The study of perinatal risk factors and the clinical and somatometric condition of infants with primary transient lactose intolerance, as well as their vitamin D supply, was carried out. The 48 children of the first six months of life were examined. Risk factors were identified in the mothers of the examined infants, which, in our opinion, were the basis for the formation of morphofunctional immaturity of the gastrointestinal tract in children (the mother’s age is more than 30 years old, iron deficiency anemia, the threat of termination of pregnancy, operative delivery, etc.). When assessing the condition of infants, somatometric status disorders were diagnosed in 54.2% of cases, of which malnutrition was detected in 76.9% of cases, and abnormal weight gain in 23.1% of cases. We have established the important fact that morphofunctional immaturity of the gastrointestinal tract and inadequate drug enteral support led in 61.5% of cases to insufficient vitamin D supply, determining metabolic disorders. We have refined a two-stage algorithm for nutritional support for patients with nutritional status disorders, including the mandatory use of micellar solutions of cholecalciferol.