Modified cow's milk formula with reduced renal acid load preventing incipient late metabolic acidosis in premature infants.

BACKGROUND: Premature infants receiving alimentation with cow's milk formulas are at a considerably high risk of developing incipient late metabolic acidosis, an early stage in the development of manifest late metabolic acidosis. Is it possible to reduce this risk by modification of the composition of a standard formula? METHODS: The mineral composition of a cow's milk preterm formula A was modified (formula B) with the aim of reducing the alimentary load to that of human milk. 160 premature infants were fed either mother's milk (n = 50) or the modified formula B (enriched with sodium and potassium) (n = 110), and their urine pH was tested twice a week. Randomly collected subgroups of infants were studied in detail for nutrient balances. The results were compared with earlier observations of 282 premature infants fed either mother's milk (n = 28) or the standard formula A (n = 254). RESULTS: Incipient late metabolic acidosis was observed in nine of 78 premature infants receiving mother's milk, 53 of 254 premature infants receiving the standard formula A, and only one of 110 premature infants fed the modified formula B. Net acid excretion was 0.58 mmol/kg/day in 11 premature infants receiving alimentation with the modified formula B compared with 1.73 mmol/kg/day in 23 premature infants fed formula A. This reduction was mainly due to an increased alkali excess (sodium + potassium-chloride) in intake and urine. CONCLUSIONS: Reduction of renal acid load with the modified formula B had a preventive effect on the rate of development of incipient late metabolic acidosis in premature infants.

[Supplementation of premature infant nutrition with calcium and phosphor for improving mineral supply of premature and small-for-gestational age newborn infants]. / Anreicherung einer Frühgeborenenmilchnahrung mit Kalzium und Phosphor zur Verbesserung der Mineralstoffversorgung Früh- und Mangelgeborener.

A standard preterm formula was supplemented with calcium (Ca) and phosphorus (P) (F-CaP: Ca 87 mg/dl, P 43 mg/dl) and compared to the non-supplemented form (F: Ca 62 mg/dl, P 36 mg/dl). VLBW and small-for-gestational-age infants (n = 79) were included in the study which was performed to look for adverse effects and to decide about a reasonable start and duration of supplementation. In preterm infants with a birth weight lower than 1500 g and a body weight of more than 2000 g, the additional supplementation with Ca and P lead to a significant higher Ca- and P-retention without further load for the kidney. In addition, preterm infants with a body weight lower than 1500 g also had a better retention of Ca and P. Both, F-CaP and F lead to a high urinary excretion of phosphorus, a high renal net acid excretion and a relatively high activity of serum alkaline phosphatase. Anthropometric measurements did not reveal any evidence for an impaired caloric absorption due to an increased fecal fat excretion. Hypercalcemia or hyperphosphatermia was not seen. Hypercalciuria occurred in less than 5% of the samples studied. The results of this study indicate that a continuation of the supplementation with Ca and P is justified in VLBW infants with a body weight of more than 2000 g. There was no evidence for adverse effects of Ca and P supplementation in VLBW infants with a body weight lower than 1500 g, who might therefore also benefit from supplementation. Further studies are necessary to investigate unsatisfactory metabolic conditions of these children e.g. the high renal load.