ailments of the patient. Leukotriene for instance frequently causes asthma, bronchial obstruction and mucus secretion. Histamine on the other hand causes vascular dilatation and cutaneous reactions such as the typical hives and the red face, but also abdominal pain and diarrhea.
MEDICA.de: Are the stomach and intestine always affected by food intolerances?
Raithel: Not always. The involvement of organs can vary. And this is a problem, because the patient first visits a physician who is in charge of the respective apparatus. If someone has a swollen nose after eating curry for instance, he primarily goes and sees an ENT doctor; if he experiences abdominal pain, he sees a gastroenterologist. Since not all specialist areas are familiar with the individual intolerance reactions and the different types of allergies, in reality the patient should first see an allergist, dermatologist or immunologist to be able to detect the allergy or intolerance reaction. But oftentimes it is not even clear whether there actually is such an intolerance reaction, so that sometimes physicians and patients are a bit helpless because they don’t know for quite a while what the underlying disease is.
Since the symptoms aren’t always just limited to the gastrointestinal tract and/or the skin, various clinical pictures emerge. Sometimes we only find isolated reactions, which lead to sneezing or swelling of the nose and watery secretion from the nose. In addition, there could be sudden migraines and headache attacks all the way to reactions that go along with joint- and muscle pain. Such rare symptoms can be noticed for instance during the clinically standardized testing of the patient with the gold standard, the double-blind placebo-controlled provocation test. These variable symptoms of allergies have also been described in literature in the past. Since the patient’s previous health history is often unreliable, in individual cases you can only trust and document, respectively, these mentioned symptoms if they occur under standardized provocation tests.
MEDICA.de: Can you give us an example of a patient who you can still remember?
Raithel: I remember a young patient very well, who suffered from joint pains in the context of ulcerative colitis. We were able to diagnose an allergic reaction to nuts and flours. During provocation testing we provoked him with a flour solution, which triggered abdominal pains and diarrhea, but also six hours later arthritis pain. This revealed that in fact symptoms that are more rarely reported, such as arthritis attacks and joint pains or also migraines, can be triggered by foods. But this interesting case also showed us, that after omitting nuts and wheat- and rye flour, the chronic enteritis of the above mentioned patient was significantly reduced and the patient was able to discontinue his drugs for the treatment of his enteritis. A similar case is also described in literature in France and shows us that allergic reactions in the gastrointestinal tract overall are still very insufficiently researched.
MEDICA.de: How do you make a diagnosis? What tests and procedures are you using and which would you advise against?
Raithel: The standard procedure, just like the guidelines recommend it, is to first take a proper past medical history (anamnesis) of the patient. Especially the diet is being checked here, because sometimes you notice that a person eats an unbalanced diet for instance and problems originated from there. A physical exam is also part of the process, listening to the lungs, looking at diagnostic findings pertaining to the skin etc. In addition, skin tests on the back or at the forearm are done to determine, whether sensitization to allergens exist. You want to find out whether the patient exhibits an immune reaction, meaning whether he has an immunologic memory against certain allergens. You always test for pollen that are very common, but also for house dust mites, animal hair and foods – with the latter you always also need to consider mold or spices, which may cause reactions. All this needs to be checked through comprehensive allergological testing.
MEDICA.de: If all those tests ended up being negative, would this then indicate food intolerance in a patient?
Raithel: Unfortunately, it’s not quite that easy. After the skin tests you would –also depending on the anamnesis- of course look at the blood and whether specific allergy antibodies, the so-called IgE antibodies, exist. If you find such antibodies you can then of course explain the disease pattern much better. We also have noticed in our Hospital that you need to look for allergy antibodies not just in the blood, but also for example locally in nasal- or intestinal discharge. That is to say there are definitely allergies that show negative in the blood, but can be substantiated in the tissue. These are so-called local seronegative allergies.