DHA supplementation and its effect on the neurodevelopment of preterm infants

Docosahexanoic acid (DHA) is a long chain omega 3 polyunsaturated fatty acid which accumulates in the brain during the last trimester of pregnancy. Preterm infants, being born early, miss out on accumulating DHA during this time and are unable to make up the deficit as they have limited ability to make DHA. Lack of DHA has been proposed as one of the reasons preterm infants have lower developmental scores than term infants, however the neurological benefits and amounts required are not clear. An Australian randomized controlled study has investigated these issues.

The study assessed the effect of supplementing preterm infants with an amount of DHA estimated to be what they would have received had they remained in utero till term (approximately 1% total fatty acids) and measured neurological outcomes at 18 months corrected age. 657 infants born <33 weeks gestation were enrolled in the trial from 5 Australian hospitals. Infants were divided into 2 groups and received breast milk or  infant formula that was either high in DHA ( 1% of total fatty acids) or contained standard amounts of DHA ( 0.3% total fatty acids) from the first 2 to 4 days of life until corrected term age. The Bayley Mental Development Index (MDI) for infants and toddlers was given at  18 months corrected age. A comparison was also done between infants weighing <1250g and those weighing 1250g or more receiving the two different feeds.

There were no overall differences in MDI scores between infants fed the high DHA feeds and those fed the standard but fewer infants in the high DHA group were mildly or severly delayed. Girls fed the high DHA feed did better than girls fed the standard, but there was no differences between boys. Infants born <1250g and fed the high DHA feeds had higher MDI scores than those fed the standard though it was not statistically significant. For infants weighing 1250g or more the MDI did not differ between the groups.

The trial shows that DHA has an effect on neurodevelopment. While a dose of 1% did not increase MDI scores overall for  infants born < 33weeks, it did improve the scores of those weighing <1250g and improved the MDI scores of girls.

Reference:

Makrides M, Gibson RA, McPhee et al. Neurodevelopment outcomes of preterm infants fed high doses of docosahexanoic acid. JAMA 2009;301(2):175-182