A randomized controlled trial of early dietary supply of long-chain polyunsaturated fatty acids and mental development in term infants

The effects of dietary docosahexaenoic acid (DHA) supply during infancy on later cognitive development of healthy term infants were evaluated in a ran domized clinical trial of infant formula milk supplemented with 0.35% DHA o r with 0.36% DHA and 0.72% arachidonic acid (AA), or control formula which provided no DHA or AA, Fifty-six 18-month-old children (26 male, 30 female) who were enrolled in the trial within the first 5 days of life and fed the assigned diet to 17 weeks of age were tested using the Bayley Scales of In fant Development, 2nd edition (BSID-II) (Bayley 1993) at the Retina Foundat ion of the Southwest, Dallas, TX. These children had also been assessed at 4 months and 12 months of age for blood fatty-acid composition, sweep visua l evoked potential (VEP) acuity, and forced-choice preferential looking (FP L) acuity (Birch et al, 1998), Supplementation of infant formula with DHA+A A was associated with a mean increase of 7 points on the Mental Development Index (MDI) of the BSID-II, Both the cognitive and motor subscales of the MDI showed a significant developmental age advantage for DHA- and DHA+AA-su pplemented groups over the control group. While a similar trend was found f or the language subscale, it did not reach statistical significance. Neithe r the Psychomotor Development Index nor the Behavior Rating Scale of the BS ID-II showed significant differences among diet groups, consistent with a s pecific advantage of DHA. supplementation on mental development. Significan t correlations between plasma and RBC-DHA at 4 months of age but not at 12 months of age and MDI at 18 months of age suggest that early dietary supply of DHA was a major dietary determinant of improved performance on the MDI.