PECULIARITIES OF FORMATION OF VITAMIN DEFICIENCY IN CHILDREN OF PRESCHOOL AGE, SUBJECTED TO CHRONIC IMPACT OF CHEMICAL RISK ENVIRONMENTAL FACTORS

There was made a study of the blood content of vitamins A, C, D, B6 and B12 in 188 children aged 6-7 years attending pre-school educational institutions located on the territory of a large industrial center with environmental pollution of organic substances of man-made origin (atmospheric air: phenol, formaldehyde, ethylbenzene, drinking water: organochlorine compounds) in concentrations exceeding hygienic standards. It has been established that even with a balanced diet provided with vitamins at the level of physiological demands, more than 75% of children have a reduced blood level of vitamins. There has been revealed a relationship between the decline of the level of provision with vitamins and a high blood content of the studied organic compounds in children. Chronic both the aerogenic and peroral intake of phenol, formaldehyde, ethylbenzene of organochlorine compounds depletes the reserve of the antioxidant defense system, as evidenced by the established feedback of the blood content of the investigated organic compounds with the content of antioxidant profile enzymes (succinate dehydrogenase and glutathione peroxidase) and total antioxidant activity of blood serum. Under conditions of a decrease in the functional activity of the enzymes of the oxidation-antioxidant system, there is increased primarily carried out by vitamins, the role of non-enzymatic responses of the antioxidant protection, which is accompanied by an increased their consumption. The activation a mechanism for increased consumption of vitamins in conditions of chronic toxic load is the basis for the formation of a vitamin deficiency associated with the exposure to organic compounds of technogenic origin. At the same time, the progressive deficiency of vitamins creates the conditions for reducing the activity of biotransformation processes of chemical substances of technogenic origin and their accumulation in biological environments. The formation of interrelated processes (elevated levels of organic compounds in the blood of technogenic origin ↔ hypovitaminosis) as the pathogenetic basis of the progressive vitamin deficiency in children requires the development of new approaches to the prevention and treatment of hypovitaminosis in children living in conditions of sanitary and hygienic troubles associated with the presence of a complex of organic compounds of technogenic origin in objects of the environment.