Calcium and phosphorus balance in extremely low birthweight infants in the first six weeks of life

Area of Science:

• Neonatal nutrition
• Pediatric gastroenterology
• Mineral metabolism

Background:

• Extremely low birthweight (ELBW) infants (<28 weeks' gestation) have unique nutritional needs.
• Breast milk is often considered optimal but may be low in essential minerals.
• Preterm formulas are designed to meet the specific requirements of premature infants.

Purpose of the Study:

• To compare calcium and phosphorus absorption and retention in ELBW infants fed breast milk versus preterm formula.
• To investigate the impact of different feeding regimens on mineral balance in premature neonates.
• To identify potential nutritional deficiencies and their clinical implications in ELBW infants.

Main Methods:

• Conducted 22 balance studies in ELBW infants (≤28 weeks' gestation).
• Assessed calcium and phosphorus intake, absorption, urinary losses, and retention.
• Compared outcomes between infants fed exclusively breast milk and those fed a preterm formula.

Main Results:

• Breast milk had significantly lower calcium and phosphorus content than preterm formula.
• Calcium absorption percentage was similar, but urinary losses were higher, leading to lower retention in breast milk-fed infants.
• Phosphorus absorption percentage was similar, but higher intake in formula-fed infants resulted in greater phosphorus retention; breast milk-fed infants showed signs of phosphorus depletion (hypophosphatemia).

Conclusions:

• ELBW infants fed breast milk alone may experience phosphorus depletion and reduced calcium retention, potentially increasing rickets risk.
• Hypophosphatemia in breast milk-fed infants may impair calcium deposition in bone and cause calciuria.
• Calcium and phosphate supplementation may be necessary for preterm infants, especially those on breast milk, from an early age to ensure adequate bone mineralization and prevent rickets of prematurity.