The effects of dietary docosahexaenoic acid (DHA) supply
during infancy on later cognitive development of healthy term
infants were evaluated in a randomized clinical trial of infant
formula. The formula-milk was supplemented with 0.35% DHA or with 0.36%
DHA and 0.72% arachidonic acid (AA), two fatty acids found in breast milk. The control formula
provided no DHA or AA.
Fifty-six, 18-month-old children (26 male, 30 female) were enrolled in the trial within the first 5 days of life. A randomized group was fed the assigned diet to 17 weeks of age and tested using the Bayley Scales of Infant
Development, 2nd edition (BSID-II). These
children were also assessed at 4 months and 12 months of
age for blood fatty-acid composition, sweep visual evoked
potential (VEP) acuity, and forced-choice preferential
looking (FPL) acuity. The tests were performed at the Retina Foundation of the Southwest, Dallas, TX.
Supplementation of infant formula with DHA+AA 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-supplemented groups over the control
group. A similar trend was found for the language
subscale, but did not reach a statistical significance. Neither the
Psychomotor Development Index nor the Behavior Rating
Scale of the BSID-II showed significant differences among
diet groups, consistent with a specific advantage of DHA
supplementation on mental development.
Significant 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.
Twenty-six percent of infants on the fortified diet scored over 115 on the mental development tests, compared to only five percent on plain formula. Ten percent of the control group scored below 85 while none of the children in the enriched group showed this developmental delay.
Docosahexanenoic acid and arachidonic acid (DHA & AA) are found in breast milk. The study may prove definitively that breast feeding is better for the cognitive development of infants. It also may lead to formulas fortified with the two fatty acids.
Read the entire study in the journal, Developmental Medicine and Child Neurology.