Higher dose of docosahexaenoic acid in the neonatal period improves visual acuity of preterm infants: results of a randomized controlled trial.

BACKGROUND Preterm infants have improved visual outcomes when fed a formula containing 0.2-0.4% docosahexaenoic acid (DHA) compared with infants fed no DHA, but the optimal DHA dose is unknown. OBJECTIVE We assessed visual responses of preterm infants fed human milk (HM) and formula with a DHA concentration estimated to match the intrauterine accretion rate (high-DHA group) compared with infants fed HM and formula containing DHA at current concentrations. DESIGN A double-blind randomized controlled trial studied preterm infants born at <33 wk gestation and fed HM or formula containing 1% DHA (high-DHA group) or approximately 0.3% DHA (current practice; control group) until reaching their estimated due date (EDD). Both groups received the same concentration of arachidonic acid. Sweep visual evoked potential (VEP) acuity and latency were assessed at 2 and 4 mo corrected age (CA). Weight, length, and head circumference were assessed at EDD and at 2 and 4 mo CA. RESULTS At 2 mo CA, acuity of the high-DHA group did not differ from the control group [high-DHA group (x +/- SD): 5.6 +/- 2.4 cycles per degree (cpd), n = 54; control group: 5.6 +/- 2.4 cpd, n = 61; P = 0.96]. By 4 mo CA, the high-DHA group exhibited an acuity that was 1.4 cpd higher than the control group (high-DHA: 9.6 +/- 3.7 cpd, n = 44; control: 8.2 +/- 1.8 cpd; n = 51; P = 0.025). VEP latencies and anthropometric measurements were not different between the high-DHA and control groups. CONCLUSION The DHA requirement of preterm infants may be higher than currently provided by preterm formula or HM of Australian women.