Food allergies and intolerances: what’s the difference?

More and more people claim to suffer from an allergy or intolerance to a food, without knowing the real difference.

The terms food allergy and intolerance are often confused with each other.

Food allergy is an adverse reaction to a food mediated by immunological mechanisms. It has the characteristic of being reproducible, in the sense that it is repeatedly caused by exposure to a certain food. It can manifest itself with various types of reaction, based on the involvement of specific antibodies and / or other cellular “mediators”. The most dangerous forms are those mediated by antibodies of the immunoglobulin E (IgE) class, but there are also non-IgE-mediated or mixed forms.

When we talk about food intolerances we refer, instead, to all those adverse reactions to food that are not mediated by the immune system such as, for example, lactose intolerance, due to the lack or reduced production of the lactase enzyme, which allows you to digest this sugar contained above all in milk and its derivatives.

The different types of food intolerance

The mechanisms underlying food intolerances are still unclear. Normally, these adverse reactions to food are divided into some main categories: enzymatic, pharmacological and “toxic”.

Enzymatic forms, such as lactose intolerance, result from the inability to metabolize substances contained in food due to the lack or deficiency of specific enzymes. Some also consider celiac disease an intolerance (in this case to gluten), but in reality it is an autoimmune disease.

The pharmacological forms are linked to excessive “sensitivity” to some substances contained in food, for example caffeine, histamine, ethanol.

The toxic forms are the most complex: these are intolerances associated with additives added to foods, such as sulphites, sodium glutamate, thickeners, sweeteners. In these cases the boundary between allergy and intolerance is often very blurred: the manifestations are so variable that the possibility of an interaction between biochemical and immunological mechanisms cannot be excluded.

Unfortunately, even today there are no scientifically validated tests to diagnose them, except for lactose intolerance (breath test).

How to diagnose a food allergy

Unlike what happens with intolerances, food allergies, especially IgE-mediated ones, can count on proven diagnostic tests.

As a rule, in the presence of suspicious symptoms, skin and/or serological tests (the determination of IgE-specific) are used. These tests help identify sensitization to various foods that may behave as allergens. However, diagnostic confirmation can only be obtained with the oral provocation test in a protected environment, which involves some risks and is therefore proposed only in selected cases.

Joycelyn Elders is the author and creator of EmpowerEssence, a health and wellness blog. Elders is a respected public health advocate and pediatrician dedicated to promoting general health and well-being.

The blog covers a wide range of topics related to health and wellness, with articles organized into several categories.

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