Vitamins are substances that are not related to proteins, fats or carbohydrates. This is an independent group of substances that are necessary for the vital activity of the organism and, with rare exceptions, are not synthesized in it.

Hence their name comes from the Latin word "vita", which means life. Another root of this complex word - "amine" originally meant that the composition of vitamins includes amino groups. Later it became known that not all vitamins contain an amino group.

General characteristics of vitamins

Vitamins have a strong effect on growth, metabolism and the physiological state of the body as a whole, and in rather small quantities. Their chemical nature is diverse.

Vitamins enter the body with food, mainly vegetable. In human tissues, they are absorbed, forming more complex substances, as a rule, they are part of the enzymes that are involved in metabolism. Therefore, if vitamins are not supplied with food, then the body is deprived of the necessary substances, which adversely affects its health. This was proved in the last century by the Russian scientist N.I. Lunin, who is the discoverer of vitamins. He not only determined the existence of a new group of substances, but also created methods for their detection, which are still used today.

Usually, if a vitamin is being studied, it is administered to experimental animals in a purified form or, conversely, it is excluded from food and the physiology and biochemistry of the experimental organisms are examined. Thus, the role of vitamins in metabolism, their various functions was clarified. It became known that they are involved in the synthesis and breakdown of amino acids, fats, nitrogenous bases of nucleic acids, some hormones, a mediator - acetylcholine, which ensures the transmission of impulses in the nervous system.

To date, more than 20 vitamins are known that are of direct importance for human health. All of them are divided into two groups: fat-soluble (A, D, E, K, etc.) and water-soluble - (B, C, P, PP, etc.).

With a normal diet and a measured lifestyle, the need for vitamins is met naturally. However, even under these conditions, in winter and spring, it is advisable to additionally consume ascorbic acid (vitamin C).

With a monotonous diet, depleted in natural plant products, vitamin metabolism disorders occur. The need for vitamins is slightly higher among young people, as well as among people employed in hazardous industries, living in harsh climatic conditions, with diseases. In such cases, people need additional nutritional supplementation with vitamins.

To preserve vitamins in food, you should follow the rules of preparation, storage of food, cooking - exclude overcooking and overcooking. For example, in damaged vegetables and fruits, ascorbic acid is destroyed faster due to the action of enzymes that break down its molecules.

The value of vitamins for the body

It is now well known that with a deficiency (hypovitaminosis, or vitamin deficiency) or an excess (hypervitaminosis) of vitamins in the body, diseases develop.

A person's daily need for vitamins largely depends on age, occupation, body weight, gender, general condition of the body, etc.

Ascorbic acid (vitamin C) is not synthesized in the human body and the need for it must be fully satisfied from the outside, with food. Therefore, in conditions of hungry and half-starved existence, the lack of vitamin C most affects health.

Lack or absence of vitamin C in food is accompanied by scurvy. With scurvy, symptoms such as weakness, shortness of breath, damage to the walls of blood vessels, bones, teeth, bleeding, and minor hemorrhages develop. First of all, bleeding gums appear. Protein metabolism is impaired, and resistance to various diseases decreases.

People living in temperate, sharply continental and arctic climates have hypovitaminosis in the spring due to the impoverishment of plant food. It should be remembered that heating food destroys this vitamin.

The human need for vitamin C is large - 63-105 mg per day. A lot of it is found in pepper, horseradish, mountain ash, currants, strawberries, citrus fruits, cabbage (especially sauerkraut), sorrel, rose hips, etc. Potatoes contain little vitamin C, but given that this vegetable is consumed in large quantities, it is also a source of ascorbic acid.

B vitamins - B1, B2, B3, B12, etc.

Lack or absence of vitamin B1 leads to beriberi disease. It is accompanied by a disorder of the nervous system, the activity of the heart, and the digestive apparatus.

This vitamin is consumed mainly with plant-based foods - brown rice, wholemeal flour, peas, etc. Significant amounts of it are found in yeast (brewer's yeast), as well as in the organs of animals - liver, kidneys, heart muscle, brain. A person should consume 2-3 mg of this vitamin per day.

In the absence or lack of vitamin B12 in the diet, a severe form of anemia (anemia) develops. It is contained mainly in the liver and intestinal walls of animals, and is also synthesized by bacteria in the human intestines. In case of violation of the secretory function of the stomach, the absorption of vitamins does not occur. Therefore, in addition to the presence of vitamins in food, it is equally important to maintain the normal secretion of this organ.

Group A vitamins

The lack of vitamins of group A in food is accompanied by changes in the skin and mucous membranes: dryness, increased desquamation of the epithelium, inflammation and softening of the mucous membrane and cornea of \u200b\u200bthe eyes, violation of the epithelium of the urogenital organs, the alimentary canal.

In addition, vision suffers due to the so-called chicken, or night, blindness. The disease received this name due to the fact that a sick person sees poorly with the onset of dusk. In this case, the formation of visual pigments of the retina is disrupted.

Sources of vitamin A are only animal products: especially fish oil, butter, liver. Plant products contain substances (provitamins), from which vitamin A is synthesized in the human body. These are carotenes of carrots, spinach, red bell peppers, green onions, lettuce, etc. The presence of fats in food determines the absorption of provitamins in the intestines.

The need for vitamins A is 1-2 mg per day.

Group D vitamins

Vitamins of group D include D 2, D 3 and others. They are called antirachitic, since rickets develops with a lack or absence of them. This disease appears in early childhood and is accompanied by impaired bone formation due to a decrease in calcium and phosphorus salts in it. The bones remain soft and curved. Teeth formation is delayed and impaired.

Vitamins of group D are found in egg yolks, butter, most of all in fish oil. In other products, it is much less. This vitamin is sufficient for an adult with a normal diet. For the prevention of vitamin D deficiency, the presence of calcium and phosphorus salts and exposure to ultraviolet rays of the sun or quartz light sources are also necessary.

The need for young children for this vitamin is 2.5-125 mcg. Adults (except pregnant women) under normal conditions of existence do not need prescriptions for preparations of this vitamin, since the need for it is small.

In addition, it can be formed in human skin under the influence of ultraviolet rays from cholesterol, which is formed in the body or comes from food. This makes clear one of the roles of sunlight (in moderation) for children's health.

Thus, in order to prevent diseases associated with varying degrees of vitamin deficiency, it is necessary to organize proper nutrition and lifestyle in general. It should be remembered that an excess of vitamins and their preparations also has a negative effect on health.

The human body is an incredibly complex system, the functioning of which depends on a wide variety of factors. One of the most important conditions for the normal functioning of organs is to obtain the required amount of biologically active substances. A lack of certain vitamins can provoke various vitamins that will negatively affect the state of the whole body.

Vitamins are a whole group of organic components, which are based on carbon, oxygen and hydrogen in various concentrations. Such substances are not produced by the body on its own, nor are they stored in it in case of excess. Nevertheless, vitamins are essential for the normal functioning of individual organs and the whole organism as a whole.

The most important function of the presented group of biologically active substances is participation in metabolic processes. Due to vitamins, metabolism is carried out continuously, around the clock. Metabolism, carried out by microelements, is the main integral part of other vital processes, such as respiration, nutrition, tissue regeneration.

In certain cases, vitamins act as catalysts in various chemical reactions in the body. For example, such substances perform an important function under a strong stress load on the body, significantly accelerating the production of certain

Vitamins have a significant effect on the condition. The concentration of such substances in the human body determines its resistance to various types of bacteria that act as causative agents of diseases.

In general, the importance of vitamins for the human body should not be underestimated, which is why you should get acquainted in more detail with their types and functions.

Fat-soluble vitamins

There are several options for the classification of biologically active substances, depending on their properties and characteristics. At the moment, the most essential property of vitamins is the ability to dissolve. In view of this, the first group includes substances that are broken down in the body by means of fatty acids and components similar in their properties.

Fat-soluble vitamins include:

Definition 1

Vitamins (vita - life, amines - a group of chemical compounds containing a nitrogen atom) are biologically active substances used by the body in small quantities (milligrams) and taking an active part in metabolism.

For the normal course of enzymatic processes in the body, the presence of vitamins is necessary. Many vitamins play the role of coenzymes - substances that come into contact with the protein molecule of the enzyme and activate their functions.

Ways of getting vitamins into the body:

• come with food;
• synthesized in the body;
• produced by their own bacteria in the intestines.

Remark 1

Vitamins are rapidly destroyed during thermal and prolonged processing of products, with prolonged contact with a metal surface.

Pathological conditions associated with impaired intake of vitamins into the body:

1. Hypovitaminosis. It occurs with a lack of vitamins. Most often occurs with a meager diet, at the end of the cold period.
2. Avitaminosis. A condition that occurs when vitamins are completely absent in food.
3. Hypervitaminosis. Excessive intake of vitamins into the body. Often occurs with uncontrolled excess use of vitamins in the form of pharmaceuticals. In this condition, the amount of a certain vitamin must be several thousand times higher than the norm.

All vitamins are divided into two groups:

• fat-soluble vitamins enter the body with food fats, without which their absorption becomes impossible (vitamins A, D, K, E);
• water-soluble vitamins (vitamins of group B, C).

Fat-soluble vitamins

Vitamin A (retinol). The daily requirement is 1-3 mg.

Sources of retinol are:

• egg yolk;
• liver of fish and marine animals;
• butter;
• in the form of carotene - provitamin A - found in tomatoes, carrots.

The role of vitamin A in the body:

• forms the visual pigment rhodopsin;
• influences the regulation of cell division;
• ensures the functioning of epithelial tissue;
• participates in mineral metabolism, cholesterol synthesis.

Signs of vitamin deficiency:

• deterioration of vision;
• lesions of the cornea of \u200b\u200bthe eye, intestines, epithelium of the genitourinary organs, skin;
• slowing down the growth of the body.

1. Vitamin D(calciferol). The daily requirement is 0.02-0.05 mg.

   Sources of calciferol are:

   • liver;
   • fish fat;
   • butter;
   • egg yolk;
   • sunlight promotes the formation of active forms.

   The role of vitamin D in the body:

   • regulates phosphorus-calcium metabolism;
   • maintains the level of Ca in the blood;
   • increases the absorption of Ca in the intestine.

   Signs of vitamin deficiency:

   • rickets;
   • disorders of phosphorus-calcium metabolism, accompanied by a violation of bone formation;
   • dysfunction of the neuromuscular apparatus;
   • disorders of the central nervous system.

2. Vitamin E(tocopherol), or anti-sterile vitamin. The daily requirement is 10-15 mg.

   Sources of tocopherol are:

   • vegetable oils (corn, sunflower, olive, etc.);
   • green parts of plants, lettuce, spinach, wheat germ, cabbage;
   • liver;
   • meat;
   • milk;
   • egg yolk;
   • butter.

   The role of vitamin E in the body:

   • participates in the formation of the pituitary gonadotropic hormone;
   • helps the accumulation of fat-soluble vitamins;
   • improves mineral, protein, fat metabolism;
   • responsible for sexual function;
   • prevents aging;
   • has antioxidant and antihypoxant effects.

   Signs of vitamin deficiency:

   • violation of fertilization processes;
   • muscular dystrophy.

3. Vitamin K(phyloquinone, vicasol, farnoquinone). The daily requirement is 0.2-0.3 mg.

   Sources of phyloquinone are:

   • green parts of plants;
   • liver;
   • synthesized by the intestinal microflora.

   The role of vitamin K in the body:

   • participates in the synthesis of blood coagulation factors;
   • increases the contractility of muscle fibers;
   • increases tissue regeneration.

   Signs of vitamin deficiency - hemorrhagic diathesis, bleeding disorders.

Water soluble vitamins

Vitamin B1 (thiamine). The daily requirement is 2-3 mg.

Sources of thiamine are:

• brewer's yeast;
• germ of cereals;
• bread;
• kidneys, liver, brain.

The role of vitamin B1 in the body:

• participates in carbohydrate metabolism;
• provides the synthesis of nucleic acids;
• is a coenzyme of the Krebs cycle;
• plays the role of a factor in the transmission of nerve impulses.

Signs of vitamin deficiency:

• take-take disease;
• damage to the nervous system;
• losing weight;
• movement disorder;
• amyotrophy;
• heart failure;
• paralysis of the limbs.

1. Vitamin B2 (ribaflavin). The daily requirement is 2-3 mg.

   Sources of ribaflavin are:

   • brewer's yeast;
   • legumes and cereals;
   • milk;
   • egg white;
   • meat, liver;
   • bird;
   • a fish.

   The role of vitamin B2 in the body:

   • carries oxygen and hydrogen;
   • participates in tissue respiration;
   • ensures the exchange of amino acids;
   • participates in the synthesis and assimilation of fats.

   Signs of vitamin deficiency:

   • damage to the mucous membranes of the mouth, lips, eyes;
   • hair loss;
   • growth arrest in children.

2. Vitamin B5 (pantothenic acid). The daily requirement is 10-12 mg. Pantothenic acid is found in almost all foods; it is synthesized by the intestinal microflora.

   The role of vitamin B5 in the body:

   • is a part of the enzymes involved in the neutralization of toxic compounds, coenzyme A;
   • catalyzes the formation of polypeptides.

   Signs of vitamin deficiency:

   • apathy;
   • general oppression;
   • instability of the cardiovascular system.

3. Vitamin B6

   • yeast;
   • liver;

   The role of pyridoxine in the body:

   Signs of vitamin deficiency:

   • nausea;
   • loss of appetite;
   • stomatitis;
   • dermatitis;
   • polyneuritis of the extremities;
   • mental disorders;
   • children may develop anemia, seizures.

4. Vitamin B12 (cyanocobalamin). The daily requirement is 0.001-0.003 mg.

   Sources of vitamin B12 are:

   • liver of animals and fish;
   • the vitamin is synthesized by the intestinal microflora, but poorly absorbed.

   The role of vitamin B12 in the body:

   • promotes the maturation of blood corpuscles;
   • ensures the conversion of carotene into vitamin A;
   • stimulates protein synthesis and the formation of nucleic acids.

   With vitamin deficiency, Addison-Birmer hyperchromic anemia develops.

5. Vitamin B6 (pyridoxine). The daily requirement is 2-4 mg.

   Sources of pyridoxine are:

   • yeast;
   • liver;
   • the vitamin is synthesized by the intestinal microflora.

   The role of pyridoxine in the body:

   • is part of the enzymes involved in protein synthesis;
   • promotes the synthesis of hemoglobin;
   • influences the exchange of sulfur-containing amino acids;
   • participates in the exchange of unsaturated fatty acids.

   Signs of vitamin deficiency:

   • nausea;
   • loss of appetite;
   • stomatitis;
   • dermatitis;
   • polyneuritis of the extremities;
   • mental disorders;
   • children may develop anemia, seizures.

6. Vitamin C(vitamin C). The daily requirement is 70-80 mg.

   Sources of ascorbic acid are:

   • black currant;
   • citrus;
   • cabbage;
   • rose hips, strawberries and many other plants;
   • liver.

   The role of ascorbic acid in the body:

   • stimulates collagen synthesis;
   • affects the rate of DNA formation;
   • controls biochemical reactions in the cells of the central nervous system;
   • increases the phagocytic properties of blood.

   With vitamin deficiency, scurvy develops, characterized by:

   • rapid fatigue;
   • hemorrhages in the gums, muscles, skin, subcutaneous adipose tissue, joints;
   • joint pain;
   • fragility of bones;
   • neuropsychiatric disorders.

Introduction

1 Vitamins

1.1 History of the discovery of vitamins

1.2 Concept and basic features of vitamins

1.3 Providing the body with vitamins

2.1 Fat-soluble vitamins

2.2 Water-soluble vitamins

2.3 Group of vitamin-like substances

Conclusion

Bibliography

Introduction

It is hard to imagine that such a well-known word as "vitamin" entered our lexicon only at the beginning of the 20th century. It is now known that vitamins are involved in the vital metabolic processes in the human body. Vitamins are vital organic compounds that are necessary for humans and animals in trace amounts, but are of great importance for normal growth, development and life itself.

Vitamins usually come from plant foods or animal products, since they are not synthesized in humans and animals. Most vitamins are precursors of coenzymes, and some compounds have signaling functions.

The daily requirement for vitamins depends on the type of substance, as well as on the age, sex and physiological state of the body. Recently, the concept of the role of vitamins in the body has been enriched with new data. It is believed that vitamins can improve the internal environment, increase the functionality of the main systems, and the body's resistance to adverse factors.

Consequently, vitamins are considered by modern science as an important means of general primary prevention of diseases, increasing efficiency, slowing down the aging process.

The purpose of this work is a comprehensive study and characterization of vitamins.

The work consists of an introduction, two chapters, a conclusion and a bibliography. The total amount of work is 21 pages.

1 Vitamins

1.1 History of the discovery of vitamins

If you look at the books published at the end of the last century, you can see that at that time the science of rational nutrition included the inclusion of proteins, fats, carbohydrates, mineral salts and water in the diet. It was believed that food containing these substances fully meets all the needs of the body, and thus, the question of good nutrition seemed to be resolved. However, the science of the 19th century was in contradiction with centuries of practice. The life experience of the population of various countries has shown that there are a number of diseases associated with nutrition and are often found among people whose food does not contain a lack of proteins, fats, carbohydrates and mineral salts.

Practitioners have long assumed that there is a direct link between the occurrence of certain diseases (for example, scurvy, rickets, beriberi, pellagra) and the nature of the diet. What led to the discovery of vitamins - these substances with miraculous properties to prevent and cure serious diseases of high-quality nutritional deficiency?

The beginning of the study of vitamins was laid by the Russian doctor N.I. Lunin, who back in 1888 established that for the normal growth and development of an animal organism, in addition to proteins, fats, carbohydrates, water and minerals, some other, as yet unknown science substances, the absence of which leads the body to death.

The proof of the existence of vitamins ended with the work of the Polish scientist Casimir Funk, who in 1912 isolated a substance from rice bran that healed the paralysis of pigeons that ate only polished rice (beriberi was the name given to this disease in people of the countries of Southeast Asia, where the population mainly one rice). Chemical analysis of the substance isolated by K. Funk showed that it contains nitrogen. Funk called the substance he discovered a vitamin (from the words "vita" - life and "amine" - containing nitrogen).

True, later it turned out that not all vitamins contain nitrogen, but the old name of these substances remained. Nowadays, it is customary to designate vitamins by their chemical names: retinol, thiamine, ascorbic acid, nicotinamide, respectively A, B, C, PP.

1.2 Concept and basic features of vitamins

In terms of chemistry, vitamins - This is a group of low molecular weight substances of various chemical nature, with pronounced biological activity and necessary for the growth, development and reproduction of the organism.

Vitamins are formed by biosynthesis in plant cells and tissues. Usually in plants they are not in active, but highly organized form, which, according to research data, is most suitable for the human body, namely in the form of provitamins. Their role is reduced to the complete, economical and correct use of essential nutrients, in which the organic matter of the food releases the necessary energy.

Only a few vitamins such as A, D, E, B12 can accumulate in the body. Lack of vitamins causes severe disorders.

The main signs vitamins:

Either they are not synthesized in the body at all, or they are synthesized in small amounts by the intestinal microflora;

Do not perform plastic functions;

Are not energy sources;

They are cofactors of many enzymatic systems;

They have a biological effect in small concentrations and affect all metabolic processes in the body, the body needs in very small quantities: from a few micrograms to several mg per day ..

Various degree of insecurity organism vitamins:

avitaminosis - complete depletion of vitamin reserves;

hypovitaminosis - a sharp decrease in the provision of this or that vitamin;

hypervitaminosis - an excess of vitamins in the body.

All extremes are harmful: both a lack and an excess of vitamins, since with excessive consumption of vitamins, poisoning (intoxication) develops. The phenomenon of hypervitaminosis concerns only vitamins A and D, an excess amount of most other vitamins is rapidly excreted from the body in the urine. But there is also the so-called subnormal security, which is associated with a deficiency of vitamins and manifests itself in a violation of metabolic processes in organs and tissues, but without obvious clinical signs (for example, without visible changes in the condition of the skin, hair and other external manifestations). If this situation is repeated regularly for various reasons, then this can lead to hypo- or avitaminosis.

1.3 Providing the body with vitamins

With a normal diet, the body's daily need for vitamins is fully satisfied. Inadequate, inadequate nutrition or impaired absorption and use of vitamins can cause various forms of vitamin deficiency.

Causes of Vitamin Depletion in organism:

1) Food quality and preparation:

Failure to comply with storage conditions in terms of time and temperature;

Inappropriate culinary processing (for example, prolonged cooking of finely chopped vegetables);

The presence of anti-vitamin factors in food (cabbage, pumpkin, parsley, green onions, apples contain a number of enzymes that destroy vitamin C, especially when finely cut)

Destruction of vitamins under the influence of ultraviolet rays, air oxygen (for example, vitamin A).

2) An important role in providing the body with a number of vitamins belongs to the microflora of the digestive tract:

In many common chronic diseases, the absorption or assimilation of vitamins is impaired;

Severe intestinal disorders, improper use of antibiotics and sulfonamide drugs lead to the creation of a certain deficiency of vitamins that can be synthesized by the beneficial intestinal microflora (vitamins B12, B6, H (biotin)).

Daily requirement for vitamins and their main functions

Vitamin	Daily need	Functions	main sources
Ascorbic acid (C)	50-100 mg	Participates in oxidation-reduction processes, increases the body's resistance to extreme influences	Vegetables, fruits, berries. Cabbage contains 50 mg. Rosehip contains 30-2000 mg.
Thiamin, aneurin (B1)	1.4-2.4 mg	Essential for the normal functioning of the central and peripheral nervous system	Wheat and rye bread, cereals - oatmeal, peas, pork, yeast, intestinal microflora.
Riboflavin (B2)	1.5-3.0 mg	Participates in redox reactions	Milk, cottage cheese, cheese, egg-tso, bread, liver, vegetables, fruits, yeast.
Pyridoxine (B6)	2.0-2.2 mg	Involved in the synthesis and metabolized IU-amino acids, fatty acids and unsaturated lipids	Fish, beans, millet, potatoes
Nicotinic acid (PP)	15.0-25.0 mg	Participates in redox reactions in cells. Insufficiency causes pellagra	Liver, kidneys, beef, pork, lamb, fish, bread, cereals, yeast, intestinal microflora
Folic acid, folicin (Sun)	0.2-0.5 mg	Hematopoietic factor, participates in the synthesis of amino acids, nucleic acids	Parsley, salad, spinat, cottage cheese, bread, liver
Cyanocobalamin (B12)	2-5 mg	Participates in the biosynthesis of nucleic acids, a factor of hematopoiesis	Liver, kidneys, fish, beef, milk, cheese
Biotin (H)	0.1-0.3 mg	Participates in metabolic reactions of amino acids, lipids, carbohydrates, nucleic acids	Oatmeal, peas, egg, milk, meat, liver
Pantothenic acid (B3)	5-10 mg	Participates in metabolic reactions of proteins, lipids, carbohydrates	Liver, kidneys, buckwheat, rice, oats, eggs, yeast, peas, milk, intestinal microflora
Retinol (A)	0.5-2.5 mg	Participates in the activity of cell membranes. It is necessary for the growth and development of humans, for the functioning of the mucous membranes. Participates in the process of photoreception - the perception of light	Fish oil, cod liver, milk, eggs, butter
Calciferol (D)	2.5-10 mcg	Regulation of calcium and phosphorus content in blood, mineralization of bones, teeth	Fish oil, liver, milk, eggs

Currently, there are about 13 vitamins that, together with proteins, fats and carbohydrates, must be present in the diet of humans and animals to ensure the normal functioning of vitamins. In addition, there is a group vitamin-like substances , which have all the properties of vitamins, but are not strictly required components of food.

Compounds that are not vitamins, but can serve as precursors of their formation in the body, are called provitamins ... These include, for example, carotenes, which are broken down in the body to form vitamin A, some sterols (ergosterol, 7-dehydrocholesterol, etc.), which are converted into vitamin D.

A number of vitamins are represented not by one, but by several compounds with similar biological activity (vitamers), for example, vitamin B6 includes pyridoxine, pyridoxal and pyridoxamine. To designate such groups, related compounds use the word "vitamin" with letter designations (vitamin A, vitamin E, etc.).

For individual compounds with vitamin activity, rational names are used that reflect their chemical nature, for example, retinal (aldehyde form of vitamin A), ergocalciferol and cholecalidiferol (forms of vitamin D).

Thus, along with fats, proteins, carbohydrates and mineral salts, the necessary complex for maintaining human life includes the fifth component of equal importance - vitamins. Vitamins take the most direct and active part in all metabolic processes of the body, and are also part of many enzymes, acting as catalysts.

2 Classification and nomenclature of vitamins

Since refers to vitamins group of substances of different chemical nature, the classification of their chemical structure complicated. Therefore, the classification is based on solubility in water or organic solvents. In line with these vitamins are divided into water-soluble and fat-soluble.

1 TO water-soluble vitamins include:

B1 (thiamine) antineuritic;

B2 (riboflavin) anti-dermatitis;

B3 (pantothenic acid) anti-dermatitis;

B6 (pyridoxine, pyridoxal, pyridoxamine) antidermatitny;

B9 (folic acid; folacin) antianemic;

B12 (cyanocobalamin) antianemic;

PP (nicotinic acid; niacin) antipellagric;

H (biotin) anti-dermatitis;

C (ascorbic acid) antiscorbutic - are involved in the structure and functioning of enzymes.

2) K fat-soluble vitamins include:

A (retinol) anticerophthalmic;

D (calciferols) antirachitic;

E (tocopherols) anti-sterile;

K (naphthoquinols) antihemorrhagic;

Fat-soluble vitamins are included in the structure of membrane systems, ensuring their optimal functional condition.

Chemically, fat-soluble vitamins A, D, E and K are isoprenoids.

3) the following group: vitamin-like substances. These usually include vitamins: B13 (orotic acid), B15 (pangamic acid), B4 (choline), B8 (inositol), W (carnitine), H1 (paraminbenzoic acid), F (polyunsaturated fatty acids), U (S \u003d methylmethionine sulfate chloride).

Nomenclature (name) is based on the use of capital letters of the Latin alphabet with a lower numeric index. In addition, the name uses names that reflect the chemical nature and function of the vitamin.

Vitamins did not become known to mankind immediately, and for many years scientists have been able to discover new types of vitamins, as well as new properties of these substances useful for the human body. Since the language of medicine throughout the world is Latin, vitamins were also designated by Latin letters, and subsequently by numbers.

The assignment of not only letters, but also numbers to vitamins is explained by the fact that vitamins acquired new properties, which seemed to be the most simple and convenient to denote with the help of numbers in the name of the vitamin. For example, consider the popular vitamin B. So, today, this vitamin can be presented in various fields, and in order to avoid confusion, it is called from "vitamin B1" and up to "vitamin B14". The vitamins included in this group are similarly named, for example, "B vitamins".

When the chemical structure of vitamins was finally determined, it became possible to name vitamins in accordance with the terminology adopted in modern chemistry. So names such as pyridoxal, riboflavin, and pteroylglutamic acid came into use. Some time passed, and it became quite clear that many organic substances, which have long been known to science, also have the properties of vitamins. Moreover, there were a lot of such substances. Of the most common, we can mention nicotinamide, lhezoinositol, xanthopterin, catechin, hesperetin, quercetin, rutin, as well as a number of acids, in particular, nicotinic, arachidonic, linolenic, linoleic, and some other acids.

2.1 Fat-soluble vitamins

Vitamin A (retinol) is the predecessor of the group " retinoids ", To which belong retinal and retinoic acid. Retinol is formed by oxidative breakdown of provitamin β-carotene. Retinoids are found in animal products, while β-carotene is found in fresh fruits and vegetables (especially carrots). Retinal determines the color of the visual pigment rhodopsin. Retinoic acid acts as a growth factor.

With a lack of vitamin A, night ("night") blindness, xerophthalmia (dryness of the cornea of \u200b\u200bthe eyes) develop, and growth disorders are observed.

Vitamin D (calciferol) when hydroxylated in the liver and kidneys forms a hormone calcitriol (1α, 25-dihydroxycholecalciferol). Together with two other hormones (parathyroid hormone, or parathyrin, and calcitonin), calcitriol is involved in the regulation of calcium metabolism. Calciferol is formed from the 7-dehydrocholesterol precursor found in human and animal skin when exposed to ultraviolet light.

If UV irradiation of the skin is insufficient or vitamin D is absent in food, vitamin deficiency develops and, as a result, rickets in children, osteomalacia (softening of bones) in adults. In both cases, the process of mineralization (calcium inclusion) of bone tissue is disrupted.

Vitamin Ε includes tocopherol and a group of related compounds with a chroman ring. Such compounds are found only in plants, especially in wheat seedlings. For unsaturated lipids, these substances are effective antioxidants.

Vitamin K - the general name of a group of substances, including phylloquinone and related compounds with a modified side chain. Lack of vitamin K, a rather rare, since these substances are produced by intestinal microflora. Vitamin K takes part in the carboxylation of residues of glutamic acid in blood plasma proteins, which is important for normalizing or accelerating the blood coagulation process. The process is inhibited by vitamin K antagonists (such as coumarin derivatives), which is used as one of the treatment methods thrombosis.

2.2 Water-soluble vitamins

Vitamin B1 (thiamin) built from two cyclic systems - pyrimidine (a six-membered aromatic ring with two nitrogen atoms) and thiazole (a five-membered aromatic ring containing nitrogen and sulfur atoms), linked by a methylene group. The active form of vitamin Β1 is thiamine diphosphate (TPP), which acts as a coenzyme in the transfer of hydroxyalkyl groups (“activated aldehydes”), for example, in the oxidative decarboxylation of α-keto acids, as well as in the transketolase reactions of the hexose monophosphate pathway. With a lack of vitamin Β1, the disease develops take it , signs of which are disorders of the nervous system (polyneuritis), cardiovascular diseases and muscle atrophy.

Vitamin B2 - a complex of vitamins, including riboflavin, folic, nicotinic and pantothenic acids. Riboflavin serves as a structural element of the prosthetic groups of flavin mononucleotide [FMN (FMN)] and flavin adenine dinucleotide [FAD (FAD)]. FMN and FAD are prosthetic groups of numerous oxidoreductases (dehydrogenases), where they function as hydrogen carriers (in the form of hydride ions).

Molecule folic acid (vitamin B9, vitamin Bc, folacin, folate) includes three structural fragments: pteridine derivative, 4-aminobenzoate and one or more residues glutamic acid. The product of folic acid reduction - tetrahydrofolic (folinic) acid [THF (THF)] - is a part of enzymes that carry out the transfer of one-carbon fragments (C1-metabolism).

Figure 2 - Fat-soluble vitamins

Folic acid deficiency is common. The first sign of deficiency is impaired erythropoiesis (megaloblastic anemia). At the same time, the synthesis of nucleoproteins and cell maturation are inhibited, abnormal precursors of erythrocytes - megalocytes appear. With an acute lack of folic acid, generalized tissue damage develops, associated with a violation of lipid synthesis and amino acid metabolism.

Unlike humans and animals, microorganisms are able to synthesize folic acid de novo ... Therefore, the growth of microorganisms is suppressed sulfa drugs, which, as competitive inhibitors, block the inclusion of 4-aminobenzoic acid in the biosynthesis of folic acid. Sulfanilamide preparations cannot affect the metabolism of animal organisms, since they are unable to synthesize folic acid.

A nicotinic acid (niacin) and nicotinamide (niacinamide) (both known as vitamin Β5, vitamin PP) are required for the biosynthesis of two coenzymes - nicotinamide adenine dinucleotide [ OVER + (NAD +)] and nicotinamide adenine dinucleotide phosphate [ NADP + (NADP +)]. The main function of these compounds, which is the transfer of hydride ions (reduction equivalents), is discussed in the section on metabolic processes. In animal organisms, nicotinic acid can be synthesized from tryptophan , however, biosynthesis is carried out with a low yield. Therefore, vitamin deficiency occurs only if all three substances are simultaneously absent in the diet: nicotinic acid, nicotinamide and tryptophan. Diseases. associated with niacin deficiency, proD are skin lesions ( pellagra), indigestion and depression.

Pantothenic acid (vitamin B3) is an amide of α, γ-dihydroxy-β, β-dimethylbutyric acid (pantoic acid) and β-alanine. The compound is required for biosynthesis coenzyme A [CoA (CoA)] participating in the metabolism mnotih carboxylic acids. Pantothenic acid is also a member of the prosthetic group acyl transfer protein (APB). Since pantothenic acid is found in many foods, vitamin B3 deficiency is rare.

Vitamin B6 - the group name of three pyridine derivatives: pyridoxal, pyridoxine and pyridoxamine ... The diagram shows the formula of iridoxal, where in the position at C-4 there is an aldehyde group (-CHO); in pyridoxine, this place is occupied by an alcohol group (-CH2OH); and pyridoxamine - methylamino (-CH2NN2). The active form of vitamin B6 is pyridoxal 5-phosphate (PLP), an essential coenzyme in amino acid metabolism. Pyridoxal phosphate is also part of glycogen phosphorylase, taking part in the breakdown of glycogen. Vitamin B6 deficiency is rare.

Figure 2 - Fat-soluble vitamins

Vitamin B12 (cobalamins; dosage form - cyanocobalamin) is a complex compound based on the cycle corrina and containing a coordinated cobalt ion. This vitamin is synthesized only in microorganisms. From food products, it is found in the liver, meat, eggs, milk and is completely absent in plant foods (note for vegetarians!). Vitamin is absorbed by the gastric mucosa only in the presence of a secreted (endogenous) glycoprotein, the so-called internal factor. The purpose of this mucoprotein is to bind cyanocobalamin and thereby protect it from degradation. In the blood, cyanocobalamin is also bound by a special protein, transcobalamin. In the body, vitamin B12 is stored in the liver.

Figure 2 - Fat-soluble vitamins

Cyanocobalamin derivatives are coenzymes involved, for example, in the conversion of methylmalonyl-CoA to succinyl-CoA, the biosynthesis of methionine from homocysteine. Cyanocobalamin derivatives are involved in the reduction of ribonucleotides by bacteria to deoxyribonucleotides.

Vitamin deficiency or impaired absorption of vitamin B12 is mainly associated with the cessation of the secretion of intrinsic factor. The consequence of vitamin deficiency is pernicious anemia.

Vitamin C (L-ascorbic acid) is the γ-lactone of 2,3-dehydrogulonic acid. Both hydroxyl groups are acidic in nature, and therefore the loss of a proton compound may exist in the form ascorbate anion ... Daily intake of ascorbic acid is necessary for humans, primates and guinea pigs, since these species lack the enzyme gulonolactone oxidase (EC 1.1.3.8), catalyzing the last step of the conversion of glucose to ascorbate.

Fresh fruits and vegetables are a source of vitamin C. Ascorbic acid is added to many beverages and foods as an antioxidant and flavoring agent. Vitamin C breaks down slowly in water. Ascorbic acid as a strong reducing agent takes part in many reactions (mainly in hydroxylation reactions).

Of the biochemical processes involving ascorbic acid, it should be mentioned collagen synthesis, tyrosine degradation, syntheses catecholamine and bile acids. The daily requirement of ascorbic acid is 60 mg - value not characteristic of vitamins. Vitamin C deficiency is rare today. The deficiency manifests itself several months later in the form of scurvy (scurvy). The consequence of the disease is atrophy of connective tissues, a disorder of the hematopoietic system, loss of teeth.

Vitamin H (biotin) found in liver, egg yolk and other foods; in addition, it is synthesized by the intestinal microflora. In the body, biotin (through the ε-amino group of the lysine residue) is associated with enzymes, for example with pyruvate carboxylase (EC 6.4.1.1), catalyzing the carboxylation reaction. During the transfer of the carboxyl group, two N-atoms of the biotin molecule in an ATP-dependent reaction bind the CO2 molecule and transfer it to the acceptor. Biotin with high affinity (Kd \u003d 10 - 15 M) and specifically binds avidin chicken egg protein. Since avidin is denatured during boiling, vitamin H deficiency can only occur when raw eggs are eaten.

2.3 Group of vitamin-like substances

In addition to the above two main groups of vitamins, a group of various chemicals is distinguished, of which part is synthesized in the body, but has vitamin properties. The body needs them in relatively small quantities, but the effect on body functions is quite strong. These include:

Indispensable nutrients with plastic function: choline, inositol.

Biologically active substances synthesized in the human body: lipoic acid, orotic acid, carnitine.

Pharmacologically active food substances: bioflavonoids, vitamin U - methylmethionine sulfonium, vitamin B15 - pangamic acid, microorganism growth factors, para-aminobenzoic acid.

Another factor has recently been discovered, called pyrroloquinoline quinone. It is known for its coenzyme and cofactor properties, but has not yet disclosed vitamin properties.

The main difference between vitamin-like substances is that, with their lack or excess, various pathological changes characteristic of vitamin deficiencies do not appear in the body. The content of vitamin-like substances in foods is enough for the life of a healthy body.

For a modern person, it is necessary to know about the precursors of vitamins. The source of vitamins, as you know, are products of plant and animal origin. For example, ready-made vitamin A is contained only in animal products (fish oil, whole milk, etc.), and in plant products only in the form of carotenoids - their precursors. Therefore, eating carrots, we get only the precursor of vitamin A, from which vitamin A itself is produced in the liver. Pro-vitamins include: carotenoids (the main one is carotene) - the precursor of vitamin A; sterols (ergosterol, 7-dehydrocholesterol, etc.) - precursors of vitamin D;

Conclusion

So, from the history of vitamins, we know that the term "vitamin" was first used to refer to a specific food component that prevented Beriberi disease, common in countries where a lot of polished rice was eaten. Since this component had the properties of an amine, the Polish biochemist K. Funk, who first isolated this substance, called it vitamin - an amine necessary for life.

Currently vitamins can be characterized as low molecular weight organic compounds, which, being a necessary component of food, are present in it in extremely small quantities compared to its main components. Vitamins are substances that ensure the normal course of biochemical and physiological processes in the body. Vitamins - a necessary element of food for humans and a number of living organisms, because are not synthesized or some of them are synthesized in insufficient quantities by this organism.

The original source vitamins are plants, where they are mainly formed, as well as provitamins - substances from which vitamins can be formed in the body. A person receives vitamins either directly from plants, or indirectly - through animal products, in which vitamins were accumulated from plant foods during the life of the animal.

Vitamins are divided into two large groups: fat-soluble vitamins and water-soluble vitamins. In the classification of vitamins, in addition to the letter designation, the main biological effect is indicated in brackets, sometimes with the prefix "anti", indicating the ability of this vitamin to prevent or eliminate the development of the corresponding disease.

For fat-soluble vitamins include: Vitamin A (anti-xerophtalic), Vitamin D (antirachitic), Vitamin E (reproduction vitamin), Vitamin K (antihemorrhagic) \\

To vitamins soluble in water include: Vitamin B1 (anti-neuritic), Vitamin B2 (riboflavin), Vitamin PP (antipellagric), Vitamin B6 (anti-dermatitis), Pantothen (anti-dermatitis factor), Biotite (vitamin H, growth factor for fungi, yeast and bacteria, antiseborrheic), Inositol ... Para-aminobenzoic acid (bacterial growth factor and pigmentation factor), Folic acid (antianemic vitamin, growth vitamin for chickens and bacteria), Vitamin B12 (antianemic vitamin), Vitamin B15 (pangamic acid), Vitamin C (anticorbent), Vitamin P (permeability vitamin ).

Main feature fat-soluble vitamins is their ability to accumulate in the body so to speak "in reserve". They can be stored in the body for a year and consumed as needed. However, too much income fat-soluble vitamins it is dangerous for the body, and can lead to undesirable consequences. Water soluble vitamins do not accumulate in the body and, in case of excess, are easily excreted in the urine.

Along with vitamins, there are substances whose deficiency, unlike vitamins, does not lead to pronounced disorders. These substances belong to the so-called vitamin-like substances :

Today, 13 low-molecular organic compounds are known, which are referred to as vitamins. Compounds that are not vitamins, but can serve as precursors of their formation in the body called provitamins ... The most important provitamin is the precursor of vitamin A - beta-carotene.

The value of vitamins for the human body is very great. These nutrients support the work of absolutely all organs and the whole body as a whole. Lack of vitamins leads to a general deterioration in the state of human health, and not in its individual organs.

Diseases that arise due to the lack of certain vitamins in food began to be called avitaminosis ... If the disease occurs due to the lack of several vitamins, it is called multivitaminosis ... More often you have to deal with a relative lack of any vitamin; such a disease is called hypovitaminosis ... If a diagnosis is made in a timely manner, vitamin deficiencies and especially hypovitaminosis can be easily cured by introducing appropriate vitamins into the body. Excessive intake of certain vitamins can cause hypervitaminosis .

List of sources used

1. Berezov, T.T. Biological Chemistry: Textbook / T.T.Berezov, B.F.Korovkin. - M .: Medicine, 2000 .-- 704 p.

2. Gabrielyan, O.S. Chemistry. Grade 10: Textbook (basic level) / O.S. Gabrielyan, F.N. Maskaev, S.Yu. Ponomarev and others - M .: Bustard. - 304 p.

3. Manuilov A.V. Fundamentals of Chemistry. Electronic textbook / A.V. Manuilov, V.I. Rodionov. [Electronic resource]. Access mode: http://www.hemi.nsu.ru/

4. Chemical encyclopedia [Electronic resource]. Access mode: http://www.xumuk.ru/encyklopedia/776.html

Introduction

CHAPTER 1. History of discovery and study of vitamins

CHAPTER 2. Vitamins and their meaning

2.1 The concept of vitamins and their importance in the body

2.2 General concept of vitamin deficiency; hypo- and hypervitaminosis

2.3 Classification of vitamins

2.4 Fat-soluble vitamins

2.4.1 Vitamin A

2.4.2 Vitamin D

2.4.3 Vitamin E

2.4.4 Vitamin K

2.5 Water-soluble vitamins

2.5.1 Vitamin C

2.5.2 Vitamin B

2.5.3 Vitamin B2

2.5.4 Vitamin B3

2.5.5 Vitamin B5 (Sun)

2.5.6 Vitamin B6

2.5.7 Vitamin B8

2.5.8 Vitamin B12

2.5.9 Vitamin B15

2.5.10 Vitamin B17

2.5.11 Vitamin PP

2.5.12 Vitamin P

2.5.13 Vitamin H

2.5.14 Vitamin N

CHAPTER 3. Determination of the content of vitamins in substances

3.1 Fat-soluble vitamins

3.2 Water-soluble vitamins

Conclusion

List of references

Introduction

“It is difficult to find such a branch of physiology and biochemistry, which would not come into contact with the doctrine of vitamins; metabolism, the activity of the sense organs, the functions of the nervous system, the phenomena of growth and reproduction - all these and many others, diverse and fundamental in their importance, in the field of biological science are closely related to vitamins, "- this is how one of the founders of Russian biochemistry, academician A. N. Bach.

Every person wants to be healthy. Health is that wealth that cannot be bought with money or received as a gift. People themselves strengthen or destroy what is given to them by nature. One of the most important elements of this constructive or destructive work is nutrition.

Everyone is well aware of the wise saying: "A man is what he eats." The food we eat contains various substances necessary for the normal functioning of all organs, contributing to the strengthening of the body, healing, and also harmful to health. Along with proteins, fats and carbohydrates, vitamins are indispensable, vital components of nutrition.

All life processes occur in the body with the direct participation of vitamins. Vitamins are part of more than 100 enzymes that trigger a huge number of reactions, help maintain the body's defenses, increase its resistance to the action of various environmental factors, and help to adapt to the ever worsening environmental situation. Vitamins play an essential role in maintaining immunity, i.e. they make our body more resistant to disease.

But few know exactly what vitamins are, where they come from, what foods they contain, what value they have for our health, how and when to take vitamins and in what quantity.

Today, a large number of people eat mainly prepackaged, processed foods. During preparation and storage, many vitamins are destroyed or removed. Manufacturers compensate for these losses with vitamin and mineral supplements of synthetic and natural origin.

During cooking, overcooking breaks down nutrients. The loss of water-soluble vitamins C and E during prolonged boiling can reach 90%.

If we constantly eat a variety of vegetables and fruits and get enough sun, there will be no vitamin deficiency. In this case, there is no need to take them in pill form.

Vitamins are very important and insufficient intake of vitamins in the human body is a global problem. In developing countries, it is closely associated with starvation or malnutrition, a large part of the population. However, in developed countries, the consumption of vitamins by most of the population does not meet the recommended standards. It is sufficient to prevent profound vitamin deficiencies, but not sufficient to optimally meet the needs of the body.

Thus, the topic of the importance of vitamins is the most relevant today. A high level of health and active longevity of citizens are the most important goals for the development of society. The state of health of each person largely depends on his lifestyle. Awareness of the responsibility for maintaining one's own health and the health of others, strict adherence to personal hygiene standards, refusal of bad habits, and a healthy lifestyle are the moral home of every citizen of Russia. And also good nutrition, rich in vitamins - an integral part of the normal life of the body.

Therefore, in the course of this work, I would like to prove that vitamins play an important role in the normal functioning of the human body and to consider each vitamin separately.

Objective: study the value of vitamins in the human body.

Tasks:

Analyze the literature on this topic.

Find out what vitamins are and what their role is in the human body.

Consider each vitamin separately.

To study the methods of determining the content of vitamins in certain substances.

Object of this work are vitamins, subject - the effect of vitamins on the metabolic processes of the human body.

CHAPTER 1. History of discovery and study of vitamins

By the second half of the 19th century, it was found that the nutritional value of food products is determined by the content in them mainly of the following substances: proteins, fats, carbohydrates, mineral salts and water.

It was considered generally accepted that if a person's food includes all these nutrients in certain quantities, then it fully meets the biological needs of the body. This opinion was firmly rooted in science and was supported by such respected physiologists of the time as Pettenkofer, Voith and Rubner.

However, practice has not always confirmed the correctness of the ingrained ideas about the biological value of food.

The practical experience of doctors and clinical observations have long indicated with no doubt the existence of a number of specific diseases directly related to nutritional defects, although the latter fully met the above requirements. This was also evidenced by the centuries-old practical experience of participants in long journeys. For a long time, scurvy was a real scourge for sailors; more sailors died from it than, for example, in battles or from shipwrecks. So, out of 160 participants in the famous Vasco de Gama expedition, which paved the sea route to India, 100 people died from scurvy.

The history of sea and land travel also provided a number of instructive examples, indicating that the onset of scurvy can be prevented, and scurvy patients can be cured if a certain amount of lemon juice or decoction of pine needles is introduced into their food.

Thus, practical experience clearly indicated that scurvy and some other diseases are associated with nutritional defects, that even the most abundant food alone does not always guarantee against such diseases, and that in order to prevent and treat such diseases, it is necessary to introduce into the body some additional substances that are not contained in all foods.

Experimental substantiation and scientific-theoretical generalization of this centuries-old practical experience became possible for the first time thanks to the research of the Russian scientist Nikolai Ivanovich Lunin, who opened a new chapter in science, who studied the role of minerals in nutrition in the laboratory of GA Bunge.

NI Lunin conducted his experiments on mice kept on artificially cooked food. This food consisted of a mixture of refined casein (milk protein), milk fat, milk sugar, milk salts and water. It seemed that all the necessary constituents of the milk were present; meanwhile, mice on such a diet did not grow, lost weight, stopped eating the food they were given, and finally died. At the same time, the control batch of mice that received natural milk developed completely normally. Based on these works, N.I. Lunin in 1880 came to the following conclusion: "... if, as the aforementioned experiments teach, it is impossible to provide life with proteins, fats, sugar, salts and water, then it follows that in milk, in addition to casein, fat, milk sugar and salts, there are still other substances that are indispensable for nutrition. It is of great interest to investigate these substances and study their significance for nutrition. "

It was an important scientific discovery that disproved the established position in nutritional science. The results of N.I. Lunin began to be contested; They tried to explain them, for example, by the fact that artificially prepared food, which he fed the animals in his experiments, was supposedly tasteless.

In 1890 K.A. Sosin repeated the experiments of N.I. Lunin with a different version of the artificial diet and fully confirmed the conclusions of N.I. Lunin. Even after that, however, the flawless conclusion was not immediately universally recognized.

A brilliant confirmation of the correctness of N.I. Lunin by establishing the cause of beriberi disease, which was especially widespread in Japan and Indonesia among the population who ate mainly polished rice. Doctor Aikman, who worked in a prison hospital on the island of Java, noticed in 1896 that chickens kept in the hospital yard and ate ordinary polished rice suffered from a disease resembling beriberi. After transferring the chickens to a diet of brown rice, the disease subsided.

Eikman's observations on a large number of prisoners in Java prisons also showed that among people who ate refined rice, beriberi fell on an average of one in 40 people, while in a group of people who ate brown rice, only one in 10,000.

Thus, it became clear that the shell of rice (rice bran) contains some unknown substance that protects against beriberi disease. In 1911, the Polish scientist Kazimierz Funk isolated this substance in crystalline form (which turned out, as it turned out later, to be a mixture of vitamins); it was fairly acid resistant and withstood boiling with 20% sulfuric acid solution. In alkaline solutions, the active principle was destroyed very quickly. By its chemical properties, this substance belonged to organic compounds and contained an amino group. Funk concluded that beriberi is only one of the diseases caused by the absence of any special substances in food.

Despite the fact that these special substances are present in food, as N.I. Lunin, in small quantities, they are vital. Since the first substance of this group of vital compounds contained an amino group and had some properties of amines, Funk (1912) proposed to call this entire class of substances vitamins (Latin vita - life, amine - the presence of an amino group). Subsequently, it turned out that many substances of this class do not contain amino groups. Nevertheless, the term "vitamins" became so firmly established that there was no point in changing it. Researchers who discovered and studied vitamins suggested calling them letters of the alphabet. So the first discovered vitamin is vitamin A. The next one was called vitamin A. B, but it turned out that it was about a whole group of substances and a serial number was added to the letter: 1, 2, etc.

After the isolation of a substance that protects against beriberi disease from food, a number of other vitamins were discovered. The works of Hopkins, Stepp, McCollum, Melanby and many other scientists were of great importance in the development of the theory of vitamins.

Currently, about 20 different vitamins are known. Installation

flax and their chemical structure; this made it possible to organize the industrial production of vitamins not only by processing the products in which they are contained in a finished form, but also artificially, by their chemical synthesis.

The research was the beginning of a comprehensive wide study of vitamins. In view of the important physiological significance of vitamins, scientists of various specializations - physiologists, chemists, biochemists - were actively involved in their study. As a result of their research, vitaminology (the study of vitamins) has grown into a large, rapidly developing branch of knowledge.

CHAPTER 2. Vitamins and their meaning

2.1 The concept of vitamins and their importance in the body

Vitamins - a group of low molecular weight biologically active organic compounds of various structure and composition, which are necessary for the proper development and life of organisms, they are irreplaceable factors of nutrition

Vitamins - vital substances that our body needs to maintain many of its functions. Therefore, a sufficient and constant intake of vitamins into the body with food is extremely important.

The biological effect of vitamins in the human body is the active participation of these substances in metabolic processes. In the metabolism of proteins, fats and carbohydrates, vitamins take part either directly or as part of complex enzyme systems. Vitamins are involved in oxidative processes, as a result of which numerous substances are formed from carbohydrates and fats, which are used by the body as energy and plastic material. Vitamins contribute to normal cell growth and development of the whole organism. Vitamins play an important role in maintaining the body's immune responses, ensuring its resistance to adverse environmental factors. This is essential in the prevention of infectious diseases.

Vitamins soften or eliminate the adverse effect of many drugs on the human body.

The lack of vitamins affects the state of individual organs and tissues, as well as the most important functions: growth, procreation, intellectual and physical capabilities, protective functions of the body. A long-term lack of vitamins leads first to a decrease in working capacity, then to a deterioration in health, and in the most extreme, severe cases, this can result in death.

Only in some cases can our body synthesize individual vitamins in small amounts. For example, the amino acid tryptophan can be converted in the body to niacin.

Vitamins are necessary for the synthesis of hormones - special biologically active substances that regulate a variety of body functions.

This means that it turns out that vitamins are substances that are indispensable factors in human nutrition, and are of great importance for the life of the body. They are essential for the hormonal system and the enzyme system in our body. They also regulate our metabolism, making the human body healthy, vigorous and beautiful.

Most of them enter the body with food, and only a few are synthesized in the intestine by the beneficial microorganisms living in it, but in this case they are not always enough. Many vitamins are quickly destroyed and do not accumulate in the body in the required quantities, therefore a person needs a constant supply them with food.

The use of vitamins for therapeutic purposes (vitamin therapy) was originally entirely associated with the impact on various forms of their deficiency. Since the middle of the 20th century, vitamins have been widely used for fortification of food, as well as feed in animal husbandry.

A number of vitamins are represented not by one, but by several related compounds. Knowledge of the chemical structure of vitamins made it possible to obtain them by chemical synthesis; along with microbiological synthesis, it is the main method for the production of vitamins on an industrial scale. There are also substances similar in structure to vitamins, the so-called provitamins, which, entering the human body, are converted into vitamins. There are chemicals that are similar in structure to vitamins, but they have the exact opposite effect on the body, therefore they are called antivitamins. This group also includes substances that bind or destroy vitamins. Some medicines (antibiotics, sulfonamides, etc.) are also anti-vitamins, which serves as further evidence of the danger of self-medication and uncontrolled use of drugs.

The primary source of vitamins is plants, in which vitamins are accumulated. Vitamins come to the body mainly with food. Some of them are synthesized in the intestine under the influence of the vital activity of microorganisms, but the amounts of vitamins formed do not always fully satisfy the needs of the body. Vitamins are involved in the regulation of metabolism; they are biological catalysts or reagents of photochemical processes occurring in the body, they also actively participate in the formation of enzymes.

Vitamins affect the absorption of nutrients, contribute to the normal growth of cells and the development of the whole organism. As an integral part of enzymes, vitamins determine their normal function and activity. Lack, and even more so the absence of any vitamin in the body leads to metabolic disorders. With a lack of them in food, a person's working capacity decreases, the body's resistance to diseases, to the action of unfavorable environmental factors. As a result of a deficiency or absence of vitamins, vitamin deficiency develops.

2.2 General concept of vitamin deficiency; hypo- and hypervitaminosis

Diseases that arise due to the absence in food of those or

other vitamins, became known as vitamin deficiency. If the disease occurs due to the absence of several vitamins, it is called multivitaminosis. However, avitaminosis, typical in its clinical picture, is now quite rare. More often you have to deal with the relative lack of any vitamin; such a disease is called hypovitaminosis. If the diagnosis is correct and timely, then vitamin deficiencies and especially hypovitaminosis can be easily cured by introducing appropriate vitamins into the body.

Excessive intake of certain vitamins into the body can cause a disease called hypervitaminosis.

Currently, many changes in metabolism in vitamin deficiency are considered as a consequence of a violation of enzyme systems. It is known that many vitamins are part of enzymes as components of their prostatic or coenzyme groups.

Many vitamin deficiencies can be considered as pathological conditions arising from the loss of functions of one or another coenzyme. However, at present, the mechanism of occurrence of many vitamin deficiencies is still unclear, therefore, it is not yet possible to interpret all vitamin deficiencies as conditions arising from dysfunctions of certain coenzyme systems.

The cause of vitamin deficiency can be not only a deficiency of vitamins in the diet, but also a violation of their absorption in the intestine, transport to tissues and transformation into a biologically active form. In case of gastric ulcer and duodenal ulcer, colitis, liver diseases and many others, the absorption of vitamins is impaired and their deficiency may occur.

Subnormal supply of vitamins is a preclinical stage of vitamin deficiency, which is detected by disorders of metabolic and physiological reactions that occur with the participation of a particular vitamin, and does not have clinical expression or is manifested only by individual nonspecific microsymptoms.

Subnormal supply of vitamins is most common, since it occurs not only under special circumstances that disturb nutrition and diseases that are the main causes of hypovitaminosis, but also in normal living conditions in practically healthy people who pay insufficient attention to the diversity of the diet. The development of this form of vitamin deficiency is facilitated by the widespread use of refined foods in the diet, devoid of vitamins in the process of their production.

Having no obvious clinical manifestations, the subnormal supply of vitamins at the same time reduces the adaptive capabilities of the body, which is expressed in a decrease in resistance to the action of infectious and toxic factors, physical and mental performance, a slowdown in recovery in acute diseases, and an increase in the likelihood of exacerbation of chronic diseases.

Hypovitaminosis is more common, the causes of which can be long-term parenteral nutrition, irrational chemotherapy, chronic intoxication and infectious diseases.

Prevention of vitamin deficiency consists in ensuring full correspondence between human needs for vitamins and their intake with food. It should be borne in mind that the entire set of vitamins necessary for a person can enter the body only if all food groups are used in the diet, while a one-sided diet, even with foods with high nutritional value, cannot provide the body with all vitamins. In particular, the point of view is erroneous that the main source of vitamins is fresh vegetables and fruits. This group of products, which is really practically the only source of vitamins C and P and one of the sources of folic acid, but it does not fully meet the body's needs for vitamins: A, D, E, K vitamins of group B. At the same time, meat and meat products are the main sources of B vitamins. Milk and dairy products supply vitamins A to the body , cereals - vitamin РР and some vitamins of group B, vegetable fats - vitamin E, animal fats - vitamins A and D.

With excessive consumption of vitamins, intoxication of the body develops, which is called hypervitaminosis. Excessive doses of fat-soluble vitamins have a more toxic effect due to their ability to accumulate in the body and less toxic - higher doses of vitamins soluble in water than the norm, since they are more easily removed by the body through the kidneys.

With the discovery of vitamins and the elucidation of their nature, new prospects have opened up not only in the prevention and treatment of vitamin deficiencies, but also in the treatment of infectious diseases. It turned out that some pharmaceutical preparations (for example, from the sulfanilamide group) partially resemble in their structure and in some chemical characteristics the vitamins necessary for bacteria, but at the same time do not possess the properties of these vitamins. Such substances "disguised as vitamins" are captured by bacteria, while the active centers of the bacterial cell are blocked, its exchange is disrupted and bacteria die.

2.3 Classification of vitamins

At present, vitamins can be characterized as low-molecular-weight organic compounds, which, being a necessary component of food, are present in it in extremely small quantities compared to its main components.

Vitamins are an essential element of food for humans and a number of living organisms because they are not synthesized or some of them are synthesized in insufficient quantities by this organism. They can be attributed to the group of biologically active compounds that exert their effect on metabolism in negligible concentrations.

Vitamins are divided into two large groups:

fat-soluble vitamins,

water-soluble vitamins.

Each of these groups contains a large number of different vitamins, which are usually denoted by letters of the Latin alphabet. It should be noted that the order of these letters does not correspond to their usual arrangement in the alphabet and does not fully correspond to the historical sequence of the discovery of vitamins.

In the given classification of vitamins, the most characteristic biological properties of this vitamin are indicated in brackets - its ability to prevent the development of a particular disease. Usually the name of the disease is preceded by the prefix "anti", indicating that this vitamin prevents or eliminates this disease.

1. FAT-SOLUBLE VITAMINS.

Vitamin A (anticerophthalmic).

Vitamin D (antirachitic).

Vitamin E (reproduction vitamin).

Vitamin K (antihemorrhagic)

2. VITAMINS, soluble in water.

Vitamin FROM (anti-affliction).

Vitamin IN 1 (anti-neuritis).

Vitamin AT 2 (regulator of metabolic processes).

Vitamin AT 3 (anti-neuritis, anti-dermatitis)

Vitamin AT 5 (Sun) (antianemic vitamin)

Vitamin AT 6 (antidermatitis).

Vitamin AT 8 (lipotropic and sedative properties).

Vitamin AT 12 (antianemic vitamin).

Vitamin B15 (pangamic acid).

Vitamin B17 (anti-cancer)

Vitamin PP (antipellagric).

Vitamin R(vitamin permeability).

Vitamin H (anti-seborrheic).

Vitamin N (antioxidant)

Many also refer to the number of vitamins and unsaturated fatty acids with two or more double bonds. All of the above water-soluble vitamins, with the exception of inositol and vitamins C and P, contain nitrogen in their molecule, and they are often combined into one complex of B vitamins.

Water-soluble vitamins include: vitamin C and all B vitamins. Water-soluble vitamins should be taken daily, since they do not accumulate in the body and are excreted within 1 to 4 days.

Another group of vitamins is fat-soluble vitamins: A, D, E, K. These vitamins can accumulate in adipose tissue and liver and, if necessary, be extracted from there by the body.

2.4 Fat-soluble vitamins

2.4.1 Vitamin A

Chemical name: retinol. Vitamin A can withstand high temperatures for a short time. The vitamin is sensitive to oxidation by atmospheric oxygen and to ultraviolet rays. Vitamin Aluchshe is absorbed and assimilated in the presence of fats.

Role in the body - the biological effect of vitamin A is to regulate the differentiation of cells, including reproductive cells, prevent keratinization of epithelial tissue, participate in the exchange of proteins, nucleic acids, some hormones, and oxidative processes. In addition, retinol supports the vision process.

Vitamin A vitamin deficiency is accompanied by systemic keratinization (keratinization) of epithelial tissue with the development of symptoms specific to each affected organ (nephritis or nephrosis develops in the kidneys, bronchitis in the lungs, etc.), as well as xerophthalmia and keratomalacia. Vitamin A hypovitaminosis can also manifest itself as night blindness (hemeralopia, twilight vision), when a person does not see in the dark due to a violation of the formation of rhodopsin (visual purpura). With severe hypovitaminosis A with damage to the epithelium of the gastrointestinal tract and urinary tract, dyspeptic disorders, a predisposition to pyelitis, urethritis, cystitis are observed.

Hypervitaminosis occurs when excessive consumption of foods rich in vitamin A and its accumulation in the liver. In children, hypervitaminosis occurs with an overdose of synthetic drugs. Clinically, it manifests itself as weight loss, nausea, vomiting, frequent bone fractures, and hemorrhages. There may be an exacerbation of gallstone disease and chronic pancreatitis (inflammation of the pancreas). To prevent hypervitaminosis, strict control of vitamin intake is required.

Daily requirement: Daily requirement:

an adult in vitamin A - 1 mg,

pregnant and lactating women - 1.25-1.5 mg,

children of the first year of life - 0.4 mg.

Sources of vitamin A: butter, liver of marine animals and fish (halibut, perch, cod, etc.), cream, cottage cheese, egg yolk. However, in the human body (in the intestinal wall and liver), vitamin A can be formed from certain pigments called carotenes, which are widely found in plant foods. It is noted that the amount of vitamins changes in accordance with the color of products in a reddish-yellow color: the more intense this color, the more vitamin in the product. The amount of vitamin in fats depends on the composition of the food that the animal eats. If the animal's food is rich in vitamins or provitamins, then its fat contains a high percentage of vitamin; thus, fish oil is 100 times richer in vitamin A , than butter, because the plant and animal plankton that fish eat is very rich in vitamin A.

Carotene

Carotene (provitamin A) is an unsaturated hydrocarbon, an orange-yellow pigment, found in fruits, leaves of flowers with a corresponding color. It can exist in four forms: alpha, beta, gamma, deltacarotene. The most active is b - carotene (provitamin A). It is believed that 1 mg of b-carotene is equivalent to 0.17 mg of vitamin A (retinol) in terms of potency.

Physiological significance:

reducing the risk of developing premature aging and tumors;

enhances the action of sex hormones;

has an anti-sclerotic effect;

use in patients with atrophic gastritis, gastric ulcer;

useful for poorly healing wounds, burns;

with exacerbation of chronic diseases of the respiratory and urinary system;

to maintain the normal condition of the skin, mucous membranes, bones, teeth, gums, hair;

useful during pregnancy and lactation;

relieves of many visual disorders, inhibits the development of glaucoma;

supports normal prostate function, especially in men over 40;

increases the body's resistance to respiratory and other infections, strengthens the immune system.

An extremely important factor in the assimilation of carotene is the presence of bile in the intestine. Unlike vitamin A, carotene in high doses is non-toxic and does not cause hypervitaminosis.

Natural sources of carotene: sorrel, pumpkin, carrots, sea buckthorn, apricots, watermelons, mustard greens, zucchini, cabbage, liver, tomatoes, asparagus, milk, chicory, spinach, egg yolks.

2.4.2 Vitamin D

Chemical name: calciferol, 7-dehydrocholesterol. cholecalceferol, ergosterol. Vitamin D is relatively resistant to oxygen in the air, as well as when heated to a temperature of 1000C and slightly higher, but prolonged exposure to air or heating to a temperature of 2000C destroys vitamin D.

Role in the body: stimulating the synthesis of a specific protein that ensures the absorption of calcium from the intestine. Vitamin D affects the absorption of phosphorus and citric acid, as well as the processes of regulation of phosphorus-calcium metabolism and the formation of bone tissue, mineralization of cartilage, reabsorption (reabsorption) of phosphorus and amino acids in the kidneys.

Avitaminosis: Vitamin D deficiency leads to impaired phosphorus-calcium metabolism, which may result in rickets (in children) or osteomalacia (in adults). With rickets, the process of absorption of calcium, phosphorus and citric acid from the intestines is disrupted. The consequence of this is a decrease in the level of calcium in the blood, which causes the active secretion of the hormone of the parathyroid glands, which promotes the excretion of calcium from the bones into the blood, and also reduces the processes of phosphorus reabsorption in the kidneys. As a result, phosphorus is excreted in the urine in large quantities. In the blood, the level of calcium and phosphorus decreases to critical values. The lack of phosphorus in the blood is replenished by washing out the latter from the bones. As a result of the leaching of calcium and phosphorus, the bones become flexible and brittle and bend under the weight of the body. Violation of normal bone formation leads to the development of a large disproportionate head, thickenings at the joints of the ribs with costal cartilages - the so-called "rosary". Lack of calcium in the muscles leads to a loss of the ability to contract (muscle hypotonia). The muscles become flabby, the sick child has a saggy stomach. In severe forms of rickets, the child is easily excited, he develops convulsions.

In adults, osteomalacia occurs - a disease associated with decalcification of bones and a violation of bone formation. Prevention of vitamin deficiency consists in proper and rational nutrition, sunbathing, systematic medical supervision.

Hypervitaminosis. The development of hypervitaminosis is based on the toxic effect of peroxide compounds formed under the influence of an excess of vitamin D. This increases the absorption of calcium and phosphorus from the intestine and their deposition in areas of bone and soft tissue growth: heart muscle, aortic wall, kidneys. Nausea, vomiting, headaches, dyspepsia, anemia, depression are often observed. Prevention of hypervitaminosis consists of strict control of vitamin intake.

Daily requirement:

for men - 5mkg,

for women - 5 mcg,

for children - 7 mcg.

Sources of vitamin D: most of the vitamin is found in some fish products: fish oil, cod liver, Atlantic herring. In eggs, its content is 2.2%, in milk - 0.05%, in butter - 1.3%, in small quantities it is present in mushrooms, nettles, yarrow, spinach.

The formation of vitamin D is facilitated by ultraviolet rays. Greenhouse-grown vegetables contain less vitamin D than garden-grown vegetables because the glass in the greenhouse frames does not allow these rays to pass through.

The need for vitamin D in adults is satisfied due to its formation in human skin under the influence of ultraviolet rays and partly due to its intake with food. In addition, the liver of an adult is capable of storing appreciable amounts of vitamin D, sufficient to meet its needs for 6 months.

2.4.3 Vitamin E

The chemical name is tocopherol, tocotrienol. Vitamin Evesma is stable, is not destroyed by the action of alkalis and acids, or by boiling or heating up to 2000C? and under the influence of ultraviolet rays.

Role in the body: tocopherol is a multiplication vitamin that has a beneficial effect on the functioning of the genital and some other glands. Vitamin E restores fertility, promotes the development of the fetus during pregnancy and the newborn baby. Vitamin is a natural antioxidant agent, prevents the oxidation of vitamin A and has a beneficial effect on its accumulation in the liver. It prevents the development of processes of formation of free radicals and fatty acid peroxides that are toxic to the body. Vitamin E promotes the assimilation of proteins and fats, participates in the processes of tissue respiration, affects the functioning of the brain, blood, nerves, muscles, improves wound healing, and delays aging. Reduces fatigue.

Vitamin E deficiency can develop after significant physical overload. In the muscles, the amount of myosin, glycogen, potassium, magnesium, phosphorus and creatine decreases sharply. In such cases, hypotension and muscle weakness are the leading symptoms. Degenerative changes in nerve cells and damage to the liver parenchyma are also observed. The main changes in vitamin deficiency occur in the genital area: the production of sex hormones stops, degeneration of secondary sexual characteristics is observed. Women, while maintaining the ability to conceive, lose the ability to carry a normal fetus. The fetus and placenta exfoliate, hemorrhages and intrauterine death may occur in embryos. Vitamin E deficiency can also be associated with hemolytic jaundice of newborns, in women - a tendency to miscarriages, endocrine and nervous disorders. Muscle weakness and paralysis develop.

Hypervitaminosis practically does not occur, since vitamin E is non-toxic, even in large doses, but those who suffer from thyroid diseases, diabetes mellitus, hypertension or rheumatic heart diseases need to be careful when taking this vitamin.

Daily requirement:

for men - 12 mcg per day,

for women - 10 mcg per day,

for children of the first year of life - 5 mg.

Some experts advise a dosage of 50 to 80 mg per day, based, in all likelihood, on the antioxidant effect of this drug.

Sources of vitamin E: the richest in them are unrefined vegetable oils: soybean, cottonseed, sunflower, peanut, corn, sea buckthorn. Especially a lot of vitamin is found in cereals, legumes, asparagus, tomatoes, lettuce,

The history of vitamins, their basic chemical properties and structure, a vital necessity for the normal functioning of the body. The concept of a lack of vitamins, the essence of hypoavitaminosis and its treatment. The content of vitamins in various foods.

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