Sequential calcium and phosphorus balance studies in preterm infants

Area of Science:

• Neonatal nutrition
• Pediatric mineral metabolism

Background:

• Premature infants (<1500g, <32 weeks gestation) require specific nutritional support.
• Enteral feeding is standard for these infants.
• Optimizing calcium and phosphorus intake is vital for bone development and overall growth.

Purpose of the Study:

• To investigate the impact of varying calcium and phosphorus concentrations in enteral formula on mineral absorption and retention in preterm infants.
• To determine optimal mineral intake levels for achieving intrauterine accretion rates.

Main Methods:

• Forty-six preterm infants were fed enterally with formulas differing in calcium and phosphorus content.
• Balance studies were conducted at multiple postnatal ages (10, 20, 30, 40 days).
• Calcium and phosphorus net absorption and retention were measured.

Main Results:

• Calcium retention was significantly influenced by postnatal age and calcium intake, with group C (125 mg/dL calcium) showing retention closest to intrauterine rates.
• Phosphorus absorption was high across all groups, regardless of calcium levels.
• Phosphorus retention increased with higher calcium intake.
• Elevated phosphorus intake (groups D & E) did not alter calcium absorption but slightly increased phosphorus retention.

Conclusions:

• Calcium intake is a key determinant of calcium retention in preterm infants, with higher levels (125 mg/dL) being most effective.
• Phosphorus is well-absorbed and its retention is enhanced by adequate calcium intake.
• Current feeding practices may need adjustment to optimize calcium and phosphorus levels for preterm infants.