Food Intolerance FAQ
Frequently Asked Questions about Food Intolerance and TrophoScan®
What is an adverse food reaction?
An adverse food reaction is defined as any symptom that occurs after ingestion. A symptom can be any change in how we feel and it can manifest for example, as a rash, as joint pain, or as fatigue.
Adverse food reactions are classified into two groups: toxic and non-toxic food reactions. A toxic food reaction is what is often referred to as food poisoning and it is caused due to the presence of harmful substances in the food. Non-toxic food reactions are divided into two subgroups: immunological and non-immunological etiology. Non-immunological food reactions include side effects from chemical food additives, substances in foods with pharmacological effects, and intolerances due to inherited deficiency or dysfunction of certain enzymes, such as lactase deficiency, which is responsible for lactose intolerance. Immune-based food reactions have been referred to as food allergies or food hypersensitivity or food intolerances.
TrophoScan® is a laboratory method (ELISA) designed and developed entirely by Diagnostiki Athinon, in order to measure adverse food reactions of immunological etiology with the participation of IgG antibodies.
What are food allergies?
Food allergy is an adverse food reaction in which an immune mechanism is involved. Immunologically motivated food reactions involve the production of antibodies against certain food-derived antigens. These reactions depend on the body's sensitivity to certain foods. This sensitivity is related to the genetic predisposition and the general health condition of the body. Food allergies are classified into IgE-mediated and non-IgE-mediated antibodies.
What promotes the development of a food allergy?
The underlying etiology of a food allergy varies from person to person. Possible causes include antigenic overload, poor digestion and absorption, stress, disorders of the intestinal flora (dysbiosis), and disorders of the immune system.
How do I find out if I have food allergies?
All it takes is a sample of blood obtained by a simple blood draw. Diagnostiki Athinon applies the ELISA methodology for the quantification of IgG antibodies and the immuno-enzymatic technique Phadia ImmunoCAP (Thermo Scientific) for the detection of IgE antibodies. ELISA is the acronym for “Enzyme-Linked ImmunoSorbent Assay”, a widely used, reliable, and sensitive laboratory technique.
The ELISA test that we apply at Diagnostiki Athinon includes one (or more) 96-well-plates, each one covered with a certain amount of purified proteins isolated from the respective foods (antigens). The patient's serum is added into the wells and the antigen-antibody binding is measured. An enzyme-antibody system is used to measure this binding, which recognizes the existing serum antibodies that are bound to the food antigens (which are attached to the wells). The action of the enzyme becomes apparent with the change of color and is measured using specialized photometers. The intensity of the color in the wells is proportional to the concentration of the antibody-food antigen complexes.
Using the ELISA method and the similar technology method ImmunoCAP, at Diagnostiki Athinon we check a patient's serum for the presence of immediate or delayed food hypersensitivity, i.e. we measure the presence of specific immunoglobulins E (IgE antibodies) and immunoglobulins G (IgG antibodies). Allergic reactions to food (and other allergens such as airborne allergens) are characterized by an increase in specific immunoglobulins in the patient's serum and the activation of inflammatory mechanisms of the immune system.
Various studies show that allergic food reactions are involved in a large number of different health problems. TrophoScan® and ImmunoCAP© tests constitute two useful tools through which the patient can assess the degree of hypersensitivity to various food allergens.
Should I eat or avoid certain foods before the test?
No, it is better to maintain your dietary habits by consuming what you usually eat. It is obvious that you should avoid any food that caused anaphylaxis, in the past. Consumption of these foods can be fatal.
Should I stop my medication before the test?
Anti-inflammatory and immunosuppressive drugs such as prednisone (cortisone) and cyclosporine, respectively, suppress or modify the function of the immune system and thus may affect the result of the tests. The choice of discontinuation, or not, of these drugs, should be done in consultation with your doctor.
What is the difference between IgE-mediated and non-IgE-mediated food allergies?
IgE-mediated food allergy involves the production of IgE antibodies to certain food antigens and usually occurs immediately after consuming the suspected food. This type of allergy is also called immediate because the symptoms appear within 2 to 3 hours after the consumption of the food. Classic food allergy occurs when IgE antibodies found on certain cells of the immune system (mast cells) recognize and bind the antigen of the food. This binding causes the secretion of certain substances, mainly histamine and others, by mast cells. These substances cause many of the symptoms of food allergies such as stomach cramps, diarrhea, skin rashes, edema, and anaphylaxis.
The non-IgE-mediated food allergy involves the production of another type of antibodies besides IgE, i.e. mainly the production of IgG antibodies. Symptoms of food allergy from IgG antibodies (food intolerance) can occur from hours to days after eating the suspicious food, and therefore they are also called delayed food allergies. In these cases, IgG antibodies bind to food antigens and form antibody-antigen complexes in the bloodstream. These complexes can be deposited into various tissues of the body and thus initiate the inflammatory process.
What is food anaphylaxis?
Anaphylactic reaction after eating a certain food is a life-threatening condition that causes swelling and bronchial spasms. It is an IgE-mediated hypersensitivity reaction that occurs immediately after consuming the responsible for the reaction food. This condition requires immediate medical help.
What are the most common symptoms and signs of food intolerance?
From the Gastrointestinal System: vomiting, constipation, diarrhea or very soft stools, bloating and gas, abdominal pain and colic, loss of appetite, malabsorption, obesity, gastroesophageal reflux disease, gastritis, and gastric ulcer.
From the Musculoskeletal System: arthralgias, myalgias, tendonitis.
From the Respiratory System: cough, chronic rhinitis, asthma, bronchitis, sinusitis.
From the Nervous System: headaches, migraines, insomnia, irritability, mood swings, anxiety, depression, attention deficit hyperactivity disorder.
From the Skin and Immune System: chronic or recurrent infections, chronic acne, eczema, atopic dermatitis, allergic conjunctivitis, recurrent ear infections.
From Other Systems: recurrent cystitis, hypoglycemia, type 2 diabetes, hypertension, arteriosclerosis, anemia, eosinophilia, poor development (for children and adolescents), chronic fatigue syndrome.
What do elevated levels of IgG antibodies against certain foods mean in TrophoScan® responses?
Elevated levels of IgG antibodies are indicative of a delayed-type of hypersensitivity to these foods. This hypersensitivity can manifest with various symptoms. Given the fact that the symptoms do not appear immediately after the consumption of the suspicious food, the detection of these symptoms is not an easy task. In general, the onset of symptoms may occur from 2 to 72 hours after eating. IgG antibodies against food antigens are in the bloodstream for about 21 days in high concentrations, while their residual action can last 2 to 3 months. Symptoms can therefore persist for weeks or months after the certain food is removed from our diet.
TrophoScan® showed elevated levels of antibodies against foods I have never eaten. How is it possible?
We consume many foods without knowing it in processed foods. Usually, manufacturers of the products may not list all the ingredients or they mention them with names that the consumer cannot recognize or some processed foods may contain some ingredients in very small quantities (due to the use of the same machines for example). How many of us can have antibodies against horse meat and how many of those who have antibodies to horse meat knowingly ate horse meat?
Other times, cross-hypersensitivity reactions may occur. For example, a delayed hypersensitivity to lemon antigens may indicate a similar hypersensitivity to other foods in the same family (in our example, orange or tangerine). There may also be cross-reactivity with antibodies to non-food antigens. For example, patients with a natural latex allergy may have cross-reactivity with banana antigens.
When assessing food intolerance, it is important to consider possible cross-reactions. Undesirable food intolerances and symptoms can occur either when the immune system detects the responsible antigen or when it detects a similar antigen. Cross-reactions are common in fruits and vegetables.
TrophoScan® showed elevated levels of antibodies against Gluten. Do I have celiac disease?
Biopsy of the affected intestine and certain blood tests, which are also performed at Diagnostiki Athinon (Tissue Transglutaminase Antibodies, Endomysial Antibodies, Antibodies against Gliadin, Molecular test for the presence of histocompatibility antigens DQ8 & DQ2) can contribute to the definitive diagnosis of celiac disease. The presence of antibodies against gluten or cereals (wheat, barley, rye, oats) does not make the diagnosis of celiac disease, but this result indicates that further investigation is needed.
How do I use the results of TrophoScan®?
You should study carefully the results of TrophoScan®. Then you should plan your diet (consult your doctor or dietitian). Once you have a diet plan, follow it and observe the improvement of your symptoms.
How long should I follow the special diet until I see an improvement in my symptoms?
Due to the relatively long half-life of IgG antibodies, it may take up to 3 months for the symptoms to improve.
