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 The human body is a very complex mechanism with many components. The largest volume in it - from 50 to 70% - is water, 18 - protein, 7-12 - fat, 4 - minerals and 1% - carbohydrates in the form of glucose.
Water is part of all body fluids. This is the environment in which all life processes take place. Dehydration of the body can lead to their violation.
Fats and carbohydrates are the main source of energy and therefore they are called energy components, and the process of energy exchange is called combustion. With excessive consumption of fats and carbohydrates, the surplus is deposited in the subcutaneous adipose tissue, which serves as a kind of storage of energy nutrients. If the body receives an insufficient amount of nutrients, some of these deposits are used to generate the necessary energy. The energy value of fats is higher than the energy value of carbohydrates: 1 g of fat supplies the body with 9 kcal, 1 g of carbohydrates - 4 kcal. An important constituent of fats are unsaturated fatty acids called vitamin F. Their content in vegetable fats is higher than in animals. Since the human body does not produce fatty acids, they must be supplied with food.
Protein is one of the most important components of the body, the carrier of life. It plays a primary role as a structural element of cells and as a functional component of enzymes, some hormones and antibodies. During fasting or with an unbalanced diet (imbalance between the amount of protein, fat and carbohydrates in the diet), the body can use protein for energy purposes (1 g of protein supplies 4 kcal). In living organisms, the formation (synthesis) of protein goes on continuously until death. During the growth period of the body, new cells are formed, later the process of synthesis and decay of protein in them takes place.
In each organism, a protein specific for this species is formed. The raw material for the formation of a person's own protein is vegetable and animal protein contained in food. In terms of biological value, animal protein is superior to plant protein. It provides the maintenance of life, growth and development of the organism, while the plant, supporting life, does not sufficiently promote growth and development. Therefore, the use of plant products in combination with animal products will help to replenish the biological value of plant protein and improve its digestibility.
Protein requirements may or may not be met, depending on the quantity and quality of the food. With a lack of protein, the growth and development of children is inhibited, anemia develops, the body's resistance decreases, etc. In our conditions, its deficiency most often occurs with inept selection of food.
Minerals (calcium, iron, phosphorus, magnesium, sulfur and iodine) perform a double role in the body: they serve as building materials for bones and teeth (calcium, phosphorus) and are part of various compounds that perform a regulatory function in the body. Vitamins A, D, E, K, C and group B perform a similar function.
How much and what kind of nutrients does a person need? The answer to this question can be found in the daily requirement rates developed by the Institute of Nutrition (Warsaw). The body's need for individual nutrients varies depending on age, sex, physiological state (pregnancy, lactation) and the type of work performed. For example, a young body needs about 2 g of protein per 1 kg of body weight, an adult - 1 g.Taking into account two factors - age and gender - six main population groups are identified: men, women, children, adolescent girls, adolescent boys and the elderly.
Children, adolescents, pregnant women and nursing mothers should receive from 1/2 to 2/3 of the total protein in the form of animal protein, other age groups - from 1/3 to 1/2. For men between the ages of 20 and 65, the nutrient requirement depends on the type of work being done. As the expenditure of physical forces increases, the body's need for fats and carbohydrates, the main suppliers of energy, increases.
It is clear that the need for nutrients in older people (over 60 years old) is lower than in people of the so-called productive age. In the norms established by the Institute of Nutrition, the total need for protein is given, as well as that part of it that must be replenished exclusively with animal protein (the column "including animal protein"). Children, adolescents, pregnant women and nursing mothers have the highest mineral requirements (relative to body weight). The young body also needs more vitamins.
Szczepanska B., Tarnowska K. Breakfasts, lunches and dinners for four seasons
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