Why are proteins, fats and carbohydrates needed? What are carbohydrates, the role of carbohydrates in the human body

Chemical properties cells that make up living organisms depend primarily on the number of carbon atoms, constituting up to 50% of the dry mass. Carbon atoms are in the main organic matter ah: squirrels, nucleic acids ah, lipids and carbohydrates. TO last group include compounds of carbon and water corresponding to the formula (CH 2 O) n, where n is equal to or greater than three. In addition to carbon, hydrogen and oxygen, the molecules may contain atoms of phosphorus, nitrogen, and sulfur. In this article we will study the role of carbohydrates in the human body, as well as the features of their structure, properties and functions.

Classification

This group of compounds in biochemistry is divided into three classes: simple sugars (monosaccharides), polymer compounds with a glycosidic bond - oligosaccharides, and biopolymers with high molecular weight - polysaccharides. Substances of the above classes are found in various types of cells. For example, starch and glucose are found in plant structures, glycogen is found in human hepatocytes and fungal cell walls, and chitin is found in the exoskeleton of arthropods. All of the above substances are carbohydrates. The role of carbohydrates in the body is universal. They are the main supplier of energy for the vital manifestations of bacteria, animals and humans.

Monosaccharides

Have general formula C n H 2 n O n and are divided into groups depending on the number of carbon atoms in the molecule: trioses, tetroses, pentoses and so on. In the composition of cellular organelles and the cytoplasm, simple sugars have two spatial configurations: cyclic and linear. In the first case, carbon atoms are connected to each other by covalent sigma bonds and form closed cycles; in the second case, the carbon skeleton is not closed and may have branches. To determine the role of carbohydrates in the body, let's consider the most common of them - pentoses and hexoses.

Isomers: glucose and fructose

They have the same molecular formula C 6 H 12 O 6, but different structural types of molecules. Previously, we already mentioned the main role of carbohydrates in a living organism - energy. The above substances are broken down by the cell. As a result, energy is released (17.6 kJ from one gram of glucose). In addition, 36 ATP molecules are synthesized. The breakdown of glucose occurs on the membranes (cristae) of mitochondria and is a chain of enzymatic reactions - the Krebs Cycle. It is the most important link in dissimilation that occurs in all cells of heterotrophic eukaryotic organisms without exception.

Glucose is also formed in mammalian myocytes due to breakdown in muscle tissue glycogen reserve. In the future, it is used as an easily disintegrating substance, since providing cells with energy is the main role of carbohydrates in the body. Plants are phototrophs and produce their own glucose during photosynthesis. These reactions are called the Calvin cycle. The starting material is carbon dioxide, and the acceptor is ribolose diphosphate. Glucose synthesis occurs in the chloroplast matrix. Fructose, having the same molecular formula as glucose, contains a ketone functional group in the molecule. It is sweeter than glucose and is found in honey, as well as the juice of berries and fruits. Thus, biological role carbohydrates in the body is primarily to use them as a quick source of energy.

The role of pentoses in heredity

Let us dwell on another group of monosaccharides - ribose and deoxyribose. Their uniqueness lies in the fact that they are part of polymers - nucleic acids. For all organisms, including non-cellular life forms, DNA and RNA are the main carriers of hereditary information. Ribose is found in RNA molecules, and deoxyribose is found in DNA nucleotides. Consequently, the biological role of carbohydrates in the human body is that they participate in the formation of units of heredity - genes and chromosomes.

Examples of pentoses containing aldehyde group and common in flora, are xylose (found in stems and seeds), alpha-arabinose (found in the gum of stone fruit trees). Thus, the distribution and biological role of carbohydrates in the body of higher plants is quite large.

What are oligosaccharides

If the remnants of monosaccharide molecules, such as glucose or fructose, are linked by covalent bonds, then oligosaccharides are formed - polymer carbohydrates. The role of carbohydrates in the body of both plants and animals is diverse. This is especially true for disaccharides. The most common among them are sucrose, lactose, maltose and trehalose. Thus, sucrose, otherwise called cane sugar, is found in plants in the form of a solution and is stored in their roots or stems. As a result of hydrolysis, molecules of glucose and fructose are formed. is of animal origin. Some people experience intolerance to this substance, associated with hyposecretion of the enzyme lactase, which breaks down milk sugar for galactose and glucose. The role of carbohydrates in the life of the body is varied. For example, the disaccharide trehalose, consisting of two glucose residues, is part of the hemolymph of crustaceans, spiders, and insects. It is also found in the cells of fungi and some algae.

Another disaccharide, maltose, or malt sugar, is found in grains of rye or barley during germination and is a molecule consisting of two glucose residues. It is formed as a result of the breakdown of plant or animal starch. IN small intestine In humans and mammals, maltose is broken down by the enzyme maltase. In its absence in pancreatic juice, a pathology occurs due to intolerance to glycogen or plant starch in foods. In this case use special diet and add the enzyme itself to the diet.

Complex carbohydrates in nature

They are very widespread, especially in the plant world, are biopolymers and have a large molecular weight. For example, in starch it is 800,000, and in cellulose - 1,600,000. Polysaccharides differ in the composition of monomers, the degree of polymerization, and the length of the chains. Unlike simple sugars and oligosaccharides, which are highly soluble in water and have a sweetish taste; polysaccharides are hydrophobic and tasteless. Let's consider the role of carbohydrates in the human body using the example of glycogen - animal starch. It is synthesized from glucose and is stored in hepatocytes and cells skeletal muscles, where its content is twice as high as in the liver. Subcutaneous fatty tissue, neurocytes and macrophages are also capable of producing glycogen. Another polysaccharide, plant starch, is a product of photosynthesis and is formed in green plastids.

From the very beginning of human civilization, the main suppliers of starch were valuable agricultural crops: rice, potatoes, corn. They are still the basis of the diet of the vast majority of the world's inhabitants. This is why carbohydrates are so valuable. The role of carbohydrates in the body is, as we see, in their use as energy-intensive and quickly digestible organic substances.

There is a group of polysaccharides whose monomers are residues hyaluronic acid. They are called pectins and are structural substances of plant cells. Apple peels and beet pulp are especially rich in them. Cellular substances pectins regulate intracellular pressure - turgor. In the confectionery industry, they are used as gelling agents and thickeners in the production of high-quality marshmallows and marmalades. IN dietary nutrition used biologically active substances, well removes toxins from the large intestine.

What are glycolipids

This interesting group complex compounds of carbohydrates and fats found in nervous tissue. It consists of the head and spinal cord mammals. Glycolipids are also found in cell membranes. For example, in bacteria they are involved in some of these compounds are antigens (substances that detect blood groups of the Landsteiner AB0 system). In the cells of animals, plants and humans, in addition to glycolipids, there are also independent fat molecules. They perform primarily an energy function. When one gram of fat is broken down, 38.9 kJ of energy is released. Lipids are also characterized by a structural function (they are part of cell membranes). Thus, these functions are performed by carbohydrates and fats. Their role in the body is extremely important.

The role of carbohydrates and lipids in the body

In human and animal cells, mutual transformations of polysaccharides and fats occurring as a result of metabolism can be observed. Nutritionists have found that excessive consumption of starchy foods leads to fat accumulation. If a person has problems with the pancreas in terms of amylase secretion or has sedentary lifestyle life, his weight may increase significantly. It's worth remembering that rich in carbohydrates food is broken down mainly into duodenum to glucose. It is absorbed by the capillaries of the villi of the small intestine and deposited in the liver and muscles in the form of glycogen. The more intense the metabolism in the body, the more actively it breaks down into glucose. It is then used by cells as the main energy material. This information serves as an answer to the question of what role carbohydrates play in the human body.

The importance of glycoproteins

Compounds of this group of substances are represented by a carbohydrate + protein complex. They are also called glycoconjugates. These are antibodies, hormones, membrane structures. The newest biochemical research it has been established: if glycoproteins begin to change their native (natural) structure, this leads to the development of such the most complex diseases like asthma rheumatoid arthritis, cancer. The role of glycoconjugates in cell metabolism is great. Thus, interferons suppress the reproduction of viruses, immunoglobulins protect the body from pathogenic agents. Blood proteins also belong to this group of substances. They provide protective and buffering properties. All of the above functions confirm the fact that physiological role carbohydrates in the body are varied and extremely important.

Where and how are carbohydrates formed?

Major suppliers of simple and complex sugars- these are green plants: algae, higher spores, gymnosperms and flowering plants. All of them contain the pigment chlorophyll in their cells. It is part of the thylakoids - the structures of chloroplasts. Russian scientist K. A Timiryazev studied the process of photosynthesis, which results in the formation of carbohydrates. The role of carbohydrates in the plant body is the accumulation of starch in fruits, seeds and bulbs, that is, in vegetative organs. The mechanism of photosynthesis is quite complex and consists of a series of enzymatic reactions that occur both in light and in darkness. Glucose is synthesized from carbon dioxide under the action of enzymes. Heterotrophic organisms use green plants as a source of food and energy. Thus, it is plants that are the first link in everything and are called producers.

In the cells of heterotrophic organisms, carbohydrates are synthesized on the channels of the smooth (agranular) endoplasmic reticulum. They are then used as energy and construction material. In plant cells, carbohydrates are additionally formed in the Golgi complex, and then go to form the cellulose cell wall. During the digestion of vertebrates, compounds rich in carbohydrates are partially broken down into oral cavity and stomach. The main dissimilation reactions occur in the duodenum. It secretes pancreatic juice containing the enzyme amylase, which breaks down starch into glucose. As mentioned earlier, glucose is absorbed into the blood in the small intestine and distributed to all cells. Here it is used as a source of energy and a structural substance. This explains the role carbohydrates play in the body.

Supramembrane complexes of heterotrophic cells

They are characteristic of animals and fungi. Chemical composition and the molecular organization of these structures are represented by compounds such as lipids, proteins and carbohydrates. The role of carbohydrates in the body is to participate in the construction of membranes. In human and animal cells there is a special structural component, called the glycocalyx. This thin surface layer consists of glycolipids and glycoproteins associated with the cytoplasmic membrane. It provides direct communication between cells and external environment. The perception of irritations and extracellular digestion also occur here. Thanks to their carbohydrate shell, cells stick together to form tissue. This phenomenon is called adhesion. Let us also add that the “tails” of carbohydrate molecules are located above the surface of the cell and directed into the interstitial fluid.

Another group of heterotrophic organisms, fungi, also have a surface apparatus called a cell wall. It includes complex sugars - chitin, glycogen. Some types of mushrooms also contain soluble carbohydrates such as trehalose, called mushroom sugar.

In unicellular animals, such as ciliates, the surface layer, the pellicle, also contains complexes of oligosaccharides with proteins and lipids. In some protozoa, the pellicle is quite thin and does not interfere with the change in body shape. And in others it thickens and becomes strong, like a shell, performing a protective function.

Plant cell wall

It also contains large amounts of carbohydrates, especially cellulose, collected in the form of fiber bundles. These structures form a framework embedded in a colloidal matrix. It consists mainly of oligo- and polysaccharides. Cell walls plant cells may become lignified. In this case, the spaces between the cellulose bundles are filled with another carbohydrate - lignin. It enhances the supporting functions of the cell membrane. Often, especially in perennial woody plants, the outer layer, consisting of cellulose, is covered with a fat-like substance - suberin. It prevents water from entering plant tissues, so underlying cells quickly die and become covered with a layer of cork.

Summarizing the above, we see that carbohydrates and fats are closely interrelated in the plant cell wall. Their role in the body of phototrophs is difficult to underestimate, since glycolipid complexes provide support and protective functions. Let's study the variety of carbohydrates characteristic of organisms of the kingdom of Drobyanka. This includes prokaryotes, in particular bacteria. Their cell wall contains a carbohydrate - murein. Depending on the structure of the surface apparatus, bacteria are divided into gram-positive and gram-negative.

The structure of the second group is more complex. These bacteria have two layers: plastic and rigid. The first contains mucopolysaccharides, such as murein. Its molecules look like large mesh structures that form a capsule around the bacterial cell. The second layer consists of peptidoglycan, a compound of polysaccharides and proteins.

Cell wall lipopolysaccharides allow bacteria to firmly attach to various substrates, such as tooth enamel or the membrane of eukaryotic cells. In addition, glycolipids promote adhesion bacterial cells between themselves. In this way, for example, chains of streptococci and clusters of staphylococci are formed; moreover, some types of prokaryotes have an additional mucous membrane - peplos. It contains polysaccharides and is easily destroyed under the influence of hard radiation or upon contact with certain chemicals, for example antibiotics.

Monosaccharides(simple sugars) consist of one molecule containing from 3 to 6 carbon atoms. Disaccharides- compounds formed from two monosaccharides. Polysaccharides are high-molecular substances consisting of a large number (from several tens to several tens of thousands) of monosaccharides.

A variety of carbohydrates are found in large quantities in organisms. Their main functions:

1. Energy: carbohydrates are the main source of energy for the body. Among the monosaccharides, these are fructose, which is widely found in plants (primarily in fruits), and especially glucose (the breakdown of one gram of it releases 17.6 kJ of energy). Glucose is found in fruits and other parts of plants, in the blood, lymph, and animal tissues. Of the disaccharides, it is necessary to distinguish sucrose (cane or beet sugar), consisting of glucose and fructose, and lactose (milk sugar), formed by a compound of glucose and galactose. Sucrose is found in plants (mainly fruits), and lactose is found in milk. They play a vital role in the nutrition of animals and humans. Great importance in energy processes have polysaccharides such as starch and glycogen, the monomer of which is glucose. They are reserve substances of plants and animals, respectively. If present in the body large quantity glucose it is used for the synthesis of these substances, which accumulate in the cells of tissues and organs. Thus, starch is found in large quantities in fruits, seeds, and potato tubers; glycogen - in the liver, muscles. As needed, these substances are broken down, supplying glucose to various organs and body tissues.
2. Structural: for example, monosaccharides such as deoxyribose and ribose are involved in the formation of nucleotides. Various carbohydrates are part of cell walls (cellulose in plants, chitin in fungi).

Lipids (fats)- organic substances that are insoluble in water (hydrophobic), but readily soluble in organic solvents (chloroform, gasoline, etc.). Their molecule consists of glycerol and fatty acids. The diversity of the latter determines the diversity of lipids. Phospholipids (containing, in addition to fatty acids, a phosphoric acid residue) and glycolipids (compounds of lipids and saccharides) are widely found in cell membranes.

The functions of lipids are structural, energetic and protective.

The structural basis of the cell membrane is a bimolecular (formed from two layers of molecules) layer of lipids, into which molecules of various proteins are embedded.

When 1 g of fat is broken down, 38.9 kJ of energy is released, which is approximately twice as much as when 1 g of carbohydrates or proteins are broken down. Fats can accumulate in the cells of various tissues and organs (liver, subcutaneous tissue in animals, seeds in plants), in large quantities forming a significant supply of “fuel” in the body.

Possessing poor thermal conductivity, fats play important role in protection against hypothermia (for example, layers subcutaneous fat in whales and pinnipeds).

ATP (adenosine triphosphate). It serves as a universal energy carrier in cells. The energy released during the breakdown of organic substances (fats, carbohydrates, proteins, etc.) cannot be used directly to perform any work, but is initially stored in the form of ATP.

Adenosine triphosphate consists of the nitrogenous base adenine, ribose and three molecules (or rather, residues) of phosphoric acid (Fig. 1).

Rice. 1. Composition of the ATP molecule

When one phosphoric acid residue is eliminated, ADP (adenosine diphosphate) is formed and about 30 kJ of energy is released, which is spent on performing some work in the cell (for example, contraction of a muscle cell, processes of synthesis of organic substances, etc.):

Since the supply of ATP in the cell is limited, it is constantly restored due to the energy released during the breakdown of other organic substances; ATP reduction occurs by adding a phosphoric acid molecule to ADP:

Thus, two main stages can be distinguished in the biological transformation of energy:

1) ATP synthesis - energy storage in the cell;

2) release of stored energy (in the process of ATP breakdown) to perform work in the cell.

Glucose, fructose, glycogen and starch are important for humans. Starch and, to a small extent, fructose and glucose are found in plants; they are an essential component of nutrition and enter the body with potatoes, flour and sugar. Glycogen, deposited primarily in the liver and muscles, is the main source of glucose in animals.

Glucose is the main thing nutrient for all cells of the body. The level of glucose in the blood is regulated by several hormones. If, due to the consumption of carbohydrates (in the form of food), the level of glucose in the blood increases, the release (secretion) of insulin by the pancreas (pancreas) increases. This speeds up the flow of glucose into the cell, where it is “burnt”, breaking down into carbon dioxide and water. This produces energy in the form of adenosine triphosphate (ATP). With incomplete “combustion”, glucose molecules can supply building material for other substances, needed by the body. The breakdown of glycogen into glucose is facilitated by catecholamines (adrenaline and norepinephrine), the release of which is associated mainly with muscular work and mental stress. The breakdown of glycogen and the release of glucose is also caused by the hormone glucagon (an insulin antagonist), which is used when blood sugar levels drop, for example, during fasting or intense physical activity.

Fat metabolism

The fat in the fat cells of both lean and obese people has the same composition. Fat is a compound of fatty acids and glycerol (triacylglycerol), 5-10% of which is phospholipids. A fat cell contains 65-70% fat, the rest is water with a small content of proteins, sugar and salts. Fat is formed in fat cells in two ways. First of all, it is formed in the liver from carbohydrates obtained from food or other routes. Fat is insoluble in water and is transported in the blood by special proteins - lipoproteins. On the surface of fat cells, triacylglycerols are released from lipoprotein molecules and are captured by fat cells, where they are deposited after slight conversion in the form of fat droplets.

The synthesis and deposition of fat in fat cells is promoted mainly by the hormone insulin and also partly by female estrogen. Insulin therefore not only helps metabolize glucose, but also affects fat synthesis.

The breakdown of stored fats in adipose tissue is caused by a number of hormones, the most important of which are catecholamines (adrenaline and norepinephrine) - formed in the adrenal glands as a result of muscular work or mental stress. Triacylglycerols are also broken down by growth hormone produced in the pituitary gland during fasting. Released unsaturated fatty acid leave the fat cell and bind in the blood to the protein albumin, which delivers them to the liver and muscles, where fatty acids can be decomposed like glucose into water and. Due to the energy released during this process, adenosine triphosphate (ATP) is synthesized, which transfers it to cells for a wide variety of processes, including working muscles.

Protein metabolism

Proteins (proteins) form the basis of living matter. The building blocks of proteins are amino acids. Dietary proteins in digestive tract are broken down into amino acids. From these cells form proteins again, necessary for the body. Protein synthesis (which is indirectly affected by insulin) is controlled by complex mechanism, violations of which - main reason hereditary diseases.

Protein metabolism occurs continuously in the body, but they serve as a source of energy only in emergency circumstances, for example, when the energy balance is disturbed, which various reasons cannot be leveled either by food intake or by using one’s own glycogen and fat reserves. In such a crisis situation, energy from amino acids (that is, proteins) begins to be released under the influence of the hormone cortisone, produced in the adrenal cortex. This is the so-called stress reaction. It is caused by a variety of unfavorable factors: injury, hunger, burns, forced inaction, overly hard work, as well as fear, anger, etc.

When burning 1 g of fat, the body receives approximately 37.6 kJ (9 kcal), while 1 g of protein or carbohydrates provides only 16.7 kJ (4 kcal).

When fats enter the intestines, the process of their breakdown into glycerol and fatty acids begins. These substances then penetrate the intestinal wall and are converted back into fats, which are absorbed into the blood. It transports fats to tissues, where they are used as energy and building materials.

Lipids are part of cellular structures, so they are necessary for the formation of new cells. Excess fat is stored as adipose tissue reserves. It should be noted that the normal amount of fat in an athlete is on average 10-12% of body weight. During the oxidation process, 9.3 kcal of energy is released from 1 g of fat.

The calorie content of food is determined by the presence of fats and carbohydrates in foods. In the body, fats are formed from fats, proteins and carbohydrates that come from food.

Fats play an important role in regulating metabolism and contributing to the normal functioning of the body. It should be noted that vegetable oils should make up at least 1/3 of the athlete’s diet.

A lack of fat in the diet leads to skin diseases, vitamin deficiencies and other diseases.

Carbohydrates

In dietetics, carbohydrates are divided into simple (sugar) and complex, which are more important from the point of view of rational nutrition. Simple carbohydrates are called monosaccharides (fructose and glucose). Monosaccharides quickly dissolve in water, which facilitates their passage from the intestines into the blood. Complex carbohydrates are made up of several monosaccharide molecules and are called polysaccharides. Polysaccharides include all types of sugars: milk, beet, malt and others, as well as fiber, starch and glycogen. Glycogen is an essential element for the development of endurance in athletes; it is a polysaccharide and is produced in the body by animals. It is stored in the liver and muscle tissue; meat contains almost no glycogen, since it disintegrates after the death of living organisms. The body absorbs carbohydrates in sufficient time a short time. Glucose, entering the blood, immediately becomes a source of energy perceived by all tissues of the body. Glucose is necessary for the normal functioning of the brain and nervous system.

Some carbohydrates are contained in the body in the form of glycogen, which in large quantities can be converted into fat. To avoid this, you should calculate the calorie content of food consumed and maintain a balance of calories consumed and calories received.

Rye and wheat bread, crackers, cereals (wheat, buckwheat, pearl barley, semolina, oatmeal, barley, corn, rice), bran and honey.

Minerals

These substances are part of tissues and participate in their normal functioning, maintain the necessary osmotic pressure in biological fluids and the constancy of the acid-base balance in the body.

Let's look at the main minerals.

Potassium is part of the cells, and sodium is contained in the intercellular fluid. For normal functioning of the body, a strictly defined ratio of sodium and potassium is necessary. It ensures normal excitability of muscle and nerve tissue. Sodium is involved in maintaining constant osmotic pressure, and potassium affects the contractile function of the heart.

Both excess and deficiency of potassium in the body can lead to disturbances in the functioning of the cardiovascular system.

Potassium is present in varying concentrations in all body fluids and helps maintain water-salt balance.

Rich natural sources of potassium include bananas, apricots, avocados, potatoes, dairy products, and citrus fruits.

Calcium is part of the bones. Its ions are involved in the normal activity of skeletal muscles and the brain. The presence of calcium in the body promotes blood clotting. Excessive amounts of calcium increase the frequency of contractions of the heart muscle, and in very high concentrations can cause cardiac arrest. The best source of calcium is dairy products; broccoli and salmon fish are also rich in calcium.

Phosphorus part of cells and intercellular tissues. It is involved in the metabolism of fats, proteins, carbohydrates and vitamins. Phosphorus salts play an important role in maintaining the acid-base balance of the blood, strengthening muscles, bones and teeth. Legumes, almonds, poultry and especially fish are rich in phosphorus.

Chlorine is part of the hydrochloric acid of gastric juice and is found in the body in combination with sodium. Chlorine is essential for the functioning of all cells in the body.

Iron is integral part some enzymes and hemoglobin. It participates in the distribution of oxygen and promotes oxidative processes. A sufficient amount of iron in the body prevents the development of anemia, decreased immunity, and deterioration of brain function. Natural source iron are green apples, fatty fish, apricots, peas, lentils, figs, seafood, meat, poultry.

Bromine found in blood and other fluids of the body. It enhances inhibition processes in the cerebral cortex and thereby promotes a normal relationship between inhibitory and excitatory processes.

Iodine is part of the hormones produced by the thyroid gland. Lack of iodine can cause disruption of many body functions. Sources of iodine are iodized salt, sea ​​fish, seaweed and other seafood.

Sulfur is part of proteins. It is contained in hormones, enzymes, vitamins and other compounds that participate in metabolic processes. Sulfuric acid neutralizes harmful substances in the liver. Sufficient presence of sulfur in the body lowers cholesterol levels and prevents the development of tumor cells. Onions, green tea, pomegranates, apples are rich in sulfur. different kinds berries

Zinc, magnesium, aluminum, cobalt and manganese are important for the normal functioning of the body. They are present in cells in small quantities, which is why they are called microelements.

Magnesium– a metal involved in biochemical reactions. It is necessary for muscle contraction and enzyme function. This trace element strengthens bone tissue, regulates heart rhythm. Sources of magnesium include avocados, brown rice, wheat germ, sunflower seeds, and amaranth.

Manganese– a microelement necessary for the formation of bone and connective tissues, the work of enzymes involved in carbohydrate metabolism. Pineapples, blackberries, and raspberries are rich in manganese.

We will consider proteins, fats, carbohydrates and all other nutrients from the point of view of human nutrition, leading active image life, i.e. exercising regularly. We would like to convey something new to you, rather than list already well-known truths. But we cannot omit some basic things because it will not be clear what comes from where. And we begin our story about protein - the most controversial and underrated nutrient.

Protein

From school we know the phrase that “life is the way of existence of protein bodies.” Those. You and I are those same protein bodies. Our hair, nails, skin, internal organs and muscles are all made of protein. Thus, protein is the main building material of our body. Unlike fats and carbohydrates, it is not formed from other substances and does not accumulate in the body. But protein is not only the building material of cells, tissues and organs. It serves as the basis for the creation of enzymes, hormones and other compounds. It is especially necessary to note such an enzyme as glutathione, which has a detoxifying effect and is the most common antioxidant in human body and perhaps the most important. Not only glucose, but also proteins are food for the brain. They supply amino acids to neurotransmitters that carry out nerve impulses into the human brain. Those. The importance of protein for the human body is difficult to overestimate.

Amino acids

Our body cannot use foreign protein for construction own cells. During the digestion process, proteins are broken down into their constituent amino acids, which are then used for the synthesis of human proteins. All amino acids are divided into replaceable ones, i.e. which can be synthesized by the body itself, and essential, which are not formed in the body and must be supplied with food. The ideal protein from the point of view of amino acid content and ratio is egg and milk protein. Far from ideal vegetable proteins having a deficiency of essential amino acids. The exception is soybeans. Therefore, it is very important for vegetarians to properly mix proteins from different plant sources that are deficient in various amino acids in order to create a relatively “healthy” diet.

How much do you need?

This is the most main question. Chronic failure protein in the diet leads to muscular dystrophy, anemia, decreased immunity. And excess is harmful, because... leads to overload of the liver and kidneys with breakdown products (purines and ketones). So how much is needed? The answer to this question will be this: protein intake should be ADEQUATE for your gender, age, physical activity and your goals. For example, a young woman whose goal is to build beautiful figure and getting rid of excess fat, should consume from 1.6 to 2.2 grams of protein per kg. own weight. Naturally, such an amount of protein should be caused by the training process, and not just by the desire to “lose weight by summer.” Then almost all the protein will be utilized in working muscles, because the speed of its conversion will increase. And him toxic effect will be neutralized. In addition, the body easily adapts to increased protein intake.

Conclusion

A healthy diet for an exerciser involves including protein in every meal. And these techniques should be at least 5-6. The source of protein should be lean beef, chicken breasts(without skin), turkey, fish, eggs, skim milk and dairy products, cheese 17%, legumes, soy (especially for women over 45), protein shakes.

Carbohydrates

If proteins are the building material, the “bricks” from which our body is built, then these are the builders who build everything. Carbohydrates are the main supplier of energy to our body, and in the most easily accessible form. In combination with proteins, they form some hormones and enzymes, as well as biologically important compounds. Carbohydrates are divided into simple and complex, digestible and indigestible. Simple carbohydrates include monosaccharides (glucose, galactose, fructose), consisting of one type of sugar; and disaccharides (sucrose, maltose, lactose), containing 2 types of sugars. And complex carbohydrates include polysaccharides (starch, glycogen, fiber and pectin), consisting of more than two sugars. What is important for us is the fact that simple carbohydrates, which do not require long digestion, are quickly absorbed into the blood and replenish the body’s energy needs. But if these needs are not present in the body, then more than 30% of carbohydrates can be converted into fats, as a reserve fuel. This is why simple carbohydrates should be consumed before training and immediately after. Then their energy will go to replenish the body’s costs and will not create any threat to the waist. And under no circumstances should you consume simple carbohydrates with fat (for example, cake) and especially at night, when energy needs are minimal. The fact is that when absorbed, simple carbohydrates increase blood sugar levels, to which the pancreas reacts by releasing insulin, a transport hormone that directly transports fat and excess sugars into fat depots. Do we need it? Another thing complex carbohydrates. They take a long time to digest, which means they do not provoke an immediate release of insulin. On the contrary, they slowly energize the entire body. Therefore, complex carbohydrates are our choice. We can find them in cereals, brown rice, durum wheat pasta, grain bread, vegetables and legumes, and boiled new potatoes.

Fats

Fats are energy concentrates (they are more than twice as high in calories as proteins and carbohydrates). In the body, fats serve for energy storage, thermal insulation, participate in water metabolism, and provide transport fat-soluble vitamins A, E, D, K are part of cells and are used by the body to build cell membranes. All are divided into two large groups - saturated and unsaturated. Saturated fats are solid animal fats. At body temperature saturated fats soften, but do not melt, and therefore can accumulate on the inner wall of blood vessels, leading to the formation of atherosclerotic plaques. Unsaturated fats in turn, they are divided into two subgroups - monounsaturated and polyunsaturated. Monounsaturated fats contained primarily in olive oil, avocado, olives. And in polyunsaturated fats one should also distinguish between Omega-6 (sunflower, corn, soybean oil, nuts and seeds) and Omega-3 (fish, fish oil, flaxseed oil, oil walnut, wheat germ oil). It is important to note that Omega-3 fatty acids are essential, i.e. they are not synthesized by the body (similarly essential amino acids) and must be regularly ingested through food. There are also fats obtained from vegetable fats through hydrogenation, so-called trans fats. Hydrogenated oils, margarines, and confectionery based on them (cookies, cakes, waffles, chips, etc.) affect fat metabolism. As a result, the level of “bad” cholesterol increases and the content of “good” cholesterol decreases. Evidence is accumulating that trans fats have harmful effects on the growth of the fetus and newborns, deteriorate the quality of breast milk in nursing mothers, and negatively affect the immune system.

Conclusion

Healthy eating means complete failure from trans fats and almost complete avoidance of direct consumption of saturated (animal) fats. We get them in sufficient quantities in hidden form (in the same olive or sunflower oils, as well as in dairy and meat products). Be sure to consume daily essential Omega-3 fats in the form of fish oil And linseed oil. And then you will become slim, and your skin and hair will thank you.

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13.04.2019 11:43:00 TOP 10 products against cellulite Complete absence cellulite remains a pipe dream for many women. But this does not mean that we should give up. The following 10 foods tighten and strengthen connective tissue– eat them as often as possible!