Why are carbohydrates needed in the human body?

What are carbohydrates and what are they for?

Carbohydrates are organic substances, an essential chemical element that is necessary for the construction of a number of important complexes in the body. They are a key component of most foods and serve as the main source of energy for humans.

Already in the very term “carbohydrate” we hear the word water. In fact, there is no water as such in these organic chemical compounds. In 1844, a Russian chemist from the Baltic states first gave such a definition to the compound of carbon (C) with a hydroxyl group (H2O). This word is firmly rooted in world science. There is another name for carbohydrates - sugars.

This is interesting!

Carbohydrates make up the bulk of all dry mass of living things, plants, bacteria and inorganic compounds on Earth. The cells of animals, plants and humans consist of carbohydrates in different quantitative ratios. For example, if for plants this figure reaches 80% of the dry mass of the plant, then for an animal this ratio is approximately 5%.

The carbohydrate class is so vast and diverse that it is difficult to imagine any organism on our planet without these substances.

Carbohydrates, as a constructor, consist of elementary particles, which in chemistry are called saccharides. The entire classification of carbohydrates is divided depending on their properties, or more precisely on the ability to dissolve in water - this process is called hydrolysis. During this process, sugars are broken down into monomers. Monomers are the smallest units of carbohydrates.

Thus, they distinguish:

Monosaccharides contain one single unit of sugar, which quickly dissolves in water and enters the bloodstream. Blood glucose levels rise sharply. Monosaccharides have a high glycemic index.
Oligosaccharides are slightly more complex carbohydrates; they contain two or more monosaccharide components. The most popular and in demand in industry is raffinose, which contains fructose, glucose and galactose. A high content of these substances is found in ordinary beets.
Polysaccharides are complex carbohydrates that contain tens or even hundreds of monomers. They dissolve in water over a longer period of time and break down into their components for quite a long time.

Concept

Carbohydrates are organic substances consisting of carbon, oxygen, and hydrogen. About 2-3% of these components accumulate in the body in the form of glycogen. Blood contains glucose in the amount of 5 g. The more trained a person is, the more glycogen he can accumulate.

The human body is capable of synthesizing carbohydrates, but in very small quantities, so most of them come with food. These components are found in plant products. For example, there are about 80% of them in cereals. And sugar contains 99.98% of these substances. Carbohydrates provide the body with energy. What else are they needed for? They are important and necessary for the functioning of many organs.

Functions of carbohydrates in the body

The main role of carbohydrates in the body of many living beings, including humans, concerns the replenishment of energy reserves. Their absence in the diet leads to depression of all organs and systems of the body. It is important to understand that not only carbons have an energy function - it is the joint work of proteins, fats and carbohydrates. When there is an excess of glucose, it is deposited into glycogen, and then through complex biochemical transformations into adipose tissue.
Carbohydrates are very necessary for the central nervous system. Brain cells function only thanks to large amounts of glucose. If the body receives the right amount of carbohydrates, the nervous system works properly, but as soon as the glucose level drops, the person becomes absent-minded, and is plagued by weakness and dizziness. This condition is common for people with low blood sugar syndrome or women on a carbohydrate-free diet.
Muscle tissue really needs clean energy during work. When contracting and relaxing, smooth muscle tissue myocytes use carbohydrate energy. Growth and increase in muscle mass are provided by protein, but in the direct presence of carbohydrates. If there is not the required amount of sugar in the blood, then the muscles are destroyed and a complete metabolic disorder occurs.
Complex carbohydrates, which include cellulose, regulate the functioning of the digestive system. Fiber itself does not provide any nutritional benefit, but it creates pressure on the intestinal wall and this stimulates its work. In addition, coarse fibers play an important role as a sorbent for the body. This removes toxins, other harmful substances and your own metabolic products. The growth of beneficial bacteria in the intestines is also ensured by fiber, because it is their food.
Fats, proteins and carbohydrates are closely interrelated. For example, for the oxidation of fat breakdown products - acetate, oxaloacetic acid is extremely necessary, which in turn is a breakdown product of carbohydrates. If there are no carbohydrates in the diet or they do not enter the body’s cells, then the body is filled with fat processing products, ketone bodies. This has a very bad effect on the human condition. If we talk about metabolic diseases, ketoacidosis is a dangerous and life-threatening condition.

Norms

Nutritionists believe that these components should be equal to 45-55% of all calories per day. How many grams of carbohydrates do you need per day? A minimum of 130 grams is required. This norm must be observed to prevent the occurrence of diseases.

How many grams of carbohydrates do you need if you have a sedentary lifestyle? Doctors recommend 4 g per 1 kg of body weight. Such standards must be followed by men and women. More active people require 5-6 g per 1 kg of body weight, and active people - 6-7 g. The last group includes people who play sports at least 3 times a week.

Athletes need to eat 8-10 g of carbohydrates per 1 kg of weight. Since such people undergo intense strength training, the volume of organic components quickly burns out. If you follow these simple rules, you can protect yourself from a number of diseases for a long time.

The path of carbohydrates in the body

To make the metabolic process, namely carbohydrate metabolism, more understandable, you need to know what path these nutrients take in the human body and what transformations they undergo.

Carbohydrates in the form of food enter the mouth. If these were monosaccharides, then they remain unchanged. But if these were polysaccharides and complex carbohydrates, then in the oral cavity they begin to transform into simpler forms: oligosaccharides and monosaccharides. Saliva contains ptyalin with an alkaline environment and it is this that begins the digestion of carbohydrates. There are practically no changes in the stomach with carbohydrates.

Final digestion and breakdown into elemental sugars occurs in the small intestine. In the duodenum, pancreatic enzymes act on the food bolus. At the distal end of the small intestine, glucose is absorbed into the blood. Its further path lies to the cells through the main barrier of our body, the liver.

The final cleansing of the blood from harmful and toxic substances takes place in the liver, and the level of glucose in the blood is stabilized there. If its level exceeds 3.3-5.5 mmol/l of blood, then the liver converts the excess into glycogen.

In case of deficiency, glucose is replenished from glycogen stores in the liver. Thus, glucose is sent to all cells of the body without exception. There, through complex transformations, energy is extracted from it to form.

Complex carbohydrates

While monosaccharides in their pure form are rarely found in nature, polysaccharides make up the bulk of food for humans and animals. They can consist of tens of hundreds of monomers.

Chemists distinguish these substances according to the general principle of their structure. Among them are:

Homopolysaccharides are substances containing the same type of monosaccharides.
Heterosaccharides consist of sugars that differ in structure and function. The group of homopolysacchorides includes known monomers.

Organic homopolysaccharides of plant origin include:

starch;
cellulose;
pectin substances.

To organic compounds of animal origin:

glycogen;
chitin.

Hormones that regulate carbohydrate metabolism in the body

For the body, the main task is to maintain the functionality of the brain, as a central organ that regulates all processes. Therefore, it is the brain that absorbs glucose the most.

The end product of glucose breakdown, or in the words of glycolysis biochemists, is an ATP molecule. It is energy in its purest form that causes muscles to contract, the heart to pump blood, and neurons to perform their important function in the brain so that a person can speak, hear and think. Everything is very cyclical and continuous. When energy production is not possible or the regulation of this process is impaired, death occurs.

This is important to know!

Insulin

This hormone is known to a wide range of people. Its deficiency leads to such a serious disease as diabetes.

Insulin is produced in the pancreas, but leaves it inactive. Activates its protein breakdown products. Insulin acts only through specific receptors located in cells. There is a type of diabetes mellitus in which a lot of insulin is produced, but there are no receptors, and similar symptoms occur.

The effect of insulin on carbohydrate metabolism:

reduces blood glucose levels to 3.3-5.5 mmol;
promotes the deposition of fats in the body by converting excess glucose into fat;
stimulates the formation of fatty deposits in the liver and fatty tissue;
affects the formation of cholesterol;
has a positive effect on the synthesis of new proteins;

Glucagon

It is also produced in the pancreas. Glucagon consists of amino acids and affects the following processes in the body:

increases the level of glucose in the blood when it decreases;
affects the active breakdown of glycogen;
affects the formation of glucose from protein and lipids;
actively stimulates the breakdown of adipose tissue;

Adrenalin

It is synthesized in the adrenal gland, namely in its medulla layer, when the hormone is released and in what quantity the brain regulates - this is a stress hormone.

When a dangerous situation arises, which, according to the brain, threatens life, a command is sent to the adrenal glands and adrenaline enters the blood:

the accumulation of glycogen in the muscles is activated, followed by its transition to glucose;
Glucose is needed by skeletal muscles for intense work, fighting or running;
reduces the amount of insulin.

Cortisol

This is also a hormone of the adrenal glands, but of the cortical part. Cortisol performs important functions:

increases blood glucose levels;
affects the redistribution of adipose tissue in the body, namely, it leads to a decrease in fat accumulation in the arms and legs and stimulates the appearance of fat on the back and abdomen;
causes the death of lymphocytes;
reduces the level of inflammation.

Thyroid hormones

The thyroid gland is perhaps the most important organ that actively influences the metabolism in the body. It is also called the cardinal gray, because many processes in the body do not occur without the influence of thyroid-stimulating hormones.

The synthesis of hormones directly depends on the supply of iodine from the external environment and this is necessary for such important functions in the body:

basal metabolism increases - the amount of energy required for digestion and the production of digestive enzymes increases;
energy metabolism in cells accelerates.

Somatotropic hormone

This is a special hormone that is produced in the pituitary gland. During the period of child growth and development, it is this hormone that affects everything. On the child’s height, weight, muscle development and skeletal growth.

In an adult body, the presence of somatotropic hormone is dangerous; when it is produced, it indicates the presence of a brain tumor and is manifested by acromegaly.

Somatotropic hormone performs the following functions in the body:

reduces glucose consumption in muscles;
increases glucose production in the liver;
increases insulin production;
the hormone makes skeletal muscle and adipose tissue cells insensitive to insulin and this leads to the accumulation of glucose in the blood.

Other Features

A person should eat foods containing these organic components to prevent deterioration of the body's condition. Carbohydrates are needed for the functioning of the immune system and reducing the risk of colds. They support the body and protect against blood clotting.

Together with proteins, they influence the formation of hormones, enzymes, and various compounds. These organic components are involved in the synthesis of RNA, DNA, and ATP. 70% of the brain’s energy activity depends on them.

What is the glycemic index

The glycemic index is a very arbitrary calculation system that relates only to carbohydrates. Thanks to it, you can determine which foods contain carbohydrates that can change blood glucose levels.

In other words, there are foods that contain large amounts of simple or complex carbohydrates with a short chain of monomers. For example, potatoes, its index is 95, which means that when 100 grams of potatoes enter the body, starch is quickly broken down and a lot of glucose enters the blood.

But the glycemic index does not determine the rate at which blood sugar rises. This indicator is calculated relative to glucose injected directly into the body.

This is interesting!

For the first time, Canadian scientist David J. A. Jenkinson proposed determining the glycemic index. He took the change in blood sugar levels after administering glucose intravenously or orally as the gold standard and took this figure as 100. All other foods with carbohydrates are calculated relative to one hundred.

For example, if you eat 100 grams of honey with a glycemic index of 90, it turns out that your blood sugar level will rise to the same level as if a person ate 90 grams of pure glucose.

Fortunately for us, all products have been converted to the glycemic index system, and there is no need to calculate it yourself. This classification of carbohydrate-containing products was developed specifically for patients with diabetes in order to correctly adjust their diet. But for people who watch their weight and lead a healthy lifestyle, this indicator is just as important.

It is generally accepted that there are two types of food distribution according to the glycemic index.

The first one is suitable for products and is divided:

low - glycemic index 55 and below;
average from 56 to 70;
high - 71 and above.

The second is designed for diets accordingly:

high - 61 and above;
average - 45-60;
low - 45 and below.

Why it is important to observe and know glycemic index levels. Because numerous studies by nutritionists and endocrinologists have proven that people whose diet is in the range of 40-55 are less likely to suffer from diabetes and heart disease.

Application of knowledge about the glycemic index

From all that has been said above, it is clear that the higher the glycemic index of a product, the higher the level of sugar in a person’s blood after consuming it.

Accordingly, the higher the glycemia, the more insulin is released from the pancreas. Insulin prevents the breakdown of stored fats and promotes the accumulation of unclaimed glucose in fat deposits.

It is important

Thus, to keep your weight within acceptable limits, you need to know what foods to eat. In addition, excess weight and increased deposition of adipose tissue negatively affects the condition of the entire body.

Therefore, there are a number of reasons why you should eat a diet with a low glycemic index:

Prevention of diseases of the visual analyzer.
Prevention of heart and vascular diseases.
Maintaining a balanced level of the body's energy reserves.
Prevention of breast cancer.
Maintaining normal weight.
Prevention of late hystosis in pregnancy and the development of diabetes in pregnant women.
To improve performance during sports training.

This is not the entire list of useful recommendations from nutritionists and therapists for maintaining the reasonable use of carbohydrates.

With the advent of fashion for healthy eating and lifestyle, the Internet has been filled with many tables indicating the glycemic index of a particular product. It is difficult for the average person to navigate rather contradictory information.

Let’s say in one source the index of pasta is 40 and classified as low, and in another source, the same pasta is assigned a glycemic index of 70. This occurs as a result of incorrect interpretation of the tables, as well as due to different types of the same product .

It is important to know!

Perhaps the most accurate and authoritative source for publishing tables with the glycemic index level should be considered the University of Sydney. This institution conducts independent research and publication of databases.

For example, in Russia and the CIS countries there are traditional and rather beloved products with a glycemic index higher than that of glucose itself.

White bread;
cornflakes;
cooked white rice;
sucrose (honey, gingerbread, refined sugar, dates, raisins);
maltose (honey, kvass, muesli, beer, marmalade and others).

To be one hundred percent sure of the result, you can conduct research on the products you are interested in yourself. To do this, you will need a healthy subject, a certain amount of pure glucose and the foods of interest. Glucose levels can be measured independently using a glucometer or in a laboratory.

High GI foods

Low GI foods

Hypoglycemia and hyperglycemia, what is it?

If a person does not have problems with the pancreas, which causes disruption of hormone synthesis, then the symptoms of hyperglycemia do not appear.

It’s a different matter if this condition is chronic and is caused by the fact that insulin does not have time to convert excess glucose into glycogen. Then three main symptoms appear that should alert a person:

Polyuria is an increased amount of urine and urination.
Polyphagia - a person eats often and a lot because the cell cannot receive glucose.
Polydipsia - a person often drinks a lot due to dry mouth and thirst caused by changes in the osmotic composition of the blood.

These are direct indications for a visit to a therapist or endocrinologist.

Another thing is hypoglycemia, a condition in which there is a lack of glucose in the peripheral blood. The cells do not receive the required amount of energy material and therefore the entire body suffers. Other reasons include:

Fluid deficiency.
Abuse of refined carbohydrates.
Using insulin or another glucose-lowering drug in excess of the required dose.
Wrong number of meals when treating diabetes.
Heavy physical activity.
Systematic alcohol consumption.
Hunger.
Malignant and benign neoplasms of the pancreas.

Hypoglycemia syndrome manifests itself in different ways, depending on the severity. Symptoms include:

hand tremors and unsteadiness of gait;
feeling of hunger, thirst;
nausea and general weakness;
increased excitability or, on the contrary, inhibition;
increased sweating, arrhythmia;
in severe cases, coma and profound neurological impairment.

Recommendations

A proper diet helps you stay fit and healthy. Food should be varied. Not only carbohydrates are needed, but also proteins and fats. If you want sweets, it is better to choose healthy foods, for example, honey, dried fruits, fresh fruits. It will be better than confectionery.

To eliminate unnecessary snacking, complex carbohydrates should be included in the menu. Nutritionists recommend consuming 20% simple and 80% complex components per day. You should not eat simple carbohydrates, such as bananas and grapes, on an empty stomach. Because of such snacks, a feeling of hunger quickly appears, so a person will consume more calories.