Food allergies

What are they

Food allergies consist of a negative and immediate response that some individuals manifest towards certain foods or food components.

According to surveys of the general population, about 30 percent of people consider themselves “allergic” to certain foods. However, from a strictly clinical point of view, food allergy has an effective incidence of around 2 percent.

In children the incidence is 3-7 percent, but in most cases the allergy disappears around the age of six.

Allergies to certain foods or individual ingredients have a strong hereditary component and are therefore often diagnosed in the first years of life.

Symptoms

The most common symptoms of food allergies are:

• runny nose or sinusitis
• Sneezing
• asthma (difficulty breathing)
• cough
• itchy mouth
• urticaria
• eczema
• eye congestion
• diarrhoea
• otitis
• chronic fatigue and irritability

Fortunately, in most cases, allergic reactions are mild. In a limited number of people, however, a violent reaction can occur that can also be lethal: anaphylactic shock. It can occur within minutes of ingestion and requires immediate medical attention.

Causes

To cause a food allergy is substantially an alteration of the immune system, at the origin of which there is certainly a genetic component.

This alteration means that a substance normally harmless to the body is considered a threat and, consequently, attacked by the immune system to be eliminated.

What distinguishes them from food intolerances Very often food allergy is defined as any negative reaction to the introduction of a certain food.

This is not the case: in most cases it is microbial food poisoning, psychological aversions to food, or intolerances to certain ingredients.

Unlike these cases, food allergy involves an activation of the immune system as a response to exposure of an allergen.

The latter is a molecule that in most people is absolutely harmless, but that in some individuals triggers a series of reactions of the immune system including the production of antibodies.

Following these events, histamine is released: it is this substance that causes the different symptoms.

Foods that cause allergies

Theoretically, any food or food component can cause an allergic response.

However, certain foods are more likely to trigger such reactions. The main ones are:

• Milk
• eggs
• soybean
• Wheat
• crustacean
• fruit
• Peanut
• walnuts

Diagnosis

The diagnosis of food allergies can be based on the principle of the exclusion diet, which involves eliminating one or more suspect foods for about two weeks.

If in 15 days the symptoms disappear, the suspect foods are reintroduced one at a time into the diet. At first in reduced quantities and then increase the doses gradually.

This method allows you to identify those to which you are allergic.

Alternatively, the RAST (radioallergosorption) test is used. Small samples of the patient’s blood are mixed with food extracts in a test tube.

If there is an allergy, the immune system cells present in the blood produce antibodies. It indicates the presence of an allergy, but does not determine the extent of sensitivity to the harmful food.

The double-blind placebo control test (DBPCF) may also be indicated. If a food is suspected to be causing an allergy, it is placed in a capsule or hidden in a food. It is then administered under close medical supervision to see if an immune response occurs.

Therapy

The only way to avoid the onset of symptoms, once the food causing the allergy has been identified, is to eliminate it completely from the diet.

For those suffering from periodic allergic reactions, it may be useful to use an antihistamine to relieve hives and swelling.

In cases of allergies to different foods (cross-allergies), the doctor may prescribe sodium cromoglycate, a compound that can limit the spasm reaction of the airways.