Background: Docosahexaenoic acid is present in high concentration in retina and does not influence visual development in preterm infants. It is still under discussion whether docosahexaenoic acid is important for visual development in term infants.
Methods: Thirty-seven infants fed formula for a median of 14 days were randomized at median age of 25 days to three formulas: a) DHAGF: 0.3 wt% docosahexaenoic acid and 0.5 wt% γ-linolenic acid; b) DHAF 0.3 wt% docosahexaenoic acid; or c) STF: standard formula without long-chain polyunsaturated fatty acids and 17 breast-fed infants were observed, using blood samples and anthropometric measurements from 1 to 4 months of age. At 4 months, visual acuity was measured by swept steadystate visual evoked potential. A cross-sectional study on 25 breast-fed infants was carried out as a reference group for the analyses.
Results: Infants fed the two docosahexaenoic acid-supplemented formula had relative docosahexaenoic acid concentrations in red blood cell phospholipids almost as high as those in breast-fed infants, whereas infants in the standard formula group had significantly lower levels. The addition of γ-linolenic acid to the formula had a positive effect on red blood cell arachidonic acid levels, compared with levels obtained using fish oil only. Visual acuity was significantly different among all feeding groups (analysis of variance;p = 0.05, means ± standard deviation: breast-fed, 0.37± 0.06 logMAR; DHAF and DHAGF combined, 0.40 ± 0.07 logMAR; and standard formula 0.44 ± 0.07 logMAR. However, there was no statistical difference among the formula groups. In a multiple regression analysis including all formula-fed infants, weight at delivery (p = 0.002), but not type of formula, was significantly associated with visual acuity at 4 months of age.
Conclusions: The addition of docosahexaenoic acid resulted in concentrations in red blood cells at similar levels as those in breast-fed infants, whereas the increase in visual acuity did not reach significance. The addition ofγ-linolenic acid resulted in higher arachidonic acid concentrations in red blood cells.
Center for Advanced Food Studies and Research Department of Human Nutrition, Royal Veterinary and Agricultural University, Frederiksberg, Denmark; and *Center for Advanced Food Studies and Department of Biochemistry and Nutrition, Technical University of Denmark, Copenhagen, Denmark; and †Department of Pediatrics, Umeå, Sweden.
Received March 3, 1997; revised October 29, 1997; accepted November 5, 1997.
Address correspondence and reprint requests to Dr. M. Hørby Jørgensen, Research Department of Human Nutrition, The Royal Veterinary and Agricultural University, Rolighedsvej 30, DK-1958 Frederiksberg C, Denmark.