Health food Introduction n utrition

2. Nutrition and vital activity, metabolism and energy in the body

What is nutrition or metabolism? It is a sign that distinguishes all living things from non-living things. In the process of metabolism, the substances that enter the body are converted through chemical changes into their own tissue substances and into final products that are excreted from the body. During these chemical transformations, energy is released and absorbed. Metabolism is a process in which many enzyme systems are involved and which is provided with the most complex regulation at different levels.

The intensity of metabolism, estimated from the total energy consumption, can vary depending on many conditions, and primarily on physical work. However, even in a state of complete rest, the metabolism and energy does not stop, and a certain amount of energy is expended to ensure the continuous maintenance of muscle tone. The determination of the intensity of metabolism is carried out under standard conditions: with complete physical and mental rest, in a supine position, no less than 14 hours after the last meal, at an ambient temperature that provides a state of comfort. The resulting value is called the basic exchange.
Starting from the age of 5, the basal metabolic rate decreases. Basal metabolism can increase with an increase or decrease in temperature, with physical and mental stress.
is the basis of life for all living things


3. Necessary components of life. Proteins, fats, carbohydrates, minerals, vitamins, water

With food, the body receives proteins, fats, carbohydrates necessary for life, as well as biologically active substances - vitamins and minerals, salts.

Proteins are the most important part of food. Protein deficiency in nutrition is one of the reasons for the increased susceptibility of the body to infectious diseases. With an insufficient amount of proteins, hematopoiesis decreases, the development of a growing organism is delayed, the activity of the nervous system, liver and other organs is disrupted, cell recovery after serious illnesses is slowed down. Excess protein in the diet can also harm the body.
Nitrogenous extractive substances contained in meat, fish and mushrooms are important in nutrition. Meat and fish broths, mushroom decoctions, due to the presence of extractive substances in them, help to improve digestion, causing increased secretion of digestive juices. At the same time, nitrogenous extractive substances in connection with the content of the so-called. purine bases require enhanced liver function.
Over half of the energy needed for normal life, the human body receives from carbohydrates..They are found predominantly in plant foods. A large amount of carbohydrates in the form of starch is found in bread, cereals, potatoes, and in the form of sugars - in sugar, confectionery, sweet varieties of fruits and berries. Carbohydrates are extremely important for the functioning of the muscles, nervous system, heart, liver and other organs.
Carbohydrates play a certain role in metabolic processes. They are necessary for the normal absorption of fats by the body. But excess sugar intake, combined with a general high-calorie diet, can lead to obesity, early development of atherosclerosis, and decreased performance. Excessive intake of sugar is especially unfavorable for the elderly, in whom excess sugar can contribute to the progression of the atherosclerotic process. In addition to these negative consequences, excessive intake of sugar can lead to hyperglycemia (high blood sugar), which adversely affects the function of the pancreas.
In a normal diet, carbohydrates should be approximately 4 times more than proteins.. The need for carbohydrates is determined by the amount of energy costs. The more intense the physical activity, the greater the amount of muscle work, the higher the need for carbohydrates. Older people, as well as those engaged in mental work and who are overweight, are advised that the amount of sugar that enters the body daily does not exceed 15% of the total daily amount of carbohydrates.
Rationing of carbohydrates can be carried out according to the caloric value of the daily diet. At the same time, for every 1000 kcal,124 g. carbohydrates. Sugar in its pure form (in jam, honey, sweets and confectionery), quickly absorbed in the intestines, causes a number of unpleasant sensations in some people: increased sweating, nausea, followed by lethargy, weakness, up to a fainting state, etc. These phenomena are explained by the fact that the amount of sugar in the blood increases rapidly and sharply, and then falls sharply, as a result of which the nervous system is excited. Therefore, you should not use more than a day100 g. sugar and sugary, including confectionery, products.
Twice a day, a dish of cereals, pasta or legumes, a dish and a side dish of potatoes or vegetables, 400–500 g of bread and about 90–100 g of sugar and sweets fully provide the daily carbohydrate requirement of an adult.
In vegetable products, along with carbohydrates that provide the body with energy, so-called non-nutritional carbohydrates - fiber. It has no practical significance as a source of energy in the diet, assimilated by about 25%, but contributes to the normal function of the intestines: irritating the walls of the intestines, it causes their movement - peristalsis. When eating food devoid of fiber, peristalsis weakens, which contributes to constipation.
Gray wheat bread, rye bread, vegetables should be included in the menu every day. Raw vegetables and fruits are very useful; they are also valuable because they contain so-called pectin substances. Being carbohydrates, pectins have some nutritional value. However, their main importance for digestion is that they contribute to better emptying of the intestines, increasing its peristalsis.
Fats are a ready-made "combustible" material that supplies the body with energy. Fats are necessary to ensure the normal absorption of proteins, certain minerals, salts, and fat-soluble vitamins by the body. The presence of fats in food gives various dishes high palatability, stimulates appetite, which is essential for normal digestion.
The fats that come with food are partly used to create fat reserves. Satisfaction of the need for fat and all its components depends on the type and quality of fat - the complementarity of animal and vegetable fats has been established. Biologically optimal balance is created when 70–80% animal fats and 20–30% vegetable fats are included in the daily diet.
The norms of fat intake into the body are calculated taking into account age, the nature of work, national characteristics and climatic conditions. In the norms of nutrition, 30% of calories are provided in the daily diet due to fat. Normalization of fat can be carried out according to the caloric value of the daily diet. At the same time, for every 1000 kcal,35 g. fat. Of certain importance is the qualitative composition of fats included in the diet. Fats of various animals, birds and fish, milk fat (mainly butter or ghee), as well as vegetable fats (sunflower, soybean, peanut, olive and other oils) are used for food.
Vegetable fats should be included in the daily diet of 20–25 g. Together with vegetable fats, beef and lard, and especially butter, should be included in the diet. Animal fats should be in the daily diet of about 75–80 g (of which40 g. in its natural form, and the rest - in various food products). The composition of the diet also includes some fat-like substances - cholesterol and lecithin. Cholesterol, which is found in significant amounts in animal fats, egg yolks, caviar, liver, kidneys, plays an important role in the life of the body, in particular in the activity of the nervous system.
Lecithin stimulates the development of a growing organism, favorably affects the activity of the nervous system, liver, stimulates hematopoiesis, increases the body's resistance to toxic substances, improves the absorption of fats, and prevents the development of atherosclerosis. A significant amount of lecithin is found in buckwheat, wheat bran, lettuce. A lot of lecithin in soy, beans and other legumes.
Mineralsare part of all the tissues of our body and are constantly consumed in the process of vital activity of the body. The daily human need for mineral salts is different. So, the daily need for sodium chloride (table salt), calcium phosphate is calculated in grams, the daily need for salts of copper, manganese, iodine is calculated in milligrams. Finally, there are such mineral salts, the daily requirement for which is calculated in thousandths of a milligram - micrograms. The body's need for mineral salts is usually fully met with a varied diet.
Among the various mineral salts that a person receives with food, table salt occupies a significant place. Insipid food, even the most varied, quickly becomes boring and disgusting. In addition, table salt is necessary to maintain a normal amount of fluid in the blood and tissues, it affects urination, the activity of the nervous system, blood circulation, and is involved in the formation of hydrochloric acid in the glands of the stomach.
In total, the body contains about300 g. salt, and in a year a person eats about5.5 kgsalt. In addition to the 3–4 g of salt found in natural foods per day, a few grams of salt are eaten with bread (in100 g. rye bread is about1.5 g, and in100 g. wheat bread - 0.5–0.8 g), a few grams are added when cooking food. On average, per day should be consumed up to12 g. salt. The bone skeleton is 1/5th of the weight of the human body, and the bones are 2/3 composed of mineral salts. The composition of bone tissue includes about 99% of all calcium present in the human body. However, the rest of the calcium plays an important role, participating in a wide variety of metabolic processes. Calcium salts are present in almost all food products, but are not always absorbed by the human body. To provide the body with the necessary amount of calcium salts, it is necessary to include in the diet products that contain a significant amount of calcium that is well absorbed by the body. Such products include milk, lactic acid products, cheese, egg yolk.
Waterrefers to substances that do not form energy when used in the body, but life is impossible without water.
When the correct amount of liquid is introduced into the diet, the proper volume (weight) of food is ensured, which creates a feeling of fullness. Average daily water requirement is approx. 35–40 ml per1 kgbody weight, i.e. OK. 2.5 l. A significant part of this norm (about 1 liter) is contained in food products: for example, in cereals - up to 80% water, in bread - about 50%, in vegetables and fruits - up to 90%. The so-called free liquid contained in soup, compote, milk, tea, coffee and other drinks should be about 1.2 liters with a total daily ration weight of approx.3 kg. The amount of water introduced into the body with food and drink varies depending on climatic conditions and the degree of intensity of physical work.
vitaminsare an essential and indispensable part of the diet. They ensure the normal functioning of the body, participate in the process of assimilation of other nutrients, help to increase the body's resistance to various harmful environmental influences, and increase the working capacity of a person.
A varied composition of food products in the diet and proper culinary processing of food contribute to the preservation of vitamins. With heavy physical labor, pregnancy, those living in the northern regions need for vitamins increases. In such conditions, there is a need to use vitamin preparations.