Related Experiment Videos
Calcium and phosphorus homeostasis in very-low-birth-weight infants appropriate for gestational age fed human milk
1Department of Paediatrics, Karl Marx-University, Leipzig, GDR.
Insights
Very-low-birth-weight (VLBW) infants fed human milk may have latent phosphorus deficiency. Supplementing with sodium dihydrogen phosphate (NaH2PO4) improved phosphorus levels but intake may still be insufficient for optimal mineral metabolism.
Area of Science:
- Neonatology
- Pediatric Nutrition
- Mineral Metabolism
Background:
- Human milk is the primary nutrition source for many infants, but its mineral content may be insufficient for very-low-birth-weight (VLBW) infants.
- VLBW infants have unique nutritional needs due to immature organ systems and rapid growth.
- Assessing mineral balance, particularly calcium and phosphorus, is crucial for VLBW infant development.
Purpose of the Study:
- To evaluate serum calcium, phosphorus, and alkaline phosphatase activity in VLBW and low-birth-weight (LBW) infants.
- To assess the impact of human milk supplementation with sodium dihydrogen phosphate (NaH2PO4) on mineral excretion.
- To determine if human milk alone supports adequate phosphorus levels in VLBW infants.
Main Methods:
- Serum calcium, phosphorus, and alkaline phosphatase were measured on days 7, 21, and 42 in 42 VLBW and 83 LBW infants.
- Renal excretion of calcium and phosphorus was measured in a subgroup of infants fed either human milk or human milk supplemented with NaH2PO4.
- Infant groups were compared based on feeding type and birth weight.
Main Results:
- Serum mineral parameters were within normal ranges for all infants.
- VLBW infants showed a tendency towards conserving phosphorus and excreting more calcium compared to LBW infants.
- NaH2PO4 supplementation increased urinary phosphorus excretion and decreased calcium excretion in VLBW infants, though values remained lower than in LBW infants.
- Alkaline phosphatase activity was normal, suggesting no delayed bone mineralization.
Conclusions:
- VLBW infants fed human milk may experience latent phosphorus deficiency, indicated by renal excretion patterns.
- Human milk's phosphorus concentration may be too low and its calcium/phosphorus ratio too high for optimal VLBW infant mineral metabolism.
- NaH2PO4 supplementation improves phosphorus status but optimal intake requires further investigation; urinary calcium/phosphorus ratio is a potential marker for latent phosphorus deficiency.
Abstract:
The concentrations of calcium and phosphorus and the activity of alkaline phosphatase in serum were evaluated in 42 very-low-birth-weight (VLBW) and 83 low-birth-weight (LBW) infants on the 7th, 21st, and 42nd day of life. 9 VLBW and 16 LBW infants were randomized for measurement of the renal excretion of calcium and phosphorus on the 3rd, 5th, 7th, 21st, and 42nd day of life during human milk feeding and 14 VLBW-infants fed human milk supplemented with 1 mmol NaH2PO4 per 100 ml. All serum parameters were found to be normal. Supplementation of human milk with NaH2PO4 leads to a tendency of higher concentrations of phosphorus than found in VLBW-infants exclusively fed with native human milk, but all differences between the two groups were not significant. VLBW-infants appeared more than LBW-infants to be conserving phosphorus and wasting calcium during human milk feeding. Supplementation of human milk with NaH2PO4 results in higher phosphorus lower calcium excretion in urine of VLBW-infants, but they do not reach the values of LBW-infants. Because the activity of alkaline phosphatase was not different between the feeding groups and in all cases within the normal range a delayed bone mineralisation cannot be assumed in the infants studied. Thus, the phosphorus deficiency which is shown by the renal excretion of calcium and phosphorus in the VLBW-infants can be considered to be latent. In the light of our data the concentration of phosphorus in human milk seems to be too low and the calcium/phosphorus ratio too high for the optimal mineral metabolism in VLBW-infants. The supplementation used improves the situation, but the phosphorus intake seems still too low. Further investigations are needed to detect the optimal phosphorus intake for these infants. The calcium/phosphorus ratio in the urine is a good marker to estimate a latent phosphorus deficiency in VLBW-infants.