Consequences of the composition of human milk for the nutrition of low-birth-weight neonates. III. Sodium and potassium
Boehm, G.; Springer, S.
Kinderarztliche Praxis 58(12): 645-651
1990
ISSN/ISBN: 0023-1495 PMID: 2098625 Document Number: 359736
The concentrations of sodium and potassium were studied in the 24 hour pooled human milk of 37 mothers delivered preterm (PTM) and of 19 mothers delivered at term (TM) from the second to the eighth postnatal day and in addition in the PTM during the third week of lactation. During the 4th week of life the sodium balance was estimated in 31 very low birth weight infants fed a human milk formula enriched with NaCl (n = 11) or NaH2PO4 (n = 11) and in 9 infants fed the same formula without supplementary sodium. The concentrations of sodium decrease significantly during the first week of lactation. The values are significantly higher in PTM than in TM during the first 3 days but decrease in both milks to values between 1 and 2 mmol/100 ml. The concentrations of potassium increase up to the 4th day of lactation and fall to approximately 1.5 mmol/100 ml at the end of the first week of lactation. There are no differences between PTM and TM. In all three balance groups the sodium balance are positive. But only in the infants fed a sodium-supplemented human milk formula the weight gain was adequate according to the protein and caloric intakes. No signs of a pathological sodium retention could be observed during the balance period. The data suggest that a sodium intake of more than 2.5 mmol/kg/day is necessary for optimal growth. Thus, the phosphorus supplementation should be done generally as 1 mmol NaH2PO4/100 ml human milk in very low birth weight infants.