Obesity and food intolerance

Author: Natalya Chekalskaya, Ph.D., endocrinologist, head of anti-age programs at the AnaCosmo clinic (Kiev)

First, let's look at how the body's ability to digest certain foods is determined. In special laboratories, of which quite a lot have appeared in Ukraine in recent years, blood is taken from a vein and a fraction of neutrophils, a certain type of leukocyte, is isolated from it. Neutrophils participate in nonspecific immune reactions of the body and are responsible for phagocytosis - the physical absorption of foreign bodies (bacteria, destroyed parts of dead cells, individual protein molecules, etc.). In this case, the neutrophil flows around the foreign body and, after it is inside the cell, “digests” it.

As “stomach juice”, neutrophils use strong oxidizing agents like hydrogen peroxide, which, with the participation of special enzymes, release atomic oxygen, which destroys foreign bodies. This reaction is accompanied by a weak glow (so-called chemiluminescence), which can be detected using special instruments.

Then, extracts from more than 130 food products are added one by one to the neutrophil fraction of the blood of the subjects, and the tolerability or intolerance of a particular product is determined by the activity of the chemiluminescence reaction.

It seems that everything is simple, but, as usual, there are more questions than answers. And the most important question that should interest a person who is planning to undergo testing for food intolerance (by the way, it must be said that the procedure itself is not that cheap) is what is “food intolerance”?

Classification of food allergies

The first operational classification of pathological reactions to food was proposed in 1984 by the Committee on Adverse Reactions to Food of the American Academy of Allergy and Immunology (AAAI) in collaboration with the National Institute of Allergy and Infectious Diseases (NIAID) and published in the guidelines of the National Institutes of Health (NIH). This classification systematized various adverse reactions to food, but was difficult to implement in practice.

Currently, the classification of pathological reactions to food is used, which was proposed at the XV Congress of the European Academy of Allergy and Clinical Immunology (Stockholm, 1994). This classification was based on the mechanisms of development of pathological reactions, which are divided into two types - toxic and non-toxic reactions.

Toxic reactions develop after consuming products containing substances of natural or artificial origin that are toxic to the human body. For example, natural toxins from the seeds of fruits and berries (cyanides), toxins formed in food as a result of food storage (biogenic amines), contamination (mold aflatoxin in cereals, PSP and DSP seaweed toxins in crustaceans and molluscs) or heat treatment (hemagglutinins in undercooked beans). Industrial food additives (preservatives, dyes, fillers, flavor enhancers, thickeners), the amount of which has noticeably increased in food products in recent years, can also have a toxic effect on the human body.

Non-toxic reactions, in turn, are divided into immunopathological and immunoindependent.

Immunopathological (immune-mediated) reactions are true food allergies (from the Greek alios - “other”, ergon - “action”). This condition is associated with immune mechanisms and develops due to an immediate hypersensitivity reaction mediated by immunoglobulin E (IgE). True food allergy 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 British Allergy Association estimates that true food allergies affect 1.5% of the population. It usually develops in infancy, most often in individuals with a clear hereditary predisposition to atopy. Up to 20% of infants are allergic to one or more foods, most commonly cow's milk, but the number of children with food allergies declines as children age, so that 6% of older children, 4% of adolescents, and 1–2% of adults are affected.

Immune-independent (non-immune) reactions - true food intolerance (food intolerance; synonyms: delayed food allergy - delayed food allergy, masked (hidden) food allergy - masked (hidden) food allergy). Food intolerance is also associated with immune mechanisms, but this involves a delayed-type hypersensitivity reaction, probably mediated by immunoglobulin G (IgG).

The mechanism of food intolerance

Food intolerance syndrome, or delayed-type food allergy, not mediated by IgE-related reactions, was first described by the American physician Herbert Rinkel back in 1936. Until recently, food intolerance, especially hidden allergies, was not considered a significant factor in the development of chronic diseases. However, recent studies have found that not all food products are broken down to their elementary molecular components, which then enter the circulatory system through the intestinal wall. Some food components (most often proteins) in the form of macromolecules that are not completely destroyed can enter the blood through the intestinal wall, which, in the case of regular daily penetration, can lead to various diseases and disruption of the normal functioning of our organs, systems and tissues.

Of course, the immune system does not remain indifferent to the appearance of macromolecules in the blood. Considering them as foreign, it organizes the fight against them, producing IgG4 antibodies both at the sites of their penetration into the blood (in the intestinal wall), and in the circulatory system and in tissues where macromolecules can be carried by the bloodstream. As a result of the immune response, immune complexes are formed that can damage various cellular structures in the tissues of the human body.

The formation of food intolerance is facilitated by the presence of diseases of the gastrointestinal tract: gastritis, chronic cholecystitis, chronic pancreatitis, colitis, intestinal dysbiosis.

The differences between pseudoallergic reactions and true allergies are that, despite clinical symptoms similar to true allergies, pseudoallergic reactions do not involve specific antibodies or sensitized lymphocytes to food components.

Etiology of food intolerance

Almost all food products, excluding salt and sugar, are antigenic to one degree or another. The antigenic properties of products that cause allergies more often than others have been more or less fully studied. The sensitizing properties are especially pronounced in products of protein origin - both animal and plant.

Research conducted in the USA found that the cause of food intolerance in 93% of cases is eight foods: eggs, peanuts, milk, soy, fish, tree nuts, crustaceans, wheat.

Cow's milk

This is the most powerful and common food allergen. The problem of allergy to cow's milk is, first of all, important in the nutrition of young children, in whom food allergies are much more common than in adults, due to the high permeability of the intestinal wall, enzyme deficiency and the entry of undigested food proteins into the bloodstream.

Unmodified milk proteins can be absorbed at any age. Milk contains about 20 proteins with varying degrees of antigenicity. Casein, α-lactalbumin, bovine serum albumin and bovine γ-globulin were obtained in purified form.

Bovine serum albumin and α-lactalbumin are destroyed by boiling, so patients sensitive to these fractions tolerate milk well after 15–20 minutes of boiling.

The most powerful sensitizing allergen in milk is 3-lactoglobulin . Its molecular weight ranges from 17,000 to 34,000 Daltons.

The antigenic activity of casein is relatively low.

Sensitization to cow's milk components can occur in utero and through mother's milk. The combination of allergies to cow's milk and beef is rare. If you are sensitized to species-specific proteins, cow's milk can be replaced with goat's milk.

When preparing a diet for patients with food intolerance to milk proteins, it is necessary to take into account that milk is included in many ready-made foods (certain types of bread products, creams, chocolate, ice cream, etc.). Cheese contains mainly casein and some α-lactalbumin, so some patients with milk allergies may include it in their diet. Condensed and powdered milk contain all the antigenic proteins of milk.

Eggs

Chicken eggs are also a common food allergen, since egg proteins can be absorbed unchanged in the intestines. The scientific literature has described severe reactions, including anaphylactic shock, to minimal amounts of egg white.

Note that the antigenic properties of the proteins in the white and yolk of an egg are different, so some patients can eat only the white or only the yolk without harm to their health. If you are allergic to chicken eggs, you cannot replace them with duck or goose eggs, since chicken egg proteins are not species-specific. An allergy to chicken eggs is often combined with an allergy to chicken meat. It should also be taken into account that eggs are used in the manufacture of many food products: rich breads, cookies, cakes, muffins, ice cream, candies, etc. In addition, cultures of viruses and rickettsia for the preparation of vaccines against influenza, typhus, yellow fever are grown on chicken embryo, so the finished vaccines contain a slight admixture of egg proteins. However, even in such small concentrations they can cause severe reactions, sometimes fatal, in people with an allergy to egg whites.

Fish and seafood

Fish has not only pronounced antigenic, but also histamine-releasing properties. Perhaps because of this, reactions to eating food, as well as to inhaling vapors during cooking fish, are especially severe, sometimes life-threatening. Patients with a high degree of sensitivity usually cannot tolerate all types of fish. With a low degree of sensitivity, intolerance to one or more related species is more common.

The antigenic components of crustaceans (crayfish, crabs, shrimp, lobsters) have not been precisely established. However, it is known that all of them have a pronounced cross-antigenicity, that is, in the case of intolerance to one type of crustacean, all others should be eliminated from the diet. Cross-sensitivity to daphnia (a freshwater crustacean), which causes inhalation allergies when used as dry food for aquarium fish, is also possible.

Meat

Despite its high protein content, meat rarely causes food allergies. The antigenic composition of meat from different animals differs. Therefore, patients who are allergic to beef can eat lamb, pork, and chicken without fear. High degrees of hypersensitivity are rare.

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

Cereals

It is believed that wheat, rye, millet, corn, rice, barley, oats often cause sensitization, but rarely cause severe allergic reactions. The exception is buckwheat, which, according to some observations, tends to lead to the development of serious intolerance reactions. After the research of AA Rowe (1937), great importance began to be attached to allergies to wheat, especially in the formation of bronchial asthma and allergic rhinitis. Apparently, in patients with hay fever caused by sensitization to pollen of cereal grasses (timothy, cocksfoot, fescue, etc.), allergies to food grains are not so rare, as a result of which the course of the disease becomes year-round.

When prescribing elimination diets, the doctor must know the technology for preparing basic food products and remember that wheat flour is included in many sausages, sausages, etc. Rice and wheat flour are also included in some types of cosmetic powder.

Vegetables and fruits

Vegetables, fruits and berries can also cause allergies. Strawberries, strawberries and citrus fruits are traditionally known as strong allergens. Fruits of plants from the same botanical family usually have common antigenic properties. Allergies to fruits and vegetables are almost always associated with allergies to the pollen of the corresponding plants. Allergens from fruits and vegetables are often heat labile and are destroyed by cooking.

Nuts and cocoa

Nuts cause sensitization relatively often and sometimes to a high degree. Although severe reactions are more common when eating one type of nut, cross-sensitivity to other types of nuts is possible. Patients with hay fever with an allergy to hazel (hazel) pollen often cannot tolerate nuts. Nuts are widely used in the confectionery industry. Highly sensitive patients may have reactions to minute amounts of the nut, such as in nut butters.

But the importance of chocolate and cocoa as a cause of true food allergies is exaggerated. More often, chocolate causes pseudo-allergic reactions or delayed allergic reactions. High degrees of hypersensitivity are rare. Allergic reactions to coffee, spices and seasonings (pepper, mustard, mint) are also known.

Factors contributing to the development of food intolerance

The first alarming symptom is a genetically determined predisposition to allergies. Approximately half of patients with food intolerance have a burdened allergic history: they or their blood relatives suffer from any allergic diseases (hay fever, atonic bronchial asthma).

The development of food intolerance can also be caused by nutritional disorders during pregnancy and lactation (abuse of certain foods with pronounced sensitizing activity).

Early transfer of a child to artificial feeding, malnutrition in children, expressed in the discrepancy between the volume and ratio of food ingredients to the body weight and age of the child, can also become factors contributing to the development of delayed-type food allergies.

Increased absorption of undigested proteins is facilitated by a lack of calcium salts in food, as well as a direct increase in the permeability of the intestinal mucosa, which is observed in inflammatory and dystrophic intestinal diseases, dysbiosis, helminthic and protozoal infestations. Decreased gastric acidity, insufficient pancreatic function, enzymopathies, biliary and intestinal dyskinesia also contribute to the absorption of high molecular weight compounds. With normal functioning of the gastrointestinal tract and hepatobiliary system, sensitization to food products does not develop.

Food intolerance can also develop in patients taking medications that inhibit enzymes (diaminoxidase) involved in the degradation of histamine and biogenic amines: acetylcysteine, ambroxol, aminophylline, amitriptyline, chloroquine, clavulanic acid, dihydralazine, isoniazid, metamizole, metoclopramide, pancuronium, propafenone, verapamil.

A separate symptom is psychogenic food intolerance, which occurs as a result of stress and other changes in the mental sphere.

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Based on the above factors, it becomes clear that the approach underlying elimination diets is quite interesting, but, unfortunately, has only an indirect relation to weight loss. There are many people who have varying degrees of food intolerance but are of normal or underweight. A food intolerance screening program should be used to prevent possible food allergic reactions, identify disorders of the immune system, and eliminate factors that cause food intolerance. At the same time, it should be remembered that obesity is a polyetiological disease. And only a competent, comprehensive examination, the patient’s adherence to treatment, strict adherence to recommendations for lifestyle modification, and regular monitoring of biochemical and hormonal parameters will give an effective and long-lasting result.

Source: Les Nouvelles Esthetiques Ukraine, No. 3 (67), 2011, pp. 86-89