[Food Intolerance]

The term food intolerance has been used non-specifically to define a wide range of disorders related to food intake. Recently, the use of the term "non-immunological adverse reactions to foods" (RANIAs) was recommended as a more correct clinical definition. The pathophysiological mechanisms can be diverse, sometimes unknown, and there are no validated diagnostic tests, making it difficult to obtain accurate data. The clinical manifestations of non-immunological adverse reactions to foods affect more than one organ or system; and gastrointestinal symptoms (pain, abdominal distension, flatulence, and diarrhea) are the most common. Non-immunological adverse reactions to foods are divided into independent and dependent on host factors. Foods may contain chemicals with pharmacological activity and be present naturally, such as vasoactive amines (histamine) and salicylates, or added for preservation, to improve appearance or flavor (monosodium glutamate, tartrazine, sulfites, and benzoates). In some cases, these types of reactions may be like to hypersensitivity reactions. Concomitant alcohol consumption may worsen symptoms by inhibiting histamine breakdown and increasing intestinal permeability. In patients diagnosed with non-immunological adverse reactions to foods, it is important to rule out some psychological problems: aversions or eating disorders.

[Classification of food allergy: generalities]

The prevalence of food allergy has increased in some regions of the world, and with it the incidence, according to geographical variability, in the phenotype and clinical manifestations. Food allergy arises from the specific immune response induced by exposure to the proteins of a certain food. Food intolerance refers to non-immune reactions, caused by unique physiological characteristics of the individual, including metabolic, toxic, pharmacological and undefined mechanisms. Adverse reactions to foods are classified as: IgE-mediated: Type I Hypersensitivity, non-IgE-mediated: Type IV Hypersensitivity, mixed: Types I and IV Hypersensitivity Non-Allergic; toxic, pharmacological, metabolic, intolerances. These types of alterations are rare but have increased in recent years; These include protein-induced enterocolitis syndrome, which can cause emesis, diarrhea and hypotension, and shock, which begins two hours after ingestion of the allergen. Protein-induced allergic proctocolitis is a condition that includes allergy to cow's milk protein. Delayed reactions usually affect the digestive system, are more insidious in their onset and are not immediately controlled, even with the suspension of food. There are eight foods responsible for 90% of food allergies: milk, eggs, soy, wheat, peanuts, walnuts, fish, and shellfish.

[Differential diagnosis in food allergy]

It is important to establish the differential diagnosis of food allergy with other disorders, for example: toxic reactions that occur in any person exposed to a sufficient amount of some allergen, and non-toxic reactions that depend on individual susceptibility (food allergy or intolerance). The differential diagnosis is decisive to establish the appropriate treatment. Food intolerance involves adverse reactions to foods without any immunological response involved, and commonly manifests with gastrointestinal symptoms (malaise, abdominal pain or diarrhea). Food allergy is an exaggerated reaction of the immune system, often mediated by IgE, that can trigger serious symptoms (hives, inflammation, respiratory distress, even anaphylaxis). The complex thing is because the symptoms sometimes overlap. To establish an accurate diagnosis, exhaustive clinical evaluation, laboratory tests and, in some cases, controlled provocation tests are required. It is important to understand these distinctions, because treatment and management vary significantly. Food intolerance involves the elimination or reduction of the food that triggers the allergic reaction and requires rigorous measures (complete avoidance of the allergen and availability of epinephrine in cases of severe reactions).