To test the hypothesis that long-chain polyunsaturated fatty acid (LCPUFA) supplementation in infancy would improve cognition into later childhood (after 9 years) at both general and specific levels.

A comprehensive cognitive battery was completed by 107 formerly preterm infants (mean age: 128 months). As infants, they had been assigned randomly to receive LCPUFA-supplemented (N = 50) or control (N = 57) formula, between birth and 9 months; the docosahexaenoic acid level (DHA) in the supplemented formulas was 0.5%. In addition to randomized comparisons, we planned supplementary analyses to examine the effects of both gender and feeding group (those receiving some maternal breast milk versus those receiving none).

There were no significant differences between randomized diet groups on any cognitive measure. There was significant interaction between gender and supplementation; girls only showed beneficial effects of LCPUFAs on literacy. Significant interaction also occurred between feeding group and supplementation; increases of 0.7 SD in verbal IQ, full-scale IQ, and memory scores were found for the LCPUFA group, but only for infants who received only formula and no maternal breast milk.

The results of this post-9-year cognitive follow-up study in a randomized trial of LCPUFA-supplemented formula for preterm infants suggest no overall group effects but indicate that gender-specific and diet-specific effects may exist. The data provide some evidence that LCPUFAs are a key factor in the cognitive benefits of breast milk. Caution is advised in data interpretation because of the small groups used.

PMID: 21930549

See following website for full manuscript.