ABSTRACT
The content of 25-hydroxycholecalciferol, calcium and phosphorus in blood serum was measured in 80 premature infants aged 12 to 120 days depending on the type of feeding and rickets prevention. Administration of vitamin D in a dose of 400 IU and increase of calcium consumption up to 110-120 mg and of phosphorus to 45-57 mg per kg body weight at the expense of calcinated cottage introduction into the diet provide for the optimal levels of 25-hydroxycholecalciferol and calcium in the blood of these children. Administration of calcium and phosphorus to children receiving breast feeding in doses of 80-90 and 33-37 mg/kg, respectively, is not sufficient for the maintenance of calcium homeostasis and endogenous supply with vitamin D even if the latter is given prophylactically. When children are fed with the mixture Maliutka, the maximal permissible dose of vitamin D may amount to 800 IU a day. Administration of vitamin D in a dose of 3750 IU is fraught with a danger of hypervitaminosis D in the presence of high alimentary supply with calcium and phosphorus and does not make calcium homeostasis return to normal in the presence of low supply with these mineral substances.