Basic nutrients: proteins, fats, carbohydrates

Human food contains basic nutrients: proteins, fats, carbohydrates; vitamins, microelements, macronutrients. Since our whole life is a metabolism in nature, then for a normal existence an adult must eat three times a day, replenishing his "reserve" of nutrients.

In the body of a living person, the processes of oxidation (connection with oxygen) of various nutrients are continuously going on. Oxidation reactions are accompanied by the formation and release of heat necessary to maintain the vital processes of the body. Thermal energy ensures the activity of the muscular system. Therefore, the harder the physical labor, the more food the body requires.

The energy value of food is usually expressed in calories. Calorie - the amount of heat required to heat 1 liter of water at a temperature of 15 ° C by one degree. The calorie content of food is the amount of energy that is generated in the body as a result of the assimilation of food.

1 gram of protein, when oxidized in the body, releases an amount of heat equal to 4 kcal; 1 gram of carbohydrates = 4 kcal; 1 gram of fat = 9 kcal.

Protein

Proteins support the main manifestations of life: metabolism, muscle contraction, irritability of nerves, the ability to grow, decelerate, and think. Proteins are found in all tissues and body fluids, being their main part. The composition of proteins includes a variety of amino acids that determine the biological significance of a particular protein.

Essential amino acids are formed in the human body. Essential amino acids enter the human body only with food. Therefore, for a physiologically full-fledged vital activity of the body, the presence of all essential amino acids in food is required. A lack of even one essential amino acid in food leads to a decrease in the biological value of proteins and can cause protein deficiency, despite a sufficient amount of protein in the diet. The main supplier of essential amino acids: meat, milk, fish, eggs, cottage cheese.

The human body also needs proteins of plant origin, which are found in bread, cereals, vegetables - they contain nonessential amino acids. Products containing animal and plant proteins provide the body with substances that are necessary for its development and life.

An adult's body should receive about 1 gram of protein per 1 kg of total weight. It follows from this that the "average" adult weighing 70 kg should receive at least 70 g of protein per day (55% of the protein should be of animal origin). With heavy physical exertion, the body's needs for protein increase.

Proteins in the diet cannot be replaced by any other substances.

Fats

Fats surpass the energy of all other substances, participate in recovery processes, being a structural part of cells and their membrane systems, serve as solvents for vitamins A, E, D, and promote their assimilation. Also, fats contribute to the development of immunity and help the body keep warm.

Lack of fat leads to disruption of the activity of the central nervous system, changes in the skin, kidneys, and organs of vision.

The composition of fats contains polyunsaturated fatty acids, lecithin, vitamins A, E. The average need for an adult in fat is 80-100 g per day, including vegetable fat - 25-30 g.

Due to fat in food, one third of the daily energy value of the diet is provided; there are 37 g of fat per 1000 kcal.

Fats are found in sufficient quantities in the brain, heart, eggs, liver, butter, cheese, meat, lard, poultry, fish, milk. Vegetable fats that do not contain cholesterol are especially valuable.

Carbohydrates

Carbohydrates are the main source of energy. The share of carbohydrates accounts for 50-70% of the calorie content of the daily diet. The need for carbohydrates depends on the energy consumption of the body.

The daily requirement for carbohydrates for an adult engaged in mental or light physical labor is 300-500 g / day. People who are engaged in hard physical labor, the need for carbohydrates is much higher. In obese people, the energy intensity of the diet can be reduced by the amount of carbohydrates without compromising health.

Bread, cereals, pasta, potatoes, sugar (net carbohydrate) are rich in carbohydrates. An excess of carbohydrates in the body disrupts the correct ratio of the main parts of food, thereby disrupting metabolism.

Vitamins

Vitamins are not energy suppliers. However, they are needed in small quantities to maintain normal functioning of the body, regulating, directing and accelerating metabolic processes. The vast majority of vitamins are not produced in the body, but come from outside with food.

With a lack of vitamins in food, hypoavitaminosis develops (more often in winter and spring) - fatigue increases, weakness, apathy are observed, efficiency decreases, and the body's resistance falls.

The actions of vitamins in the body are interrelated - a lack of one of the vitamins leads to metabolic disorders of other substances.

All vitamins are divided into two groups:water-soluble vitamins andfat-soluble vitamins .

Fat-soluble vitamins - vitamins A, D, E, K.

Vitamin A - affects the growth of the body, its resistance to infections, it is necessary to maintain normal vision, the condition of the skin and mucous membranes. Vitamin A is rich in fish oil, cream, butter, egg yolk, liver, carrots, lettuce, spinach, tomatoes, green peas, apricots, oranges.

Vitamin D - promotes the formation of bone tissue, stimulates the growth of the body. Lack of vitamin D in the body leads to disruption of the normal absorption of calcium and phosphorus, causing the development of rickets. Vitamin D is rich in fish oil, egg yolk, liver, fish roe. There is little vitamin D in milk and butter.

Vitamin K - participates in tissue respiration, blood clotting. Vitamin K is synthesized in the body by intestinal bacteria. Vitamin K deficiency is caused by diseases of the digestive system or taking antibacterial drugs. Vitamin K is rich in tomatoes, green parts of plants, spinach, cabbage, nettles.

Vitamin E (tocopherol) affects the activity of the endocrine glands, the metabolism of proteins, carbohydrates, and provides intracellular metabolism. Vitamin E has a beneficial effect on pregnancy and fetal development. Vitamin E is rich in corn, carrots, cabbage, green peas, eggs, meat, fish, olive oil.

Water-soluble vitamins - vitamin C, B vitamins.

Vitamin C (ascorbic acid) - actively participates in redox processes, affects carbohydrate and protein metabolism, increases the body's resistance to infections. Rich in vitamin C fruits of rose hips, black currants, chokeberries, sea buckthorn, gooseberries, citrus fruits, cabbage, potatoes, deciduous vegetables.

The group of vitamites B includes 15 independent vitamins, soluble in water, which take part in metabolic processes in the body, the process of hematopoiesis, and play an important role in carbohydrate, fat, and water metabolism. B vitamins are growth stimulants. Rich in B vitamins, brewer's yeast, buckwheat, oatmeal, rye bread, milk, meat, liver, egg yolk, green parts of plants.

Microelements and macronutrients

Mineral substances are part of the cells and tissues of the body, participate in a variety of metabolic processes. Macronutrients are needed by the body in relatively large quantities: calcium, potassium, magnesium, phosphorus, chlorine, sodium salts. Trace elements are needed in very small quantities: iron, zinc, manganese, chromium, iodine, fluorine.

Iodine is found in seafood, cereals, yeast, legumes, liver are rich in zinc; copper and cobalt are found in beef liver, kidneys, chicken egg yolk, honey. Berries and fruits contain a lot of potassium, iron, copper, phosphorus.

Proteins, fats, carbohydrates, minerals and vitamins are essential substances that are essential for life. The purpose of each of them is different.

Human food contains many ingredients. Macronutrients are proteins, carbohydrates, and fats. Micronutrients are everything else, including vitamins, electrolytes, and trace minerals.

It is known that the body of an adult weighing about 70 kg contains about 40 kg of water, 15 kg of protein, 7 kg of fat, 3 kg of mineral salts, 0.7 kg of carbohydrates. But the body is not a warehouse where everything that is laid is kept intact. In the human body, metabolic processes are constantly taking place, some substances are burned, oxidized, excreted, and instead new substances are needed, and of the most various purposes.

It is calculated, for example, that over 70 years of life a person drinks 50 tons of water, eats 2.5 tons of protein, 2.3 tons of fat, over 10 tons of carbohydrates, almost 300 kg of table salt.

PROTEINS

Proteins (proteins) are the building blocks of the body. They represent the basis of the structural elements of cells and tissues. The main manifestations of life are associated with proteins: metabolism, muscle contractions, irritability of nerves, the ability to grow and reproduce, and even the highest form of movement of matter - thinking.

The myriad of different types of proteins that we meet in animals and plants are built from just 20 naturally occurring amino acids, the combination of which in protein molecules can lead to their enormous diversity.

The body has only negligible protein reserves, despite the fact that proteins make up of the human body. The only source of protein formation in the body is the amino acids of food proteins. Therefore, proteins are completely irreplaceable in human nutrition.

Are proteins contained in various food products of equal value to the human body?

The nutritional value of various types of proteins depends on their amino acid composition. Some amino acids can be synthesized from carbon and nitrogen-containing precursors in the body. Their presence in the diet is optional. They are called interchangeable. The same amino acids, which must necessarily come from the outside with food, are called essential. Several amino acids are considered conditionally irreplaceable. From this point of view, the huge variety of proteins found in food is unequal. The study of the amino acid composition of various products has shown that proteins animal origin more consistent with the structure of the human body. The amino acid composition of egg proteins is taken as ideal, since their assimilation by the human body is close to 100%. The degree of assimilation of other products of animal origin is also very high: milk (75-80%), meat (70-75%), fish (70-80%), etc. Most plant foods (especially cereals) contain proteins of reduced biological value due to a lack of essential amino acids. Favorable, therefore, is the combination of vegetable and dairy products. For example, the combination of a slice of wheat bread with a glass of milk makes their total amino acid formula much more favorable than when the same products are consumed separately.

What are the signs of protein malnutrition? Protein malnutrition is manifested by loss of energy, weakness, decreased muscle mass, edema, fatty liver, skin rashes, poor regeneration, and a low immune response. The mortality rate of children with protein malnutrition from infection reaches 30-40%.

The most important sources of protein: meat, fish, eggs, cheese, milk, bread, potatoes, beans, soybeans, peas.

FATS

Edible fats are genuine energy concentrates. When oxidized in the human body, 1 g of fat is released 9.3 kcal, i.e. 2, 4 times more than in the oxidation of carbohydrates and proteins. However, fats are used by the body not only for energy, but also for plastic purposes. The fatty acids contained in them are utilized during the formation of cellular and subcellular membranes that regulate all aspects of the body's life. Some of the fatty acids are essential, i.e. they cannot be synthesized in the body and, therefore, without their regular intake with food, it is impossible to maintain the normal state of the body. Essential fatty acids include linoleic and alpha-linolenic acids. The lack of essential fatty acids in diets leads to a delay in the development of a growing organism, disturbances in the structure and functions of cell membranes, dryness and inflammation of the skin, impaired pregnancy and a number of other signs of health disorders. Linoleic acid is the most common in natural products. There is a lot of it in sunflower, corn, soybean, cottonseed oils. Much less in olive oil.

If vegetable oils are stored for a long time, in contact with air, oxidation and polymerization products of unsaturated fatty acids can accumulate in them, which have a pronounced negative effect on the body. A very unfavorable effect on the properties of vegetable oils is exerted by their prolonged heating, for example, frying many portions of pies, donuts, potatoes and other culinary products in the same oil. The resulting thick tarry products can damage the liver and even cause the development of malignant tumors.

Many people are very interested in the question of the allegedly stimulating effect of food cholesterol on the development of the atherosclerotic process. Cholesterol is found in many foods of animal origin and is practically absent from plants. However, it does not belong to essential food substances, as it is easily synthesized in the body from the oxidation products of carbohydrates and fats. The content of cholesterol in blood and tissues depends mainly not on the amount in food, but on the intensity of the processes of its synthesis and decay in the body itself.

What are the human needs for fats?

These values ​​are not as definite as for protein substances, since a significant part of the fatty components of the body can be synthesized in the human body, primarily from carbohydrates. A reasonable daily intake of fat for a middle-aged person is close to 100 g, and vegetable oils - by 20-30 g.

CARBOHYDRATES

Carbohydrates, synthesized from carbon dioxide and water, are the most abundant organic molecules on earth. Carbohydrates include sugar and starch, which are the main sources of energy for the human body. Dairy products contain large amounts of the less sweet, milk sugar - lactose.

Carbohydrates are essential because of the high energy requirements of the central nervous system (i.e., the brain) of mammals. The brain has a limited ability to use non-carbohydrate energy sources. In humans, the estimated brain requirement is 100 g of glucose per day.

Despite the fact that a person consumes significantly more carbohydrates than fats and proteins, their reserves in the body are small. This means that the supply of them to the body must be regular. The need for carbohydrates to a very large extent depends on the energy expenditure of the body. For manual workers and athletes, it is much higher. Unlike proteins, and to a certain extent, fats, the amount of carbohydrates in diets can be reduced without harm to health.

The most important sources of carbohydrates: bread, buckwheat groats, semolina, rice, sugar, potatoes, watermelon, carrots, beets, grapes, apples.

Sweets, pastries, cakes, jams, ice cream and other sweets are the most attractive sources of carbohydrates and are an undoubted danger for overweight people. A distinctive feature of these products, the number of which has been growing rapidly in recent decades, is their high calorie content and low content of essential nutritional factors.

What is the maximum amount of carbohydrates that can be tolerated?

The maximum utilization rate of carbohydrates is 4 mg / kg per minute, which corresponds to about 400 g per day (1500 kcal / day) for the average person.

What level of sugar consumption can be normal?

It depends on age, nature of work, active rest. Consuming 80-100 grams of sugar a day for a healthy young person can generally only benefit. For athletes and for people associated with intense physical work, these standards may be slightly increased. In mature and old age, as well as people leading a sedentary lifestyle, it is recommended to reduce sugar consumption.

VITAMINS

Vitamins do not provide energy, but are absolutely necessary in minimal quantities to sustain life. Vitamins are essential because not synthesized or almost not synthesized by the cells of the body. Their most important biological role, as a rule, is associated with the fact that they are part of biological catalysts - enzymes or hormones, which are powerful regulators of metabolic processes in the body. Currently, several dozen vitamins are known, but not all of them are urgently needed for human life.

On the basis of physical and chemical properties, vitamins are usually divided into: water-soluble (vitamin C, B vitamins) and fat-soluble vitamins (F, D, E and K).

Prolonged lack of vitamins in the diet leads to characteristic diseases called vitamin deficiencies, the severe forms of which are almost never found at the present time. More often hypovitaminosis occurs, which are characterized by: increased fatigue, weakness, apathy, decreased performance, increased susceptibility to infections. In summer and autumn, food is richer in vitamins than in winter and spring.

With increased physical and mental work, under the influence of adverse effects on the body, as well as under such physiological conditions as pregnancy, breastfeeding, the need for vitamins increases significantly.

Chronic deficiency of various vitamins is associated with cardiovascular disease, cancer, cataracts, arthritis, diseases of the nervous system and photosensitivity. Very young, very old, stressed, and sick people are at greatest risk of vitamin deficiency. Each vitamin is believed to play a specific role in the development of various diseases. Liver diseases are associated with a deficiency of fat-soluble vitamins (vitamins A, D, K). Up to 90% of vitamin A is stored in the liver. Vitamin D is activated in the liver and spleen.

The most important sources of vitamin A: fish oil, red carrots, red peppers, egg yolk, beef liver, cow oil, sorrel, green onions, red tomatoes.

The most important sources of vitamin B1 and B2: bread, yeast, eggs, beans, meat.

The most important sources of vitamin C: red peppers, green onions, cabbage, lemons, currants, rose hips (the maximum content of vitamin C in comparison with other products), spinach.

MACRO AND MICROELEMENTS

The human body needs a systematic supply of mineral salts. Among them, salts of sodium, potassium, calcium, magnesium, phosphorus and chlorine, which are macronutrients, since they are needed daily in relatively large quantities. Iron, zinc, manganese, chromium, iodine, fluorine are necessary in very small quantities, and therefore they are called trace elements.

Sodium salts (table salt, which we eat, often in abundance!), And potassium salts (vegetables and fruits) are especially closely related to water metabolism. Calcium and phosphorus form the mineral basis of the skeleton, therefore, the requirements for them are especially great during the growth period. Milk and dairy products are excellent sources of easily digestible calcium and phosphorus.

The body of an adult contains 3-5 g of iron. About 70% of this amount is part of hemoglobin. Iron deficiency is common. Good sources of iron are liver, meat, fish. From plant foods - beans, whole grains.

Zinc is present in bones and zinc deficiency impairs wound healing. In children, zinc deficiency can cause stunted growth. The best sources of zinc are meat, fish, dairy products, as well as legumes, whole grains, and nuts.

Iodine is used in the synthesis of thyroid hormones. Its main source in the diet is seafood. Iodine deficiency causes goiter in adults and mental retardation (cretinism) in children.

The discovery that chromium is irreplaceable was made over 20 years ago. It turned out that chromium plays an important role in the regulation of glucose metabolism. Chromium is also involved in the regulation of triglyceride levels. Pharmaceutical yeast, liver and potatoes, and seafood are good sources of chromium. Chromium deficiency causes insulin resistance and can in some cases contribute to the development of diabetes in adulthood.

Fluoride deficiency leads to the development of dental caries. Therefore, fluoride is often used as a component in toothpastes.

FIBER

Fibers are the constituent parts of the plant cell membrane, resistant to the action of the digestive enzymes of the human small intestine. They are classified according to their degree of solubility in water. Water-soluble fibers (pectins, gums) are, for the most part, efficiently broken down by bacteria in the colon. Water-insoluble (lignin, fiber) pass through the digestive tract mostly unchanged. Dietary fiber is a complex blend of both types of fiber.

Dietary fiber contributes to the normal functioning of the colon. Insoluble fibers have a laxative effect. Fiber supplementation for constipation is an effective and low-cost treatment, especially for the elderly.

The use of fibers is useful for various conditions and diseases of a person:

Diabetes: increasing fiber intake has been shown to improve blood sugar control and increase insulin sensitivity.

Obesity: fibers provide feelings of fullness and help in long-term body weight management.

Hyperlipidemia: The addition of soluble fiber, especially oat bran, to the diet causes a decrease in serum lipid levels.

Sources of fiber are fruits, vegetables, legumes and whole grains. Fiber is currently believed to reduce the risk of coronary artery disease, diabetes and colon cancer.

KGBUZ "City Clinical Polyclinic No. 3"

Ageeva Elena Afanasyevna, chief gastroenterologist of the city of Khabarovsk, doctor of the highest qualification category

In order for your body to function well, you must supply it with the necessary nutrients in appropriate quantities. The most important of these are carbohydrates, fats and proteins.

Carbohydrates energy source

Carbohydrates are fuel for the body, are an energy material and should supply about 55-60% of the body's caloric order. Carbohydrates are very important for the functioning of the body, especially for the brain, which is almost entirely dependent on a constant supply of glucose with blood.

Carbohydrates are divided into simple and complex. Simple, i.e. so-called free sugars, assimilated immediately after consumption, which gives an immediate injection of energy, unfortunately, it is short-lived. This group of carbohydrates includes, among other things, fruits, milk or sugar, with which we sweeten drinks. Complex carbohydrates are absorbed more freely and longer, and they are the main thing in vegetables, grains, legumes, seeds and nuts. From the number of carbohydrates, you should choose whole grain pastries, pasta, oatmeal and bran - rich in fiber. Individuals who want to lose weight should completely eliminate simple carbohydrates from the diet, especially white sugar - cakes, sweets and other foods.

Composite tissue - protein

Protein is the main constituent of tissues. In the process of digestion, proteins consumed along with food are decomposed into amino acids, which are used to build new tissues and synthesize its own protein from the body. The requirement for this nutrient depends on age, gender and physical activity, but should, on average, represent about 10-15% of the diet. Protein can be of animal or vegetable origin. So the first has a high biological value, and its source is, for example, meat, poultry, fish, eggs, milk, cheeses and yoghurts. Low protein rich in legumes, nuts and some vegetables. To increase its biological value - which is especially significant for vegetarians - it is necessary to supply the body with protein derived from various plant sources, since in some plant proteins the limiting amino acid is usually another amino acid.

Essential fats for the body

Fats are a source of energy for the body, protect internal organs, some fatty acids are involved in the production of hormones, and in addition, they allow the absorption of certain vitamins (A, D, E, K). All fats are a mixture of three types of fatty acids: saturated, unsaturated. For our diet to be healthy, we must limit the intake of saturated (butter, cheese, sour cream, red meat) fats, which raise the concentration of cholesterol in the blood, and increase the intake of unsaturated fats (vegetable oils, fish). Such fats play an important role in keeping the brain and eyes working properly and also have a salutary effect on the heart and cardiovascular system. The source of this type of fat is especially fatty sea fish such as salmon, herring, also walnuts, soybean and rapeseed oil. Fats should provide about 25-30% of the energy value and preferably unsaturated fats.

Vitamins and minerals

Vitamins are necessary for a person for proper growth and development, as well as the course of many metabolic processes. Since they cannot be created by the body, they must be supplied with food. They are divided into two groups - fat-soluble and plant-based. The first includes vitamins A, E, D, and K, and the second includes vitamins from the B group and vitamin C. But mineral components are chemical elements that are also necessary for the proper development of the body. They consist of macronutrients, those whose daily requirement reaches more than 100 mg (calcium, magnesium, potassium) and trace elements that the body requires no more than 100 mg (iron, zinc, copper, iodine).

Nutrients are the main building blocks of the body. These are the bonds that appear in foods that are digestible and assimilable by consumption. Our body is made up of proteins, fats, carbohydrates and minerals. Most of all is water, because we need a huge amount of it to function properly. Other substances are created in the body.

Food supplies the human body with the energy it needs for full life. And it is thanks to regular nutrition and the complex physicochemical reactions it produces (which is what the people call metabolism or metabolism) that life is maintained. Food contains many nutrients, without which any general growth, development and functioning of the body would be impossible. We'll cover these nutrients in lesson two.

Below we will consider:

We will also explain what is the value of each of the substances.

Protein

Proteins are the main building blocks of the body and the basis of its cells and tissues. About 20% of them consists of the human body and more than 50% - cells. The body cannot store proteins in tissues "for later", which is why it is required that they be supplied with food every day.

Proteins contain essential amino acids that are not synthesized in the human body - these are arginine, histidine, threonine, phenylalanine, valine, isoleucine, leucine, methionine, lysine and tryptophan. Proteins can have different biological values, which depend on how much and what amino acids they contain, what is the ratio of essential and nonessential amino acids, and what is their digestibility in the gastrointestinal tract.

As a rule, proteins of animal origin have greater biological value. For example, eggs, liver, meat and milk can boast an optimal ratio of essential acids. And they are assimilated by 97%, while vegetable proteins are assimilated only by 83-85%, because plant products contain a large amount of non-digestible (ballast) substances.

Plant foods generally contain small amounts of protein and are deficient in methionine, lysine and tryptophan. Only legumes (such as soybeans, beans and peas) are high in protein (24% to 45%). 20% of protein is found in nuts and sunflower seeds. In terms of the composition of amino acids, proteins of rye, rice and soy are close to animal proteins.

The body's need for protein is determined by a person's age, sex, nature of work, national dietary habits and climatic conditions in which he lives. Usually, adults who are not engaged in active physical work should take protein per day at the rate of slightly less than 1 g per 1 kg of body weight. Food protein should provide 1/6 of the weight and 10-13% of the total energy requirement of the body, and 55% of the recommended protein intake should be of animal origin. If a child or adult is engaged in physical labor, his need for protein increases.

Fats

Edible fats are esters of higher fatty acids and glycerin. Esters of fatty acids have an even number of carbon atoms, and the fatty acids themselves are divided into two large groups - saturated and unsaturated fats. The former are rich in solid animal fats (there can be up to 50% of the total mass), and the latter are rich in liquid oils and seafood (in many oils, for example, in olive, flaxseed, corn and sunflower oils, unsaturated fats can be up to 90%). In the human body, the normal fat content is 10-20%, but in cases of disorders of fat metabolism, this figure can increase up to 50%.

Fats and fat-like substances make up the cell membranes and membranes of nerve fibers, take part in the synthesis of vitamins, hormones and bile acids. Fat deposits, in turn, are considered the body's energy reserve. The energy value of fats is more than 2 times higher than the value of carbohydrates and proteins. When 1 g of fat is oxidized, 9 kcal of energy is released.

Adults should consume 80 to 100 g of fat per day, which provides up to 35% of the total energy value of the diet. Linoleic and linolenic fatty acids are essential (not synthesized in the body), and must be taken with food. They are found in the fat of a number of fish and marine mammals, nuts and vegetable oils. Together with other higher unsaturated fatty acids, they do not allow the development of atherosclerosis, make the body more resistant to infectious diseases.

As for the nutritional value of fats, it is due to the presence of essential fatty acids, the presence of vitamins A, E and D, their absorption and digestibility. The maximum biological value is inherent in fats with linoleic and other higher unsaturated acids. How well fat is absorbed depends on its melting point: if it is lower than body temperature, then fats are absorbed by 97-98%, and if the melting temperature is 50-60 ° C, then they will be absorbed by only 70-80%.

Along with food, fat-like substances such as fat-soluble vitamins, phospholipids and sterols enter the body. Of the sterols, the best known is cholesterol, which is found in animal products. But in the body it can also be synthesized by intermediate metabolic products of fats and carbohydrates.

Cholesterol is a source of hormones and bile acids, plus a precursor to vitamin D3. Once in the blood and bile, cholesterol remains in them as a colloidal solution formed by interaction with phosphatides, unsaturated fatty acids and proteins. When the metabolism of these substances is impaired (or there is a deficiency), cholesterol turns into small crystals that settle on the walls of blood vessels and bile ducts, which is why atherosclerosis develops and gallstones are formed.

Carbohydrates

Foods contain carbohydrates in the form of glucose and fructose (monosaccharides), lactose and sucrose (oligosaccharides), pectin substances, fiber, glycogen and starch (polysaccharides). Carbohydrates are the main source of energy for humans: when only 1 g of carbohydrates are oxidized, 4 kcal are released.

For a person not engaged in physical work, the average need for carbohydrates is 400-500 g per day, 2/3 of the daily diet in weight terms and 60% in caloric terms. If a person is actively working physically, the rate becomes larger.

When choosing food, it is best to stop your choice on polysaccharides, i.e. on products containing pectin, glycogen, starch, etc., and, if possible, avoid oligo-monosaccharides - products containing lactose, fructose, glucose, sucrose, etc. Polysaccharides are digested more slowly, and the dynamics of glucose concentration (the end product of digestion) in body fluids is much more favorable for subsequent metabolism. It is also important that polysaccharides are not sweet in taste, due to which the likelihood of their increased consumption decreases.

The disaccharide lactose can be found in abundance in milk and dairy products. But plants are rightfully considered the main supplier of carbohydrates to the body, because their percentage in them is 80-90% of dry mass. Plant foods also contain a variety of indigestible and indigestible polysaccharides such as cellulose. You need to know that thanks to the coarse fiber, non-digestible food, intestinal motility is stimulated, a number of catabolites (even toxic) in the large intestine are absorbed, cholesterol is excreted, and beneficial intestinal bacteria are supplied with nutrients. On average, an adult should take 25 grams of carbohydrates per day.

Vitamins

Vitamins are essential nutrients (nutrients) of organic origin and of a wide variety of chemical structures. They are needed for proper metabolism in the human body. Their daily allowance is usually measured in mg (milligram) and μg (microgram), and it depends, as before, on the person's age, gender, nature of work and health status.

Vitamins are water-soluble (vitamins of group B and vitamin C) and fat-soluble (vitamins A, D, E, K):

• Almost all B vitamins are found in egg whites, yeast, liver, legumes, and the outer parts of grains.
• Vitamin C (ascorbic acid) is found in green parts of plants, berries, vegetables, citrus fruits and other fruits, in particular in acidic ones, as well as in the kidneys and liver.
• Vitamin A is rich only in animal products - cheeses, sturgeon caviar, cod liver, cattle liver, butter. Plus, it is synthesized in the body through provitamin A (carotene), which is found in orange-colored fruits, berries and vegetables.
• Sources of vitamin D are cod liver oil, fish roe, milk fat, and liver. The synthesis of this vitamin occurs due to the effects of ultraviolet radiation.
• Vitamin E is found in green vegetable leaves, egg yolks and vegetable oils.
• Vitamin K is supplied to the body by the liver, potatoes, tomatoes and leafy vegetables.

Fresh vegetables store vitamins best of all, so it is recommended to eat them as often as possible. If they are stewed and boiled, the content of vitamins will decrease. And if you make a sourdough or subject vegetables to quick freezing, vitamins will be stored in vegetables for a long time.

The value of vitamins for humans is very great. It is expressed in the fact that vitamins serve as a component that is needed for the proper functioning of enzymes; they take part in metabolic processes, help the body grow and develop, strengthen the immune system. With a lack of vitamins, the mechanisms of the nervous system and the visual apparatus are disrupted, skin problems, vitamin deficiencies and hypovitaminosis appear, the immune status weakens, etc. It should be remembered that the most deficient (especially during winter and early spring) vitamins are vitamins A, B1, B2 and C.

Minerals

Mineral substances are constituents of tissues and organs, which explains their huge role in the physical and chemical processes taking place in the body. Some minerals are found in cells, while others are in tissue fluid, lymph and blood (in which minerals are suspended in the form of ions).

The most important for the functioning of the body are sulfur, chlorine, phosphorus, potassium, magnesium and calcium. These elements help the body build tissues and cells and also support the functions of the central nervous system, muscles, and heart. In addition, they neutralize harmful acids - metabolic products.

Calcium is a building block for bone tissue, and it is especially necessary for children whose skeletons are at the stage of formation. Calcium enters the body with vegetables, fruits and dairy products.

Phosphorus is equally important because also participates in the structure of bones, and more than half of all available phosphorus is in the bones. If there is enough phosphorus in the body, there will always be a normal metabolism of carbohydrates and a strong nervous system. Phosphorus is found in legumes, grains, fish, milk and meat.

Naturally, the body needs magnesium, bromine, iodine, zinc, cobalt, fluoride and other trace elements (we will talk in more detail about them, as well as about vitamins in the next lesson), which are contained in food in minimal amounts (less than 1 mg per 1% ). Many enzymes, hormones, vitamins consist of them; they most directly affect the development of the body and metabolism.

Deficiency of any trace element in the body causes specific diseases such as tooth decay (lack of fluoride), severe anemia (lack of copper or cobalt), endemic goiter (lack of iodine) and others. Particular attention must be paid to ensure that the child's body is supplied with minerals. If up to 2 months they are received enough with mother's milk, then at the 3rd month they need to be added to the juices of vegetables, fruits and berries. Starting from the 5th month, it is necessary to supply complementary foods with minerals (oat and buckwheat cereals, meat, eggs, fruits and vegetables).

Water

Water and mineral substances dissolved in it serve as the basis of the internal environment of the body - this is the main part of tissue fluid, lymph and plasma. Not a single vital process in the body (especially thermoregulatory and enzymatic processes) is possible without a sufficient amount of water.

Water exchange is influenced by parameters such as humidity and ambient temperature, dietary patterns, and even behavior and clothing. An adult should provide his body with about 2-3 liters of fluid. Men are advised to drink about 3 liters, and women - about 2.3 liters, and more than half of this amount should be clean drinking water.

Energy consumption calculation

To maintain each process in the body, a certain amount of energy is spent, provided by food intake. Energy intake and expenditure are expressed in thermal units called calories. A kilocalorie is equal to the amount of heat required to raise the temperature of 1 liter of water by 1 °.

The average indicators of combustion of substances contained in food are as follows:

• 1 g protein = 4.1 kcal
• 1 g fat = 9.3 kcal
• 1 g carbohydrates = 4.1 kcal

Energy for the main energy exchange is the minimum amount of calories needed to meet the body's needs in a state of nervous and muscular rest. If a person works mentally or physically, energy exchange increases, and the amount of nutrients he needs increases.

When the human body is in extreme conditions, for example, if it is starving, the necessary energy can come from internal structures and reserves (this process is called endogenous nutrition). A person's need for energy, based on daily energy consumption, is from 1700 to 5000 kcal (sometimes more). This indicator depends on the sex of the person, his age, lifestyle and characteristics of work.

As we already know, fats, carbohydrates, proteins (proteins), minerals and vitamins are allocated among the nutrients in food. In terms of calorie content, the daily diet should correspond to daily energy consumption, and metabolism and energy consumption at home and at work should be taken into account. The approximate daily caloric intake, if the minimum daily physical activity is performed, is calculated by multiplying the normal weight (in kg) by 30 calories for women and 33 calories for men. Proteins, fats and carbohydrates should be in a ratio of 1: 1: 4. In addition, the quality of the diet also plays a role, which depends on the tastes, habits and the amount of excess body weight of each individual person.

In most cases, nutritionists recommend using diets that are standard in calories (they provide the body with 2200-2700 kcal). But the diet should include different foods - both in calorie content and in quality. You should always remember about the "empty" calories contained in bread, pasta based on white refined flour, white sugar, cookies, cakes and other sweets, sugary soft drinks and alcohol.

Each person should choose for himself such a diet that will provide him with the necessary amount of energy. It is important to ensure that the body receives as few harmful substances and "empty" calories as possible, as well as keep track of your body weight. People who are obese or, conversely, overly thin, should turn to specialists who will help you choose the right diet for every day.

In order to correctly determine the food, as well as to know how many calories there is in a particular product, it is customary to use special tables. Below you will find three such tables - for soft drinks, liquor and the most common foods.

Using the tables is as easy as shelling pears - all drinks and foods are grouped and sorted alphabetically. Opposite each drink or product there are columns that indicate the content of the required substances and the number of calories (based on 100 g of a specific product). Based on these tables, it is very convenient to compose your own diet.

Table 1 (Soft drinks)

Table 2 (Alcohol)

Table 3 (Food)

In the next lesson, we will dwell on trace elements and vitamins in more detail, find out how much a person needs them, and from what products they can be obtained, and also give some very useful tables.

Test your knowledge

If you want to test your knowledge of the topic of this lesson, you can take a short test consisting of several questions. In each question, only 1 option can be correct. After you have selected one of the options, the system automatically proceeds to the next question. The points you receive are influenced by the correctness of your answers and the time spent on passing. Please note that the questions are different each time, and the options are mixed.

The most important condition for nutrition is the correct combination of all nutrients in the daily diet of a person. These substances can be divided into six groups: 1) proteins, 2) fats, 3) carbohydrates, 4) vitamins, 5) minerals, 6) water. They should be introduced in quantities that fully cover all the body's waste, both quantitatively and qualitatively.

In the human body, oxidation processes (compounds with oxygen) of various nutrients - proteins, fats, carbohydrates - are continuously occurring, which are accompanied by the formation and release of heat. This heat is necessary for all life processes, it is spent on heating the inhaled air, to maintain body temperature. Heat energy also ensures the activity of the muscular system. The more muscle movements a person performs, the more he produces losses, which require more food to cover.

The need for more food is expressed in thermal units - calories. The calorie content of food is the amount of energy that is generated in the body as a result of the assimilation of food. A calorie is the amount of heat required to heat 1 liter (high calorie) and 1 ml (low calorie) of 15 degrees Celsius water by one degree. Each gram of protein and each gram of carbohydrates of any food, when burned in the body, generates heat, in an amount equal to 4 kcal, and when 1 g of fat is burned, 9 kcal is formed.

The daily energy expenditure within one age group is individual. It depends on the physical development of a person, the state of his nervous and endocrine systems, the intensity of movements, labor, and the general state of the body.

Food for the body is not only a source of energy. It is a building material for cells of organs and systems. In addition, it serves as a source of heat, helps to increase the body's resistance to adverse effects of external and internal factors, and improves the body's performance. Once in the alimentary canal, it is digested. At the same time, its constituent parts - proteins, fats, and carbohydrates - are broken down into less complex substances that are absorbed by the intestinal walls and enter the bloodstream. The blood carries them to all organs and tissues of the body and nourishes the entire body.

A complete diet should contain all the basic nutrients in the diet: proteins, fats, carbohydrates, minerals, vitamins, water - in optimal proportions, it should meet the physiological needs and capabilities of the body of both healthy and sick people.

Protein is the material from which the human body builds its own tissues. It is a complex chemical compound made up of simple elements called amino acids. Protein is also necessary for the production of enzymes, hormones in the body and maintaining resistance to adverse factors. Proteins are supplied to the body by such food products as milk, cheese, cottage cheese, eggs, meat, fish, i.e., animal products. Proteins of animal origin are "complete" proteins, as they contain all the amino acids necessary for the formation of tissues in the human body. Plant foods (potatoes, flour, cereals, vegetables, peas, beans) also contain proteins, but they do not have all the amino acids necessary for the formation of body proteins. Therefore, vegetable proteins are considered "inferior". In order for plant proteins to be well utilized by the body, they must be combined in human food with animal proteins that replenish their nutritional value.

Long-term lack of complete proteins in the diet worsens health and causes disruption of the body's vital functions. For example, a deficiency of proteins can cause a decrease in the body's resistance to various infectious diseases, leads to a delay in development, and contributes to the occurrence of anemia and other diseases.

Proteins play a large role in the regulation of blood pressure. The body's need for proteins depends on the age and physiological state of the body. The body of children, adolescents and pregnant women needs more protein (in relation to body weight) than the body of an adult. An infant needs four times more protein per kilogram of body weight (than an adult who needs one gram of protein per kilogram of body weight). On average, an adult should get about 75 to 90 grams of protein per day.

The most important sources of protein are foods such as meat, fish, eggs, cottage cheese, milk, cheese, bread, potatoes, beans, soybeans, peas.

It is very important in the diet to diversify food, because only such food provides the body with all the necessary amino acids. In order for proteins to be well digested and assimilated, the method of cooking is of great importance. When boiling and roasting meat or fish, the protein substances are greatly altered. Products that are steamed lose less extractive (odor and flavor) substances than those that are boiled in water.

Meat - 14–20; fish - 12-16; eggs - 10.8; cheese - 30; milk - 5.0; bread - 5-10; potatoes - 1.7; beans - 19.6; soybeans - 34; peas - 19.7.

Dietary fats are necessary for the body not only as a source of energy. Fats are involved in restorative processes, being a structural part of cells and their membrane systems; serve as solvents for vitamins A, E, D and promote their assimilation. By improving the palatability of food, fats increase its nutritional value. In addition, they contribute to the development of immunity and help the body retain heat and protect protein from burning. Fats are found in many animal and plant foods. Their biological value is different. Insufficient intake of fat in the body can lead to disruption of the central nervous system, changes in the skin, kidneys, organs of vision, etc. However, excessive consumption of fat leads to obesity, contributing to the appearance of various diseases (atherosclerosis, diabetes, hypertension). Vegetable and animal fats must be included in the diet. Animal fats are more valuable because some of them, such as butter, contain vitamins.

The average adult need for fat is 80-100 g per day, including vegetable fat - 25-30 g.

In food, due to fat, 33% of the daily energy value of the diet should be provided, which, according to modern data, is optimal. When 1 g of fat is burned, 9 kcal is formed.

Fats are found in sufficient quantities in foods such as brains, hearts, eggs, liver, butter, cheese, meat, lard, poultry, fish, milk. Vegetable fats are also valuable, especially in the diet of the elderly, since they do not contain cholesterol. Skillful use of fats in cooking is of great importance. In medical nutrition, it is recommended to put butter in the finished dish before serving it to the patient. Fats added to ready-made food are easier to digest and assimilate by the body than those that are impregnated with food in the process of their preparation. When roasting over high heat, the chemical composition of fats changes, and the resulting substances irritate the biliary tract and gallbladder. Therefore, fried foods are contraindicated in liver diseases. It is not recommended to use butter for frying; it is better to use vegetable oils or ghee. Butter decomposes at high temperatures, and the vitamin A contained in it dies.

Carbohydrates are the main source of energy. Due to carbohydrates, the body receives about 2/3 of thermal energy. Each gram of carbohydrates provides 4 kcal of energy. Most carbohydrates in the form of sugar and starch are found in plant foods. For example, in sugar, carbohydrates account for almost 90%, in potato starch, 70–80%. A lot of carbohydrates are found in pasta, rice, buckwheat, bun, rye bread. There are few carbohydrates in fresh vegetables. Vegetables and fruits contain large amounts of water and fiber, which are almost indigestible. Particles of undigested fiber enhance intestinal peristalsis, protect against constipation. A lot of fiber is found in vegetables, fruits, and wholemeal products. In medical nutrition, fiber is sometimes consumed in large quantities. For example, in the treatment of obesity, the body needs to be given non-nutritious, non-nutritive, but voluminous food that eliminates the feeling of hunger. On the contrary, in case of stomach ulcers and other diseases, when the stomach and other organs of the digestive tract cannot be irritated, the amount of fiber is reduced to a minimum. Fiber helps to eliminate cholesterol from the body, so it needs to enrich anti-sclerotic diets.

Digested carbohydrates are absorbed into the blood as sugar. In order to maintain a certain ratio of sugar in the blood, it is advisable to introduce most of the carbohydrates into the body in the form of starch. In this case, due to the slow breakdown of starch in the digestive tract, the formed sugar is gradually absorbed into the blood. However, if it is necessary for the tissues to receive sugar quickly, for example, with strong mental or physical stress, with weakened heart activity, then it is recommended to consume a lot of sugar, sometimes it is injected directly into the blood. Sugar, especially glucose, is absorbed by the body easily and quickly.

The importance of carbohydrates in medical nutrition is very important. If a sick body cannot normally absorb proteins or fats, then carbohydrates should form the basis of nutrition at this time. For diseases of the heart or liver, the patient is recommended such carbohydrates as sugar, honey, glucose, fruit juice and some others.

In case of diabetes mellitus, carbohydrates, and especially sugar, are almost not given. In the case of rheumatism and various inflammations, the use of carbohydrates, especially sugar, is also limited. The daily requirement of carbohydrates ranges from 300 to 500 g. For enhanced nutrition or, if desired, increase the weight of carbohydrates, you can give up to 600 g per day, but not more. Each gram of carbohydrates delivers 4 kcal. For medicinal purposes, the amount of carbohydrates in food can be significantly reduced: a bed patient can be given up to 120–150 g, and a walker - up to 250–300 g per day.

Receiving too much carbohydrates, the body stores them in the form of fats.

In order to preserve carbohydrates, food must be steamed or in a little water. Sugar is easier to digest and absorbed by the body than starch, as it dissolves faster in water. The average daily intake of sugar and other sweets ranges from 80-100 g.

An excess amount of carbohydrates in the diet disrupts the correct ratio of the main parts of food, which, in turn, leads to metabolic disorders, a decrease in protein intake delay, water retention in the body, the formation of an increased fat content, which is deposited almost does not participate in metabolic processes.

Sugar, honey, cereals, flour, vegetables, especially potatoes, fruits are rich in carbohydrates. The most easily absorbed carbohydrates are found in sugar, honey, fruits, milk.

Rye bread - 42–45; wheat bread - 43-50; buckwheat groats - 64; semolina - 70; rice - 72; sugar - 75–90; honey - 95–99; potatoes - 20; white cabbage - 5; watermelon - 9; carrots - 7-8; beets - 10; grapes - 17; apples - 11.

For the normal functioning of the body, it is necessary that the diet includes vitamins - substances that do not supply the body with energy, but are absolutely necessary to maintain life. They direct and accelerate metabolic processes. The body does not produce vitamins. They come either with food or in the form of synthetic preparations. Natural vitamins are healthier for the body than synthetic drugs.

The amount of vitamins consumed should correspond to the needs of the body. Prolonged lack of vitamins in the diet leads to vitamin deficiency. But hypovitaminosis is more common, the development of which is associated with a lack of vitamins in food. This is especially true during the winter-spring months.

Vitamins are divided into two groups: water-soluble - soluble in water and fat-soluble - only in fats. The group of fat-soluble vitamins includes vitamins A, D, E, K. Water-soluble - vitamin C (ascorbic acid) and B vitamins (B1, B2, PP and others).

Vitamin A affects the growth of the body, its resistance to infections. It is necessary to maintain normal vision, skin and mucous membranes. Lack of vitamin A causes the appearance of the so-called night blindness, which is especially dangerous for vehicle drivers. At dusk, a person quickly loses orientation, sees objects indistinctly, his visual reactions are slowed down. With a lack of vitamin A, hair loss, brittleness or oily seborrhea are noted, the skin of the face becomes rough, dry, has a painful appearance and no cream will help in this case until the nutritional gap is filled.

Vitamin A is contained in large quantities in fish oil, cream, butter, egg yolk, liver, milk. In some plant foods: carrots, peppers, lettuce, spinach, tomatoes, green peas, apricots, parsley, green onions, rose hips and sea buckthorn. However, it should be borne in mind that vitamin A, like other fat-soluble vitamins, is much better absorbed together with fat, for which it is useful to use products containing carotene in various combinations with oil.

Vitamin A and carotene are well preserved in food when cooked over low heat without access to air.

Vitamin D contributes to the formation of bone tissue and stimulates the growth of the body. With a lack of vitamin D in food, the normal absorption of calcium and phosphorus by the body is disrupted, which leads to rickets. The largest amount of vitamin D is found in fish oil, egg yolk, liver, and fish roe. Vitamin D is found in milk and butter in small amounts.

Vitamin K is involved in tissue respiration, contributes to the maintenance of normal blood clotting. Lack of it can occur with diseases of the digestive system or when taking various antibacterial drugs. Vitamin K is found mainly in tomatoes, green parts of plants, spinach, cabbage, nettle.

Vitamin C is of great value for the body. Vitamin C, or ascorbic acid, is actively involved in redox processes, affects carbohydrate and protein metabolism, and increases the body's resistance to various infections.

With insufficient intake of vitamin C with food, increased fragility of small blood vessels develops, a tendency to hemorrhages on the skin and mucous membranes, bone fractures, and pustular diseases. The growth processes slow down, the secretion of gastric juice decreases, the motor function of the small intestine is weakened, the formation of a number of hormones is disrupted, the reserves of the carbohydrate glycogen in the liver decrease, the gums swell, and the teeth become loose.

In the human body, vitamin C is not formed or accumulated, but enters the body with food. It is found in many fresh vegetables and fruits. The richest in them are the fruits of rose hips, black currants, chokeberries, sea buckthorn, gooseberries, citrus fruits, cabbage, potatoes, sweet peppers, and sour apples. Vitamin C is water soluble; it easily breaks down when heated and exposed to alkalis, oxidizes when it comes into contact with certain metals (iron, copper), breaks down from exposure to atmospheric oxygen and loses its useful properties. In the process of culinary processing and storage of vegetables and fruits, up to 70% of it is destroyed. With these properties of vitamin C in mind, the following cooking rules should be followed:

1) peel vegetables and prepare meals just before eating;

2) put vegetables for cooking in boiling water, since it contains less oxygen in the air;

3) cook vegetables in a sealed container;

4) store cooked vegetable dishes for no more than 1.5 hours;

5) use the liquid in which vegetables were cooked for soups;

6) vegetables cooked for vinaigrette or salad, especially peeled, should not be stored for a long time.

The adult requirement for vitamin C is 70-100 mg per day. In winter, vitamin C can be obtained from potatoes, as well as fresh and sauerkraut.

The group of B vitamins consists of water-soluble, independent vitamins that take part in metabolic processes in the body, the process of hematopoiesis, and also plays an important role in carbohydrate, fat and water metabolism. B vitamins are growth stimulants. With its lack, headaches, fatigue, a feeling of weakness and muscle weakness, a disorder of the digestive tract and nervous system, and brittle nails appear.

Vitamins of this group are found in brewer's and baker's yeast, buckwheat and oatmeal, rye bread, milk, meat, liver, egg yolk, cauliflower, barley, green peas, potatoes, hazelnuts and walnuts, peanuts. Products made from wholemeal flour are especially rich in vitamin B1.

Vitamin B1 is preserved well during the culinary processing of food.

The body's need for vitamins is 1.5–2.0 mg per day and depends on energy consumption. Since B vitamins dissolve well in water and are easily oxidized by atmospheric oxygen, to preserve them, it is necessary to avoid prolonged soaking of products; it is not recommended to leave them in the air in a crushed form.

Deficiency of vitamin B2 manifests itself in growth retardation, disorders of the skin and mucous membranes (the formation of cracks, ulcers in the corners of the mouth, peeling of the skin, inflammation of the mucous membranes of the eyes, etc.). Its deficiency leads to rapid eye fatigue, weakening of visual acuity, and photophobia occurs. This vitamin is rich in kidneys, tongue, chicken, veal, beef, chicken eggs, milk, dairy products, buckwheat and oatmeal and cereals from them, beans, peas, cabbage, spinach, rose hips, yeast, liver.

It retains well in food during cooking.

Vitamin E is involved in the metabolism of proteins, carbohydrates, fats and fat-soluble vitamins. Vitamin E affects the activity of the endocrine glands, favorably affects the course of pregnancy and fetal development. Food is preserved well during the cooking process. Most of this vitamin is found in corn grains, cabbage, green peas, eggs, meat and fish products, vegetable oils, wheat, oats, rye, barley, parsley, celery, liver, kidneys, butter.

There is a close relationship between the action of individual vitamins. A lack of one of the vitamins in food leads to a violation of the metabolism of other vitamins. A complete diet should be balanced not only in terms of calories. It is necessary to strive to obtain all important vitamins mainly through food. If the caloric content of food is provided mainly through the use of animal and vegetable products rich in proteins, fats and carbohydrates, then the source of vitamins is mainly vegetables and fruits, which are also used as medicinal food products. Their role is especially significant in the prevention and treatment of colds and flu. The systematic consumption of vegetables and fruits increases a person's resistance to many unfavorable factors, both internal and external, so during the season it is necessary to eat more berries, fruits, vegetables in their raw form, or to prepare dishes from them that do not require heat treatment - salads, cold soups, cocktails, juices.

The food must necessarily contain minerals that are part of the cells and tissues of the body. They are necessary for the normal assimilation of food, the formation of the skeleton, the production of hormones, the correct hematopoiesis, the functioning of the cells of the nervous system, the development and activity of the endocrine glands, etc. Their significance is very great, without them the human body could not exist, could not function ... To provide the body with a daily supply of minerals in sufficient quantities, it is necessary to know the sources and content of these elements. The main minerals include calcium, potassium, sodium, phosphorus, magnesium, iron, copper.

Calcium is essential for proper growth and development of the body, normal heart function, blood clotting, and proper muscle, nerve and skeletal formation. Almost 90% of all calcium in the body is found in bone tissue.

Long-term lack of calcium in the diet leads to serious changes in the body, causing diseases such as dental caries, rickets, decalcification of bones. As a result of calcium deficiency, joint pains often appear, mistaken for rheumatism.

Calcium is contained in many products of animal and plant origin, but it is not absorbed equally from them. In plant foods, calcium is contained in difficult-to-dissolve compounds that are poorly absorbed. Calcium is best absorbed from milk and dairy products, where it is combined with protein. Therefore, it is so important to consume enough of them in the daily diet.

Phosphorus is a substance that, like calcium, is essential for building bones and teeth. It is also found in the blood corpuscles, nerve tissues of the brain and other tissues of the body. Phosphorus is found in a variety of foods. Its greatest amount is found in meat, egg yolk, fish, cheeses, oat and buckwheat cereals, legumes, nuts, vegetables, bread products, as well as in the brain, liver and kidneys.

Magnesium participates in metabolism, together with calcium and phosphorus, participates in the formation of the skeleton, increases and improves intestinal activity, increases bile secretion, and participates in the transmission of nervous excitement. Mainly magnesium is found in wheat, rye, buckwheat, millet, barley, oats.

Iron plays an important role in the body's recovery processes and is an integral part of hemoglobin. Its deficiency in the diet can cause anemia (anemia). For people, it is very important to have a sufficient intake of iron from food, since its reserves in the body are limited. The daily intake of iron is 6-15 mg for children and adolescents, and 12-15 mg for adults.

The greatest amounts of iron are found in the liver, kidneys, fish, eggs, beans, black bread, legumes, oatmeal, buckwheat and pearl barley, green parts of plants and fruits.

Potassium and sodium play an important role in the processes of water-salt metabolism and pressure regulation.

The body's need for sodium is met by the consumption of table salt added to food. On average, a person needs 5-10 grams of salt per day. However, this amount is insufficient when performing hard physical work, or in the hot season, since a person, sweating, loses large amounts of salt with sweat, sometimes reaching 20 g per day. Sodium deficiencies are best made up for with saltier foods or salty drinks. Both a lack of and an excess of salt leads to disorders of the body. As a result of insufficient salt intake, a feeling of weakness, nausea, fatigue, thirst, muscle cramps appears, and appetite decreases. An excess of salt creates an excessive load on the circulatory and excretory organs, leads to water retention in the body, and increases thirst. Food products, especially of plant origin, contain few sodium salts.

With a deficiency in the body of potassium, blood pressure decreases and muscle tone decreases. The body needs potassium more than sodium, since potassium is necessary for the activity of the muscles of the heart and intestines.

Potatoes, carrots, cabbage, parsley, spinach, legumes, apricots, raisins, and prunes are rich in potassium.

For the proper functioning of the body, other minerals are also needed, the so-called trace elements - cobalt, zinc, iodine, fluorine, manganese, copper.

Trace elements enter the body with food.

Iodine is essential for the production of the thyroid hormone (thyroxine). This hormone plays an important role in the metabolism. For humans, not only iodine deficiency is dangerous, but also its excess. As a result of a lack of iodine, goiter develops, an excess of iodine causes an increased function of the thyroid gland. The daily requirement for iodine is satisfied when its content in food and water is from 0.15 to 0.2 mg. The amount of iodine in food depends on the content of this element in soil, water, air. Most of all iodine is found in coastal areas. The largest source of iodine from food is marine fish, eggs and some vegetables. Table salt, which is sold in stores, is also often fortified with iodine.

Cereals, yeast, legumes, liver are rich in zinc; copper and cobalt are found in beef liver, kidneys, chicken egg yolk, honey.

The mineral composition of berries and fruits is very diverse. They contain a lot of potassium, iron, copper, phosphorus, etc. Moreover, all these minerals are well absorbed. The importance of fruits and berries is especially great for those who suffer from disorders of the cardiovascular system, in particular, hypertension, circulatory disorders, kidney damage with the formation of edema. The potassium in these foods enhances the excretion of fluids from the body.

Low calorie content, absence of fats and cholesterol, high content of vitamin C make fruits and berries and dishes from them indispensable in the diet of patients with atherosclerosis and other diseases.

Water, which makes up almost 70% of the human body's weight, is found in every cell in the body. Water dissolves food substances entering the digestive tract, ensures their digestion, absorption and metabolism. Digested substances can only enter the bloodstream when dissolved in liquid. Water regulates proper blood circulation and blood pressure, promotes the distribution of nutrients into the body and the elimination of toxins through the kidneys, skin and large intestine. We absorb water not only in the form of liquids, it is included in all foods. Most of all water is contained in vegetables - up to 90%, least of all - in rendered fats and dried products.

A person should receive 2-3 liters of water per day, including the water contained in food.