It is sometimes difficult to tell the difference between allergy and food. Dr M.-C. Bertière, nutritionist, explains the differences to us!

A food allergy is linked to a defense mechanism of the immune system following the ingestion of a food identified as dangerous by the body. There are particularly allergenic foods, such as peanuts, eggs, fish and seafood. In contact with these products, the body will produce antibodies called Immunoglobulin E (IgE), responsible for the allergy mechanism.

The first allergic reaction is often mild and can lead to skin rash, such as hives or angioedema, allergic rhinitis, asthma, or digestive symptoms like colic or vomiting. You should know that each new contact with the allergenic agent worsens the intensity of the crisis, and can cause anaphylactic shock (= drop in blood pressure, arrhythmia and loss of consciousness which can lead to death).

Our specialist’s opinion

In a food allergy, the body reacts to a food protein, which triggers an immunological mechanism. It involves the removal of all foods containing the affected protein until healing.

These are linked to the release of histamines in the body, molecules playing a role in the mechanism of true allergies. Certain foods like wine, fermented cheeses, fish and shellfish are naturally high in histamines. Other products such as strawberries, tomatoes or egg white have the ability to cause the body to release histamines. These histamines cause a pseudo-allergic reaction which can lead to confusion since they present the same clinical signs of the latter, usually those of a skin reaction. Unlike true allergies, this is a non-immunological mechanism. Medical tests will be enough to rule out the hypothesis of an allergy.

It is difficult to measure the extent of food intolerances because they are difficult to diagnose. The British Allergy Foundation claims that 45% of the population of Europe and North America is affected. The National Health Nutrition Program (PNNS) in France and the Association Québécoise des Allergies Alimentaires (AGAA) in Canada consider that food allergies affect 3 to 4% of adults and 6 to 8% of children. Young children are the most affected by food allergies since they are 3 to 4 times more affected than adults. However, a majority of allergies are resolved before the age of 7 on average.

Food allergies should not be underestimated. For example, an allergy to milk proteins in infants could cause growth retardation if it is not replaced by an equivalent substitute, usually hydrolysates. Angioedemas, which can cause airway obstruction, and anaphylactic shock are still responsible for many deaths. An allergic reaction with a risk of anaphylaxis should be treated immediately with epinephrine (= adrenaline).