Nutritional balance studies in very-low-birth-weight infants: enhanced nutrient retention rates by an experimental formula.

An experimental infant developed to meet the specific nutritional needs of very-low-birth-weight infants was evaluated by 96-hour balance studies in ten preterm infants (birth weight: 1,130 to 1,530 gm). The formula contained 23.2 gm/liter of protein (whey protein/casein ratio, 60:40), 44.1 gm/liter of fat (50% medium-chain triglycerides) and 85.0 gm/liter of carbohydrate (50% lactose, 50% Polycose), and provided relatively higher amounts of calcium, phosphorus, vitamin D, and electrolytes than are in human milk. All infants were fed 150 ml/kg/day (120 calories/kg/day) by intermittent gavage. Balance studies were carried out nine days following establishment of oral intake. The mean (+/- SEM) nutrient retention rates revealed by balance studies in these infants (calcium, 170 +/- 4 mg/kg/day; phosphorus, 78 +/- 3 mg/kg/day; nitrogen, 426 +/- 8 mg/kg/day; sodium, 1.4 +/- 0.1 mEq/kg/day) were comparable to normal fetal accretion rates. The mean (+/- SEM) fat absorption was 92.5 +/- 0.9%. No clinical intolerances or biochemical abnormalities were observed, and adequate postnatal growth was achieved in all infants. The diet proved to be nutritionally advantagaeous and safe for very-low-birth-weight infants.