Utilization of supplemental iron by premature infants fed fortified human milk

Nutrient requirements for preterm infant formulas

Achieving appropriate growth and nutrient accretion of preterm and low birth weight (LBW) infants is often difficult during hospitalization because of metabolic and gastrointestinal immaturity and other complicating medical conditions. Advances in the care of preterm-LBW infants, including improved nutrition, have reduced mortality rates for these infants from 9.6 to 6.2% from 1983 to 1997. The Food and Drug Administration (FDA) has responsibility for ensuring the safety and nutritional quality of infant formulas based on current scientific knowledge. Consequently, under FDA contract, an ad hoc Expert Panel was convened by the Life Sciences Research Office of the American Society for Nutritional Sciences to make recommendations for the nutrient content of formulas for preterm-LBW infants based on current scientific knowledge and expert opinion. Recommendations were developed from different criteria than that used for recommendations for term infant formula. To ensure nutrient adequacy, the Panel considered intrauterine accretion rate, organ development, factorial estimates of requirements, nutrient interactions and supplemental feeding studies. Consideration was also given to long-term developmental outcome. Some recommendations were based on current use in domestic preterm formula. Included were recommendations for nutrients not required in formula for term infants such as lactose and arginine. Recommendations, examples, and sample calculations were based on a 1000 g preterm infant consuming 120 kcal/kg and 150 mL/d of an 810 kcal/L formula. A summary of recommendations for energy and 45 nutrient components of enteral formulas for preterm-LBW infants are presented. Recommendations for five nutrient:nutrient ratios are also presented. In addition, critical areas for future research on the nutritional requirements specific for preterm-LBW infants are identified.

Neonatal iron nutrition

Preterm infants are prone to iron deficiency. Their total body iron content at birth is low and gets further depleted by clinical practices such as uncompensated phlebotomy losses and exogenous erythropoietin administration during the neonatal period. Early iron deficiency appears to adversely affect cognitive development in human infants. To maintain iron sufficiency and meet the iron demands of catch-up postnatal growth, iron supplementation is prudent in preterm infants. A dose of 2-4 mg/kg/day is recommended for preterm infants who are fed exclusively human milk. A dose of 6 mg/kg/day or more is needed with the use of exogenous erythropoietin or to correct preexisting iron deficiency. However, due to the poor antioxidant capabilities of preterm infants and the potential role of iron in several oxidant-related perinatal disorders, indiscriminate iron supplementation should be avoided.

Using stable isotopes to assess mineral absorption and utilization by children

Adequate mineral intake is a crucial part of a healthy diet for children-it supports appropriate growth and development and provides protection against childhood conditions like anemia and helps to prevent future adult diseases such as osteoporosis. Challenges in performing and interpreting studies in infants and children have hampered the accurate assessment of their mineral utilization. Many of the most powerful techniques used in adults, such as radioisotope testing, are not appropriate for use in children. In recent years, advanced mineral stable-isotope techniques have been developed to fill this gap. Pediatric applications include studies of calcium absorption and kinetics during puberty and evaluation of the calcium-iron interaction in infants and toddlers. The effects of genetics in determining calcium absorption and bone turnover may become an important research area. The goals and methods of ongoing mineral stable-isotope research in infants and children are examined in this report. In the past, the cost and difficulties in obtaining isotopes have limited such research. This situation has improved considerably, although relatively few nutrition research laboratories are prepared to perform sample analyses.