Effect of nutrition on the nutritional status in preterm infants with very low birth weight

Introduction. Postnatal growth retardation in premature infants with very low birth weight (VLBW) remains an unresolved problem. There are different approaches regarding the duration of use of breast milk fortifiers during breastfeeding and specialized formulas during formula feeding, as well as the timing of the appointment of complementary feeding. Objective: to evaluate the physical development and component body composition in VLBW infants, depending on nutritional support over the first year of life. Materials and methods. The study included ninety three VLBW premature infants of 2 to 11 months postnatal age (PNA). The main (1st) group included infants (n = 74) who received dietary correction depending on the nutritional status, while no such intervention was performed in the (2nd) comparison group (n = 19). Up to 64 weeks of postconceptional age (PCA), weight, body length, and head circumference were assessed using INTERGROWTH-21st international growth standards, then in the software “WHO Anthro (2009)”. Fat and fat-free (lean) mass were determined using the air plethysmography method (PEA POD, LMi, USA). Results. The analysis of the nutritional status revealed a moderate deviation, not exceeding 1 sigma, decrease in indices (Z-scores) of anthropometric indices in infants of the 1st and 2nd groups by PNA of 2–3 months. Further in infants of the 1st group on the background of prolonged use of fortified nutrition (breast milk fortifier or specialized formulas for preterm infants) and timely introduction of complementary foods, nutritional deficiencies throughout the first year of life in general were not revealed. In the 2nd group of infants without additional correction of nutrition by 4–5 months of age, the development of mild nutritional deficiency was noted by 6–7 months of age. By 6–7 months of age, it turned into moderate nutritional deficiency, which persisted until 8–9 months of age and then turned into mild nutritional deficiency. Analysis of the component body composition showed that during the observation period, the fat-free body mass (FFM) gain in infants in the 1st group was 3.40 kg, in Group 2 infants — 2.2 kg. At the same time, % body fat mass (FM) in infants in groups 1 and 2 had no significant differences (%FM 1 = 19.3 [15.3–22.5], %FM 2 = 19.9 [16.7–24.6], p = 0.769) and did not exceed the values characteristic of preterm infants. Conclusion. A comprehensive assessment of the nutritional status of VLBW infants during the first year of life allowed us to eva­luate the positive impact of long-term use of fortified diets and timely introduction of certain complementary foods. Optimization of nutrition made it possible to prevent the development of nutritional deficiency, which can have a significant positive impact on their further growth, development, and health status.