Fractional deposition of metabolizable energy (ME) in very low birth weight infants (VLBW): 28

The increasing survival of VLBW premature infants requires a precise knowledge of utilization of essential nutrients (P=protein F=fat, C=carbohydrate) in order to design suitable dietary regimes Energy balance (EB), substrate utilization for oxidation (0) and tissue deposition studies were performed on VLBW premature infants (n=10; gest. age 27-31 weeks; birth weight 940 - 1280 g; postnat. age 1 - 4 weeks) fed by own mother's milk (6 studies on 4 infants) or humanized milk (SMA 20/24 Wyeth; 13 studies on 6 infants). EB for growth was determined by the equation: EB = ME - 0 (P+F+C). By increasing the net energy intake (NEI) from 50 to 150 Kcal/kg/day, resting metabolic rate (RMR) increased from 38 to 58 Kcal/kg/day in the formula fed infants (FFI) and from 45 to 58 in the breast fed infants (BFI). In a range of 50-110 Kcal/kg/day NEI the RMR was consistently higher in BFI. The latter deposited more P than FFI at the same level of NEI. At a NEI of 100 Kcal/kg/day FFI deposited 1 g P/day in contrast to the 2 g/kg/day P deposition observed in the BFI. Tissue deposition of F increases with the enhancement of NEI in both FFI and BFI but the relationship is the reverse to that observed for P deposition. At a 100 Kcal/kg/day NEI 18 Kcal/kg/day energy is deposited as F in the BFI in contrast to the 28 Kcal/kg/day deposition in FFI. It is concluded that the quality of growth (P v.F deposition) in response to a specific diet composition may be defined by our investigative approach.