Carbohydrates in food.Carbohydrates are the main and easily accessible source of energy for the human body. All carbohydrates are complex molecules consisting of carbon (C), hydrogen (H) and oxygen (O), the name comes from the words “coal” and “water”.
Of the main sources of energy known to us, we can distinguish three:
Carbohydrates (up to 2% of reserves)
- fats (up to 80% of reserves)
- proteins (up to 18% of reserves )Carbohydrates are the most fast fuel, which is primarily used for energy production, but their reserves are very small (on average 2% of the total) because their accumulation requires a lot of water (4g of water is needed to retain 1g of carbohydrates), but water is not required to store fat.
The body's main reserves of carbohydrates are stored in the form of glycogen (complex carbohydrate). Most of it is contained in the muscles (about 70%), the rest in the liver (30%).
You can find out all the other functions of carbohydrates as well as their chemical structureCarbohydrates in foods are classified as follows.
Types of carbohydrates.
Carbohydrates, in a simple classification, are divided into two main classes: simple and complex. Simple ones, in turn, consist of monosaccharides and oligosaccharides, complex ones of polysaccharides and fibrous ones.
Simple carbohydrates.
MonosaccharidesGlucose(“grape sugar”, dextrose).
Glucose is the most important of all monosaccharides, as it is structural unit most food di- and polysaccharides. In the human body, glucose is the main and most universal source of energy for metabolic processes. All cells of the animal body have the ability to metabolize glucose. At the same time, not all cells of the body, but only some of their types, have the ability to use other energy sources - for example, free fatty acids and glycerol, fructose or lactic acid. During the metabolic process, they are broken down into individual molecules of monosaccharides, which, through multi-stage chemical reactions, are converted into other substances and are ultimately oxidized to carbon dioxide and water - used as “fuel” for cells. Glucose is a necessary component of metabolism carbohydrates. When its level in the blood decreases or its concentration is high and it is impossible to use, as happens in diabetes, drowsiness occurs and loss of consciousness may occur (hypoglycemic coma).
Glucose “in its pure form”, as a monosaccharide, is found in vegetables and fruits. Grapes are especially rich in glucose - 7.8%, sweet cherries - 5.5%, raspberries - 3.9%, strawberries - 2.7%, plums - 2.5%, watermelon - 2.4%. Among vegetables, pumpkin contains the most glucose - 2.6%, white cabbage - 2.6%, and carrots - 2.5%.
Glucose is less sweet than the most famous disaccharide, sucrose. If we take the sweetness of sucrose as 100 units, then the sweetness of glucose is 74 units.Fructose(fruit sugar).
Fructose is one of the most common carbohydrates fruit. Unlike glucose, it can penetrate from the blood into tissue cells without the participation of insulin (a hormone that reduces glucose levels in the blood). For this reason, fructose is recommended as the safest source carbohydrates for diabetic patients. Some of the fructose enters the liver cells, which convert it into a more versatile “fuel” - glucose, so fructose can also increase blood sugar, although to a much lesser extent than other simple sugars. Fructose is easier to convert into fat than glucose. The main advantage of fructose is that it is 2.5 times sweeter than glucose and 1.7 times sweeter than sucrose. Its use instead of sugar helps reduce overall consumption carbohydrates.
The main sources of fructose in food are grapes - 7.7%, apples - 5.5%, pears - 5.2%, cherries - 4.5%, watermelons - 4.3%, black currants - 4.2% , raspberries – 3.9%, strawberries – 2.4%, melons – 2.0%. The fructose content in vegetables is low - from 0.1% in beets to 1.6% in white cabbage. Fructose is contained in honey - about 3.7%. It has been reliably proven that fructose, which has a significantly higher sweetness than sucrose, does not cause tooth decay, which is promoted by sugar consumption.Galactose(a type of milk sugar).
Galactose not found in free form in products. It forms a disaccharide with glucose - lactose (milk sugar) - the main carbohydrate milk and dairy products.Oligosaccharides
Sucrose(table sugar).
Sucrose is a disaccharide (a carbohydrate consisting of two components), formed by molecules glucose and fructose. The most common type of sucrose is - sugar. The sucrose content in sugar is 99.5%; in fact, sugar is pure sucrose.
Sugar breaks down quickly gastrointestinal tract, glucose and fructose are absorbed into the blood and serve as a source of energy and the most important precursor of glycogen and fats. It is often called an “empty calorie carrier” because sugar is pure carbohydrate and does not contain others nutrients, such as, for example, vitamins, mineral salts. Of the plant products, the most sucrose is contained in beets - 8.6%, peaches - 6.0%, melons - 5.9%, plums - 4.8%, tangerines - 4.5%. In vegetables, except beets, a significant sucrose content is noted in carrots - 3.5%. In other vegetables, the sucrose content ranges from 0.4 to 0.7%. In addition to sugar itself, the main sources of sucrose in food are jam, honey, confectionery, sweet drinks, and ice cream.Lactose(milk sugar).
Lactose breaks down in the gastrointestinal tract to glucose and galactose under the action of an enzyme lactase. A deficiency of this enzyme leads to milk intolerance in some people. Undigested lactose serves as a good nutrient for intestinal microflora. In this case, profuse gas formation is possible, the stomach “swells”. In fermented milk products most of lactose is fermented to lactic acid, so people with lactase deficiency can tolerate fermented milk products without unpleasant consequences. In addition, lactic acid bacteria in fermented milk products suppress the activity of intestinal microflora and reduce the adverse effects of lactose.
Galactose, formed during the breakdown of lactose, is converted into glucose in the liver. With a congenital hereditary deficiency or absence of the enzyme that converts galactose into glucose, a serious disease develops - galactosemia , which leads to mental retardation.
Lactose content in cow's milk is 4.7%, in cottage cheese - from 1.8% to 2.8%, in sour cream - from 2.6 to 3.1%, in kefir - from 3.8 to 5.1%, in yoghurts - about 3%.Maltose(malt sugar).
Formed when two glucose molecules combine. Contained in such products as: malt, honey, beer, molasses, bakery and confectionery products made with the addition of molasses.Athletes should avoid consuming pure glucose and foods rich in simple sugars in large quantities, as they trigger the process of fat formation.
Complex carbohydrates.
Complex carbohydrates are composed primarily of repeating units of glucose compounds. (glucose polymers)Polysaccharides
Plant polysaccharides (starch).
Starch- the main digestible polysaccharide, it is a complex chain consisting of glucose. It accounts for up to 80% of carbohydrates consumed in food. Starch is a complex or “slow” carbohydrate, so it is the preferred source of energy for both weight gain and weight loss. In the gastrointestinal tract, starch is hydrolyzed (the decomposition of a substance under the influence of water) and is broken down into dextrins (starch fragments), and ultimately into glucose, and in this form is absorbed by the body.
The source of starch is herbal products, mainly cereals: cereals, flour, bread, and potatoes. Cereals contain the most starch: from 60% in buckwheat (kernel) to 70% in rice. Of the cereals, the least amount of starch is contained in oatmeal and its processed products: oatmeal, Hercules oat flakes - 49%. Pasta contains from 62 to 68% starch, bread made from rye flour, depending on the type - from 33% to 49%, wheat bread and other products made from wheat flour - from 35 to 51% starch, flour - from 56 (rye) to 68% (premium wheat). There is also a lot of starch in legumes - from 40% in lentils to 44% in peas. You can also note the high starch content in potatoes (15-18%).Animal polysaccharides (glycogen).
Glycogen- consists of highly branched chains of glucose molecules. After eating, a large amount of glucose begins to enter the blood and the human body stores excess glucose in the form of glycogen. When your blood glucose levels begin to decrease (for example, while doing physical exercise), the body breaks down glycogen with the help of enzymes, as a result of which glucose levels remain normal and organs (including muscles during exercise) receive enough of it to produce energy. Glycogen is deposited mainly in the liver and muscles. It is found in small quantities in animal products (in the liver 2-10%, in muscle tissue - 0.3-1%). Total stock glycogen is 100-120 g. In bodybuilding, only the glycogen that is contained in muscle tissue matters.Fibrous
Dietary fiber (indigestible, fibrous)
Dietary fiber or dietary fiber refers to nutrients that, like water and mineral salts, do not provide the body with energy, but plays a huge role in its life. Dietary fiber found primarily in plant foods that are low or very low in sugar. It is usually combined with other nutrients.Types of fiber.
Cellulose and Hemicellulose
Cellulose present in wholemeal wheat flour, bran, cabbage, young peas, green and waxy beans, broccoli, Brussels sprouts, cucumber peels, peppers, apples, carrots.
Hemicellulose found in bran, cereals, unrefined grains, beets, Brussels sprouts, mustard green shoots.
Cellulose and hemicellulose absorb water, making it easier for the colon to function. Essentially, they “bulk” waste and move it through the colon faster. This not only prevents constipation, but also protects against diverticulosis, spasmodic colitis, hemorrhoids, colon cancer and varicose veins.Lignin
This type of fiber is found in cereals eaten for breakfast, in bran, stale vegetables (when vegetables are stored, the lignin content in them increases, and they are less digestible), as well as in eggplants, green beans, strawberries, peas, and radishes.
Lignin reduces the digestibility of other fibers. In addition, it binds to bile acids, helping to lower cholesterol levels and speeds up the passage of food through the intestines.Gums and Pectin
Comedy found in oatmeal and other oat products, and dried beans.
Pectin present in apples, citrus fruits, carrots, cauliflower and cabbage, dried peas, green beans, potatoes, strawberries, strawberries, fruit drinks.
Gums and pectin affect absorption processes in the stomach and small intestine. By binding to bile acids, they reduce fat absorption and lower cholesterol levels. They delay gastric emptying and, by coating the intestines, slow down the absorption of sugar after meals, which is useful for diabetics, as it reduces the required dose of insulin.Knowing the types of carbohydrates and their functions, it arises next question –
What carbohydrates and how much should you eat?
In most products, the main component is carbohydrates, so there shouldn’t be any problems getting them from food, so carbohydrates make up the bulk of most people’s daily diet.
Carbohydrates that enter our body with food have three metabolic pathways:1) Glycogenesis(complex carbohydrate food that enters our gastrointestinal tract is broken down into glucose and then stored in the form complex carbohydrates– glycogen in muscle and liver cells, and is used as a backup source of nutrition when the blood glucose concentration is low)
2) Gluconeogenesis(the process of formation in the liver and renal cortex (about 10%) - glucose, from amino acids, lactic acid, glycerol)
3) Glycolysis(breakdown of glucose and other carbohydrates to release energy)Carbohydrate metabolism is primarily determined by the presence of glucose in the bloodstream, an important and versatile source of energy in the body. The presence of glucose in the blood depends on the last meal and the nutritional composition of food. That is, if you recently had breakfast, then the concentration of glucose in the blood will be high if long time abstain from food – low. Less glucose means less energy in the body, this is obvious, which is why you feel a loss of strength on an empty stomach. At a time when the glucose content in the bloodstream is low, and this is very well observed in morning hours, after a long sleep, during which you did not in any way maintain the level of existing glucose in the blood with portions of carbohydrate food, the body begins to replenish itself in a state of fasting with the help of glycolysis - 75%, and 25% with the help of gluconeogenesis, that is, the breakdown of complex stored carbohydrates, as well as amino acids, glycerin and lactic acid.
Also, not a little important pancreatic hormone regulates the concentration of glucose in the blood - insulin. Insulin is a transport hormone; it carries excess glucose into muscle cells and other tissues of the body, thereby regulating the maximum level of glucose in the blood. In people who are prone to obesity and do not watch their diet, insulin converts excess carbohydrates entering the body with food into fat; this is mainly typical for fast carbohydrates.
To choose the right carbohydrates from the whole variety of foods, such a concept is used as - glycemic index.Glycemic index- this is the rate of absorption of carbohydrates supplied with food into the bloodstream and the insulin response of the pancreas. It shows the effect of foods on blood sugar levels. This index is measured on a scale from 0 to 100, depending on the type of food, different carbohydrates are absorbed differently, some quickly, and accordingly they will have a high glycemic index, some slowly, the standard for rapid absorption is pure glucose, it has a glycemic index equals 100.
The GI of a product depends on several factors:
- Type of carbohydrates (simple carbohydrates have a high GI, complex carbohydrates have a low GI)
- Amount of fiber (the more there is in food, the lower the GI)
- Method of food processing (for example, heat treatment increases GI)
- Content of fats and proteins (the more of them in food, the lower the GI)There are many different tables that determine the glycemic index of foods, here is one of them:
The glycemic index table of foods allows you to take right decisions, choosing which foods to include in your daily diet and which ones to deliberately exclude.
The principle is simple: the higher the glycemic index, the less often you include such foods in your diet. Conversely, the lower the glycemic index, the more often you eat such foods.However, fast carbohydrates will also be useful to us in such important techniques food like:
- in the morning (after a long sleep, the concentration of glucose in the blood is very low, and it must be replenished as quickly as possible in order to prevent the body from receiving the necessary energy for life with the help of amino acids, by destroying muscle fibers)
- and after training (when energy expenditure on intense physical labor significantly reduces the concentration of glucose in the blood, after training perfect option accept faster carbohydrates, to replenish them as quickly as possible and prevent catabolism)How much carbohydrates should you eat?
In bodybuilding and fitness, carbohydrates should make up at least 50% of all nutrients (naturally, we do not consider “cutting” or losing weight).
There are plenty of reasons to load yourself up with lots of carbs, especially when it comes to whole, unprocessed foods. However, first of all, you must understand that there is a certain limit to the body’s ability to accumulate them. Imagine a gas tank: it can only hold a certain number of liters of gasoline. If you try to pour more into it, excess will inevitably spill out. Once carbohydrate stores have been converted into required amount glycogen, the liver begins to process the excess into fat, which is then stored under the skin and in other parts of the body.
The amount of muscle glycogen you can store depends on your degree of muscle mass. Just as some gas tanks are larger than others, muscles vary from person to person. The more muscular you are, the more glycogen your body can store.
To make sure what you receive correct amount carbohydrates - no more than prescribed - calculate your daily consumption using the following formula. To build muscle mass per day you should take -7g carbohydrates per kilogram of body weight (multiply your weight in kilograms by 7).
Once you have raised your carbohydrate intake to the required level, you must add additional strength training. Eating plenty of carbohydrates when training for bodybuilding will provide you with more energy, allowing you to exercise harder, longer, and achieve better results.
You can calculate your daily diet by studying this article in more detail.
General characteristics, structure and properties of carbohydrates.
Carbohydrates - these are polyhydric alcohols that contain, in addition to alcohol groups, an aldehyde or keto group.
Depending on the type of group in the molecule, aldoses and ketoses are distinguished.
Carbohydrates are very widespread in nature, especially in the plant world, where they make up 70–80% of the dry matter mass of cells. In the animal body they account for only about 2% of body weight, but here their role is no less important.
Carbohydrates can be stored in the form of starch in plants and glycogen in the body of animals and humans. These reserves are used as needed. In the human body, carbohydrates are deposited mainly in the liver and muscles, which are its depot.
Among other components of the body of higher animals and humans, carbohydrates account for 0.5% of body weight. However, carbohydrates are important for the body. These substances, together with proteins in the form proteoglycans form the basis of connective tissue. Carbohydrate-containing proteins (glycoproteins and mucoproteins) are an integral part of the body’s mucus (protective, enveloping functions), plasma transport proteins and immunologically active compounds(blood group-specific substances). Some carbohydrates serve as “spare fuel” for organisms to obtain energy.
Functions of carbohydrates:
Energy – carbohydrates are one of the main sources of energy for the body, providing at least 60% of energy costs. For the activity of the brain, blood cells, and kidney medulla, almost all energy is supplied through the oxidation of glucose. Upon complete breakdown, 1 g of carbohydrates is released 4.1 kcal/mol(17.15 kJ/mol) energy.
Plastic – carbohydrates or their derivatives are found in all cells of the body. They are part of biological membranes and cell organelles, participate in the formation of enzymes, nucleoproteins, etc. In plants, carbohydrates serve mainly as supporting materials.
Protective – viscous secretions (mucus), secreted by various glands, are rich in carbohydrates or their derivatives (mucopolysaccharides, etc.). They protect the internal walls of the hollow organs of the gastrointestinal tract and airways from mechanical and chemical influences, and the penetration of pathogenic microbes.
Regulatory – human food contains a significant amount of fiber, the rough structure of which causes mechanical irritation of the mucous membrane of the stomach and intestines, thus participating in the regulation of the act of peristalsis.
Specific – individual carbohydrates perform special functions in the body: they participate in the conduction of nerve impulses, the formation of antibodies, ensuring the specificity of blood groups, etc.
The functional significance of carbohydrates determines the need to provide the body with these nutrients. The daily requirement for carbohydrates for a person is on average 400 - 450 g, taking into account age, type of work, gender and some other factors.
Elementary composition. Carbohydrates consist of the following chemical elements: carbon, hydrogen and oxygen. Most carbohydrates have the general formula C n (H 2 O ) n. Carbohydrates are compounds consisting of carbon and water, which is the basis for their name. However, among carbohydrates there are substances that do not correspond to the given formula, for example, rhamnose C 6 H 12 O 5, etc. At the same time, substances are known whose composition corresponds to the general formula of carbohydrates, but in terms of their properties they do not belong to them (acetic acid C 2 H 12 O 2). Therefore, the name “carbohydrates” is quite arbitrary and does not always correspond to the chemical structure of these substances.
Carbohydrates- these are organic substances that are aldehydes or ketones of polyhydric alcohols.
Monosaccharides
Monosaccharides are polyhydric aliphatic alcohols that contain an aldehyde group (aldoses) or a keto group (ketoses).
Monosaccharides are solid, crystalline substances that are soluble in water and have a sweet taste. Under certain conditions, they are easily oxidized, as a result of which aldehyde alcohols are converted into acids, as a result of which aldehyde alcohols are converted into acids, and upon reduction, into the corresponding alcohols.
Chemical properties of monosaccharides :
Oxidation to mono-, dicarboxylic and glycuronic acids;
Reduction to alcohols;
Formation of esters;
Formation of glycosides;
Fermentation: alcoholic, lactic acid, citric acid and butyric acid.
Monosaccharides that cannot be hydrolyzed into simpler sugars. The type of monosaccharide depends on the length of the hydrocarbon chain. Depending on the number of carbon atoms, they are divided into trioses, tetroses, pentoses, and hexoses.
Trioses: glyceraldehyde and dihydroxyacetone, they are intermediate products of glucose breakdown and are involved in the synthesis of fats. both trioses can be prepared from the alcohol glycerol by dehydrogenation or hydrogenation.
Tetroses: erythrose – actively participates in metabolic processes.
Pentoses: ribose and deoxyribose are components of nucleic acids, ribulose and xylulose are intermediate products of glucose oxidation.
Hexoses: they are most widely represented in the animal and plant world and play a large role in metabolic processes. These include glucose, galactose, fructose, etc.
Glucose (grape sugar) . It is the main carbohydrate of plants and animals. The important role of glucose is explained by the fact that it is the main source of energy, forms the basis of many oligo- and polysaccharides, and is involved in maintaining osmotic pressure. The transport of glucose into cells is regulated in many tissues by the pancreatic hormone insulin. In the cell, in the course of multi-stage chemical reactions, glucose is converted into other substances (intermediate products formed during the breakdown of glucose are used for the synthesis of amino acids and fats), which are ultimately oxidized to carbon dioxide and water, which releases energy used by the body to support life. The level of glucose in the blood is usually used to judge the state of carbohydrate metabolism in the body. When the level of glucose in the blood decreases or its concentration is high and it is impossible to use it, as happens with diabetes, drowsiness occurs and loss of consciousness may occur (hypoglycemic coma). The rate at which glucose enters the tissues of the brain and liver does not depend on insulin and is determined only by its concentration in the blood. These tissues are called insulin-independent. Without the presence of insulin, glucose will not enter the cell and will not be used as fuel.
Galactose. A spatial isomer of glucose, differing in the location of the OH group at the fourth carbon atom. It is part of lactose, some polysaccharides and glycolipids. Galactose can isomerize into glucose (in the liver, mammary gland).
Fructose (fruit sugar). Found in large quantities in plants, especially fruits. There is a lot of it in fruits, sugar beets, and honey. Easily isomerizes to glucose. The breakdown pathway of fructose is shorter and energetically more favorable than that of glucose. Unlike glucose, it can penetrate from the blood into tissue cells without the participation of insulin. For this reason, fructose is recommended as the safest source of carbohydrates for diabetics. Some of the fructose enters the liver cells, which convert it into a more versatile “fuel” - glucose, so fructose can also increase blood sugar levels, although to a much lesser extent than other simple sugars.
According to their chemical structure, glucose and galactose are aldehyde alcohols, fructose is a ketone alcohol. Differences in the structure of glucose and fructose also characterize differences in some of their properties. Glucose reduces metals from their oxides; fructose does not have this property. Fructose is absorbed from the intestine approximately 2 times slower than glucose.
When the sixth carbon atom in a hexose molecule is oxidized, hexuronic (uronic) acids : from glucose - glucuronic, from galactose - galacturonic.
Glucuronic acid takes an active part in metabolic processes in the body, for example in the neutralization of toxic products, is part of mucopolysaccharides, etc. Its function is that it combines into organic low with substances that are poorly soluble in water. As a result, the bound substance becomes water-soluble and is excreted in the urine. This route of elimination is especially important for water soluble steroid hormones, their breakdown products, and also for the release of breakdown products of medicinal substances. Without interaction with glucuronic acid, further breakdown and release of bile pigments from the body is disrupted.
Monosaccharides may have an amino group .
When replacing the OH group of the second carbon atom in a hexose molecule with an amino group, amino sugars - hexosamines are formed: glucosamine is synthesized from glucose, galactosamine is synthesized from galactose, which are part of cell membranes and mucous membranes polysaccharides both in free form and in combination with acetic acid.
Amino sugars are called monosaccharides thatIn place of the OH group there is an amino group (- N H 2).
Amino sugars are the most important component glycosaminoglycans.
Monosaccharides form esters . OH group of a monosaccharide molecule; like any alcohol group can react with acid. In the interim exchangeSugar esters are of great importance. To turn it onin metabolism, sugar must becomephosphorus ester. In this case, the terminal carbon atoms are phosphorylated. For hexoses these are C-1 and C-6, for pentoses these are C-1 and C-5, etc. PainMore than two OH groups are not subject to phosphorylation. Therefore, the main role is played by mono- and diphosphates of sugars. In the name phosphorus ester usually indicate the position of the ester bond.
Oligosaccharides
Oligosaccharides contain two or more monosaccharide. They are found in cells and biological fluids, both in free form and in combination with proteins. Disaccharides are of great importance for the body: sucrose, maltose, lactose, etc. These carbohydrates perform an energy function. It is assumed that, being part of cells, they participate in the process of “recognition” of cells.
Sucrose(beet or cane sugar). Consists of glucose and fructose molecules. She is is a plant product and the most important component nent of food, has the sweetest taste compared to other disaccharides and glucose.
The sucrose content in sugar is 95%. Sugar is quickly broken down in the gastrointestinal tract, glucose and fructose are absorbed into the blood and serve as a source of energy and the most important precursor of glycogen and fats. It is often called a “carrier of empty calories,” since sugar is a pure carbohydrate and does not contain other nutrients, such as vitamins and mineral salts.
Lactose(milk sugar) consists of glucose and galactose, synthesized in the mammary glands during lactation. In the gastrointestinal tract it is broken down by the enzyme lactase. A deficiency of this enzyme leads to milk intolerance in some people. Deficiency of this enzyme occurs in approximately 40% of the adult population. Undigested lactose serves as a good nutrient for intestinal microflora. In this case, profuse gas formation is possible, the stomach “swells”. In fermented milk products, most of the lactose is fermented to lactic acid, so people with lactase deficiency can tolerate fermented milk products without unpleasant consequences. In addition, lactic acid bacteria in fermented milk products suppress the activity of intestinal microflora and reduce the adverse effects of lactose.
Maltose consists of two mo glucose molecules and is the main structural component of starch and glycogen.
Polysaccharides
Polysaccharides - high molecular weight carbohydrates, consisting of a large number of monosaccharides. They have hydrophilic properties and, when dissolved in water, form colloidal solutions.
Polysaccharides are divided into homo- and hete ropolysaccharides.
Homopolysaccharides. Contains monosaccharides Yes, only one type. Gak, starch and glycogen fasting are made only from glucose molecules, inulin - fructose. Homopolysaccharides are highly branched structure and are a mixture of two limers - amylose and amylopectin. Amylose consists of 60-300 glucose residues linked into linear chain using an oxygen bridge, formed between the first carbon atom of one molecule and the fourth carbon atom of another (1,4 bond).
Amylose It is soluble in hot water and gives a blue color with iodine.
Amylopectin - a branched polymer consisting of both unbranched chains (1,4 bond) and branched ones, which are formed due to bonds between the first carbon atom of one glucose molecule and the sixth carbon atom of another with the help of an oxygen bridge (1,6 bond).
Representatives of homopolysaccharides are starch, fiber and glycogen.
Starch(plant polysaccharide)– consists of several thousand glucose residues, 10-20% of which are amylose, and 80-90% amylopectin. Starch is insoluble in cold water, and when hot it forms colloidal solution, called in everyday life starch paste. Starch accounts for up to 80% of carbohydrates consumed in food. The source of starch is plant products, mainly cereals: cereals, flour, bread, and potatoes. Cereals contain the most starch (from 60% in buckwheat (kernel) to 70% in rice).
Cellulose, or cellulose,- the most common plant carbohydrate on earth, produced in an amount of approximately 50 kg for every inhabitant of the Earth. Fiber is a linear polysaccharide consisting of 1000 or more glucose residues. In the body, fiber is involved in activating the motility of the stomach and intestines, stimulates the secretion of digestive juices, and creates a feeling of satiety.
Glycogen(animal starch) is the main storage carbohydrate of the human body. It consists of approximately 30,000 glucose residues, which form a branched structure. The most significant amounts of glycogen accumulate in the liver and muscle tissue, including the heart muscle. The function of muscle glycogen is that it is a readily available source of glucose used in energy processes in the muscle itself. Liver glycogen is used to maintain physiological blood glucose concentrations, primarily between meals. 12-18 hours after eating, the glycogen supply in the liver is almost completely depleted. The content of muscle glycogen decreases noticeably only after prolonged and strenuous physical work. When there is a lack of glucose, it is quickly broken down and restores its normal level in the blood. In cells, glycogen is associated with cytoplasmic protein and partially with intracellular membranes.
Heteropolysaccharides (glycosaminoglycans or mucopolysaccharides) (the prefix “muco-” indicates that they were first derived from mucin). They consist of various types of monosaccharides (glucose, galactose) and their derivatives (amino sugars, hexuronic acids). Other substances were also found in their composition: nitrogenous bases, organic acids and some others.
Glycosaminoglycans They are jelly-like, sticky substances. They perform various functions, including structural, protective, regulatory, etc. Glycosaminoglycans, for example, make up the bulk of the intercellular substance of tissues and are part of the skin, cartilage, synovial fluid, and the vitreous body of the eye. In the body, they are found in combination with proteins (proteoglycans and glycoprotsides) and fats (glycolipids), in which polysaccharides account for the bulk of the molecule (up to 90% or more). The following are important for the body.
Hyaluronic acid- the main part of the intercellular substance, a kind of “biological cement” that connects cells, filling the entire intercellular space. It also acts as a biological filter that traps microbes and prevents their penetration into the cell, and participates in the exchange of water in the body.
It should be noted that hyaluronic acid breaks down under the action of a specific enzyme, hyaluronidase. In this case, the structure of the intercellular substance is disrupted, “cracks” form in its composition, which leads to an increase in its permeability to water and other substances. This is important in the process of fertilization of an egg by sperm, which are rich in this enzyme. Some bacteria also contain hyaluronidase, which greatly facilitates their penetration into the cell.
X ondroitin sulfates- chondroitinsulfuric acids serve as structural components of cartilage, ligaments, heart valves, umbilical cord, etc. They promote the deposition of calcium in bones.
Heparin is formed in mast cells, which are found in the lungs, liver and other organs, and is released into the blood and intercellular environment. In the blood, it binds to proteins and prevents blood clotting, acting as an anticoagulant. In addition, heparin has an anti-inflammatory effect, affects the metabolism of potassium and sodium, and performs an antihypoxic function.
A special group of glycosaminoglycans are compounds containing neuraminic acids and carbohydrate derivatives. Compounds of neuraminic acid with acetic acid are called opalic acids. They are found in cell membranes, saliva and other biological fluids.
§ 1. CLASSIFICATION AND FUNCTIONS OF CARBOHYDRATES
Even in ancient times, humanity became acquainted with carbohydrates and learned to use them in their Everyday life. Cotton, flax, wood, starch, honey, cane sugar are just some of the carbohydrates that have played a role important role in the development of civilization. Carbohydrates are among the most abundant in nature organic compounds. They are integral components of the cells of any organisms, including bacteria, plants and animals. In plants, carbohydrates account for 80–90% of dry mass, in animals – about 2% of body weight. Their synthesis from carbon dioxide and water is carried out by green plants using energy sunlight (photosynthesis ). The overall stoichiometric equation for this process is:
Glucose and other simple carbohydrates are then converted into more complex carbohydrates such as starch and cellulose. Plants use these carbohydrates to release energy through the process of respiration. This process is essentially the reverse of photosynthesis:
Interesting to know! Green plants and bacteria annually absorb approximately 200 billion tons of carbon dioxide from the atmosphere through the process of photosynthesis. In this case, about 130 billion tons of oxygen are released into the atmosphere and 50 billion tons of organic carbon compounds, mainly carbohydrates, are synthesized.
Animals are not capable of synthesizing carbohydrates from carbon dioxide and water. By consuming carbohydrates with food, animals use the energy accumulated in them to maintain vital processes. High content carbohydrates characterize such types of our food as baked goods, potatoes, cereals, etc.
The name "carbohydrates" is historical. The first representatives of these substances were described summary formula C m H 2 n O n or C m (H 2 O) n. Another name for carbohydrates is Sahara – is explained by the sweet taste of the simplest carbohydrates. In terms of their chemical structure, carbohydrates are a complex and diverse group of compounds. Among them there are quite a few simple connections with a molecular weight of about 200, and giant polymers whose molecular weight reaches several million. Along with carbon, hydrogen and oxygen atoms, carbohydrates may contain atoms of phosphorus, nitrogen, sulfur and, less commonly, other elements.
Classification of carbohydrates
All known carbohydrates can be divided into two large groups – simple carbohydrates And complex carbohydrates. A separate group consists of carbohydrate-containing mixed polymers, for example, glycoproteins– complex with a protein molecule, glycolipids – complex with lipid, etc.
Simple carbohydrates (monosaccharides, or monosaccharides) are polyhydroxycarbonyl compounds that are not capable of forming simpler carbohydrate molecules upon hydrolysis. If monosaccharides contain an aldehyde group, then they belong to the class of aldoses (aldehyde alcohols), if they contain a ketone group, they belong to the class of ketoses (keto alcohols). Depending on the number of carbon atoms in the monosaccharide molecule, trioses (C 3), tetroses (C 4), pentoses (C 5), hexoses (C 6), etc. are distinguished:
The most common compounds found in nature are pentoses and hexoses.
Complex carbohydrates ( polysaccharides, or poliosis) are polymers built from monosaccharide residues. When hydrolyzed, they form simple carbohydrates. Depending on the degree of polymerization, they are divided into low molecular weight ( oligosaccharides, the degree of polymerization of which is usually less than 10) and high molecular weight. Oligosaccharides are sugar-like carbohydrates that are soluble in water and have a sweet taste. Based on their ability to reduce metal ions (Cu 2+, Ag +), they are divided into restorative And non-restorative. Polysaccharides, depending on their composition, can also be divided into two groups: homopolysaccharides And heteropolysaccharides. Homopolysaccharides are built from monosaccharide residues of the same type, and heteropolysaccharides are built from residues of different monosaccharides.
The above with examples of the most common representatives of each group of carbohydrates can be presented in the following diagram:
Functions of carbohydrates
The biological functions of polysaccharides are very diverse.
Energy and storage function
Carbohydrates contain the bulk of calories consumed by a person through food. The main carbohydrate supplied with food is starch. It is contained in bakery products, potatoes, as part of cereals. The human diet also contains glycogen (in liver and meat), sucrose (as additives to various dishes), fructose (in fruits and honey), and lactose (in milk). Polysaccharides, before being absorbed by the body, must be hydrolyzed with the help of digestive enzymes to monosaccharides. Only in this form are they absorbed into the blood. With the bloodstream, monosaccharides enter organs and tissues, where they are used to synthesize their own carbohydrates or other substances, or are broken down to extract energy from them.
The energy released as a result of the breakdown of glucose is stored in the form of ATP. There are two processes for the breakdown of glucose: anaerobic (in the absence of oxygen) and aerobic (in the presence of oxygen). As a result of the anaerobic process, lactic acid is formed
which in severe physical activity accumulates in the muscles and causes pain.
As a result of the aerobic process, glucose is oxidized to carbon monoxide (IV) and water:
As a result of aerobic breakdown of glucose, much more energy is released than as a result of anaerobic breakdown. In general, the oxidation of 1 g of carbohydrates releases 16.9 kJ of energy.
Glucose may be subject to alcoholic fermentation. This process is carried out by yeast under anaerobic conditions:
Alcoholic fermentation is widely used in industry for the production of wines and ethyl alcohol.
Man learned to use not only alcoholic fermentation, but also found the use of lactic acid fermentation, for example, to obtain lactic acid products and pickle vegetables.
There are no enzymes in the human or animal body that can hydrolyze cellulose; however, cellulose is the main component of food for many animals, in particular ruminants. The stomachs of these animals contain large quantities of bacteria and protozoa that produce the enzyme cellulase, catalyzing the hydrolysis of cellulose to glucose. The latter can undergo further transformations, as a result of which butyric, acetic, and propionic acids are formed, which can be absorbed into the blood of ruminants.
Carbohydrates also perform a reserve function. Thus, starch, sucrose, glucose in plants and glycogen in animals they are the energy reserve of their cells.
Structural, supporting and protective functions
Cellulose in plants and chitin in invertebrates and fungi they perform supporting and protective functions. Polysaccharides form a capsule in microorganisms, thereby strengthening the membrane. Lipopolysaccharides of bacteria and glycoproteins of the surface of animal cells provide selectivity of intercellular interaction and immunological reactions of the body. Ribose serves as a building material for RNA, and deoxyribose for DNA.
Performs a protective function heparin. This carbohydrate, being a blood clotting inhibitor, prevents the formation of blood clots. It is found in the blood and connective tissue of mammals. Bacterial cell walls formed by polysaccharides, held together by short amino acid chains, protect bacterial cells from adverse effects. In crustaceans and insects, carbohydrates participate in the construction of the exoskeleton, which performs a protective function.
Regulatory function
Fiber enhances intestinal motility, thereby improving digestion.
The possibility of using carbohydrates as a source of liquid fuel – ethanol – is interesting. WITH for a long time They used wood to heat their homes and cook food. IN modern society this type of fuel is being replaced by other types - oil and coal, which are cheaper and more convenient to use. However, plant raw materials, despite some inconveniences in use, unlike oil and coal, are a renewable source of energy. But its use in engines internal combustion difficult. For these purposes, it is preferable to use liquid fuel or gas. From low-grade wood, straw or other plant materials containing cellulose or starch, liquid fuel can be obtained - ethanol. To do this, you must first hydrolyze cellulose or starch to obtain glucose:
and then subject the resulting glucose to alcoholic fermentation to produce ethyl alcohol. Once purified, it can be used as fuel in internal combustion engines. It should be noted that in Brazil, for this purpose, billions of liters of alcohol are produced annually from sugar cane, sorghum and cassava and used in internal combustion engines.
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 found in the main organic substances: proteins, nucleic acids ah, lipids and carbohydrates. The last group includes 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 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
They have a 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. Included cell 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 views 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 enzymatic reactions- 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 the breakdown of glycogen reserves in muscle tissue. 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 in the molecule functional group ketones. 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 fast source obtaining 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 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 an 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 residues of monosaccharide molecules, such as glucose or fructose, are linked 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 due to hyposecretion of the lactase enzyme, which breaks down milk sugar into 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 the small intestine of 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, a special diet is used and the enzyme itself is added 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 sweet 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 reserved in hepatocytes and skeletal muscle cells, 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 hyaluronic acid residues. 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 they are used both biologically active substances, well removes toxins from the large intestine.
What are glycolipids
This is an interesting group of complex compounds of carbohydrates and fats found in nerve 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 molecules fat 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 leads a sedentary lifestyle, his weight may increase significantly. It is worth remembering that carbohydrate-rich foods are broken down mainly in the duodenum into 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 energetic 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 latest biochemical research has established that if glycoproteins begin to change their native (natural) structure, this leads to the development of such complex diseases as asthma, rheumatoid arthritis, and 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 are confirmed by the fact that the physiological role of carbohydrates in the body is diverse and extremely important.
Where and how are carbohydrates formed?
The main suppliers of simple and complex sugars 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 process 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 structural substance. This explains the role carbohydrates play in the body.
Supramembrane complexes of heterotrophic cells
They are characteristic of animals and fungi. The chemical composition and 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. Human and animal cells have a special structural component called the glycocalyx. This thin surface layer consists of glycolipids and glycoproteins associated with cytoplasmic membrane. It provides direct communication between cells and the 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. The cell walls of plant cells can become lignified. In this case, the spaces between the cellulose bundles are filled with another carbohydrate - lignin. It enhances support functions 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 the adhesion of bacterial cells to each other. 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, such as antibiotics.
Carbohydrates are one of the essential elements necessary to maintain the optimal state of the human body. These are the main suppliers of energy, consisting of carbon, hydrogen and oxygen. They are found mainly in foods plant origin, namely in sugars, baked goods, whole grain cereals and cereals, potatoes, fiber (vegetables, fruits). It is a mistake to believe that dairy and other predominantly protein products do not contain carbohydrates. For example, milk also contains carbohydrates. They are milk sugar - lactose. From this article you will learn what groups carbohydrates are divided into, examples and differences between these carbohydrates, and you will also be able to understand how to calculate their required daily intake.
Main groups of carbohydrates
So, now let’s figure out what groups carbohydrates are divided into. Experts distinguish 3 main groups of carbohydrates: monosaccharides, disaccharides and polysaccharides. To understand their differences, let's look at each group in more detail.
- Monosaccharides are also simple sugars. Contained in large quantities in (glucose), fruit sugar (fructose), etc. Monosaccharides dissolve well in liquid, giving it a sweet taste.
- Disaccharides are a group of carbohydrates that are broken down into two monosaccharides. They are also completely soluble in water and have a sweet taste.
- Polysaccharides are the last group, which are insoluble in liquids, do not have a distinct taste and consist of many monosaccharides. Simply put, these are glucose polymers: the well-known starch, cellulose (the cell wall of plants), glycogens (a storage carbohydrate in fungi, as well as animals), chitin, peptidoglycan (murein).
Which group of carbohydrates does the human body need most?
Considering the question of what groups carbohydrates are divided into, it is worth noting that most of them are found in products of plant origin. They contain a huge amount of vitamins and nutrients, so carbohydrates must be present in the daily diet of every person leading a healthy and active lifestyle. To provide the body with these substances, it is necessary to consume as much grains (porridge, bread, crispbreads, etc.), vegetables and fruits as possible.
Glucose, i.e. regular sugar is a particularly useful component for humans, as it has a beneficial effect on mental activity. These sugars are almost instantly absorbed into the blood during digestion, which helps increase insulin levels. At this time, a person experiences joy and euphoria, so sugar is considered to be a drug that, if consumed in excess, causes addiction and negatively affects general state health. That is why the intake of sugar into the body should be controlled, but it cannot be completely abandoned, because glucose is a reserve source of energy. In the body, it is converted into glycogen and deposited in the liver and muscles. At the moment of breakdown of glycogen, muscle work is performed, therefore, it is necessary to constantly maintain its optimal amount in the body.
Norms for carbohydrate consumption
Since all carbohydrate groups have their own characteristic features, their consumption should be strictly dosed. For example, polysaccharides, unlike monosaccharides, must enter the body in larger quantities. In accordance with modern nutrition standards, carbohydrates should make up half of the daily diet, i.e. approximately 50% - 60%.
Calculation of the amount of carbohydrates required for life
Each group of people requires a different amount of energy. For example, for children aged 1 to 12 months physiological need in carbohydrates fluctuates within 13 grams per kilogram of weight, but one should not forget into which groups the carbohydrates present in the child’s diet are divided. For adults aged 18 to 30 years, the daily intake of carbohydrates varies depending on the area of activity. So, for men and women involved in mental labor, the consumption rate is about 5 grams per 1 kilogram of weight. Therefore, with normal body weight healthy man needs approximately 300 grams of carbohydrates per day. This figure also varies depending on gender. If a person is engaged primarily in heavy physical labor or sports, then when calculating the norm of carbohydrates, it is used following formula: 8 grams per 1 kilogram of normal weight. Moreover, in this case, it also takes into account what groups the carbohydrates supplied with food are divided into. The above formulas allow you to calculate mainly the amount of complex carbohydrates - polysaccharides.
Approximate sugar consumption standards for certain groups of people
As for sugar, in its pure form it is sucrose (glucose and fructose molecules). For an adult, only 10% of sugar from the number of calories consumed per day is considered optimal. To be precise, adult women need approximately 35-45 grams of pure sugar per day, while men need about 45-50 grams of pure sugar. For those who are actively involved in physical labor, the normal amount of sucrose ranges from 75 to 105 grams. These numbers will allow a person to carry out activities and not experience a loss of strength and energy. As for dietary fiber (fiber), their amount should also be determined individually, taking into account gender, age, weight and activity level (at least 20 grams).
Thus, having determined into which three groups carbohydrates are divided and understanding the importance in the body, each person will be able to independently calculate their required amount for life and normal performance.