Biochemistry

mineralization processes. Vitamin D affects carbohydrate metabolism, regulates the reaction cycle of tricarboxylic acids. Influencing the accumulation of calcium by mitochondria, vitamin D is also one of the regulators of oxidation and phosphorylation in the tissue respiration chain. Calciferol deficiency. With vitamin D deficiency, rickets develop in children, bone tissue softens in adults (osteomalacia). Early signs of rickets are changes in the function of the autonomic region of the central nervous system. Children become restless, shy, they have disturbed sleep, sweating increases. Then there are changes from the side of the skeletal system, teething of milk teeth and the closing of the fontanelles of the skull are delayed. The chest is deformed ( “ chicken breast ” ), spinal deformity and curvature of the legs may occur. The development of this disease contributes to the insufficient content of high-grade proteins and calcium in the diet. At the same time, calcium salts are not deposited in the bone tissue, so that the bones become “ soft ” . They become sensitive when pressed, their fragility increases, teeth grind. Lack of nutrition of unsaturated fatty acids, calcium, phosphorus and some vitamins (A, C, group B) impair the absorption of calcium. In older people, a deficiency of calciferol leads to the release of calcium from bones, softening of bones (osteoporosis). At the same time, bone strength decreases, fractures often occur. Hypervitaminosis develops if an increased amount of vitamin D enters the body. At the same time, there is an increased absorption of calcium and phosphorus from the intestine and their deposition not only in the bones, but also in the soft tissues - the heart muscle, vascular walls. Daily intake for adults is up to 100 ME (2.5 pg) for children - 500 ME (12.5 pg). Under normal conditions of life, with the full adult diet is not lacking in vitamin D. Sources. Vitamin D is found mainly in foods of animal origin (in the liver, milk fats, eggs, caviar, fish of fatty varieties). Partially, it is formed in the skin from 7-dehydrocholesterol under the influence of ultraviolet rays. Tocopherols (vitamin E, reproduction vitamin). Tocopherols are a group of vitamins that have an ability to protect animals from infertility and maintain the function of reproduction (from the Greek, tokos - childbirth, offspring, fero - carry). The first information about the existence of a vitamin that regulates the process of reproduction appeared in 1920. However, only in 1936, three vitamers of vitamin E were isolated from various vegetable oils. Tocopherol was synthesized in 1938. Structure and physicochemical properties. Tocopherol and its chemical analogues are derivatives of trimethylhydroquinone alcohol phytol. 266