Allergies and intolerances are not the same: they are both “adverse reactions”, but with totally different characteristics. They are two different modes of the organism to respond and react to the interaction with foreign substances.
We talk about intolerance when there is a negative reaction of the organism, triggered by the ingestion of one or more foods (or active substances) and that depends on a difficulty in digesting or metabolizing such food or its component. Food allergies and intolerances includes several diseases that affect the metabolism of carbohydrates, proteins and lipids.
People with this kind of problem have enzyme deficits, that means they do not have those particular proteins (enzymes) that the body needs to metabolize and assimilate certain foods or parts of them. They are usually free from birth, but it is a disorder that can also be acquired over time. It is a reaction that involves metabolism but not the immune system and is strictly dependent on the amount of the unwanted food that has been ingested (dose-dependent).
Symptoms are often like allergic ones and may also appear after a few days, which makes them more difficult to recognize and relate to the food taken. They usually identify with diarrhea, swelling and abdominal cramps.
Allergies and intollerances to lactose.
The most common cause of food intolerance is lactose, which is the sugar contained in milk. People with lactose intolerance have a lactase deficiency, the digestive enzyme that splits lactose into glucose and galactose so that it is absorbed and used by the body. If intolerance is serious, it is important to be careful and read food labels carefully: lactose is used in many ready-made foods.
Another example of allergies and intolerances is the favism, which consists of a congenital defect of an enzyme normally present in red blood cells, glucose-6-phosphate-dehydrogenase, essential for their vitality and function. The deficiency of this enzyme causes a sudden destruction of the red blood cells (hemolysis) and therefore the appearance of hemolytic anaemia. When a person deficient in enzyme ingests broad beans, peas or certain medicines (such as sulphamides, salicylates, quinidine, menadione), these inhibit the activity of this enzyme and the red cells already lacking are further depleted. In serious cases, about half of the red blood cells are destroyed; the skin and the mucous membranes then become intensely pale, as well as yellowish, the urine hypercolored and the signs of a cardiovascular collapse appear.
We mean a disease that affects individual genetically predisposed individuals and consists of the immune system’s reaction to an allergen. Allergens are harmless substances for most people, and, in food, they correspond to food components or food itself.
The reaction is expressed at first contact through the formation of specific antibodies, called immunoglobulins E (IgE), which have the task of defending the organism from what the organism itself recognizes as foreign. It is the same reaction that the organism manifests against bacteria and viruses and can be very violent. Allergic reactions are usually independent doses: even a very small amount can trigger a reaction whose severity is subjective and unpredictable.
The role of histamine.
In occasion of a possible and subsequent exposure, following the reaction between the food”allergenic” and the antibody, the histamine is released: a substance that acts as chemical mediator of the inflammation, but which also has the role of neurotransmitter.
Histamine is primarily responsible for the characteristic symptoms of all allergic reactions such as itching, runny nose, coughing or wheezing.
How do allergic symptoms occur?
The reaction to allergens causes several symptoms that can involve different organs at the same time. Symptoms occur shortly after ingestion and may be of different types, depending on the types of antibodies or other cellular mediators involved in addition to IgE. Generally they manifest themselves as: itching; eruptions of the skin; swelling; difficulty in breathing. The most serious reaction that our organism can manifest is anaphylactic shock, which appears within one hour of the ingestion of the allergen.
Anaphylactic shock always requires urgent hospitalization, because it can lead to breathing difficulties, sudden falls in blood pressure, loss of consciousness and in the most serious cases –death.
The most common food allergens are: cereals containing gluten (wheat, rye, barley, oats, spelt); milk and milk products; eggs and egg products; fish and fish products; crustaceans and crustacean products; molluscs and mollusc products; peanuts and peanut products; nuts (almonds, hazelnuts, nuts, pistachios and their products); lupins and products thereof; soya and soya products; celery and celery products; sesame seeds and sesame seed products; mustard and products thereof; sulphur dioxide and sulphites.
Coeliac disease is the inability to digest and metabolise gluten, a protein complex in wheat, wheat and cereals. It is hardly classifiable among the common allergies and intolerances, because it strongly involves also the immune system (characteristic of allergies), without however involving the IgE. Gluten is a protein complex in wheat, wheat and similar cereals such as barley, rye, spelt, triticale and consequently in all foods containing them as ingredients. The ingestion of gluten, even in small quantities, causes damage to the intestinal mucosa in affected subjects. As a result some nutrients are poorly absorbed, with the appearance of symptoms such as swelling and abdominal pain, vomiting, constipation, weight loss.
If you notice that you are an intolerant or allergic person, it is important to refrain from eating suspicious food and to contact your doctor as soon as possible, who will advise you to protect your health.
When we buy, let us remember that in the case of packaged foods it is important to check and read the label well, which is required by law to indicate the allergens present. This indication must be shown in a different way from the other ingredients, so that the presence can be quickly displayed. In the case of bulk products, indications on allergens must be given at the point of sale with a sign, in the original packaging or in a book of ingredients.
Some examples of indications that we can find on the packages and to which we must pay attention: may contain (allergen); produced in establishments where it is used (allergen); product in non-separated food supply chains, in which it is also processed (allergen).
If we realize that we are allergic, we must also pay attention to the hidden allergens, that is those allergens present in a way that is not obvious. The industry has greatly increased the possibility of unexpectedly finding the presence of allergens in food such as milk or soy in sausages, casein in in wine, fish jelly used as a simple cake topping, etc. triggering reactions in foods deemed harmless to that allergen.
The hidden allergen may be present in the packaged food for various reasons: errors in the wording of warnings; errors in packaging; presence of ingredients from direct allergenic sources; processing aids and aromas; accidental contamination phenomena at an industrial level related to the use of production and/or packaging chains not adequately separated.
It is therefore important that the accuracy of what is stated on consumer health labels is ensured by current legislation. In case of need or doubt about what is indicated on the label, it is better to contact the manufacturer directly for clarification. It is really important to know your allergies and intolerances. Do you need help? Ask to our nutritionists now.