The role and application of carbohydrates. The use of carbohydrates in medicine

Carbohydrates are an integral component of cells and tissues of any living organism, be it a plant, an animal, or a human. They make up the bulk of the organic matter of planet Earth. Carbohydrates are a fairly extensive class of compounds. Among them you can find substances with different properties. Due to this feature, the functions of carbohydrates are very wide. Today we will analyze the main properties, the physiological role and application of carbohydrates in various directions of the food (and not only) industry.

Sources of carbohydrates

The main sources of carbohydrates are products of plant origin. Namely: bread, cereals, vegetables, fruits, berries. As for products of animal origin, some of them are also rich in carbohydrates. This is, first of all, milk, which contains so-called milk sugar.

Food products can contain different carbohydrates. Therefore, the importance, application of carbohydrates and their functions are very extensive. In cereals and potatoes there is starch - a complex carbohydrate insoluble in water, which is split into simple sugars by the action of digestive juices. In fruits, vegetables and berries these substances are presented in the form of simple sugars: fruit, beetroot, reed, grape and so on. They dissolve in water and are well absorbed by the body. Sugars, soluble in water, are rapidly absorbed into the blood.

The use of carbohydrates

It is believed that the bulk of carbohydrates should be consumed in a complex form, and only 20-25% in simple. This contributes to the gradual intake of sugars in the tissue. If a person gets enough carbohydrates with food, they are deposited in the liver and muscles in the form of "animal starch" of glycogen. With a lack of carbohydrates, the glycogen reserve is split into glucose and used for the needs of the body (nutrition of cells and tissues). If the body receives their excess, they become fatty. By the way, carbohydrates also include fiber, which is necessary for proper digestion.

Carbohydrates are essential components of the diet, therefore they not only determine the energy homeostat of the organism, but also participate in the biosynthesis of a number of carbon-containing polymers. For a lifetime, a person on average uses about 14 tons of these compounds. Of these, approximately 2.5 tons are in simple form. The use of proteins, fats, carbohydrates and their derivatives in food is not evenly distributed. Carbohydrates are the main part of our diet. They consume 4 times more than proteins or fats. With a simple, mixed diet, about 60% of the energy a person receives from carbohydrates. Their main task in the body is to give energy. The more physical activity in a person's life, the more he needs carbohydrates. With a sedentary lifestyle, the need for these substances decreases. For those who are not engaged in manual labor, the daily requirement for carbohydrates is approximately 400 grams.

About 50-65% of carbohydrates enter our body with grain products. 15-25% - with sugar and sugar-containing products. About 10% - with roots and tubers. And about 5-7% - with fruits and vegetables.

Carbohydrates are a very strong stimulant of external secretion of the pancreas and the most active stimulator of insulin synthesis, which plays an important role in regulating carbohydrate metabolism and maintaining optimal glucose homeostasis. Overloading with simple carbohydrates over the years leads to hyperplasia of β-cells, then - to the weakening of the insulin apparatus and the creation of prerequisites for the development of diabetes mellitus.

Classification of carbohydrates

Depending on the structure, the ability to dissolve and the rate of assimilation, the carbohydrates contained in food products are divided into simple and complex. To simple carry monosaccharides (fructose, glucose, galactose) and disaccharides (sucrose, lactose). To complex - polysaccharides (fiber, starch, glycogen). In addition to the carbohydrates given for example, in each class there are other less well-known substances.

Simple carbohydrates

Mono- and disaccharides dissolve well in water and are quickly absorbed by the body. They have a pronounced sweet taste, so they are often called simply sugars. The most common monosaccharide is glucose, contained in various fruits and berries, as well as synthesized by the cleavage of di- and polysaccharides. Glucose, once ingested, quickly finds its use. It forms glycogen, nourishes the brain tissue and muscles (including the heart), and also regulates the level of sugar in the blood. With physical activity, glucose can be used directly as an energy source.

Fructose has similar properties. It can be considered as a very valuable, easily assimilated carbohydrate. But, in comparison with glucose, fructose is still slowly absorbed by the intestine, and, hitting the blood, leaves the bloodstream faster. Up to 80% of fructose is retained in the liver, preventing excessive blood sugar. However, in the liver of fructose it is easier to synthesize glycogen than glucose. Compared with sucrose, fructose is better absorbed and has greater sweetness. Due to the last property for the required level of sweetness of the product, less fructose can be used, thereby reducing the overall consumption of sugars. This takes place in the construction of a diet of limited caloric content. Considering the use of carbohydrates in life, special attention should be paid to dietary nutrition. Fructose is often used as a sweetener in the production of products for people with diabetes.

With an excess of sucrose, fat metabolism is broken and fat formation increases. In addition, it has long been proven that with the increase in the amount of sugar entering the body, the synthesis of fats from complex carbohydrates, directly fat and even protein, is enhanced. Consequently, the amount of sugar consumed by a person can largely regulate fat metabolism.

With abundant use of sugar, the cholesterol metabolism begins to increase and its content in the blood increases. In addition, excess sugar has a bad effect on the work of the intestinal microflora - the mass of putrefactive microorganisms increases, putrefactive processes are accelerated, and flatulence develops. The least of these side effects are observed with the use of fructose. The main source of this carbohydrate are fruits and berries. A lot of fructose and glucose is found in honey: 37.1% and 36.2%, respectively. All the sugar that is in the watermelon is fructose, it is here about 8%.

The next monosaccharide is galactose. It does not occur in food in its free form. Galactose is the product of the splitting of lactose, the main carbohydrate of milk.

As for disaccharides, the main one in our diet is sucrose. During hydrolysis, it is split into fructose and glucose. The main sources of sucrose are beet and cane sugar. In sugar-sand, the content of this carbohydrate reaches 99.75%. In addition, sucrose is found in fruits, vegetables and melons.

Complex carbohydrates

Polysaccharides are distinguished by a more complex structure of the molecule and extremely weak solubility in water. This class includes: starch, fiber, glycogen and pectin substances. The use of carbohydrates of this class is spread to varying degrees. The main food value is starch. Its high content in cereals is the main factor that determines their nutritional value. In the average person's diet, starch takes up to 80% of the total amount of carbohydrates consumed. Once in the body, it turns into simple carbohydrates and performs their functions.

As for glycogen, in our body it plays the role of energy material, which feeds working muscles and internal organs. Glycogen is recovered through rheosynthesis due to glucose.

Pectin is a soluble substance that is well absorbed in the body. As modern research in the field of healthy nutrition shows, pectin can be used for preventive and therapeutic purposes in diseases of the gastrointestinal tract.

Fiber is very similar in structure to polysaccharides. Its high content is famous for grain products. In addition to the amount of fiber in the product, great importance is its quality. The more gentle this carbohydrate is, the better it is split in the intestines, and the more useful the person brings. These properties are possessed by the fiber of vegetables and potatoes. An important feature of this polysaccharide is the ability to remove cholesterol from the human body. Now we will consider in more detail the use of carbohydrates.

Parenteral nutrition

The use of carbohydrates in medicine today is rapidly developing. Parenteral nutrition - intravenous injection of nutrients into the body. Used in cases where the patient does not have the opportunity to eat independently. The use of carbohydrates in parenteral nutrition is very common. They are used for the simple reason that they are the most affordable source of energy for the human body. The energy value of carbohydrates is 4 kcal / g. The daily human need for energy ranges from 1.5 to 2 thousand kilocalories. Hence the problem of the isolated application of carbohydrates to cover this need. In terms of an isotonic glucose solution, to fully cover the human need for calories, pour from 7 to 10 liters of solution. This can lead to the development of hyperhydration, pulmonary edema and cardiovascular disorders.

The use of more concentrated solutions of glucose is fraught with other unpleasant consequences - the emergence of hyperosmolarity of the plasma and irritations of the intima of the veins (the development of phlebitis and thrombophlebitis). And in order to exclude the risk of osmotic diuresis, it is necessary to maintain the infusion rate of glucose in the range from 0.4 to 0.5 g / kg / h. If you convert this indicator to an isotonic glucose solution, you will get a little over 500 mm per hour for a patient weighing 70 kg. To prevent the violation of tolerance to carbohydrates and the consequent complications, insulin is added to the glucose solution. The calculation is based on the formula: 1 ED for 3-4 grams of dry glucose. Insulin not only positively affects the utilization of glucose, but also promotes normal adsorption of amino acids.

The use of carbohydrates in medicine depends on their type. Parenteral nutrition is widely used: fructose, glucose, sorbitol, dextran, glycerol and ethyl alcohol.

Dietary food

There are many diets that are based on the complete or partial exclusion of carbohydrates from the diet, as well as increased consumption of proteins and fats. The US Department of Agriculture conducted a survey according to which it was found that people who eat carbohydrate-rich foods mostly have normal weight. Food, which contains a lot of carbohydrates, is more nutritious, but less caloric.

As is known, in America more than half of the population suffers from the problem of overweight. And the number of such people is steadily growing. A long survey of the population for food consumed showed that people with a predominant carbohydrate diet receive fewer calories than the lovers of proteins and fats, with the same amount of food eaten. This group of people from all the respondents, and there were more than 10,000 people, the lowest body weight. The reason is that for 1000 calories of carbohydrate-containing foods, you have a lot of fiber and water. This group of people received with food more nutrients, namely: vitamins A and C, carotene, calcium, iron and magnesium. Fats, cholesterol, zinc, sodium and vitamin B12, in their diet were contained in an insignificant degree.

The use of carbohydrates and fats in foods is closely related. However, like the use of carbohydrates with proteins. The high efficiency of carbohydrates as sources of energy lies in their ability to save protein. When a large amount of carbohydrates is ingested, the body uses less amino acids as its energy material. In general, these substances are not essential components of nutrition, since they can be synthesized from amino acids and glycerin, nevertheless, their role can not be underestimated. The use of carbohydrates in food should be at least 50 grams per day. Otherwise, there may be disturbances in metabolic processes.

However, excessive consumption of carbohydrates leads to the formation of subcutaneous fat. When building a diet, it is important not only to satisfy the human need for these substances, but also to balance the consumption of their various types. It is important to trace the ratio of simple and complex carbohydrates. When the body receives a lot of sugars, they can not be fully synthesized into glycogen and become triglycerides, which promote the formation of fatty tissues. When the blood content of insulin is increased, this process is accelerated.

Complex carbohydrates, unlike simple, split slowly, so their content in the blood increases gradually. In this regard, it is advisable that the main carbohydrate part in foodstuffs is precisely the digestible substances. Their share should be from 80 to 90 percent. The lack of complex carbohydrates is especially noticeable for those who suffer from diabetes, obesity, atherosclerosis and diseases of the cardiovascular system.

As you already understood, most of all carbohydrates are used in nutrition and medicine. But the field of application of carbohydrates does not end there. Where else are they used?

Glucose

This carbohydrate is well absorbed by the body and can be used in the composition of some medications. In addition, glucose is widely used in the confectionery industry. With its help make marmalade, caramel, gingerbread and other products. In the textile industry, it plays the role of a reducing agent. And in the production of glycine and ascorbic acids, glucose is the starting product. With its help, they also synthesize some industrial sugars.

Glacial fermentation is of great importance . It occurs when cabbage, cucumber, milk and other products are sour, as well as when silageing forages. In the production of beer, alcoholic fermentation of glucose is used.

Starch

Starch is a valuable nutrient. To make it easier to digest by the body, the products are subjected to a temperature treatment. Under high-temperature conditions, partial hydrolysis of starch occurs , as well as the formation of water-soluble dextrins. Dextrins, having got into the digestive tract, are hydrolyzed to glucose, which is well absorbed by the body. If we talk about the use of carbohydrates in industry, we can not ignore starch. The main products that are derived from it are glucose and molasses. This further expands the area in which the application of carbohydrates takes place. Briefly describe the process of obtaining glucose and molasses from starch can be as follows.

Starch is heated in a mixture with dilute sulfuric acid. Excess acid is neutralized by chalk. The precipitate of calcium sulphate, which is formed during neutralization, is filtered off. Then the solution is evaporated and glucose is isolated from it. If you do not bring the process of hydrolysis to the end, you get a mixture of glucose with dextrins, which is called molasses. It is used in the confectionery industry. In addition, dextrins obtained from starch are widely used as an adhesive and a thickener for paints. Starch proves how diverse the application of carbohydrates can be. Chemistry of processes, at the same time, is not at all complicated.

Previously, starching was used, which allows you to breathe a second life into the fabric and extend its life. Starch and products derived from it are also used in the textile, pharmaceutical and foundry industries.

Cellulose

The practical benefits of carbohydrates have always been no less important than their biological role. The use of carbohydrates can be found in completely different directions of human activity. Cellulose (cellulose) is used by man since ancient times. First, man began to use wood as fuel and building material. Then, from cotton, flax and other fibrous plants, they learned how to make a thread. Later, technologies appeared that made it possible to obtain paper from wood. Paper, in its essence, is a thin layer of fiber fibers, which are pressed and glued. The result is a sturdy, smooth surface over which ink does not spread.

Initially, only vegetable materials (stalks of cotton and rice) were used for making paper. From it, mechanically, they extracted fibers. But as the society developed, the sources listed were not enough to cover the need for paper. The bulk of it goes to newspapers. Considering that the quality of the paper does not play a special role here, up to 50 percent of the ground wood began to be added to it. Later, there were technologies that allow to get rid of such accompanying wood substances as tar, lignin and so on. Here such diverse can be practical application of carbohydrates.

To date, the most common method of isolating cellulose is sulfite. It is used in various areas where carbohydrates are used. The chemistry of the process is very simple. According to this method, the wood is ground and cooked in a mixture with calcium hydrogen sulphate. Then, the cellulose freed from all impurities is separated on the filters. The obtained liquor has monosaccharides in its composition, therefore it is used as a raw material for the production of alcohol. And cellulose is also used in the manufacture of viscose, acetate and copper-ammonia fibers.

Sometimes carbohydrates are confused with hydrocarbons. Despite the fact that these two classes of substances are consonantly called, they have nothing to do with each other. The use of saturated hydrocarbons in everyday life and at work is a completely different story.

Conclusion

Today you and I have deepened our knowledge of such substances as carbohydrates. Properties, the use of carbohydrates and their benefits to humans confirm that these substances are the most important biological components on our planet. They are literally everywhere and in everything. But this is not the main thing, but the fact that without carbohydrates our life would be impossible. Too much is the use of carbohydrates in life.