Intake of adequate nutrients in preterm infants is difficult at best, and most often does not accomplish meeting the recommended dietary intakes (RDI).  A nutrient deficit therefore accrues, leading to postnatal malnutrition and growth retardation.  This study assesses the dietary intake in a prospective single observer design in 105 preterm infants with a body weight of < 1750 grams and a gestational age of < 34 weeks who were admitted to the Neonatal Intensive Care Unit over a 6 month period.  Actual intake was subtracted from the recommended energy intake (120 kcal/kg/day) and protein (3 g/kg/day), and nutritional deficits were calculated.  Infants were weighed on admission and throughout the hospital stay.

Nutrient intakes meeting current RDI’s were rarely achieved during early life.  By the end of the first week, cumulative energy and protein deficits were 406 +/- 92 and 335 +/- 86 kcal/kg and 14 +/- 3 and 12 +/- 4 g/kg in infants < 30 and those at > 31 weeks, respectively.  By the end of the fifth week, cumulative energy and protein deficits were 813 +/- 542 and 382 +/- 263 kcal/kg and 23 +/- 12 and 13 +/- 15 g/kg.  The z scores were –1.14 +/- .6 and -.82 +/- .5 for infants at < 30 and > 31 weeks.  Stepwise regression analysis indicated that variation in dietary intake accounted for 45% of the variation in changes in z score.  The authors concluded that preterm infants inevitably accumulate a significant nutrient deficit in the first few weeks of life.

Editor’s Comments:  This study clearly demonstrated that there is an accumulated nutrient deficit in preterm infants in an NICU setup.  It also clearly suggests that the nutritional approach to the care of these infants needs to be re-thought, perhaps with a more aggressive approach, i.e. enteral or parenteral feedings.  However, even early parenteral or enteral supplementation might be limited as these infants might not be able to tolerate it.  A more aggressive enteral feeding is also hard to attain in the first few days of life, and it could lead to necrotizing enterocolitis or other adverse effects.  The long-term consequences of this accumulated nutrient deficit may be important.  It is generally assumed that poor growth in the preterm low birth weight infants primarily reflects inadequate nutrient intake, and in this study there was a 45% variation in growth related to such.  Nonetheless, despite poor growth during the initial stages of life, most premature infants grow well thereafter and attain a normal height, unless there are other complications.  Once the infant matures, the nutrient deficits are recouped and there is nutritional recovery with catch-up growth.  However it should be kept in mind that nutrient deficits in early infancy might have other devastating consequences.  The data from this study suggest that the clinician is in a quandary and that a more realistic picture regarding the quantity and quality of nutritional care in low birth weight infants needs to be re-thought.

Fima Lifshitz, MD

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