Omega-3 fatty acids and neurodevelopmental status in infants

Nutrition Research Newsletter, July, 2002

Some studies show that breast-fed infants compared to formula-fed infants score higher on tests of cognitive and academic ability. Due to these studies, there is considerable interest in the specific role of human milk components that might account for any possible enhancement in neurodevelopment outcome.

Docosahexaenoic acid (DHA) and arachidonic acid (AA) are both present in human milk and are the mot prevalent omega-3 and omega-6 fatty acids, in the brain respectively, and are thought to be essential components of the structural lipids of synaptosomal membranes. It has also been found that DHA and AA can be synthesized from their respective dietary precursors, alpha-linolenic acid and linoleic acid (LA), respectively. Therefore, a recent article in the Journal of Human Nutrition and Dietetics studied the influence of alpha-linolenic acid (ALA) intake and, hence, the influence of plasma and/or erythrocyte phospholipid content of DHA during early infancy on neurodevelopmental outcome of term infants.

Infants enrolled in the study were randomly and blindly assigned to receive one of four formulae as their sole source of nutrition form birth to 120 days of age. The formulae differed only in ALA content ranging from 0.4 to 3.2% of total fatty acids and the LA:ALA ratios ranged from 44 to 4.8. The Bayley Scales of Infant Development, the Clinical Adaptive Test/Clinical Linguistic and Auditory Milestone Scale (CAF/CLAMS) and the Gross Motor Scale of the Revised Gesell Developmental Inventory were administered at a mean age of 12 months to the infants.

The ALA contents of the plasma and erythrocyte phospholipid fractions were highest in the group that received the highest ALA intake but the lowest LA:ALA ratio. The group fed the formula with the lowest ALA content had the lowest mean plasma and erythrocyte phospholipid DHA content at four months of age. Group 1, which received the lowest ALA intake from birth to 120 days of age and had the lowest mean plasma and erythrocyte phospholipid contents of DHA at 120 days of age, had lower scores on every neurodevelopmental measure than any of the other groups. In addition, the mean GM DQ of this group was significantly lower than that of Group 2 but not that of either Group 3 or 4.

As expected, the plasma and erythrocyte phospholipid contents of omega-3 LC-PUFA were highest in those who received the highest ALA intake and lowest in those who received the lowest ALA intake. The results suggest that the omega-3 fatty acid status during early infancy may be important with respect toneurodevelopmental status at one year of age. However, the relevance of these findings to the debate about whether term infant formulae should be supplemented with DHA is not clean This study does not directly address the issue of whether the apparent need for DHA can be met more effectively by providing dietary DHA rather than its precursor.

R. G. Voigt, C.L. Jensen, J.K. Fraley, et al., Relationship between omega-3 Long-Chain Polyunsaturated Fatty Acid Status During Early Infancy and Neurodevelopmental Status at 1 Year of Age, J Hum Nutr Dietet; 15: 111-120 (April 2002) [Correspondence to: Robert G. Voigt, Department of Pediatric and Adolescent Medicine, Division of Developmental and Behavioral Pediatrics, Mayo Clinic, 200 First Ave SW, Baldwin 3A, Rochester, MN 55905. Tel: 507-284-6556; Fax: 507-284-9744; E-mail: voigt.robert@mayo.edu]