The main sources of energy for humans are. It is the content of these substances that is often described nutritional value products. Proteins are responsible for the formation internal organs, muscle tissue and liquids. Fats form cell membranes, create protective shells for internal organs, help absorb vitamins and produce hormones. What is the role of carbohydrates in the human body?
The role of carbohydrates in the human body is great. Carbohydrates are the main source of energy necessary for the functioning of all organs, muscles, growth and cell division. Carbohydrates are broken down very quickly, and when they are broken down, a lot of energy is released. Carbohydrate-rich foods instantly create a feeling of fullness without causing a feeling of heaviness in the stomach. In some cases, it becomes very important that the digestion of carbohydrates does not cause the so-called “afternoon depression”. This term refers to a state of lethargy, apathy, and drowsiness after eating. Afternoon depression occurs when the body directs all its energy to digesting and assimilating food. During important projects, exams, and other occasions that require concentration, afternoon depression is simply unacceptable. That is why in such situations it is advised to eat food rich in carbohydrates, such as chocolate or candy. A person does not feel hungry, receives the necessary amount of energy, and his body is not overloaded with difficult-to-digest food.
Carbohydrates are also important for normal functioning all organs and systems. Thus, hormones, enzymes, and secretions are produced mainly by proteins, but carbohydrates are also involved in synthesis processes. In the absence of carbohydrates, the body would not have enough energy for external activities, the work of internal organs, or the growth and division of cells.
A person receives carbohydrates from food. Experts distinguish simple carbohydrates - monosaccharides, and complex carbohydrates - polysaccharides. Monosaccharides include glucose, fructose and galactose, and polysaccharides include starch, pectin and fiber. Monosaccharides are found mainly in honey, sugar, confectionery, and fruits. We get polysaccharides from vegetables, legumes and cereals. Experts consider fruits, vegetables, legumes and grains to be the most valuable sources of carbohydrates. Confectionery, of course, gives energy, but refined sugar brings more harm than good.
Nutritionists recommend eating foods rich in carbohydrates separately from other foods. This is explained by several reasons. Firstly, carbohydrates begin to break down already in the esophagus, and fats and proteins are processed longer and more difficult. When proteins are broken down, the body receives a lot of energy, and there is no need to break down fats into energy. As a result, fats obtained from food become reserves and go into body fat. Secondly, sugar causes food to ferment in the stomach, causing bloating, heartburn, and belching. Secretion is impaired gastric juice, digestion and absorption of food becomes less efficient.
Carbohydrates play important role in the life of the human body. To be healthy, you need to monitor the quality of food and choose natural sources carbohydrates. Be healthy!
Carbohydrates - organic compounds consisting of carbon, hydrogen and oxygen. They are synthesized in plants from water and carbon dioxide under the influence of sunlight.
Food includes simple and complex, digestible and indigestible carbohydrates. The main simple carbohydrates are glucose, galactose and fructose (monosaccharides), sucrose, lactose and maltose (disaccharides). Complex carbohydrates (polysaccharides) include starch, glycogen, fiber, pectin, and hemicellulose.
Carbohydrates are necessary for the normal metabolism of proteins and fats in the human body.. In combination with proteins, they form some hormones and enzymes, secretions of the salivary and other mucus-forming glands, as well as other important compounds.
Of particular importance are fiber, pectins, and hemicellulose, which are only partially digested in the intestines and are an insignificant source of energy. However, these polysaccharides form the basis dietary fiber and play an important role in nutrition. Carbohydrates are found mainly in foods of plant origin.
Glucose
Glucose is the main energy supplier for the brain. It is found in fruits and berries and is necessary for energy supply and the formation of glycogen in the liver.
Fructose
Fructose almost does not require the hormone insulin for its absorption, which makes it possible to recommend its sources for diabetes mellitus, but in limited quantities. The main suppliers of sucrose are sugar, confectionery products, jam, ice cream, sweet drinks, as well as some vegetables and fruits: beets, carrots, apricots, peaches, sweet plums and others. In the intestine, sucrose is broken down into glucose and fructose.
Lactose
Lactose is found in dairy products. With congenital or acquired (most often as a result of intestinal diseases) deficiency of the lactose enzyme in the intestine, the breakdown of lactose into glucose and galactose is disrupted and intolerance to dairy products occurs.
IN fermented milk products There is less lactose than in milk, since when milk is fermented, lactic acid is formed from lactose.
Maltose
Maltose (malt sugar) is an intermediate product of the breakdown of starch by digestive enzymes and enzymes of sprouted grains (malt). The resulting maltose breaks down into glucose. Maltose is found in free form in honey, malt extract (maltose molasses), and beer.
Starch
Starch makes up 80% or more of all carbohydrates in the human diet. Its sources are flour, cereals, pasta, bread, legumes and potatoes.
Starch is digested relatively slowly, breaking down into glucose. Starch from rice and semolina is digested easier and faster than from millet, buckwheat, pearl barley and barley groats, from potatoes and bread.
Complex carbohydrate
Complex carbohydrate fiber is not digested in the human body, but stimulates the intestines and creates conditions for development beneficial bacteria. It must be present in food products (found in vegetables, fruits, wheat bran).
Pectins
Pectins stimulate digestion and promote excretion harmful substances. There are especially many of them in apples, plums, gooseberries, and cranberries.
Lack of carbohydrates leads to disruption of fat and protein metabolism, consumption of food proteins and tissue proteins. accumulate in the blood harmful products incomplete oxidation of fatty acids and some amino acids, the acid-base state of the body shifts to the acidic side. At severe shortage Carbohydrates cause weakness, drowsiness, dizziness, headaches, hunger, nausea, sweating, trembling hands. These phenomena quickly disappear after taking sugar. With long-term restriction of carbohydrates in the diet, their amount should still not be below 100 g.
Excess carbohydrates may lead to obesity. Systematic overconsumption sugar and others easily digestible carbohydrates contributes to the manifestation of latent diabetes mellitus due to overload and then depletion of pancreatic cells that produce the insulin necessary for the absorption of glucose.
But sugar itself and products containing it do not cause diabetes mellitus, but can only be risk factors for the development of an already existing disease.
What are carbohydrates and the question immediately arises - why are they needed? Some people, for unknown reasons, recognize them as harmful and declare war on them. Currently, there is a clear trend towards a general proteinization of nutrition. For some reason, some people believe that proteins are healthy, and that other components, including carbohydrates, are not needed by the body (see). However rational nutrition suggests a slightly different balance and suggests that not only protein is needed by the body, but also other nutrients.
What are carbohydrates and why do the body need them?
By chemical composition they are composed of carbon, oxygen and hydrogen. Humans contain about 3% carbohydrates. Of these, part (6%) is deposited in the liver in the form of glycogen, 0.5% in the heart and about 3% in muscle tissue. In absolute terms, the body of an adult male contains about 0.5 kg of glycogen. In addition, sugars are found in the form of glucose in the blood plasma in dissolved form. True, it is not much, about 5 g. The more highly trained a person is, the more pronounced his glycogen-forming function is. And read how to use shorts for weight loss.
To a small extent, the body is able to synthesize carbohydrates. However, the bulk of them comes from outside. For the most part they are contained in plant foods. Cereals contain 80% of them, and the sugar content is close to 100.
Functions of carbohydrates
- Energy component. They are the main suppliers of energy to the body. They account for up to 60% of all daily energy. When oxidized, 1 g of carbohydrates provides energy equivalent to 4.1 kcal. At the same time, water is formed. With a lack of carbohydrates, previously accumulated water begins to be consumed and weight loss occurs. Many people mistake this for burning fat. But this has nothing to do with this process. This only means that glycogen reserves are running low.
- Construction function (plastic). They consist of enzymatic structures and membrane cell formations. Carbohydrates are included in the polysaccharide structure and organization of complex proteins. They make up complex molecules and build ATP. They are representatives of the storage of information at the gene level, which is the DNA molecule. They are also included in RNA.
- Specific function. They are credited with the role of substances with anticoagulant properties. They prevent blood clotting when it is not necessary. The body makes sure that a certain supply of them is created. Glycogen exists for this purpose. They consist of receptors for certain hormonal substances that are capable of exerting some antitumor effect. Read about the connection between hormones and weight.
- A function associated with the supply of nutritional components. The body stores carbohydrates in the form of glycogen. It is a rapidly mobilized reserve depot associated with energy. Glycogen provides the body's need for glucose. This relates to the glycogen-forming function of the liver. By creating a depot in muscle structures, it provides the body with the opportunity for physical activity.
- Protection function. consists of class representatives complex carbohydrates. The composition of the mucus that covers the surface of the bronchi, lines inner surface nose, includes mucopolysaccharides. They prevent the penetration of dust particles, microbial flora, foreign bodies.
- Regulation function. Fiber refers to carbohydrates. It does not break down in the intestines, but is capable of activating its peristalsis. As a result, nutrient absorption and digestion in general are improved.
Types of carbohydrates
Pasta, representatives of the fruit and vegetable assortment, and other products are carbohydrates. All carbohydrates can be divided into the following groups:
- monosaccharides. This includes representatives of simple carbohydrates. Digestive enzymes they are not split. They come from outside with foods or are formed in the body by breaking down complex carbohydrates. If their content increases, the hormone insulin produced by the pancreas begins to activate. Redirection occurs to tissues where glycogen is synthesized with its participation. Fats can also be synthesized from them;
- disaccharides. They consist of several monosaccharides, the number of which ranges from 2 to 10. A typical representative is sucrose. All of them have a sweetish taste;
- polysaccharides. Belong to the class of complex carbohydrates containing huge amount monosaccharides.
To feel great and be energetic, you need to eat right. The diet should include proteins, fats and carbohydrates. If there is a shortage of any components, a person feels discomfort, lethargy, weakness and malaise.
Carbohydrates enable normal functioning. What are they for? These substances are a source of energy. As they are processed into glucose, the body becomes more active and alert. At the same time, you should know how many carbohydrates you need to consume per day so as not to harm your health.
Concept
Carbohydrates - organic matter, consisting of carbon, oxygen, 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 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.
Species
Before you find out how much carbohydrates you should consume, you should familiarize yourself with their types. These components are nutrient for the brain and provide the energy needs of all people.
Carbohydrates are:
- Simple;
- Complex;
- Easily digestible;
- Difficult to digest.
TO simple types include glucose, galactose and fructose. Such substances are quickly absorbed and sharply increase blood sugar levels. Doctors recommend that many people limit their diet as much as possible. This means that you need to consume sugar, honey, and sweets in smaller quantities.
Complex carbohydrates are starch, glycogen, fiber, pectin. Many nutritionists recommend organizing your menu so that it consists of 60% carbohydrates. Substances are needed for correct exchange proteins and carbohydrates complex type? Together with proteins, they synthesize hormones and enzymes, which is important for the functioning of the entire body.
Of great importance are those that are practically not digested in the intestines and are not a source of energy. But these hard-to-digest carbohydrates are important in the digestion process. Thanks to them, intestinal function is stimulated and digestion improves.
Starch is digested slowly, but long period increases blood sugar. The body also needs it, but in moderation. The substance supplied with rice, semolina, potatoes, and bread is digested faster than that found in millet, buckwheat, and barley.
Glycogen, which is called animal starch, accumulates in muscle and liver cells. It is found in animal products. The component creates an energy reserve that can replenish the lack of glucose in the body at any time.
Difference between simple and complex carbohydrates
Complex carbohydrates give you a feeling of fullness. What are they for? There's a man with them for a long time doesn't want to eat. After these substances enter the body, it takes a long time before they are processed into glucose. This category includes cellulose, starch, glycogen. Such substances are found in vegetables, cereals, and pasta.
Simple carbohydrates are needed for easy satiety, but after a while you will still feel hungry. When such components are present in the body, they are quickly converted into glucose. As the body fights sugar surges, it removes excess sugar into fat deposits. Therefore, a person quickly gets fat. Such components are found in sugar, sweets, grapes, bananas, buns, corn, and white rice.
Functions
Every person should eat carbohydrates. What they are needed for can be understood from their main functions:
- They are sources of energy for the brain.
- Maintains the tone of body tissues.
- Protect the body from the proliferation of bacteria in the intestines.
- Stimulates good absorption of fats.
- Many carbohydrates are enriched with fiber, so consuming them will prevent constipation and other diseases.
Such functions are necessary to maintain human health. But like any other component, carbohydrates should be consumed in moderation. This will prevent the occurrence of diseases.
Other Features
A person should eat foods containing these organic components to prevent deterioration of the body's condition. Carbohydrates are needed for work immune system, 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.
Sources of carbohydrates
Simple carbohydrates are found in sugar, sweets, chocolate, and dried fruits. They are present in baked goods - waffles, cakes, buns. Bread and pasta are also sources of this substance. If a product contains sugar and flour, then they are classified as fast carbohydrates. Those who are losing weight and athletes exclude them from their diet.
Complex carbohydrates are found in cereals - buckwheat, rice, rolled oats and legumes - peas, beans, lentils. They are found in whole grain bread. These components must be included in the diet, as they are considered a source of energy for the brain and muscles. Moderate amounts of carbohydrates are found in bananas, grapes, and persimmons. How sour berry or fruit, the less such substances it contains. Carbohydrate foods include potatoes and juices. A minimum of such substances is found in cottage cheese, milk, and cheese. If you eat such foods in moderation, they will not harm your health.
Deficiency and excess
With a lack of carbohydrates, the metabolism of fats and proteins is disrupted, so harmful components accumulate in the body. Because of this, the pH balance changes to acidic environment. How to determine that the body lacks these substances? Symptoms may include drowsiness, lethargy, hunger, headaches and nausea. To improve your condition, you need to include carbohydrates in your diet. This will increase the amount of sugar in your blood and improve your well-being.
There are cases of excess carbohydrates. This leads to obesity, increasing insulin in the blood. If you constantly eat a lot of such food, latent diabetes may appear. Doctors say that excess carbohydrates cause deterioration in the functioning of the pancreas. People with diabetes should not eat a lot of these foods to prevent complications. This is why it is important to know how much carbohydrates you should eat.
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? sedentary life? Doctors recommend 4 g per 1 kg of body weight. Such standards must be followed by men and women. More active people requires 5-6 g per 1 kg of mass, and mobile - 6-7 g. K last group include people who exercise at least 3 times a week.
Athletes need to eat 8-10 g of carbohydrates per 1 kg of weight. Since such people have intense strength training, then the volume of organic components burns quickly. If you follow these simple rules, then you can protect yourself from a number of diseases for a long time.
It helps to be cheerful and healthy proper diet. Food should be varied. Not only carbohydrates are needed, but also proteins and fats. If you want sweets, then it’s better to choose healthy products eg honey, dried fruits, fresh fruit. 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.
Carbohydrates constitute the main part of the diet and provide 50-60% of its energy value. When 1 g of digestible carbohydrates are oxidized, the body releases 4 kcal.
Carbohydrates perform the following physiological functions:
energy- with all types of physical labor there is an increased need for carbohydrates. Carbohydrates are the main source of energy for the central nervous system.
plastic- they are part of the structures of many cells and tissues and participate in the synthesis of nucleic acids. Glucose is constantly found in the blood, glycogen is in the liver and muscles, galactose is part of brain lipids, lactose is part of human milk, etc. Carbohydrates, in combination with proteins and lipids, form some enzymes, hormones, mucous secretions of glands, immunoglobulins and other biologically important compounds.
Of particular importance are fiber, pectins, hemicellulose, which are almost not digested in the intestines and are minor sources of energy. However, they are the main component dietary fiber and are extremely necessary for the body for the normal functioning of the digestive tract.
In the body, carbohydrates can be formed from proteins and fats. They are deposited in limited quantities and human reserves are small. Carbohydrates are found mainly in plant foods.
IN food products carbohydrates are presented in the form simple And complex carbohydrates.
TO simple carbohydrates include monosaccharides (hexoses - glucose, fructose, galactose; pentoses - xylose, ribose, arabinose), disaccharides (lactose, sucrose, maltose), To complex - polysaccharides (starch, glycogen, fiber, pectins).
Simple carbohydrates have good solubility, are easily digested and are used to form glycogen.
Digestible carbohydrates are the main suppliers of energy for the body. They have a pronounced sweet taste. Their relative sweetness varies. Due to the trend of reducing the caloric content of food, food additives and sweeteners are currently used to regulate body weight, as well as for patients with diabetes. Table 4 shows the sweetness of carbohydrates and sugar substitutes (sucrose is taken as 100%).
Monosaccharides
Glucose - is the most common monosaccharide, formed in the body as a result of the breakdown of disaccharides and starch in food. It is absorbed into the blood within 5-10 minutes. after entering the stomach.
Glucose is the main supplier of energy for brain neurons, muscle cells(including heart muscle) and red blood cells, which suffer most from a lack of glucose. In a day, a person’s brain consumes about 100 g of glucose, striated muscles - 35 g, red blood cells - 30 g. Other tissues can use free fatty acids or ketone bodies.
A constant level of glucose is maintained in human blood serum (glycemia), on an empty stomach is 3.3-5.5 mmol/l, which is ensured by constantly occurring processes: glycogenolysis(breakdown of glycogen with the release of glucose into the blood) and gluconeogenesis(glucose synthesis from non-carbohydrate components). These processes are regulated by pancreatic hormones ( insulin And glucagon) and adrenal cortex (glucocorticoids).
Hypoglycemia – reduced content glucose in blood serum.
Hyperglycemia– increased glucose levels in the blood serum.
These conditions can develop both in various metabolic diseases and in healthy person(reactive hyperglycemia is observed after eating, hypoglycemia - during hunger). Hyperglycemia due to a defect in insulin secretion or action is characteristic of diabetes mellitus.
Hypoglycemia in a healthy person leads to activation of eating behavior, i.e. Glucose is involved in the regulation of appetite, which must be taken into account when developing diets aimed at weight loss.
In the practice of dietetics at the end of the twentieth century, the concept appeared glycemic index (GI), used to determine the ability of carbohydrate-containing foods and dishes to increase blood glucose levels. The GI of glucose is taken as a starting point equal to 100. The higher the GI of foods and dishes, the faster the glycemic level increases after their consumption. With low GI values of foods and dishes, glucose enters the blood slowly and evenly. The GI value is affected not only by the type of carbohydrates, but also by the amount of food, the content and ratio of other components in it - fats, dietary fiber. Information about the GI of different products is given in Table 5.
The most glucose is contained in honey - about 35%, a lot in grapes - 7.8%, in cherries, cherries, gooseberries - watermelon, raspberries, black currants - about 4.5-5.5%, in pears and apples - about 2%.
Fructose Of all known natural sugars, it has the greatest sweetness; to achieve a taste effect, it requires almost 2 times less than glucose and sucrose. Fructose is absorbed slower than glucose in the intestines.
Most of it is utilized by tissues without insulin, while another, smaller part, is converted into glucose, so in case of diabetes it is necessary to limit the intake of large amounts of fructose. It should be noted that products with high content Fructose may promote faster weight gain than glucose. The fructose content in food products is presented in Table 6.
Galactose - a monosaccharide of animal origin, part of lactose. Participates in the formation of glycolipids (cerebrosides), proteoglycans. The latter are part of the intercellular substance of connective tissue.
Pentoses in nature they are presented mainly as structural components of complex non-starch polysaccharides (hemicellulose, pectins), nucleic acids and other natural polymers.