Vitamins, biologically active organic compounds that the body needs in small amounts, which are part of enzymes and have a catalyzing effect on the metabolism of proteins, fats and carbohydrates; participate in the regulation of the functional state of organs and systems.
The human body cannot synthesize vitamins, so the main source of them are food products (see table Content of vitamins in food pdf 117 KB). Synthesis of vitamins in nature is realized by plants. The man gets vitamins directly with plant food or indirectly through animal products (meat, milk, and so on), in which the vitamins were accumulated from plant materials during the life of the animal.
In some cases, with food products in an organism are not ready vitamins, and organic compounds, which in its chemical structure similar to vitamins and are called provitamins. Provitamins into the body in the appropriate vitamins (see Carotene). Synthesis of some vitamins is carried out by the intestinal flora, it is not significant and can't fully satisfy the needs of vitamins.
Entering the body, vitamins are connected with the specific protein complexes (apparments), resulting in the formation enzymes (see).
Currently, there are dozens of connections that can be attributed to the vitamins, but also directly relevant to nutrition and health have only about 20 of them. They are indicated by the letters of the Latin alphabet: a, b, C, D, E, H, K, etc. that is connected mainly with the history of the discovery of a vitamin and firmly continues to this day. However, as the establishment of the exact chemical structure of vitamins they receive different names, reflecting their chemical nature, so that the letter of vitamins gradually fall into disuse.
Classification of vitamins based on their solubility in water or fat.
Water-soluble vitamins: B1 (thiamine, aneurine), B2 (Riboflavin), PP (Niacin, nicotinic acid, nicotinic acid amide), a group of vitamin B6 (pyridoxine, pyridoxal, and pyridoxamine), B12 (cobalamine), folic acid (folacin, pteroylglutamic acid), B3 (Pantothenic acid), H (Biotin), choline, Inositol (misonoza), C (ascorbic acid), P (bioflavonoids).
Fat-soluble vitamins: a (retinol, axerophthol), D (calciferol), E (Tocopherols), K (phylloquinone).
The quantity of the vitamins we need, is negligible in comparison with the need in proteins, fats and carbohydrates. The human need for vitamins varies depending on the age of the work performed, the environmental condition of the body, climatic conditions, the composition of the diet and other large expenditure of energy metabolism processes proceed more intensively, which in turn requires more vitamins (see table "Daily norms of human need for vitamins pdf 87,3 KB). At various diseases of the norm requirements of vitamins can increase depending on the nature of the disease, condition of the organism and its individual characteristics.
Insufficient intake of certain vitamins or violation of their assimilation leads to the development of pathological processes in the form of specific Hypo - and avitaminosis. Excessive intake of certain vitamins leads to the reason.
There is a group of substances, which in various ways violates biochemical use of vitamins living cell. These substances are called antivitamins. They can be divided into two main groups. The first group includes chemical substances that inactivate vitamins through their cleavage, destruction or binding molecules of vitamins in an inactive form. The second group includes chemical, structural or similar structurally related to vitamins. As a result of antivitamins both groups disrupted normal during the process of metabolism. Antivitamins the properties of certain medications (antibiotics, sulfa drugs, dikumarina, and others). Therefore, when the course of treatment with these drugs, as a rule, are at the same time the vitamin.
Vitamins as preparations - see articles on individual vitamins.