Violation of carbohydrate metabolism. Deciphering the analysis of carbohydrate metabolism Carbohydrate metabolism what

26 . 05.2017

A tale about carbohydrate metabolism in the human body, about the causes of failure in the body, about how carbohydrate metabolism can be improved and whether this failure can be treated with pills. I have covered everything in this article. Go!

- You, Ivan Tsarevich, do not look at me. I'm wolf. I'm supposed to eat only meat. All sorts of herbs and fruits and vegetables are important for a person. Without them, you will have neither strength nor health ...

Hello friends! A lot has been said about how important carbohydrate metabolism is in the human body, but there is nothing more forgotten than common truths. Therefore, without describing complex biochemistry, I will briefly tell the main thing that in no case should be thrown out of my head. So, read my presentation and remember!

Useful variety

In other articles, I have already reported that everything is divided into mono-, di-, tri-, oligo- and polysaccharides. Only simple ones can be absorbed from the intestinal tract, complex ones must first be split into their component parts.

The pure monosaccharide is glucose. It is she who is responsible for the level of sugar in our blood, the accumulation of glycogen as a "fuel" in the muscles and liver. It gives strength to muscles, provides brain activity, forms ATP energy molecules, which are spent on the synthesis of enzymes, digestive processes, cell renewal and the removal of decay products.

Diets for various diseases sometimes include a complete rejection of carbohydrates, but such effects can only be short-term, until a therapeutic effect is achieved. But you can regulate the process of losing weight by reducing carbohydrates in food, because a lot of reserves is just as bad as a little.

Carbohydrate metabolism in the human body: a chain of transformations

Carbohydrate metabolism in the human body (CA) begins when you put carbohydrate food in your mouth and start chewing it. In the mouth there is a useful enzyme - amylase. It initiates the breakdown of starch.

Food enters the stomach, then into the duodenum, where an intensive process of splitting begins, and finally into the small intestine, where this process continues and ready-made monosaccharides are absorbed into the blood.

Most of it settles in the liver, being converted into glycogen - our main energy reserve. Glucose enters the liver cells without difficulty. Accumulate, but to a lesser extent. To penetrate the cell membranes inside the myositis, you need to spend some of the energy. Yes, there is not enough space.

But muscle loads help penetration. It turns out an interesting effect: muscle glycogen is quickly produced during physical activity, but at the same time, it is easier for a new replenishment to seep through cell membranes and accumulate in the form of glycogen.

This mechanism partly explains the development of our muscles in the process of playing sports. Until we train the muscles, they are not able to accumulate a lot of energy "in reserve".

About the violation of protein metabolism (BO), I wrote.

A story about why you can not choose one and ignore the other

So we found out that the most important monosaccharide is glucose. It is she who provides our body with an energy reserve. Then why can't you eat only it, and spit on all the other carbohydrates? There are several reasons for this.

1. In its pure form, it is immediately absorbed into the bloodstream, causing a sharp jump in sugar. The hypothalamus gives a signal: “Reduce to normal!” The pancreas releases a portion of insulin, it restores the balance by sending the excess to the liver and muscles in the form of glycogen. And so again and again. Very quickly, the cells of the gland will wear out and cease to function normally, which will lead to other serious complications, which will be impossible to correct.

1. The predator has the shortest digestive tract, and synthesizes the carbohydrates necessary for energy replenishment from the same residues of protein molecules. He's used to it. Our human is arranged somewhat differently. We should get carbohydrate food, in the amount of about half of all nutrients, including sake, which help peristalsis and provide food for beneficial bacteria in the thick section. Otherwise, constipation and putrefactive processes with the formation of toxic waste are guaranteed to us.

1. The brain is an organ that cannot store energy like muscles or the liver. For its work, a constant supply of glucose from the blood is necessary, and more than half of the total supply of liver glycogen goes to it. For this reason, with significant mental stress (scientific activity, passing exams, etc.), it can. This is a normal, physiological process.

1. For the synthesis of proteins in the body, not only glucose is needed. The remains of polysaccharide molecules provide the necessary fragments for the formation of the "building blocks" we need.

1. Together with plant foods, other useful substances come to us, which can also be obtained from animal foods, but without dietary fiber. And we have already found out that they are very necessary for our intestines.

There are other equally important reasons why we need all sugars, not just monosaccharides.

Carbohydrate metabolism in the human body and its diseases

One of the well-known disorders of carbohydrate metabolism are hereditary intolerance to certain sugars (glucogenoses). So lactose intolerance in children develops due to the absence or insufficiency of the enzyme - lactase. Symptoms of an intestinal infection develop. Having confused the diagnosis, you can cause irreparable harm to the baby by feeding him with antibiotics. With such a violation, the treatment consists in adding the appropriate enzyme to the milk before drinking.

There are other failures in the digestion of individual sugars due to a lack of appropriate enzymes in the small or large intestine. It is possible to improve the situation, but there are no pills for violations. As a rule, these ailments are treated by eliminating certain sugars from the diet.

Another well-known disorder is diabetes, which can be either congenital or acquired as a result of improper eating behavior, (apple shape), and other diseases that affect the pancreas. Since insulin is the only factor that lowers blood sugar, its deficiency causes hyperglycemia, which leads to diabetes mellitus - a large amount of glucose is excreted from the body through the kidneys.

With a sharp decrease in blood sugar, the brain suffers first of all. Convulsions occur, the patient loses consciousness and falls into a hypoglycemic coma, from which he can be taken out if an intravenous infusion of glucose is made.

Violations of UO lead to the associated violation of fat metabolism, an increase in the formation of triglycerides in low-density lipoproteins in the blood - and as a result, nephropathy, cataracts, oxygen starvation of tissues.

How to normalize carbohydrate metabolism in the human body? Balance in the body is achieved. If we are not talking about hereditary sores and ailments, we ourselves, quite consciously, are responsible for all violations. The substances that were discussed mainly come with food.

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Carbohydrates or glucides, as well as fats and proteins, are the main organic compounds of our body. Therefore, if you want to study the issue of carbohydrate metabolism in the human body, we recommend that you first familiarize yourself with the chemistry of organic compounds. If you want to know what carbohydrate metabolism is and how it occurs in the human body, without going into details, then our article is for you. We will try to tell in a simpler way about carbohydrate metabolism in our body.

Carbohydrates are a large group of substances, which mainly consists of hydrogen, oxygen and carbon. Some complex carbohydrates also contain sulfur and nitrogen.

All living organisms on our planet are made up of carbohydrates. Plants consist of almost 80% of them, animals and humans contain much less carbohydrates. Carbohydrates are mainly contained in the liver (5-10%), muscles (1-3%), brain (less than 0.2%).

We need carbohydrates as a source of energy. When oxidizing just 1 gram of carbohydrates, we get 4.1 kcal of energy. In addition, some complex carbohydrates are reserve nutrients, while fiber, chitin and hyaluronic acid give tissues strength. Carbohydrates are also one of the building blocks of more complex molecules such as nucleic acid, glycolipids, etc. Without the participation of carbohydrates, the oxidation of proteins and fats is impossible.

Types of carbohydrates

Depending on how the carbohydrate is able to decompose into simpler carbohydrates using hydrolysis (i.e., splitting with the participation of water), they are classified into monosaccharides, oligosaccharides and polysaccharides. Monosaccharides are not hydrolyzed and are considered simple carbohydrates consisting of 1 sugar particle. This is, for example, glucose or fructose. Oligosaccharides are hydrolyzed to form a small number of monosaccharides, and polysaccharides are hydrolyzed into many (hundreds, thousands) of monosaccharides.

Glucose is not digested and is absorbed unchanged into the blood from the intestine.

Disaccharides are distinguished from the class of oligosaccharides - for example, cane or beet sugar (sucrose), milk sugar (lactose).

Polysaccharides are carbohydrates that are made up of many monosaccharides. These are, for example, starch, glycogen, fiber. Unlike monosaccharides and disaccharides, which are absorbed almost immediately in the intestines, polysaccharides are digested for a long time, which is why they are called heavy or complex. They take a long time to break down, which allows you to maintain a stable blood sugar level, without the insulin spikes that simple carbohydrates cause.

The main digestion of carbohydrates occurs in the juice of the small intestine.

The supply of carbohydrates in the form of glycogen in the muscles is very small - about 0.1% of the weight of the muscle itself. And since the muscles cannot work without carbohydrates, they need a regular supply of them through the blood. In the blood, carbohydrates are in the form of glucose, the content of which ranges from 0.07 to 0.1%. The main stores of carbohydrates in the form of glycogen are found in the liver. A person weighing 70 kg has about 200 grams (!) of carbohydrates in the liver. And when the muscles “eat up” all the glucose from the blood, glucose from the liver enters it again (previously, glycogen in the liver is split into glucose). Stocks in the liver are not eternal, so you need to replenish it with food. If carbohydrates are not supplied with food, then the liver forms glycogen from fats and proteins.

When a person is engaged in physical work, the muscles deplete all glucose reserves and a condition called hypoglycemia occurs - as a result, the work of the muscles themselves and even nerve cells is disrupted. That is why it is important to follow the right diet, especially nutrition before and after training.

Regulation of carbohydrate metabolism in the body

As follows from the above, all carbohydrate metabolism comes down to blood sugar levels. Blood sugar levels depend on how much glucose enters the bloodstream and how much glucose is removed from it. The entire carbohydrate metabolism depends on this ratio. Sugar in the blood comes from the liver and intestines. The liver only breaks down glycogen into glucose if blood sugar levels drop. These processes are regulated by hormones.

A decrease in blood sugar levels is accompanied by the release of the hormone adrenaline - it activates the liver enzymes that are responsible for the entry of glucose into the blood.

Carbohydrate metabolism is also regulated by two pancreatic hormones - insulin and glucagon. Insulin is responsible for transporting glucose from the blood to the tissues. And glucagon is responsible for the breakdown of glucagon in the liver into glucose. Those. glucagon raises blood sugar, while insulin lowers it. Their action is interconnected.

Of course, if the blood sugar level is too high, and the liver and muscles are saturated with glycogen, then insulin sends the “unnecessary” material to the fat depot - i.e. stores glucose as fat.

Carbohydrates are organic, water-soluble substances. They are made up of carbon, hydrogen and oxygen, with the formula (CH 2 O) n where ‘n’ can range from 3 to 7. Carbohydrates are found mainly in plant foods (with the exception of lactose).

Based on the chemical structure, they are divided into three groups:

• monosaccharides
• oligosaccharides
• polysaccharides

Types of carbohydrates

Monosaccharides

Monosaccharides are the "basic units" of carbohydrates. The number of carbon atoms distinguishes these basic units from each other. The suffix "ose" is used to identify these molecules in the category of sugars:

• triose is a monosaccharide with 3 carbon atoms
• tetrose is a monosaccharide with 4 carbon atoms
• pentose is a monosaccharide with 5 carbon atoms
• hexose is a monosaccharide with 6 carbon atoms
• heptose - monosaccharide with 7 carbon atoms

The hexose group includes glucose, galactose and fructose.

• , also known as blood sugar, is the sugar into which all other carbohydrates in the body are converted. Glucose can be obtained through digestion or formed as a result of gluconeogenesis.
• Galactose does not occur in free form, but more often in combination with glucose in milk sugar (lactose).
• Fructose, also known as fruit sugar, is the sweetest of the simple sugars. As the name implies, a large amount of fructose is found in fruits. While a certain amount of fructose enters directly into the blood from the digestive tract, it is converted into glucose sooner or later in the liver.

Oligosaccharides

Oligosaccharides consist of 2-10 linked monosaccharides. Disaccharides, or double sugars, are formed from two monosaccharides linked together.

• Lactose (glucose + galactose) is the only type of sugar that is not found in plants, but is found in milk.
• Maltose (glucose + glucose) - found in beer, cereals and germinating seeds.
• Sucrose (glucose + fructose) - Known as table sugar, this is the most common disaccharide that enters the body with food. It is found in beet sugar, cane sugar, honey and maple syrup.

Monosaccharides and disaccharides form a group of simple sugars.

Polysaccharides

Polysaccharides are formed from 3 to 1000 monosaccharides linked together.

Types of polysaccharides:

• - vegetable form of storage of carbohydrates. Starch exists in two forms: amylose or aminopectin. Amylose is a long, unbranched chain of spirally twisted glucose molecules, while amylopectin is a highly branched group of linked monosaccharides.
• It is a non-starch structural polysaccharide found in plants and is usually difficult to digest. Examples of dietary fiber are cellulose and pectin.
• Glycogen - 100-30,000 glucose molecules linked together. storage form of glucose.

Digestion and assimilation

Most carbohydrates we consume are in the form of starch. Starch digestion begins in the mouth under the action of salivary amylase. This process of digestion by amylase continues in the upper part of the stomach, then the action of amylase is blocked by stomach acid.

The digestion process is then completed in the small intestine with the help of pancreatic amylase. As a result of the breakdown of starch by amylase, the disaccharide maltose and short branched chains of glucose are formed.

These molecules, now in the form of maltose and short branched chain glucose, will then be broken down into individual glucose molecules by enzymes in the cells of the small intestine epithelium. The same processes occur during the digestion of lactose or sucrose. In lactose, the link between glucose and galactose is broken, resulting in the formation of two separate monosaccharides.

In sucrose, the link between glucose and fructose is broken, resulting in the formation of two separate monosaccharides. Individual monosaccharides then enter the blood through the intestinal epithelium. When ingesting monosaccharides (such as dextrose, which is glucose), no digestion is required and they are absorbed quickly.

Once in the blood, these carbohydrates, now in the form of monosaccharides, are used for their intended purpose. Since fructose and galactose are eventually converted to glucose, I will refer to all carbohydrates digested as "glucose" in what follows.

Digested glucose

Assimilated, glucose is the main source of energy (during or immediately after a meal). This glucose is catabolized by the cells to provide energy for the formation. Glucose can also be stored in the form of glycogen in muscles and liver cells. But before that, it is necessary that glucose enters the cells. In addition, glucose enters the cell in different ways depending on the cell type.

To be absorbed, glucose must enter the cell. The transporters (Glut-1, 2, 3, 4 and 5) help her with this. In cells where glucose is the main source of energy, such as the brain, kidneys, liver, and red blood cells, glucose uptake occurs freely. This means that glucose can enter these cells at any time. In fat cells, the heart, and skeletal muscle, on the other hand, glucose uptake is regulated by the Glut-4 transporter. Their activity is controlled by the hormone insulin. In response to elevated blood glucose levels, insulin is released from the beta cells of the pancreas.

Insulin binds to a receptor on the cell membrane, which, through various mechanisms, leads to the translocation of Glut-4 receptors from intracellular storage to the cell membrane, allowing glucose to enter the cell. Skeletal muscle contraction also enhances translocation of the Glut-4 transporter.

When muscles contract, calcium is released. This increase in calcium concentration stimulates the translocation of GLUT-4 receptors, facilitating glucose uptake in the absence of insulin.

Although the effects of insulin and exercise on Glut-4 translocation are additive, they are independent. Once in the cell, glucose can be used to meet energy needs or synthesized into glycogen and stored for later use. Glucose can also be converted to fat and stored in fat cells.

Once in the liver, glucose can be used to meet the energy needs of the liver, stored as glycogen, or converted to triglycerides for storage as fat. Glucose is a precursor of glycerol phosphate and fatty acids. The liver converts excess glucose into glycerol phosphate and fatty acids, which are then combined to synthesize triglycerides.

Some of these formed triglycerides are stored in the liver, but most of them, along with proteins, are converted into lipoproteins and secreted into the blood.

Lipoproteins that contain much more fat than protein are called very low density lipoproteins (VLDL). These VLDLs are then transported through the blood to adipose tissue, where they will be stored as triglycerides (fats).

Accumulated glucose

Glucose is stored in the body as the polysaccharide glycogen. Glycogen is made up of hundreds of glucose molecules linked together and is stored in muscle cells (about 300 grams) and liver (about 100 grams).

The accumulation of glucose in the form of glycogen is called glycogenesis. During glycogenesis, glucose molecules are alternately added to an existing glycogen molecule.

The amount of glycogen stored in the body is determined by carbohydrate intake; a person on a low-carb diet will have less glycogen than a person on a high-carb diet.

To use stored glycogen, it must be broken down into individual glucose molecules in a process called glycogenolysis (lysis = breakdown).

Meaning of glucose

The nervous system and brain need glucose to function properly, as the brain uses it as its main source of fuel. When there is insufficient supply of glucose as an energy source, the brain can also use ketones (by-products of incomplete breakdown of fats), but this is more likely to be considered as a fallback option.

Skeletal muscles and all other cells use glucose for their energy needs. When the required amount of glucose is not supplied to the body with food, glycogen is used. Once glycogen stores are depleted, the body is forced to find a way to get more glucose, which is achieved through gluconeogenesis.

Gluconeogenesis is the formation of new glucose from amino acids, glycerol, lactates, or pyruvate (all non-glucose sources). Muscle protein can be catabolized to provide amino acids for gluconeogenesis. When provided with the required amount of carbohydrates, glucose serves as a “protein saver” and can prevent the breakdown of muscle protein. Therefore, it is so important for athletes to consume enough carbohydrates.

Although there is no specific intake for carbohydrates, it is believed that 40-50% of calories consumed should come from carbohydrates. For athletes, this estimated rate is 60%.

What is ATP?
Adenosine triphosphate, the ATP molecule contains high-energy phosphate bonds and is used to store and release the energy needed by the body.

As with many other issues, people continue to argue about the amount of carbohydrates the body needs. For each individual, it should be determined based on a variety of factors, including: type of training, intensity, duration and frequency, total calories consumed, training goals, and the desired result based on body constitution.

Brief findings and conclusion

• Carbohydrates = (CH2O)n, where n ranges from 3 to 7.
• Monosaccharides are the "basic units" of carbohydrates
• Oligosaccharides are made up of 2-10 linked monosaccharides
• Disaccharides, or double sugars, are formed from two monosaccharides linked together, disaccharides include sucrose, lacrose and galactose.
• Polysaccharides are formed from 3 to 1000 monosaccharides linked together; these include starch, dietary fiber and glycogen.
• As a result of the breakdown of starch, maltose and short branched chains of glucose are formed.
• To be absorbed, glucose must enter the cell. This is done by glucose transporters.
• The hormone insulin regulates the operation of Glut-4 transporters.
• Glucose can be used to form ATP, stored as glycogen or fat.
• The recommended carbohydrate intake is 40-60% of total calories.

Continuing to consider fine-tuning our body by changing the basics of the nutrition plan, we need to consider all types. And today we will look at one of the most important elements in nutrition. How does our body metabolize carbohydrates, and how to eat right so that it benefits your athletic goals and achievements, and not the other way around?

General information

The regulation of carbohydrate metabolism is one of the most complex structures in our body. The body runs on carbohydrates as its main source of fuel. A system is being adjusted that allows you to use carbohydrates as a priority source of nutrition, with maximum energy efficiency.

Our body consumes energy exclusively from carbohydrates. And only if there is not enough energy, it will reconfigure, or use protein tissue as a fuel source.

Stages of carbohydrate metabolism

The main stages of carbohydrate metabolism are divided into 3 main groups:

1. Convert carbohydrates to energy.
2. insulin reaction.
3. Use of energy and excretion of waste products.

The first stage is the fermentation of carbohydrates

Unlike adipose tissue, or protein products, the transformation and decomposition of carbohydrates into the simplest monosaccharides occurs already at the stage of chewing. Under the influence of saliva, any complex carbohydrate is transformed into the simplest dextrose molecule.

In order not to be unfounded, we propose to conduct an experiment. Take a piece of unsweetened bread and start chewing it for a long time. At a certain stage, you will feel the sweet taste. This means that the glycemic index of bread under the influence of saliva has grown and has become even higher than that of sugar. Further, everything that has not been crushed is already digested in the stomach. For this, gastric juice is used, which at different speeds breaks down certain structures to the level of the simplest glucose. Dextrose is directly sent to the circulatory system.

The second stage is the distribution of the received energy in the liver

Almost all incoming food goes through the stage of infiltration with blood in the liver. They enter the circulatory system from the liver cells. There, under the influence of hormones, the glucagon reaction begins and the dosage of saturation with carbohydrates transport cells in the circulatory system.

The third stage is the transition of all sugar into the blood

The liver is able to process only 50-60 grams of pure glucose for a certain time, sugar almost unchanged enters the bloodstream. Then it starts circulation to all organs, filling them with energy for normal functioning. In conditions of high consumption of carbohydrates with a high glycemic index, the following changes occur:

• Sugar cells replace oxygen cells. This begins to cause oxygen starvation of tissues and a decrease in activity.
• At a certain saturation, the blood thickens. This makes it difficult to move through the vessels, increases the load on the heart muscle, and as a result worsens the functioning of the body as a whole.

The fourth stage is the insulin response

It is an adaptive response of our body to excessive blood sugar saturation. In order to prevent this from happening, at a certain threshold, insulin begins to be injected into the blood. This hormone is the main regulator of blood sugar levels, and when it is deficient, people develop diabetes mellitus.

Insulin binds glucose cells, turning them into glycogen. are several sugar molecules linked together. They are an internal source of nutrition for all tissues. Unlike sugar, they do not bind water, which means they can move freely without causing hypoxia or blood clots.

So that glycogen does not clog the transport channels in the body, insulin opens the cellular structure of internal tissues, and all carbohydrates are completely locked in these cells.

To bind sugar molecules into glycogen, the liver is involved, the processing rate of which is limited. If there are too many carbohydrates, a backup conversion method is launched. Alkaloids are injected into the bloodstream, which bind carbohydrates and turn them into lipids, which are deposited under the skin.

The fifth stage is the secondary use of accumulated reserves

In the body, athletes have special glycogen depots that a person can use as a backup source of "fast food". Under the influence of oxygen and increased loads, the body can carry out aerobic glycolysis from cells located in the glycogen depot.

The secondary degradation of carbohydrates occurs without insulin, as the body is able to independently regulate the level of how many glycogen molecules it needs to decompose to obtain the optimal amount of energy.

The last stage is the excretion of waste products

Since sugar in the process of being used by the body undergoes chemical reactions with the release of thermal and mechanical energy, the product of vital activity remains at the output, which in its composition is closest to pure coal. It binds with the rest of the human waste products, and is excreted from the circulatory system first into the gastrointestinal tract, where, after complete transformation, it is excreted through the rectum to the outside.

Differences between glucose and fructose metabolism

The metabolism of fructose, which has a structure different from glucose, is somewhat different, so the following factors must be taken into account:

• Fructose is the only available source of fast carbohydrates for people suffering from diabetes.
• fruit is lower than any other product. For example, watermelon is one of the sweetest and largest fruits, has a glycemic load of about 2. This means that there are only 20 grams of fructose per kilogram of watermelon. To achieve the optimal dosage at which it will be converted into adipose tissue, you need to eat about 2.5 kilograms of this sweet fruit.
• Fructose tastes sweeter than sugar, which means that using fructose-based sweeteners, you can consume less carbohydrates in general.

Now consider how the metabolism of carbohydrates to fructose and glucose, respectively, differs.

Glucose metabolism	Fructose metabolism
Some of the incoming sugar is absorbed in the liver cells.	Practically not absorbed in the liver.
Activates the insulin response.	.In the process of metabolism, alkaloids are released that poison the body.
Activates the glucagon response.	They do not participate in the transition of food sources to external sugar.
It is the body's preferred source of energy.	Pass into adipose tissue without the participation of insulin.
Participates in the creation of glycogen cells.	They cannot participate in the creation of glycogen reserves due to the more complex structure and completed form of the monosaccharide.
Low sensitivity and possibility of conversion to triglycerides.	High probability of turning into adipose tissue with relatively low consumption.

Functions of carbohydrates

Considering the basics of carbohydrate metabolism, we will mention the main functions of sugar in our body.

1. Energy function. Carbohydrates are the preferred energy source due to their structure.
2. opening function. Carbohydrate triggers insulin, and can open up cells without destroying them for other nutrients to enter. This is why gainers are more popular than pure protein shakes.
3. storage function. The body uses them and accumulates them in case of an emergency stressful situation. He does not need transport proteins, which means that he can oxidize the molecule much faster.
4. Improving the functioning of brain cells. Brain fluid can only work if there is enough sugar in the blood. Try to start learning something on an empty stomach, and you will realize that all your thoughts are occupied with food, and not at all with learning or development.

Outcome

Knowing the characteristics of metabolism and the main functions of carbohydrates in our body, it is difficult to overestimate their importance. To successfully lose weight or gain muscle mass, you need to maintain the correct energy balance. And remember, if you limit carbohydrates in your diet, creating, the body will first of all begin to eat muscle, and not body fat at all. If you want to know more about this, learn about the features of fat metabolism.

Not the last role is played by carbohydrates. People who care about their own health know that complex carbohydrates are preferable to simple ones. And that it is better to eat food for longer digestion and energizing throughout the day. But why exactly? What is the difference between the processes of assimilation of slow and fast carbohydrates? Why sweets should be used only to close the protein window, and honey is better to eat only at night? To answer these questions, let's take a closer look at the metabolism of carbohydrates in the human body.

What are carbohydrates for?

In addition to maintaining optimal weight, carbohydrates in the human body perform a huge amount of work, a failure in which leads not only to obesity, but also to a host of other problems.

The main tasks of carbohydrates are to perform the following functions:

1. Energy - Approximately 70% of calories come from carbohydrates. In order to realize the process of oxidation of 1 g of carbohydrates, the body needs 4.1 kcal of energy.
2. Construction - take part in the construction of cellular components.
3. Reserve - create a depot in the muscles and liver in the form of glycogen.
4. Regulatory - Some hormones are glycoproteins in nature. For example, thyroid and pituitary hormones - one structural part of such substances is protein, and the other is carbohydrate.
5. Protective - heteropolysaccharides are involved in the synthesis of mucus, which covers the mucous membranes of the respiratory tract, digestive organs, and the genitourinary tract.
6. They are involved in cell recognition.
7. They are part of the membranes of erythrocytes.
8. They are one of the regulators of blood clotting, as they are part of prothrombin and fibrinogen, heparin (- textbook "Biological Chemistry", Severin).

For us, the main sources of carbohydrates are those molecules that we get from food: starch, sucrose and lactose.

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Steps in the breakdown of saccharides

Before considering the features of biochemical reactions in the body and the effect of carbohydrate metabolism on athletic performance, let's study the process of splitting saccharides with their further transformation into the very one that athletes so desperately get and spend while preparing for competitions.

Stage 1 - pre-digestion with saliva

Unlike proteins and fats, carbohydrates begin to break down almost immediately after they enter the mouth. The fact is that most of the products that enter the body contain complex starchy carbohydrates, which, under the influence of saliva, namely the amylase enzyme, which is part of it, and the mechanical factor, are broken down into simple saccharides.

Stage 2 - influence of stomach acid on further digestion

This is where stomach acid comes into play. It breaks down complex saccharides that have not been exposed to saliva. In particular, under the action of enzymes, lactose is broken down to galactose, which subsequently turns into glucose.

Stage 3 - absorption of glucose into the blood

At this stage, almost all fermented fast glucose is directly absorbed into the blood, bypassing the fermentation processes in the liver. The energy level rises sharply, and the blood becomes more saturated.

Stage 4 - satiety and insulin response

Under the influence of glucose, the blood thickens, which makes it difficult to move and transport oxygen. Glucose replaces oxygen, which causes a protective reaction - a decrease in the amount of carbohydrates in the blood.

The plasma receives insulin and glucagon from the pancreas.

The first opens the transport cells to move sugar into them, which restores the lost balance of substances. Glucagon, in turn, reduces the synthesis of glucose from glycogen (consumption of internal energy sources), and insulin “holes” the main cells of the body and puts glucose there in the form of glycogen or lipids.

Stage 5 - carbohydrate metabolism in the liver

On the way to complete digestion, carbohydrates collide with the body's main defender - liver cells. It is in these cells that carbohydrates, under the influence of special acids, bind into the simplest chains - glycogen.

Stage 6 - glycogen or fat

The liver can process only a certain amount of monosaccharides in the blood. Rising insulin levels make her do it in no time. If the liver does not have time to convert glucose into glycogen, a lipid reaction occurs: all free glucose, by binding with acids, is converted into simple fats. The body does this in order to leave a reserve, however, in view of our constant nutrition, it “forgets” to digest, and the glucose chains, turning into plastic fatty tissues, are transported under the skin.

Stage 7 - secondary splitting

In the event that the liver coped with the sugar load and was able to convert all carbohydrates into glycogen, the latter, under the influence of the hormone insulin, has time to stock up in the muscles. Further, under conditions of lack of oxygen, it is broken down back to the simplest glucose, not returning to the general bloodstream, but remaining in the muscles. Thus, bypassing the liver, glycogen supplies energy for specific muscle contractions, while increasing endurance (- "Wikipedia").

This process is often referred to as "second wind". When an athlete has large stores of glycogen and simple visceral fats, they will turn into clean energy only in the absence of oxygen. In turn, alcohols contained in fatty acids will stimulate additional vasodilation, which will lead to better cell susceptibility to oxygen in conditions of its deficiency.

Features of metabolism according to GI

It is important to understand why carbohydrates are divided into simple and complex. It's all about them, which determines the rate of decay. This, in turn, triggers the regulation of carbohydrate metabolism. The simpler the carbohydrate, the faster it gets to the liver and the more likely it is to be converted into fat.

An approximate table of the glycemic index with the total composition of carbohydrates in the product:

Features of metabolism according to GN

However, even foods with a high glycemic index are not able to disrupt the metabolism and functions of carbohydrates in the way that it does. It determines how strongly the liver will be loaded with glucose when using this product. When a certain GL threshold is reached (about 80-100), all calories in excess of the norm will be automatically converted into triglycerides.

Approximate table of glycemic load with total calories:

Insulin and glucagon response

In the process of consuming any carbohydrate, be it sugar or complex starch, the body starts two reactions at once, the intensity of which will depend on the previously discussed factors and, first of all, on the release of insulin.

It is important to understand that insulin is always released into the blood in pulses. And this means that one sweet pie is as dangerous for the body as 5 sweet patties. Insulin regulates the thickness of the blood. This is necessary so that all cells get enough energy without working in hyper- or hypo-mode. But most importantly, the speed of its movement, the load on the heart muscle and the ability to transport oxygen depend on the density of the blood.

The release of insulin is a natural response. Insulin perforates all the cells in the body that are capable of receiving additional energy, and locks it in them. If the liver has coped with the load, glycogen is placed in the cells, if the liver has not coped, then fatty acids enter the same cells.

Thus, the regulation of carbohydrate metabolism occurs solely due to the release of insulin. If it is not enough (not chronically, but one-time), a person may experience a sugar hangover - a condition in which the body requires additional fluid to increase blood volume, and dilute it by all available means.

Subsequent energy distribution

The subsequent distribution of carbohydrate energy occurs depending on the type of addition, and the fitness of the body:

1. In an untrained person with a slow metabolism. Glycogen cells with a decrease in glucagon levels return to the liver, where they are processed into triglycerides.
2. At the athlete. Glycogen cells under the influence of insulin are massively locked in the muscles, providing an energy reserve for the following exercises.
3. In a non-athlete with a fast metabolism. Glycogen returns to the liver, being transported back to the level of glucose, after which it saturates the blood to the borderline level. By this, it provokes a state of exhaustion, because despite sufficient nutrition with energy resources, the cells do not have the appropriate amount of oxygen.

Outcome

Energy metabolism is a process in which carbohydrates are involved. It is important to understand that even in the absence of direct sugars, the body will still break down tissues to the simplest glucose, which will lead to a decrease in muscle tissue or body fat (depending on the type of stressful situation).