Rickets in premature infants fed different formulas

Area of Science:

• Neonatology
• Pediatric Nutrition
• Nutritional Biochemistry

Background:

• Rickets is a significant concern in very-low-birth-weight (VLBW) infants.
• The role of infant formula composition in rickets development requires further investigation.
• Soy-based formulas are sometimes used for VLBW infants, but their impact on bone health is not fully understood.

Purpose of the Study:

• To investigate the association between different infant formulas and the incidence of rickets in VLBW infants.
• To compare the effects of soy isolate formula versus milk-based formulas on bone metabolism markers.
• To identify potential risks associated with soy isolate formula feeding in VLBW infants.

Main Methods:

• A randomized controlled trial involving 46 VLBW infants (<= 1,500 gm).
• Infants were assigned to receive Isomil (soy isolate), Similac with Iron (milk-based), or Similac 24 LBW (hypercaloric milk-based) for 3-4 months.
• Postnatal monitoring included serum calcium, phosphorus, alkaline phosphatase, and albumin levels, along with radiologic diagnosis of rickets.

Main Results:

• Rickets was diagnosed in 60% of infants fed Isomil, compared to 5% fed Similac with Iron.
• Infants on Isomil exhibited significantly lower serum phosphorus and higher alkaline phosphatase levels.
• No significant rickets incidence was observed in infants fed milk-based formulas.

Conclusions:

• Soy isolate formula is associated with a high frequency of rickets in VLBW infants.
• Milk-based formulas did not show a similar increased risk for rickets.
• Prolonged feeding of soy isolate formulas is not recommended for VLBW infants due to potential mineral bioavailability issues and high rickets incidence.