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Realism (from Late Latin reālis - material) is an artistic method in art and literature. The history of realism in world literature is unusually rich. The very idea of it changed at different stages of artistic development, reflecting the persistent desire of artists for a truthful depiction of reality.

Illustration by V. Milashevsky for the novel by Charles Dickens “The Posthumous Papers of the Pickwick Club.”

Illustration by O. Vereisky for L. N. Tolstoy’s novel “Anna Karenina”.

Illustration by D. Shmarinov for F. M. Dostoevsky’s novel “Crime and Punishment.”

Illustration by V. Serov for M. Gorky’s story “Foma Gordeev”.

Illustration by B. Zaborov for the novel by M. Andersen-Nexo “Ditte - Child of Man.”

However, the concept of truth, truth is one of the most difficult in aesthetics. For example, the theoretician of French classicism N. Boileau called for being guided by the truth and “imitating nature.” But the romantic V. Hugo, an ardent opponent of classicism, urged “to consult only with nature, truth and your inspiration, which is also truth and nature.” Thus, both defended "truth" and "nature".

The selection of life phenomena, their assessment, the ability to present them as important, characteristic, typical - all this is connected with the artist’s point of view on life, and this, in turn, depends on his worldview, on the ability to grasp the advanced movements of the era. The desire for objectivity often forces the artist to depict the real balance of power in society, even contrary to his own political convictions.

The specific features of realism depend on the historical conditions in which art develops. National historical circumstances also determine the uneven development of realism in different countries.

Realism is not something given and unchangeable once and for all. In the history of world literature, several main types of its development can be outlined.

There is no consensus in science about the initial period of realism. Many art historians attribute it to very distant eras: they talk about the realism of cave paintings of primitive people, about the realism of ancient sculpture. In the history of world literature, many features of realism are found in the works of the ancient world and the early Middle Ages (in folk epic, for example, in Russian epics, in chronicles). However, the formation of realism as an artistic system in European literature is usually associated with the Renaissance (Renaissance), the greatest progressive revolution. A new understanding of life by a person who rejects the church sermon of slavish obedience is reflected in the lyrics of F. Petrarch, the novels of F. Rabelais and M. Cervantes, in the tragedies and comedies of W. Shakespeare. After centuries of medieval churchmen preaching that man is a “vessel of sin” and calling for humility, Renaissance literature and art glorified man as the supreme creature of nature, seeking to reveal the beauty of his physical appearance and the richness of his soul and mind. The realism of the Renaissance is characterized by the scale of images (Don Quixote, Hamlet, King Lear), the poeticization of the human personality, its capacity for great feeling (as in Romeo and Juliet) and at the same time the high intensity of the tragic conflict, when the clash of personality with the inert forces opposing it is depicted .

The next stage in the development of realism is educational (see. Education), when literature becomes (in the West) an instrument of direct preparation for the bourgeois-democratic revolution. Among the educators there were supporters of classicism; their work was influenced by other methods and styles. But in the 18th century. The so-called Enlightenment realism was also taking shape (in Europe), the theorists of which were D. Diderot in France and G. Lessing in Germany. The English realistic novel, whose founder was D. Defoe, author of Robinson Crusoe (1719), acquired worldwide significance. In the literature of the Enlightenment, a democratic hero appeared (Figaro in the trilogy of P. Beaumarchais, Louise Miller in the tragedy “Cunning and Love” by I. F. Schiller, images of peasants in A. N. Radishchev). Enlighteners assessed all phenomena of social life and people's actions as reasonable or unreasonable (and they saw the unreasonable, first of all, in all the old feudal orders and customs). They proceeded from this in their depiction of human character; their positive heroes are, first of all, the embodiment of reason, the negative ones are a deviation from the norm, the product of unreason, the barbarism of former times.

Enlightenment realism often allowed for convention. Thus, the circumstances in the novel and drama were not necessarily typical. They could be conditional, as in the experiment: “Suppose a person finds himself on a desert island...”. At the same time, Defoe depicts Robinson’s behavior not as it could actually be (the prototype of his hero went wild, even lost his articulate speech), but as he wants to present a man, fully armed with his physical and mental strength, as a hero, conqueror of forces nature. Faust in I. V. Goethe, shown in the struggle for the establishment of high ideals, is also conventional. Features of a well-known convention also distinguish D. I. Fonvizin’s comedy “The Minor.”

A new type of realism emerged in the 19th century. This is critical realism. It differs significantly from both the Renaissance and the Enlightenment. Its flourishing in the West is associated with the names of Stendhal and O. Balzac in France, C. Dickens, W. Thackeray in England, in Russia - A. S. Pushkin, N. V. Gogol, I. S. Turgenev, F. M. Dostoevsky, L.N. Tolstoy, A.P. Chekhov.

Critical realism portrays the relationship between man and the environment in a new way. Human character is revealed in organic connection with social circumstances. The subject of deep social analysis has become the inner world of man; critical realism therefore simultaneously becomes psychological. Romanticism, which sought to penetrate the secrets of the human “I,” played a large role in the preparation of this quality of realism.

Deepening the knowledge of life and complicating the picture of the world in the critical realism of the 19th century. do not mean, however, some kind of absolute superiority over previous stages, for the development of art is marked not only by gains, but also by losses.

The scale of the images of the Renaissance was lost. The pathos of affirmation characteristic of the Enlighteners, their optimistic faith in the victory of good over evil, remained unique.

The rise of the labor movement in Western countries, the formation in the 40s. XIX century Marxism not only influence the literature of critical realism, but also give rise to the first artistic experiments in depicting reality from the perspective of the revolutionary proletariat. In the realism of such writers as G. Weert, W. Morris, the author of the Internationale E. Pothier, new features are outlined that anticipate artistic discoveries socialist realism.

In Russia, the 19th century was a period of exceptional strength and scope in the development of realism. In the second half of the century, the artistic achievements of realism, bringing Russian literature to the international arena, won it worldwide recognition.

The richness and diversity of Russian realism of the 19th century. allow us to talk about its different forms.

Its formation is associated with the name of A. S. Pushkin, who led Russian literature onto the broad path of depicting “the fate of the people, the fate of man.” In the conditions of the accelerated development of Russian culture, Pushkin seems to be catching up with its previous lag, paving new paths in almost all genres and, with his universality and his optimism, turning out to be akin to the titans of the Renaissance. Pushkin’s work lays the foundations of critical realism, developed in the work of N.V. Gogol and after him in the so-called natural school.

Performance in the 60s. revolutionary democrats led by N. G. Chernyshevsky gives new features to Russian critical realism (the revolutionary nature of criticism, images of new people).

A special place in the history of Russian realism belongs to L. N. Tolstoy and F. M. Dostoevsky. It was thanks to them that the Russian realistic novel acquired global significance. Their psychological mastery and insight into the “dialectic of the soul” opened the way for the artistic quests of 20th century writers. Realism in the 20th century all over the world bears the imprint of the aesthetic discoveries of L. N. Tolstoy and F. M. Dostoevsky.

The growth of the Russian liberation movement, which by the end of the century transferred the center of the world revolutionary struggle from the West to Russia, leads to the fact that the work of the great Russian realists becomes, as V. I. Lenin said about L. N. Tolstoy, “a mirror of the Russian revolution” according to their objective historical content, despite all the differences in their ideological positions.

The creative scope of Russian social realism is reflected in the wealth of genres, especially in the field of the novel: philosophical and historical (L. N. Tolstoy), revolutionary journalistic (N. G. Chernyshevsky), everyday (I. A. Goncharov), satirical (M. E. Saltykov-Shchedrin), psychological (F. M. Dostoevsky, L. N. Tolstoy). By the end of the century, A.P. Chekhov became an innovator in the genre of realistic stories and a kind of “lyrical drama”.

It is important to emphasize that Russian realism of the 19th century. did not develop in isolation from the world historical and literary process. This was the beginning of an era when, according to K. Marx and F. Engels, “the fruits of the spiritual activity of individual nations become the common property.”

F. M. Dostoevsky noted as one of the features of Russian literature its “capacity for universality, all-humanity, all-response.” Here we are talking not so much about Western influences, but about the organic development in line with European culture of its centuries-old traditions.

At the beginning of the 20th century. The appearance of M. Gorky's plays "The Bourgeois", "At the Demise" and especially the novel "Mother" (and in the West - the novel "Pelle the Conqueror" by M. Andersen-Nexo) testifies to the formation of socialist realism. In the 20s Soviet literature declares itself with major successes, and in the early 30s. In many capitalist countries, a literature of the revolutionary proletariat is emerging. The literature of socialist realism is becoming an important factor in world literary development. It should be noted that Soviet literature as a whole retains more connections with the artistic experience of the 19th century than literature in the West (including socialist literature).

The beginning of the general crisis of capitalism, two world wars, the acceleration of the revolutionary process throughout the world under the influence of the October Revolution and the existence of the Soviet Union, and after 1945 the formation of the world system of socialism - all this affected the fate of realism.

Critical realism, which continued to develop in Russian literature until the October Revolution (I. A. Bunin, A. I. Kuprin) and in the West, in the 20th century. received further development, while undergoing significant changes. In critical realism of the 20th century. in the West, a variety of influences are more freely assimilated and intersected, including some features of the unrealistic movements of the 20th century. (symbolism, impressionism, expressionism), which, of course, does not exclude the struggle of realists against non-realistic aesthetics.

From about the 20s. In the literature of the West, there is a tendency towards in-depth psychologism, the transmission of the “stream of consciousness”. The so-called intellectual novel of T. Mann arises; subtext takes on special significance, for example, in E. Hemingway. This focus on the individual and his spiritual world in Western critical realism significantly weakens its epic breadth. Epic scale in the 20th century. is the merit of the writers of socialist realism (“The Life of Klim Samgin” by M. Gorky, “Quiet Flows the Don” by M. A. Sholokhov, “Walking in Torment” by A. N. Tolstoy, “The Dead Remain Young” by A. Zegers).

Unlike the realists of the 19th century. writers of the 20th century more often they resort to fantasy (A. France, K. Chapek), to convention (for example, B. Brecht), creating parable novels and parable dramas (see Parable). At the same time, in the realism of the 20th century. the document, the fact, triumphs. Documentary works appear in different countries within the framework of both critical realism and socialist realism.

Thus, while remaining documentary, the autobiographical books of E. Hemingway, S. O'Casey, I. Becher, such classic books of socialist realism as “Report with a Noose Around the Neck” by Yu. Fuchik and “The Young Guard” by A. A. Fadeeva.

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The food we eat every day is not only a way to quench hunger and thirst, but also a source of strength and energy. It is with food that substances that provide energy enter our body. for the normal functioning of organs, and increasing our ability to withstand physical and emotional stress.

What factors influence the level of energy reserves of the body?

Each person needs a certain amount of energy to maintain his body in good shape.

And this depends on the following factors:

Age - the larger and more mature the organism, the more energy it consumes;
Floor human - men, as a rule, need more energy;
Physical activity level - physical work, sports, vigorous activities - all this takes away a large amount of energy and calories from us;
- many people mistakenly believe that in the absence of strong physical activity, the body does not need a large amount of energy, but enhanced brain activity and stable functioning of the nervous system are impossible without the supply of nutrients;
Insufficient rest , increased fatigue.

What substances give the body energy?

To maintain the required amount of vital energy, you need to eat the right food, which, due to its composition, will saturate the body with useful substances and give strength. To choose such food products, you first need to understand which substances are most beneficial for us and without which elements a person may feel tired even after a long rest.

The energy entering the human body with food is measured in kilocalories and is determined depending on the content of proteins, fats and carbohydrates in the product. Thus, carbohydrates and proteins emit just over 4 kcal/g, and fats – just over 9 kcal/g.

However, in addition to direct energy expressed in calories, many vitamins and macroelements give us vitality. Due to their beneficial effect on the functioning of internal organs, they ensure the normal functioning of the entire body as a whole and the availability of strength to carry out any type of activity.

These basic substances include the following:

Complex carbohydrates in particular, glucose, which ensures the normal functioning of the brain and nervous system;
Fiber - gives a feeling of fullness, perfectly satisfying the feeling of hunger, in addition, normalizes the amount of sugar in the blood;
Magnesium, participating in many biochemical reactions occurring in the body;
Iron- prevents the development of anemia, and, as a result, prevents excessive human fatigue;
Selenium- a microelement, which is a strong antioxidant, helps maintain proper energy levels and a person’s emotional state;
Vitamin B1 (thiamine), which is sometimes called the “vitamin.” It participates in energy metabolism, supporting the function of carbohydrate breakdown;
Pyridoxine, or vitamin B6 - actively participates in the synthesis of hemoglobin and the formation of new red blood cells, ensures the normal functioning of the nervous system;
Vitamin B8- takes part in fat metabolism, is a strong antidepressant;
Biotin, or vitamin B7 - ensures the metabolism of the main substances responsible for the body receiving calories - proteins, fats and carbohydrates, in addition, helps synthesize enzymes involved in the carbohydrate process;
Vitamin A - is a powerful antioxidant that supports the body’s recovery function after heavy exercise;
Vitamin E - It has strong antioxidant properties and also helps restore the energy centers of cells (mitochondria).

20 foods that give the body maximum energy

In nature there are a lot of substances and useful elements that directly or indirectly saturate our body with the necessary energy and give vitality. Their main source is food, the most useful of which are listed in our table. Bookmark it so you always know how to quickly replenish your energy supply!

20 best energy drinks:

Water. Water itself is not a source of energy that can be expressed in calories, however, if you do not drink enough liquid, a person can quickly lose strength. Water helps remove harmful substances from the body, the presence of which makes us prone to increased fatigue. Besides, water serves as a conductor of nutrients when they enter the blood.
Oatmeal. Its main feature is the ability to charge the body with energy, the source of which is fiber and carbohydrates. When eating oatmeal, the feeling of fullness and vigor remains for a long time. It also contains B vitamins, which are involved in the body’s metabolic processes.
Bananas. Their composition differs in that they contain two types of carbohydrates – some of them are absorbed quickly and give a feeling of fullness almost instantly, while others are broken down more slowly and supply the body with energy later. Bananas also have a high calorie content, as a result of which they are recommended for consumption by people whose livelihoods are associated with active physical activity. This fruit also contains a large amount of potassium, which has a positive effect on the strength of muscle contractions, the functioning of the nervous system and concentration.
Beef. Contains a large amount of protein, B vitamins, bioactive iron, zinc. Thanks to these substances, beef meat gives the body strength and endurance, strengthens blood vessels, increases hemoglobin levels, and strengthens muscle and bone tissue. In addition, eating beef improves the functioning of the gastrointestinal tract and normalizes acidity levels.
Seafood. In large quantities, such products contain protein, which is much better absorbed by the body than in the types of meat more familiar to us - pork and beef. Due to their low calorie content, nutritionists often include seafood products in diets and recommend them to people who want to lose weight. Besides, seafood contains iodine, which stimulates the normal functioning of the thyroid gland and the human endocrine system, magnesium, which has a beneficial effect on the functioning of the nervous system, and selenium, which improves testosterone production.
Pumpkin seeds. They contain most of the essential acids existing in nature that our body needs to obtain energy and strength. Pumpkin seeds are rightfully considered to be the record holder for the content of phosphorus, magnesium, manganese and B vitamins.
Honey. It has been proven that its use significantly reduces fatigue, increases performance, and reduces the likelihood of nervous disorders. Due to its rich vitamin and mineral composition, honey has bactericidal and antifungal properties, improves immunity, and improves the functioning of the kidneys, liver and stomach.
Chicken eggs. In terms of their nutritional value, eggs are in no way inferior to meat; moreover, they are 98% absorbed by the body and their consumption does not lead to excess weight gain. This product helps strengthen the immune system, normalizes metabolism, activates mental activity, improves the condition of skin, teeth and hair, increases potency and the production of sex hormones.
Dairy products. They are a balanced and indispensable product for people. and dairy products contain a large amount of nutrients, have high nutritional value, strengthen the immune system and increase the body's resistance to infections. Separately, it is worth mentioning fermented milk products, which normalize the activity of the gastrointestinal tract and improve the functioning of the liver and kidneys.
Legumes. Due to the content of potassium and folic acid, they increase immunity, purify the blood, increase resistance to diseases, and help remove waste and toxins from the body. And what other products help remove toxins from the body - we tell you in our topic.
Nuts. They are a nutritious product that promotes quick satiety. Due to the content of dietary fiber and fatty acids, they are able to cleanse the intestines, and in addition, normalize lipid metabolism and improve blood composition. Nuts develop memory, promote concentration, stabilize male reproductive function and normalize blood pressure. Read more about products to improve memory in our special topic.
Dark chocolate. Helps restore the body's strength, stimulates brain function, and thanks to the presence of serotonin and tryptophan, prevents the occurrence of depression and neuroses. Chocolate improves heart function, prevents varicose veins, helps remove harmful substances from the body, and is especially useful for smokers and people living in unfavorable environmental areas.
Cabbage. Its use stimulates metabolic processes, gives an anti-inflammatory and partially analgesic effect. Cabbage saturates the body with many useful substances, including B vitamins, PP, folic acid, potassium salts, phosphorus, zinc and iron.
Wild rice It contains an almost complete list of proteins necessary for humans, as a result of which it gives strength, improves metabolic processes, and stimulates the functioning of the immune system.
Pomegranate. Its use improves the functions of the nervous system, normalizes hemoglobin levels, and helps to recover when the body is exhausted. Pomegranate improves immunity, removes radionuclides from the body, restores hormonal balance, helps in the treatment of tuberculosis, normalizes stomach function, and is a good diuretic and antiseptic.
Oranges. They are a source of dietary fiber, vitamins C, A, phenols, citric acid, potassium, folic acid. Oranges saturate the body with biologically active substances, have a beneficial effect on the cardiovascular system, help prevent the formation of kidney stones, anemia, lower blood pressure, and stabilize blood cholesterol levels.
Apples. Thanks to the large amount of carbohydrates, they saturate the body with vitality, allow you to lead an active lifestyle without losses to the body and maintain muscle tone. Apples saturate our body with a large amount of vitamins and macroelements, which benefit almost all internal organs.
Mackerel. It is a good remedy for the prevention of rickets, strengthens teeth, bones and human hair, prevents the development of cancer, improves vision, stabilizes the functioning of the nervous system, and resists atherosclerosis.
Berries: strawberries, raspberries, cranberries, black currants. Their use improves immunity, strengthens memory, improves metabolism, increases visual acuity, and regulates blood sugar levels.
Spinach. Significantly increases performance and stress resistance. Spinach normalizes carbohydrate metabolism in the body, prevents exhaustion, prevents many diseases of the organs of vision, optimizes intestinal function and helps normalize weight.

Are there foods that take away energy?

In addition to foods that give us strength and energy, there are also those whose consumption has the opposite effect. Due to the content of toxic or harmful substances and a large number of food additives difficulties arise in digestion and breakdown, which provokes not only heaviness in the stomach, but also gives a feeling of general weakness and lethargy.

Remember the foods that drain your energy:

Food, containing a large amount salt;
Acute food;
Products with a lot of content fats;
Fried products, especially their constant use;
Flour products;
Food with a lot of content artificial additives various purposes (flavors, preservatives, stabilizers, flavor enhancers);
Alcohol.

When drawing strength and energy from the food you eat, do not forget to include in your diet as many healthy foods as possible that not only give you a feeling of satiety, but also bring benefits.

Try to reduce or completely eliminate foods that are harmful to us - and then your body will certainly work at full strength, ensuring health for many years!

Vitamins are the most important group of essential nutritional factors. They enter the body with plant and animal products, some are synthesized in the body by intestinal bacteria (enterogenic vitamins). However, their share is significantly less than food. They are absolutely irreplaceable food components, since they are used for the synthesis of coenzymes in the cells of the body, which are an essential part of complex enzymes.

The concentration of vitamins in tissues and the daily need for them are small (from a few micrograms to tens and hundreds of milligrams), but with insufficient intake of vitamins into the body, characteristic and dangerous pathological changes occur. The presence of vitamins in food was first discovered by the Russian doctor N.I. Lunin (1880). Subsequently, vitamins were discovered during the study of diseases such as beriberi, scurvy and others, which are now known to arise due to vitamin deficiency. According to Academician V.A. Engelhardt, vitamins revealed themselves not by their presence in the body, but by their absence.

Addison-Biermer disease (pernicious anemia, pernicious anemia) was described more than 100 years ago and was long considered incurable. The first cases of recovery were noted in 1926, when raw liver was used for treatment. The search began immediately for a substance contained in the liver that has a therapeutic effect. In 1948, this substance - vitamin B 12 - was isolated. Its content in the liver turned out to be very small - about 1 mcg per 1 g of liver, i.e. 1/1,000,000 of the weight of the liver. Seven years later, the structure of vitamin B 12 (cobalamin) was elucidated (Fig. 62).

Administration of vitamin B 12 quickly cures pernicious anemia. However, it turned out that the method of administration matters: intramuscular injections cure anemia, but taking the vitamin by mouth does not cure it. If vitamin B 12 is taken orally along with gastric juice, a cure also occurs.

It follows that gastric juice contains some substance necessary for the absorption of vitamin B 12 when administered orally. This substance (intrinsic factor, Castle factor) has now been isolated: it turned out to be a glycoprotein, which in healthy people is synthesized in the cells of the stomach and secreted into the gastric juice. Intrinsic factor selectively binds vitamin B 12 (one molecule of vitamin per one molecule of protein); then, already in the intestine, this complex attaches to specific receptors on the enterocyte membrane, and the vitamin is transferred across their membrane, i.e. absorption.

Pernicious anemia usually develops as a complication of gastritis, and its forms in which the formation of gastric juice is sharply reduced. Hence such symptoms as pain in the stomach, lack of appetite. In this case, there is no internal factor in the stomach and, therefore, absorption of vitamin B 12 is impossible: the vitamin contained in food is excreted in feces. The development of anemia is already a consequence of a lack of vitamin B 12 in tissues.

Vitamin B 12 performs coenzyme functions. In the human body there are two coenzyme forms of vitamin B 12 (cobalamin):

methylcobalamin - in the cytoplasm
deoxyadenosylcobalamin - in mitochondria.

In methylcobalamin, instead of an adenosyl group connected to a cobalt atom (see Fig. 62), there is a methyl group. The main role in the development of anemia belongs to the deficiency of methylcobalamin, which serves as a coenzyme in transmethylation reactions. Transmethylation reactions occur, in particular, during the synthesis of nucleotides and nucleic acids. Therefore, with a lack of methylcobalamin, the synthesis of nucleic acids is impaired. This manifests itself primarily in tissues with intense cellular proliferation. These include hematopoietic tissue. The division and maturation of cells of the erythrocyte series are disrupted, the cell sizes exceed normal, a significant part of the cells - the precursors of erythrocytes - are destroyed in the bone marrow, the number of erythrocytes in the circulating blood is sharply reduced, their sizes are increased. In the absence of treatment, changes occur in other tissues, and the disease ends in the death of the patient. Administration of 100-200 mcg of vitamin B 12 daily for about two weeks cures the disease.

Another coenzyme form of vitamin B 12 - deoxyadenosylcobalamin - is involved in the metabolism of methylmalonic acid, which is obtained in the body from fatty acids with an odd number of carbon atoms, as well as from branched carbon chain amino acids. With a deficiency of vitamin B 12 methyl malonic acid accumulates in the body and is excreted in large quantities in the urine; its determination in urine is used to diagnose pernicious anemia.

Methylmalonic acid is toxic to nerve tissue and, if left untreated, causes degeneration of the posterolateral columns of the spinal cord.

The only source of vitamin B 12 in nature are microorganisms that synthesize it from other substances; through the soil it enters plants, and with plants into animal organisms. For humans, the main source of vitamin B 12 is animal food. The liver is richest in vitamins - about 100 mcg per 100 g of liver; Beef meat contains about 5 mcg of vitamin per 100 g of meat. The daily human need for this vitamin is 2.5-5 mcg.

General characteristics of vitamins

Vitamins are usually designated by letters of the Latin alphabet according to their chemical structure or effect. The modern classification of vitamins is based on their ability to dissolve in water and fat. There are fat-soluble (A, D, E) and water-soluble (B 1, B 2, B 6, B 12, C, etc.) vitamins. Characteristics of the main vitamins are given in table. 12.4.

Table 12.4. Characteristics of essential vitamins
Name	Requirement per day	Content Sources	Influence	Signs of deficiency
Fat-soluble vitamins
Vitamin A (retinol)	1.5-2.5 mg	Animal fats, meat, fish, eggs	Vision, growth, reproduction	Impaired twilight vision, dry skin, corneal damage (xerophthalmia)
Vitamin D (calciferol)	2.5 mcg	Liver, fish, caviar, eggs	Exchange of calcium and phosphorus	Bone formation disorder (rickets)
Vitamin E (tocopherol)	10-20 mg	Green vegetables, cereal seeds, eggs, vegetable oils	Reproduction, metabolism	Skeletal muscle atrophy, infertility
Water-soluble vitamins
Vitamin K (phylloquinone)	0.2-0.3 mg	Spinach, lettuce, tomatoes, liver, synthesized by intestinal microflora	Blood clotting vitamins	Bleeding, hemorrhage
Vitamin B 1 (thiamine)	1.3-2.6 mg	Cereals, dairy products, eggs, fruits	Metabolism, stomach and heart functions	Damage to the nervous system (beriberi disease)
Vitamin B 2 (riboflavin)	2-3 mg	Cereals, yeast, vegetables, milk, meat	Metabolism, vision, hematopoiesis	Growth disturbance, skin lesions
Vitamin B 12 (cyanocobalamin)	2-3 mcg	Liver, kidneys, fish, eggs, produced by microorganisms	Metabolism, hematopoiesis	Anemia (anemia)
Vitamin C (ascorbic acid)	60-100 mg	Fresh fruits, berries	Metabolism, redox processes	Decreased capillary strength (bleeding, scurvy)
B 3, PP (nicotinic acid)	15-25 mg	Meat, liver, wholemeal bread	Metabolism in the skin	Pellagra

Most vitamins are part of coenzymes and it is for this reason that the body needs them. Vitamin A serves as a cofactor for a non-enzymatic protein - rhodopsin, or visual purple; This retinal protein is involved in the perception of light. Vitamin D (more precisely, its derivative - calcitriol) regulates calcium metabolism; According to the mechanism of action, it is rather similar to hormones - regulators of metabolism and body functions. How vitamin E (tocopherol) participates in metabolism remains not entirely clear. The functions of each vitamin are discussed in more detail in other sections.

There is a group of substances that, in a strict sense, do not belong to vitamins (according to the mechanism of their participation in metabolism), but are similar to vitamins in the sense that under certain conditions their deficiency occurs: these are the so-called vitamin-like substances. These include pangamic acid (vitamin B 15), S-methylmethionine (vitamin U), inositol, choline and some other compounds.

The need for pangamic acid and S-methylmethionine probably arises only when the essential amino acid methionine is insufficient in food. Both of these substances, like methionine, contain methyl groups, which are used for the synthesis of a number of other compounds. S-Methylmethionine is used as an effective medicine in the treatment of gastric ulcers.

Inositol and choline are part of complex lipids; Choline, in addition, can also serve as a source of methyl groups in the synthesis of other compounds. Both substances in the body of a healthy person are synthesized from glucose (inositol) or serine and methionine (choline) in the required quantities.

Hypovitaminosis. Conditions in which the concentration of vitamins in the tissues of the body is reduced are called hypovitaminosis. They arise due to a lack of vitamins in food or a violation of their absorption in the gastrointestinal tract.

Hypovitaminosis can clinically manifest itself in a very characteristic way: with a lack of vitamin B 12, pernicious anemia develops, vitamin D - rickets, vitamin C - scurvy, vitamin B 1 - beriberi, etc. Treatment of hypovitaminosis comes down to the introduction of vitamins (in food or medications). If left untreated, worsening hypovitaminosis inevitably leads to death.

Most often, mild forms of hypovitaminosis occur, which do not manifest themselves as a clearly defined disease. Their cause is usually a general malnutrition, which results in a lack of many vitamins at once. This kind of hypovitaminosis is not uncommon among urban residents at the end of winter, due to insufficient consumption of vegetables and a reduced amount of vitamins in long-stored products.

Many vitamins are synthesized by microorganisms that inhabit the human intestine, and part of the human body’s need for vitamins is satisfied from this source. When treated with antibiotics, sulfonamides and other drugs that inhibit the intestinal flora, hypovitaminosis may occur. Therefore, with this treatment, vitamins are also prescribed at the same time.

There are also hereditary forms of hypovitaminosis. As already noted, most vitamins are part of coenzymes. The synthesis of coenzymes is carried out with the participation of enzymes, like all chemical transformations in the body. If there is a hereditary defect in an enzyme involved in the conversion of a vitamin into a coenzyme, then a deficiency of this coenzyme occurs. It manifests itself as a deficiency of the corresponding vitamin (hypovitaminosis), although the concentration of the vitamin in the tissues may be high.

Hypervitaminosis. Excessive consumption of vitamins leads to metabolic disorders and body functions, which are partly associated with the specific role of the vitamin in metabolism, and partly have the nature of nonspecific poisoning. Hypervitaminosis occurs relatively rarely, since there are mechanisms for eliminating excess vitamins from tissues, and only the consumption of large quantities of the vitamin can be dangerous.

Fat-soluble vitamins, especially A and D, are more toxic than other vitamins. For example, hypervitaminosis is known among newcomers to the Arctic who, out of ignorance, eat polar bear liver (the locals do not eat it): after a small portion, headaches, vomiting, and visual disturbances occur and even death may occur. This is due to the high content of vitamin A in the liver of a polar bear: a few grams of liver can satisfy a person’s annual need for this vitamin.

Origin of vitamins. Plants synthesize all the organic substances that make up their tissues, including vitamins (with the exception of vitamin B 12), as well as all amino acids (there are no essential amino acids for them). Many microorganisms also do not require external sources of these substances. From animal organisms, vitamins and essential amino acids come mainly from plants, from herbivores - directly, from predators - as a result of feeding on herbivores. Vitamin B 12 is synthesized only by microorganisms. Vitamin B 12 is especially actively produced by microorganisms that inhabit the rumen of ruminants and also reproduce in manure: in wastewater from farmyards, the concentration of vitamin B 12 can be 1000 times higher than in the liver of animals.

During the evolution of heterotrophic organisms, whose food contained ready-made vitamins and amino acids, there was no longer a need to form their own enzymes for the synthesis of many of these substances, and the corresponding genes were lost. In this case, simplification of the metabolic system and saving of cell resources are achieved. At the same time, the body becomes dependent on external sources of these substances, which become essential nutritional factors. The set of essential nutritional factors is different for different animal species.

For example, ascorbic acid (vitamin C) is a vitamin for humans, monkeys, guinea pigs, but dogs, rats and many other animals do not need it: ascorbic acid is synthesized in their bodies from glucose. Vitamin PP synthesis occurs in almost all organisms, from plants to humans; its predecessor is tryptophan. However, in humans, the rate of synthesis is not sufficient to fully satisfy the body's need for this vitamin. In cats, vitamin PP is not synthesized at all.

Proteins are among the most important nutrients. They form the basis of every living cell, every living organism. Science has proven that a lack of proteins has a detrimental effect on the health and ability to work not only of children and adolescents, but also of adults.
Proteins are complex chemical substances that, under the influence of digestive juices, break down in the intestines into their constituent parts - chemical compounds soluble in water or in the juices of the digestive canal. These protein breakdown products, called amino acids, are absorbed through the intestinal wall into the blood; Proteins are created from them in the human body.

Depending on the amino acid composition, proteins can be complete or incomplete. If proteins contain the amino acids necessary for the body and in the required proportions, then they are considered complete.
The most valuable proteins include milk, meat, fish, eggs, i.e. proteins contained in products of animal origin. Proteins contained in products of plant origin are generally inferior in value to animal proteins. However, the proteins in potatoes, cabbage and some other vegetables can be considered complete.

The proteins contained in grain products are of lower quality, but when they are combined with other proteins, especially animal proteins, their value increases. For example, buckwheat contains protein, which is low in some amino acids important for the body, but when buckwheat porridge is consumed with milk, this deficiency is compensated. There are even fewer essential amino acids in millet proteins. But when products such as meat, potatoes, etc. are consumed together with millet products, a set of amino acids is obtained that meets the needs of the body.

Hence the conclusion: the more diverse the composition of the products included in the diet, the greater the opportunity to obtain high-quality proteins from food. A prerequisite for this is the presence of a sufficient amount of animal proteins in the food.
In the body of humans and animals, continuous oxidation of substances occurs, or, as they say, combustion. It is necessary to maintain life and performance, for the functioning of the heart, liver, stomach and other internal organs.
The amount of heat that is released in the body during the combustion of food substances is expressed in calories. When 1 g of protein is burned, as well as 1 g of carbohydrates, 4.1 large calories are released.

Fats.

Of all nutrients, fats are the most concentrated source of energy. When burning each gram of fat, 9.3 large calories are released, i.e. more than two times more than when burning proteins and carbohydrates. Therefore, they give a greater feeling of fullness. Being a necessary component of food, fats improve its taste, increase digestibility, and, due to their high calorie content, make it possible to reduce the volume of food. However, in large quantities, fats are difficult to digest and poorly absorbed by the human body.

Fats are divided into animal and vegetable. The most valuable fat is found in milk, sour cream, cheese, cottage cheese and animal oil. The fat in these products is easily digestible and contains a number of essential vitamins (A and B). Among other animal fats, lard and poultry fat have the best digestibility and taste. Beef and lamb lard are less digestible than other fats.
Vegetable fats and margarine, although inferior in taste and lack of vitamins to milk fat, are of great importance in nutrition and are well absorbed. Fortification of these fats with vitamins A and B further increases their nutritional value.

Carbohydrates.

The source of carbohydrates in the diet is plant products, i.e. bread, flour, cereals, potatoes, vegetables, fruits and berries. Among animal products, carbohydrates in the form of milk sugar are found in milk. Since plant foods are in most cases cheaper than animal foods, carbohydrates are the cheapest source of energy.

In various foods, carbohydrates are presented in the form of starch, sugars and fiber. Sugars and starch are well absorbed. At the same time, sugars, due to their good solubility, quickly enter the blood, while starch, exposed to the action of digestive juices, first breaks down into simpler substances - sugars, which are then gradually absorbed and pass into the blood. This helps maintain a certain level of sugar in the blood and gradually deliver it to the tissues. Therefore, it is advisable that most of the carbohydrates enter the body in the form of starch.

Fiber changes little in the human digestive canal and is poorly absorbed. It is found in significant quantities in rye bread, in some cereals - oatmeal, millet, barley, and in a number of vegetables. However, it would be wrong to conclude that fiber is not needed. A certain amount of it is necessary for the proper functioning of the gastrointestinal tract.
Proteins, fats and carbohydrates are often called the main nutrients that provide the body with the necessary amount of energy and compensate for the waste of substances in the process of life. However, science has proven that for human health it is absolutely necessary that his food also include mineral salts and vitamins.

Mineral salts.

Of these salts, the most studied effects on the body are calcium, phosphorus, iron, magnesium, chlorine, and sodium.

Calcium and phosphorus are the main components of bones. Therefore, their content in food is especially important for the body. Calcium is also necessary for normal heart function; Phosphorus is part of the nervous tissue of the human body.
Iron is necessary for the formation of hemoglobin in the blood.
Magnesium affects the functioning of the heart, as well as the condition of the skeletal system.

Sodium chloride, i.e. ordinary table salt, is of great importance for the body. Both its deficiency and excess have a harmful effect on human health. Under normal temperature conditions, 12-15 g of this salt per day is enough for adults.
Not all sources of minerals are equal. Calcium from milk and dairy products is best absorbed, while calcium contained in bread products, especially coarse rye and wheat bread, is absorbed much less well.
Phosphorus is found in significant quantities in bread products, potatoes, milk, meat, and eggs. It is well absorbed, but it should be noted that phosphorus contained in animal products has a more beneficial effect on the nervous system than phosphorus contained in plant products.

Iron is found in baked goods, fresh herbs, and meat. Milk and its products are low in iron.

Vitamins.

These substances are extremely important for human health. Their absence and even deficiency leads to a number of diseases and negatively affects health.

All known vitamins are divided into two groups: water-soluble vitamins and fat-soluble vitamins. Of the most important vitamins, the first group includes vitamins C and group B, and the second group includes vitamins A and D.
Vitamin C is of great importance for the body, as it protects against the occurrence of scurvy, improves a person’s well-being and helps increase the body’s resistance to infectious diseases.

This vitamin is found almost exclusively (with the exception of fresh milk) in plant foods, mainly vegetables and fruits. The main sources of it in the diet are fresh potatoes, cabbage, tomatoes, green onions, lettuce and other greens. A large amount of this vitamin is found in black currants, lemons, tangerines, and some varieties of apples (Antonovka, anise, etc.). Dried vegetables, fruits and berries, with the exception of rose hips, contain almost no vitamin C. Grain products also do not contain vitamin C.

Vitamins B 1 B 2 and PP, related to the B vitamins, have been the most studied.
Vitamin B1 is of great importance for the nervous system. With a lack of this vitamin, a person experiences rapid fatigue, drowsiness, irritability, and pain in the joints and muscles. A complete lack of vitamin B1 in food leads to serious illnesses.
Vitamin B1 is found in large quantities in the shell of grains, especially wheat. Therefore, the most important source of it in the diet is wheat bread made from low grade flour. On the contrary, wheat bread made from 1st and higher grades of flour, semolina and rice are poor in these vitamins. A significant amount of it is found in legumes, oatmeal, etc.

Vitamin B 2 promotes better digestibility of food. It is necessary for normal growth and development of the body.
Vitamin B2 is found in significant quantities in milk, in some by-products - liver, heart; vegetables - cabbage, tomatoes, etc., as well as legumes.

Vitamin PP, otherwise called nicotinic acid, protects the human body from diseases of the central nervous system and gastrointestinal tract.
A significant amount of this vitamin is found in meat, milk, wheat bread made from wallpaper flour and second-grade flour, and legumes. Yeast and some other products are richest in it.

Vitamin A plays the largest role among fat-soluble vitamins. It is of great importance for the normal functioning of the visual organs and increases the body's resistance to infectious diseases.
This vitamin is found in some animal products - milk, butter and ghee, cheese, fatty cottage cheese and sour cream, eggs, liver. In addition, the most important source of this vitamin in the diet is carotene, a substance from which vitamin A is formed in the body (in the liver).
Carrots, green onions, tomatoes, lettuce and other greens are rich in carotene, and apricots are among the fruits. Carotene is best absorbed by the body when it is dissolved in fat. Therefore, carrots, for example, are recommended to be used in the diet in fried form.

All vitamins, but to varying degrees, are characterized by significant losses during storage and especially during cooking. Vitamin C is the most unstable. It dissolves during long-term storage of products in water and is quickly destroyed when heated in the presence of atmospheric oxygen. Therefore, it is not recommended to keep peeled potatoes and vegetables in water for a long time; they should only be placed in boiling water and cooked at low boil in a closed container so that they come into less contact with air.

It should be remembered that any heating significantly reduces the vitamin C content of the product.