Among the listed forms of food intolerance, true food allergy takes a special place..

This is due to the fact that it is both one of the common causes and a consequence of many acute and chronic diseases, not only disabling patients, but sometimes life-threatening.

The prevalence of true (IgE-mediated) food allergy is not as high as many doctors believe.

According to domestic and foreign researchers, it varies widely: from 0.01 to 50%.

Probably, a number of specialists in the concept of " According to the British Allergy Association, true food allergy affects 1.5% of the population, it usually develops in infancy, most often in individuals with a clear hereditary predisposition to atopy.

20% of infants are allergic to one or more foods, most often to cow's milk, but the number of children with food allergies decreases with age, so that 6% of older children, 4% of adolescents and 1-2% of adults suffer from food allergies.

Almost all food products have varying degrees of antigenicity, excluding salt and sugar.. Antigenic properties have been studied more or less fully in products that cause allergies more often than others.. The most pronounced sensitizing properties in products of protein origin, both animal and vegetable.

Cow's milk.

Cow's milk is the most potent and common allergen. The problem of cow's milk allergy is especially important for the nutrition of young children, who, due to the high permeability of the intestinal wall, enzyme deficiency and the ingress of undigested food proteins into the bloodstream, food allergies are generally much more common than in adults.

Unchanged milk proteins can be absorbed at any age. Milk contains about 20 proteins with varying degrees of antigenicity. Purified casein, ?-lactalbumin, ?-lactoglobulin, bovine serum albumin and bovine ?-globulin were obtained.

Boiling destroys bovine serum albumin and a-lactalbumin, therefore, patients sensitive to these fractions tolerate milk well after boiling for 15-20 minutes. The strongest sensitizing milk allergen is ?-lactoglobulin. Its molecular weight ranges from 17,000 to 34,000. Casein antigenic activity is comparatively low.

Sensitization by components of cow's milk can occur in utero and through mother's milk. Combinations of cow's milk and beef allergies are rare. Milk is included in many ready-made foods (some types of bread, creams, chocolate, ice cream, etc..

Cheese contains mostly casein and some ?-lactalbumin, so some people with milk allergies may include it in their diet.. Condensed and powdered milk contains all antigenic milk proteins. If sensitized to species-specific proteins, cow's milk can be replaced with goat's.

Eggs.

Chicken eggs are known to be a common food allergen. Egg proteins can be absorbed unchanged in the intestines. Severe reactions have been described, including anaphylactic shock, to minimal amounts of eggs.

The antigenic properties of protein and yolk proteins are different, so some patients can eat only protein or only yolk without harm to health. If you are allergic to chicken eggs, you cannot replace them with duck or goose eggs, since the proteins of the chicken egg are not species-specific. Chicken egg allergy is often associated with chicken meat allergy.

Eggs are used in the manufacture of many food products: rich varieties of bread, cookies, cakes, muffins, ice cream, sweets. Cultures of viruses and rickettsia for the preparation of vaccines against influenza, typhus, yellow fever are grown on a chicken embryo.

Finished vaccines contain a small admixture of egg proteins, but can cause severe, sometimes fatal reactions in people with egg protein allergies.

A fish.

Fish has not only pronounced antigens, but also histamine-releasing properties. It is possible that in this regard, reactions to food intake, as well as to inhalation of fish vapors during cooking, are especially severe, sometimes life-threatening..

Highly sensitive patients usually cannot tolerate all types of fish. With a low degree of sensitivity, intolerance to one or more closely related species is more common.

Crustaceans (crayfish, crabs, shrimp, lobster).

Their antigenic components have not been precisely established, cross-antigenicity is sharply expressed, that is, in case of intolerance to one species, the rest should be eliminated from the diet..

Cross-sensitivity to daphnia, which is a freshwater crustacean and causes inhalation allergies, is also possible when used as dry food for aquarium fish.

Meat.

Despite its high protein content, meat rarely causes allergies. The antigenic composition of the meat of different animals is different. Therefore, patients who are allergic to beef can eat lamb, pork, chicken..

High hypersensitivity is rare. It is known that patients with horse meat allergy may have hypersensitivity to horse serum. Such patients may have an immediate allergic reaction to the first ever injection of tetanus toxoid..

Food grains.

Food grains (wheat, rye, millet, corn, rice, barley, oats) are thought to frequently cause sensitization but rarely cause severe reactions. The exception is buckwheat, which, according to some observations, tends to cause serious reactions..

After research A. Rowe (1937) attached great importance to wheat allergies, especially in the formation of bronchial asthma and allergic rhinitis. Apparently, it is not so rare in patients with hay fever caused by sensitization to pollen of cereal grasses (timothy, hedgehog, fescue), there is an allergy to food grains, so the course of the disease becomes year-round.

When prescribing elimination diets, the doctor should know the technology for preparing basic food products and remember that wheat flour is a part of many sausages, sausages. Rice and wheat flours are found in some powders.

Vegetables, fruits and berries.

Traditionally known as "

Plants from the same botanical family usually share common antigenic properties.. It has been noticed that patients with hay fever allergic to birch pollen often do not tolerate apples, as well as carrots, which have nothing to do with this family. When heat treated, the antigenicity of vegetables, fruits and berries decreases.

Nuts cause sensitization relatively often and sometimes to a high degree. Although severe reactions are more likely to be caused by one nut species, cross-sensitivity with other types is not excluded.

Patients with hay fever allergic to hazel pollen (hazel) often cannot tolerate nuts.

Nuts are widely used in the confectionery industry. Highly sensitive patients may have reactions to minimal amounts of nut, such as nut butters.

Chocolate.

The importance of chocolate and cocoa as the cause of true food allergies is exaggerated. More often chocolate causes pseudo-allergic reactions or allergic reactions proceeding in a delayed manner. High hypersensitivity is rare.

Known allergic reactions to coffee, spices and seasonings (pepper, mustard, mint).

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