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Parenteral nutrition for infants: effect of high versus low calcium and phosphorus content
Insights
High calcium and phosphorus in parenteral nutrition stabilized vitamin D levels and phosphorus reabsorption in infants. Low levels of these minerals in parenteral nutrition increased vitamin D and phosphorus reabsorption, indicating stress on infant homeostasis.
Area of Science:
- Neonatal nutrition
- Pediatric mineral metabolism
- Parenteral nutrition
Background:
- Infant mineral homeostasis is critical for growth and development.
- Parenteral nutrition (PN) is essential for infants unable to receive adequate nutrition orally.
- Optimizing calcium (Ca) and phosphorus (P) content in PN is crucial for maintaining mineral balance.
Purpose of the Study:
- To investigate the impact of high versus low Ca and P content in PN on mineral homeostasis in infants.
- To assess the effects on serum 1,25 dihydroxyvitamin D [1,25(OH)2D] and tubular reabsorption of phosphorus (TRP).
Main Methods:
- 18 infants received either low (20 mg Ca/dl, 15.5 mg P/dl) or high (60-80 mg Ca/dl, 46.5-62 mg P/dl) Ca and P content PN.
- Vitamin D dosage was fixed at a low level (25 IU/dl) for all infants.
- Mineral homeostasis markers, including serum 1,25(OH)2D and TRP, were monitored for up to 6 weeks.
Main Results:
- The high Ca, P PN group maintained stable serum 1,25(OH)2D within the normal range and TRP below 90%.
- The low Ca, P PN group showed elevated serum 1,25(OH)2D and TRP consistently above 90%, indicating homeostatic stress.
- No significant differences were observed in other measured parameters like parathyroid hormone, calcitonin, or other minerals between the groups.
Conclusions:
- High Ca and P content (60 mg Ca/dl, 46.5 mg P/dl) in PN can support stable Ca and P homeostasis in infants.
- This high mineral content appears to minimize stress on infant homeostatic mechanisms without increasing urinary calcium excretion.
- Optimizing PN mineral composition is key to preventing metabolic disturbances in vulnerable infants.
Abstract:
Calcium (Ca) and phosphorus (P) homeostasis were determined in 18 infants (birth weight, 2,810 +/- 135 g; gestational age, 37.4 +/- 0.5 weeks; mean +/- SEM) who received high or low Ca and P content (Ca, P) parenteral nutrition (PN) with a fixed, low dose of vitamin D (25 IU/dl). Nine infants were randomized into low (standard) Ca, P (20 mg Ca and 15.5 mg P/dl) and nine into high Ca, P (60-80 mg Ca and 46.5-62 mg P/dl) PN, and then were studied for up to 6 weeks. The high Ca, P group had stable serum 1,25 dihydroxyvitamin D [1,25(OH)2D], which consistently remained within the normal range (less than 116 pg/ml). Tubular reabsorption of phosphorus (TRP) also was stable and remained consistently less than 90%. The low Ca, P group had elevated and higher 1,25(OH)2D (p = 0.03) than the high Ca, P group. The mean serum 1,25(OH)2D concentration rose from 32 to 112, 115, and 133 pg/ml over a period of 6 weeks. TRP also was higher (p = 0.02) and remained consistently greater than 90%. There were no significant differences between groups in serum parathyroid hormone, calcitonin, Ca, Mg, P, alkaline phosphatase, vitamin D binding protein, and 25 hydroxyvitamin D concentrations; urine Ca/creatinine and Mg/creatinine ratios, and fractional excretion of sodium (Na). Thus, a "high" Ca (60 mg/dl) and P (46.5 mg/dl) content in PN solutions can result in stable serum 1,25(OH)2D and TRP, presumably reflecting minimal stress to Ca and P homeostatic mechanisms without further increase in urinary Ca excretion.