Protein requirements of very low birth weight infants

Objective: To review existing information regarding protein (and energy) requirements of very low birth weight infants, and to determine whether revisions may be indicated in view of the commonly observed postnatal growth failure, or in view of adverse consequences of accelerated growth. Results: Nutrient requirements of very low birth weight infants have been estimated by the factorial method and by empirical methods. These approaches yield similar estimates of nutrient requirements. The factorial method provides estimates of requirements for protein and energy, including those of extremely small infants. Empirical methods yield estimates of protein requirements but tend to exclude extremely small infants. They also provide estimates of protein intakes that lead to catch-up growth. Reports of actual nutrient intakes received by very low birth weight infants show that intakes are generally less than estimated requirements. Conclusions: Growth failure is adequately explained by insufficient nutrient intakes. Upward revision of requirements is not indicated until it can be shown that growth failure occurs despite intakes that match current estimates of requirements. Downward revision also is not indicated because accelerated growth, in spite of some adverse effects later in life, is associated with improved neurocognitive outcome.