Proteins - their role in the human body and how important they are in sports. The value of protein in human life

What do we know about the proteins that we eat daily with food? Most people are familiar with them as a muscle building material. But this is not their main task. What else do we need protein for and why do we need it so much? Let's look at all the functions of proteins in the human body and their importance in our diet.

I already started a protein topic on the blog “Lead a healthy lifestyle.” Then we talked about whether the protein is harmful or not. The topic of sports nutrition is now very popular among beginner athletes. So I couldn't help touching her. Read more.

Being the main component of all cells and organic tissues, proteins play an extremely important role in the smooth functioning of the body. They are actively involved in absolutely all vital important processes. Even our thinking is directly connected with this high-molecular organic substance. I'm not talking about metabolism, contractility, ability to grow, irritability and reproduction. All these processes are impossible without the presence of proteins.

Proteins bind water and thereby form in the body dense, characteristic of human body, colloidal structures. The famous German philosopher Friedrich Engels said that life is a way of existence of proteins that constantly interact with their environment through continuous metabolism, and as soon as this exchange stops, the protein decomposes - life itself ends.

New cells cannot be born without the participation of protein. Its main task is construction. He is the builder of young cells, without which the development of a growing organism is impossible. When this organism stops growing and reaches middle age, cells that have already outlived their own need regeneration, which takes place only with the participation of protein.

For this process, its amount must be proportional to the wear of the fabrics. Therefore, people leading a sports life associated with muscle loads (for example), you need to use more protein. The higher the load on the muscles, the more their body needs regeneration and, accordingly, protein food.

The role of specific proteins

It is necessary to maintain a constant balance of specific proteins in the body. They consist of hormones, various antibodies, enzymes and many other formations that are directly involved in the most important biochemical processes for normal life. The functions that these proteins perform are very subtle and complex. We must maintain their quantity and composition in the body at a constant level.

Protein is a complex biopolymer containing nitrogen. Its monomers are α-amino acids. Protein, depending on its type, consists of various amino acids. It is by the amino acid composition that the biological value of a protein is judged. Molecular weight of proteins: 6000-1000000 and more.

Amino acids in proteins

What are amino acids? These are organic compounds that consist of two functional groups:

carboxyl (-COOH-) - a group that determines the acidic properties of molecules;
amino group (-NH2-) - a group that gives the molecules basic properties.

There are a lot of natural amino acids. There are only 20 of them in food proteins.

There are a lot of natural amino acids. There are only 20 of them in food proteins:
alanine, arginine, asparagine, aspartic acid, valine, histidine, glycine (glycocol), glutamine, glutamic acid, isoleucine, leucine, lysine, methionine, proline, serine, tyrosine, threonine, tryptophan, phenylalanine, cystine.

Essential amino acids are 8 of the 20 listed above. These are valine, isoleucine, lysine, leucine, threonine, tryptophan, phenylalanine, methionine. They are called essential because they can only be obtained from food. These amino acids are not synthesized in our body. In children under one year old, histidine is also an essential amino acid.

If the body suffers from a deficiency of one of the essential amino acids or an imbalance in their composition, then failures begin in the body. Protein synthesis is disturbed and various pathologies can occur.

What are the types of proteins?

All proteins found in food are divided into simple and complex. Simple proteins are also called proteins, and complex proteins are also called proteids. They differ in that simple ones consist only of polypeptide chains, while complex ones, in addition to the protein molecule, also contain a prosthetic group - a non-protein part. If to speak plain language, then proteins are pure protein and proteins are not pure proteins.

Proteins are also divided according to their spatial structure into globular and fibrillar. The molecules of globular proteins have a spherical or ellipsoid shape, while the molecules of fibrillar proteins have a filamentous shape.

Simple globular proteins: albumins and globulins, glutelins and prolamins.

In milk, whey, egg white includes albumins and globulins. In turn, glutelins and prolamins are vegetable proteins contained in cereal seeds. They form the bulk of the gluten. Vegetable proteins are poor in lysine, leucine, methionine, threonine and tryptophan. But they are rich in glutamic acid.

The supporting function in the body is performed by structural proteins (protenoids). They are fibrillar proteins of animal origin. They are also resistant to digestion by digestive enzymes and generally do not dissolve in water. Protenoids include keratins (they contain a lot of cystine), collagen and elastin. The last two contain few sulfur-containing amino acids. In addition, collagen is rich in hydroxyproline and oxylysin, does not contain tryptophan.

Collagen becomes soluble in water and turns into gelatin (glutin) during a long boil. In the form of gelatin, it is used to prepare many culinary dishes.

Complex proteins include glyco-, lipo-, metallo-, nucleo-, chromo- and phosphoproteins.

Functions of proteins in the human body

Plastic function - provide the body with plastic material. Protein is construction material for cells, the main component of absolutely all enzymes and most hormones.
Catalytic function - act as accelerators of all biochemical processes.
Hormonal function - are integral part most hormones.
Specificity function - provides both individual and species specificity, which is the basis for the manifestation of both immunity and allergy.
Transport function - the protein is involved in the transport of oxygen, some vitamins, minerals, carbohydrates, lipids, hormones and other substances by the blood.

We can get protein only with food. The body does not have its reserve reserves. It is an essential component of the diet. But you should not get too carried away with protein foods, as this can lead to poisoning of the body and active reproduction.

Proteins and nitrogen balance

AT healthy body nitrogen balance is constantly maintained. The so-called state of nitrogen equilibrium. This means that the amount of nitrogen entering the body with food should be equal to the amount of nitrogen excreted from the body along with urine, feces, sweat, peeling of the skin, nails, hair.

There are concepts of positive nitrogen balance (the amount of nitrogen excreted is less than incoming) and negative nitrogen balance (the amount of nitrogen excreted is greater than incoming). A positive nitrogen balance, as a rule, is observed in children recovering from serious illnesses. This is due to their process of constant growth of children. In addition, there is such a balance.

If the processes of protein catabolism prevail over the processes of synthesis (starvation, vomiting, protein-free diet, anorexia), or if proteins are adsorbed in the digestive system, or the process of protein breakdown is observed due to serious diseases, then a negative nitrogen balance takes place.

Deficiency and excess of proteins

Proteins, getting into the body with food, are oxidized and supply the body with energy.

16.7 kJ of energy (4 kcal) is released during the oxidation of only 1 g of protein.

During fasting, the body's consumption of protein as a source of energy increases dramatically.

Proteins, getting along with food in the stomach, are broken down into amino acids. Further, these amino acids are absorbed by the intestinal mucosa and go straight to the liver. And from there, amino acids are sent to all other organs and connective tissues in order to synthesize the proteins of the human body.

Protein deficiency

If the food of the daily diet contains insufficient amounts of protein - its deficiency, then this will most likely lead to protein deficiency. Mild protein deficiency can occur when a balanced diet is disturbed, in a number of diseases that lead to impaired protein absorption, increased catabolism, and other disorders of protein and amino acid metabolism.

Too much protein

In addition to deficiency, there is also an overabundance of proteins in the body. In this case, the digestive and excretory systems undergo heavy loads, which leads to the formation of decay products in the digestive canal. And this causes intoxication and poisoning of the whole organism.

These are the functions of proteins in the body. Only one conclusion can be drawn. You need to have a proper balanced diet.

Proteins are the most important class organic matter, of which a person consists, constantly needs them.

The great importance of proteins for the body is due to their functions.

Plastic. Human tissues are built from proteins. On average, in the whole body, proteins occupy 45% of the mass of dry matter. The maximum content was found in the muscles. It reaches 34.7% total protein in the body. The content in bone tissue is 18.7% of the total concentration. The skin contains 11.5% of proteins. Other proteins are found in teeth, brain and nervous tissue, liver, spleen, heart, kidneys. The structural and plastic role of proteins in the body can be realized with a constant intake of quality products nutrition.

Energy. Oxidized in the human body, proteins supply energy in the amount of 4 kcal per 1 gram. This is a significant component in the overall energy balance.

catalytic. During life in the human body, hundreds of biochemical processes take place simultaneously. This is only possible through enzymatic acceleration. Simulation of similar reactions outside of living systems would require a lot of time, measured in hours, weeks. All enzymes are made from proteins. Without protein substances, the activity of biological catalysts is not feasible.

Regulatory. All processes in the human body are regulated by specific substances - hormones that are formed in the glands. internal secretion. Chemical nature hormones are different. Many hormones are proteins, such as insulin, some pituitary hormones. Insufficient intake of protein substances in the body can provoke changes in the hormonal background.

Transport. Carrier proteins deliver a variety of molecules throughout the body. For example, hemoglobin delivers oxygen to all organs, capturing it in surface layers lung tissue, freeing at the place of delivery.

Protective. Demonstrated by proteins such as interferon, globulins. Protection mechanisms are implemented differently. For example, immunoglobulins, being antibodies, bind foreign pathogens into inactive complexes. Interferon neutralizes the ability of viruses to reproduce. Proteins of biological catalysts - lysozymes, break down bacterial cells. The protective physiological role of protein makes possible life a person surrounded by disease-causing "neighbors".

Buffer. In human liquid systems, in particular, in the blood, for the normal functioning of the body, a constant acidity of the medium must be maintained. When it changes due to various factors buffer proteins can restore the constant composition. Hemoglobin has a particularly pronounced buffering capacity.

Receptor. Few people think about the work of the most complex system of information transmission in the human body. Required Members of this process are protein receptors. The receptor role of a protein in a cell is reduced to launching a chain of biochemical transformations, as a result of which we respond to signals. For example, in order for us to pull our hand away from a hot object, protein receptors must work. If their functioning is disturbed, the normal activity of the body becomes impossible. The retina of the eye also perceives color optical waves through the participation of a protein receptor called rhodopsin.

The presented main functions of proteins illustrate the importance of this class of substances in providing normal life person.

In the 19th century, scientists stated:

protein bodies are unique, are the essence of life;
a constant exchange of substances between living beings and the surrounding nature is necessary.

These provisions remain unchanged to this day.

Main composition of proteins

The huge molecular units of a simple protein, called a protein, are made up of chemically connected small blocks - amino acids with the same and different fragments. Such structural compositions are called heteropolymers. In natural proteins, only 20 representatives of the amino acid class are always found. The main composition of proteins is characterized by the obligatory presence of carbon - C, nitrogen - N, hydrogen - H, oxygen - O. Sulfur - S is often found. Complex proteins, called proteids, contain other substances in addition to amino acid residues. Accordingly, they may contain phosphorus - P, copper - Cu, iron - Fe, iodine - I, selenium - Se.

Aminocarboxylic acids of natural proteins are classified according to chemical structure and biological importance. Chemical classification important for chemists, biological - for everyone.

In the human body, there are constantly two streams of transformations:

splitting, oxidation, utilization of products received with food;
biological synthesis of new essential substances.

12 of the amino acids always found in natural proteins can be created by the biological synthesis of the human body. They are called interchangeable.

8 amino acids are never synthesized in humans. They are indispensable, must be supplied regularly with food.

On the basis of the presence of essential aminocarboxylic acids, proteins are divided into two classes.

Complete proteins have everything needed by the body human amino acids. The required set of essential amino acids contains the proteins of cottage cheese, dairy products, poultry, large meat cattle, marine and freshwater fish, eggs.

In defective proteins of one or more important acids may not be enough. These include vegetable proteins.

To assess the quality of food proteins, the medical world community compares them with an "ideal" protein that has strictly adjusted proportions of essential and essential essential amino acids. There is no "ideal" protein in nature. Animal squirrels are closest to it. Plant proteins often lack one or more amino acids to the standard concentration. If the missing substance is added, the protein will become complete.

The main sources of proteins of plant and animal origin

In the domestic scientific community, engaged in a comprehensive study of food chemistry, a group of Professor A.P. Nechaev, his colleagues, students stands out. The team carried out determinations of the protein content in the main food products available on the Russian market.

Important! The identified figures inform about the protein content in 100 g of the product, freed from the inedible part.

Protein content in plant foods

Most a large number of protein is found in soy, pumpkin seeds, peanuts (34.9 - 26.3 g).
Values from 20 to 30 g were found in peas, beans, pistachios, sunflower seeds.
Almonds, cashews, hazelnuts are characterized by numbers from 15 to 20 gr.
Walnuts, pasta, most cereals (except rice, corn grits) contain from 10 to 15 grams of protein per 100 grams of product.
In the range from 5 to 10 grams fall rice, corn grits, bread, garlic, dried apricots.
In 100 grams of cabbage, mushrooms, potatoes, prunes, some varieties of beets, the protein content is from 2 to 5 grams.
Raisins, radishes, carrots, sweet peppers have little protein, their rates do not exceed 2 grams.

If you could not find a plant object here, then the concentration of protein in it is too low or it is not there at all. For example, there is very little protein in fruit juices, in natural vegetable oils- not at all.

Protein content in animal products

The maximum protein concentration was found in fish roe, hard and processed cheeses, rabbit meat (from 21.1 to 28.9 g).
A large number of products contain from 15 to 10 grams of protein. This is a bird sea fish(except capelin), cattle meat, shrimp, squid, cottage cheese, cheese, freshwater fish.
capelin, egg, pork contain from 12.7 to 15 grams of protein per 100 grams of product.
Yogurt, curd cheese are characterized by the numbers 5 - 7.1 gr.
Milk, kefir, fermented baked milk, sour cream, cream contain from 2.8 to 3 grams of protein.

Of no interest is information about the main sources of proteins of plant and animal origin in products that have undergone multi-stage technological processing (stew, sausages, ham, sausages). They are not recommended for regular healthy eating. Short-term use of such products is not essential.

The role of protein in nutrition

As a result metabolic processes New protein molecules are constantly being formed in the body to replace the old ones. The rate of synthesis in different organs is not the same. Proteins of hormones, for example, insulin, are restored (resynthesized) very quickly, in hours, minutes. Proteins of the liver, intestinal mucosa are regenerated in 10 days. Protein molecules of the brain, muscles, connective tissue are restored the longest, restorative synthesis (resynthesis) can last up to six months.

The recycling and synthesis process is characterized by a nitrogen balance.

In a mature person, full health nitrogen balance zero. In this case, the total mass of nitrogen supplied with proteins in the process of nutrition is equal to the mass excreted with decay products.
Young organisms develop rapidly. The nitrogen balance is positive. A lot of protein comes in, less is excreted.
Aging, sick people have a negative nitrogen balance. The mass of nitrogen excreted with metabolic products is greater than that supplied by food intake.

The role of protein in nutrition is to provide a person with the required amount of amino acid components suitable for participating in the biochemical processes of the body.

To ensure a normal metabolism, it is important to know how much protein a person needs to consume per day.

Domestic and American physiologists recommend eating 0.8 - 1 g of protein per 1 kg of human weight. The numbers are very average. The amount strongly depends on the age, nature of work, lifestyle of a person. On average, it is recommended to consume from 60 grams to 100 grams of protein per day. For men involved in physical work, the rate can be increased to 120 grams per day. For people who have undergone surgical operations, infectious diseases, the norm also increases to 140 grams per day. Diabetics are recommended diets with high content protein products, which can reach 140g per day. People with metabolic disorders, a tendency to gout, should consume much less protein. The norm for them is 20 - 40 grams per day.

For people involved in active sports that build muscle mass, the norm increases significantly, it can reach 1.6-1.8 g per 1 kg of an athlete's weight.

Important! It is advisable for the trainer to clarify the answer to the question - how much protein should be consumed per day during exercise. Professionals have information about energy costs for all types of training, ways to maintain the normal functioning of the athlete's body.

For the implementation of all physiological functions It is important not only the presence of essential amino acids in the protein, but also the efficiency of their assimilation. Protein molecules have different levels of organization, solubility, and degree of accessibility to digestive enzymes. 96% of milk proteins, eggs are broken down efficiently. In meat, fish, 93-95% of proteins are safely digested. The exception is the proteins of the skin and hair. Vegetable protein-containing products are digested by 60-80%. In vegetables, 80% of proteins are digested, in potatoes - 70%, in bread - 62-86%.

Lack of protein in the body leads to significant changes in metabolism. Such pathologies are called dystrophy, kwashiorkor. For the first time, a violation was detected in the inhabitants of the wild tribes of Africa, it is characterized by a negative nitrogen balance, disruption of the intestines, muscle atrophy, growth arrest. A partial lack of protein may present with similar symptoms, which may be mild for a while. Especially dangerous is the lack of protein in the body of a child. Such dietary disorders can provoke the physical and intellectual inferiority of a growing person.

Excess protein in the body overloads the excretory system. The load on the kidneys increases. With existing pathologies in the renal tissue, the process can be aggravated. It is very bad if an excess of protein in the body is accompanied by a lack of other valuable food components. In ancient times, in the countries of Asia, there was a method of execution in which the condemned was fed only meat. As a result, the offender died from the formation of decay products in the intestines, followed by poisoning.

A reasonable approach to providing the body with protein guarantees efficient work all life systems.

Protein is one of the key nutrients that must be supplied to the human body every day. To understand the role of protein in human nutrition and life, it is necessary to give a concept of what these substances are.

Proteins (proteins) are organic macromolecules, which, in comparison with other substances, are giants in the world of molecules. Human proteins consist of segments of the same type (monomers), which are amino acids. There are many varieties of protein.

But, despite the different composition of protein molecules, they all consist of only 20 types of amino acids.

The importance of proteins is determined by the fact that it is with the help of proteins in the body that all life processes are carried out.

To produce your own proteins human body it is necessary that the protein that comes from outside (as part of food) is split into its constituent particles - monomers (amino acids). This process is carried out in the process of digestion in digestive system(stomach, intestines).

After the breakdown of the protein as a result of the action of the digestive enzymes of the stomach, pancreas, intestines on food, the monomers, from which their own protein is then built, must enter the bloodstream through the intestinal wall by absorption.

And only then, from the finished material (amino acids), in accordance with the program laid down in a certain gene, will the synthesis of one or another protein be produced, which in this moment time is needed by the body. All these complex processes, which are called protein biosynthesis, take place every second in the cells of the body.

For the synthesis of a complete protein in the food entering the body (animal or plant origin) all 20 amino acids must be present, especially 8, which are indispensable and can enter the human body only by eating protein foods.

Based on the foregoing, it becomes clear the important role good nutrition for normal protein synthesis.

Symptoms of protein deficiency in the body

The lack of protein of alimentary or other nature negatively affects human health (especially during periods of intensive growth, development, recovery after illness). The lack of proteins comes down to the fact that the processes of catabolism (the breakdown of one's own protein) begin to prevail over its synthesis.

All this leads to dystrophic (and in some cases atrophic) changes in organs and tissues, dysfunction hematopoietic organs, digestive, nervous and other systems of the macroorganism.

With protein starvation or a pronounced deficiency, the endocrine system also suffers, the synthesis of many hormones and enzymes. In addition to the obvious weight loss and loss of muscle mass, a number of common symptoms indicating a lack of protein.

A person begins to experience weakness, severe asthenia, shortness of breath on exertion, and palpitations. In a patient with a lack of protein, the absorption in the intestines of the main food nutrients, vitamins, calcium, iron and other substances is already disturbed for the second time, symptoms of anemia, and digestive disorders are observed.

Typical symptoms with a lack of proteins from the side skin are dry skin, mucous membranes, sluggish loose skin with reduced turgor. With a lack of protein intake, the function is impaired reproductive organs, violated menstrual cycle and the possibility of conception, bearing the fetus. Protein deficiency leads to sharp decline immunity due to both humoral and cellular components.

Functions of proteins in the human body:

Plastic function is one of the main roles of a protein, since most of human organs and tissues (in addition to water) consists of proteins and their derivatives (proteoglycans, lipoproteins). Protein molecules make up the so-called basis (backbone of tissues and cells) of the intercellular space and all cell organelles.

Hormonal regulation. Since most of the hormones produced by the endocrine system are protein derivatives, hormonal regulation of metabolic and other processes in the body is impossible without proteins. Hormones such as insulin (affects blood glucose levels), TSH and others are protein derivatives.
Thus, a violation of the formation of hormones leads to the appearance of multiple human endocrine pathology.

enzymatic function. Biological oxidation reactions and many others would proceed hundreds of thousands of times slower if it were not for enzymes and coenzymes, which are natural catalysts. Protein substances are natural catalysts that provide the necessary intensity and speed of reactions. In violation of the production of certain enzymes, it decreases, for example, digestive function pancreas.

Proteins are natural carriers (transporters of other macromolecules) of proteins, lipids, lipoproteins, carbohydrates, molecules that have a smaller composition (vitamins, metal ions, micro and macro elements, water, oxygen). If the synthesis of these proteins is disturbed, many diseases may occur. internal organs. Often these are hereditary diseases, for example, anemia, storage diseases.

The protective role of proteins consists in the production of specific immunoglobulin proteins that play one of the key roles in immune defense reactions. A decrease in immune defense contributes to frequent infectious diseases, their severe course.

A feature of protein metabolism in the human body is that, unlike fats and carbohydrates that can be stored in reserve, proteins cannot be stored for future use. With a lack of protein, the body's own protein can be consumed for the needs of the body (at the same time muscle mass decreases).

With starvation and a significant lack of protein, the supply of carbohydrates and fats is first consumed for energy needs. With the depletion of these reserves, protein is spent on energy needs.

Normal human need for protein

The human need for proteins varies greatly and averages 70-100 grams per day. Of this total animal protein should be at least 30-60 grams. The amount of protein that must be taken into the body depends on a large number constituent factors. The individual norm of protein intake depends on gender, functional state, age, motor activity, nature of work, climate.

The need for protein also depends on whether a person is healthy or sick.

At various diseases The amount of protein that should be consumed daily with food may vary. For example, high-protein nutrition is necessary for tuberculosis, convalescence after infectious diseases, debilitating processes, diseases accompanied by prolonged diarrhea. Diet with reduced level protein is prescribed for diseases of the kidneys with a sharply impaired function and pathology of nitrogen metabolism, liver.

In addition to the total protein content in daily diet it is necessary that the composition used protein products consisted of all the amino acids that make up the proteins of the body, including essential ones. This condition is satisfied mixed food, which includes both animal and vegetable proteins in the optimal combination.

According to the content of amino acids, all protein products are divided into complete and inferior. Proteins enter the human body in the form of proteins of both animal and vegetable origin. More complete in amino acid composition are meat, fish, dairy products. Vegetable protein is considered less complete for some amino acids. Nevertheless, for the optimal ratio and balance of amino acids, proteins of both animal and vegetable origin must be present in food.

What foods contain protein?

Most protein is found in meat products. The diet uses red meat (beef, pork, lamb and other varieties), poultry meat (chicken, duck, goose). These types of meat and products prepared on their basis differ in protein composition and animal fat content.

By-products (liver, heart, lungs, kidneys) are also suppliers of protein, but it must be remembered that these products contain a lot of fat and cholesterol.

Very useful in human nutrition is fish protein (sea, freshwater), as well as seafood. Fish should be present in the diet of a healthy person at least 2-3 times a week. Different types fish differ in protein content. For example, a low-protein fish like capelin contains about 12% protein, while tuna has about 20% protein. Seafood and fish are very useful, as they contain phosphorus, calcium, fat soluble vitamins, iodine.

Fish contains less connective tissue fibers, so it is better digested, suitable for diet food. Fish products compared with meat products that have undergone a similar heat treatment, are less high-calorie, although they create a feeling of satiety after their use.

Milk and dairy products are a valuable source of complete protein. Dairy products are of particular importance in the organization of nutrition for children. Dairy products differ in protein and fat content. Most protein in cottage cheese and cheese. Milk contains protein, but its content in this product inferior to cottage cheese, cheese.

Source of vegetable protein for a person are numerous cereals, cereals and products prepared on their basis. Bread, pasta and other products are essential components in the diet. There is a lot of vegetable protein in cereals, but it is less complete in terms of amino acid composition, so a variety of cereal products should be used in the diet, since each of them contains a slightly different set of amino acids.

Vegetable protein must be present in the daily diet. A significant protein content is achieved in legumes. In addition, another property is important: legumes contain a lot of dietary fiber, vitamins, and little fat.

Plant seeds (sunflower seed), soy, different kinds nuts (hazelnuts, walnuts, pistachios, peanuts and others) are very useful protein foods. In addition to the high content of valuable protein, these products contain a significant amount of vegetable fat, which does not contain cholesterol. The use of nuts and seeds allows you to enrich the diet not only valuable proteins, but also polyunsaturated fatty acids which are biological cholesterol antagonists.

Vegetables and fruits practically do not contain protein, but they have the whole set of vitamins that take part in many metabolic processes, including digestion and protein synthesis reactions.

Thus, the diet of a healthy and sick person should be balanced for all food nutrients, including protein. A varied diet can provide all the essential amino acids. The amount of incoming protein in a healthy and sick person in case of diseases should be strictly regulated by a doctor.

Proteins, like vitamins and others useful material, is an integral part of the healthy functioning of our body

Most of our illnesses are associated with malnutrition especially with high protein intake. Experts never tire of repeating what our body needs balanced diet. The exclusion of some product from our diet can also lead to trace elements, which in turn leads to disruption of the body.

Most often, people underestimate the role of proper nutrition in the functioning of our body. According to a sociological survey, it became known that 50% (of those surveyed) do nothing to maintain their health.

Proteins play an important role in the formation of tissues (organs, muscles, etc.), they are needed in the synthesis of hormones, and are also necessary for the formation of enzymes. Transfer of necessary information from one cell to another nervous system also associated with proteins. Proteins help in the process of blood coagulation, DNA represents protein molecules, and proteins are also involved in the energy processes of the body (4 kcal of energy is obtained from 1 g of protein).

From this we can conclude that proteins are involved (directly or indirectly) in most of the processes that take place in our body. If there is a lack of proteins in the body, then all of the above processes will suffer.

The process of protein digestion happens at different speeds. Proteins obtained by the body from fish meat or dairy products are digested most quickly, followed by proteins obtained from meat products. Vegetable proteins are digested more slowly.

What proteins should be preferred? Nutritionists say that in order to maintain the normal functioning of the body, the menu must include 30% vegetable proteins and 70% animal proteins. These data should only be changed if you have any pathology: for example, when renal pathology preference should be given to proteins of plant origin.

The surrounding climate also plays an important role in the required amount of proteins. So, for example, vegetarians from Asia are quite healthy with daily use 30-40g of proteins, while the Eskimos consume 200-300g of proteins.

In my own way chemical composition proteins can be divided into complete and incomplete. To determine the usefulness of proteins, the presence of essential amino acids is considered, since it can synthesize all the rest itself. Complete proteins in their composition have all the essential amino acids in the amount that the body needs.

Animal proteins have full set essential amino acids (meat, fish, eggs and milk).

Proteins of vegetable origin are considered incomplete, with the exception of legumes. Beans contain the same amount of protein as animal products.

For the full functioning of the body proteins of animal origin are necessary, as they are absorbed by 94-97%. However, this does not mean that you should not include vegetable proteins in your menu. For the full growth and development of the body, a balance between animal and vegetable proteins is necessary.

Properties squirrel depend both on its composition and on the arrangement of amino acids in the molecule. Moreover, the order of amino acids in a protein molecule plays a very important role in the performance of their functions.

Amino acids, synthesized in our body, are called interchangeable. Some amino acids are not formed in the human body - these are essential amino acids. Proteins containing the entire set of essential amino acids are biologically complete. They are found in animal food, and in some food plants - soybeans, peas, beans.

If accept value of milk proteins(it contains all the essential amino acids) for 100, then the biological value of meat and fish can be expressed by the number 95, potatoes - 85, rye bread- 75, rice - 58, peas - 55, wheat - 50.

Everything must come with food. essential amino acids, a deficiency of at least one of them can lead to the death of the body, since each of the essential amino acids affects certain of its functions.

The importance of proteinin not only in digestion, but in all human life. Enzymes are built from proteins - biological catalysts that speed up chemical reactions flowing in the body.

And the fact that meat food makes people irritable and cruel, by analogy with predatory animals, also does not stand up to criticism. After all, as the advocates of vegetarianism argue: "Herbivorous animals are distinguished by a complaisant disposition, even nature has not deprived them of strength and power. Take for example an elephant - it is powerful and kind, and ferocity and bloodthirstiness are inherent in lions." Although the zoological arguments, and we have already understood this, are rather contradictory, it is not difficult to see that in these primitive arguments the causes are replaced by consequences: it is not meat food that makes predators predatory, but people of a certain type aggressive and socially dangerous. According to these arguments, it turns out that if a lion is fed with carrots, he will become quiet, like a rabbit, and the rabbit will become brutalized from meat. But for some reason it seems to me that both of them will die before they have time to get used to food unusual for them.

An uncompromising vegetarian, in order to get 50-70 g of fat, must eat 4-5 kg of plant products daily, and at least 70% of them must be oilseeds. Thus, partial and even more complete rejection of animal products today can also be considered as a kind of tribute to "fashionable" diets.

What protein is involved in formation of muscle tissue, as if it goes without saying, but not everyone knows that he is also involved in skeletal construction.

This is due to the fact that protein foods help the absorption of calcium, while a decrease in the level of protein in food impairs the absorption of this element of the intestinal mucosa. But more than 90% of calcium is concentrated in human bones: it is this element that gives strength to the skeleton. However, these functions of calcium in the body are not exhausted; it increases the excitability of the neuromuscular apparatus, promotes blood clotting, reduces the permeability of the walls blood vessels. Calcium is involved in the work of the heart muscle, contributes to the implementation therapeutic effect cardiac glycosides, stimulates liver function, activates the enzyme lipase. Therefore, protein foods enriched with calcium, especially milk and dairy products, are biologically more complete than foods of purely plant origin with low content calcium.

Calcium deficiency in the body, provoked by the rejection of animal proteins, leads to a violation of a number of physiological functions, in particular, mental and physical performance, in children, bone formation is inhibited, and in adults, bones are resorbed.

The following historical example is very indicative in this respect.

In 1857, 8 years old, Vanya Pavlov, future laureate Nobel Prize, fell from a high platform and became seriously ill after that. Maybe the boy would not have survived if he had not taken him to himself. Godfather- Abbot of the suburban Trinity Monastery. The old man knew the healing power protein nutrition and so he fed his godson with eggs, milk, and boiled chickens. In the mornings he did gymnastics with him, in the summer he made him swim, ride, play gorodki, and in the winter - shovel snow and skate. The boy always and willingly helped the hegumen to take care of the garden and garden. The abbot himself was distinguished by enviable health, which he confidently considered the result of a healthy diet. Later, Ivan Petrovich Pavlov wrote that indifference to food is imprudence, and he said more than once that it was thanks to proper nutrition retained high performance, endurance and clarity of thought until his full 86 years.

A completely opposite metamorphosis occurred with another representative of the Russian intelligentsia, who decided at an advanced age to become a vegetarian. Unlike little Vanya, who was ill in childhood, little Levushka was an extremely healthy boy, and even in his mature years, fighting near Sevastopol, Lev Nikolaevich did not complain about his health. Having retired and, according to the definition of V. I. Ulyanov-Lenin, becoming a "hardened human being", Tolstoy amazed those around him physical health, carrying water, cycling and skating at almost 80 years old. True, worldwide famous writer he stopped eating meat only in his old age after the scene he saw at the Tula slaughterhouse, when they began to rip off the skin from the fallen bull, and life still beat in the huge body of the animal and large tears rolled from blood-filled eyes. Back in Yasnaya Polyana, Lev Nikolaevich, for reasons of exclusively moral order, completely refused meat and literally immediately his appearance begins to change. Here is what his wife Sofya Andreevna writes 7 years before the writer’s death: “It is so painful for me to see him suffering, weak, fading and oppressed in spirit and body. Take his head in both hands or kiss his emaciated hands with gentle caress, and he will look indifferently. Something is going on in him, what does he think?" The change that took place with L. N. Tolstoy after the transition from his usual mixed food to vegetable food is completely understandable and quite explainable.

Dietary protein deficiency had a negative impact on his life. First of all, the nitrogen balance was disturbed, and protein breakdown began to prevail over its synthesis. Experiencing a lack of protein, the body began to "eat" own tissues. It is not surprising that seven years later the final clouding of reason led Tolstoy to death.

protein deficiency in nutrition reduces the body's resistance to infections, as the level of antibody formation decreases. The synthesis of other protective factors, lysozyme and interferon, is also disrupted, which aggravates the course inflammatory processes. Reducing the intake of protein from food, or increasing its consumption in the body (with severe physical work or as a result of disease) causes protein deficiency. A severe form of protein deficiency is called kwashiorkor. This disease is more common in children. In Russia, kwashiorkor is not observed, but the disease is often found in developing countries in Asia, Africa, Central and South America.

Uncompensated squirrel in the body adversely affects the activity cardiovascular, respiratory and other systems. Lack of protein impairs appetite, which in turn reduces the influx of protein from food - a vicious cycle occurs.

In order to prevent this from happening, it is necessary to constantly introduce physiologically into the body required amount protein with food.