title: Meta-analysis of dietary essential fatty acids and long-chain polyunsaturated fatty acids as they relate to visual resolution acuity in healthy preterm infants.
abstract: OBJECTIVE
  To derive combined estimates of visual resolution acuity differences between healthy preterm infants consuming different compositions and ratios of essential fatty acids (EFAs) and docosahexaenoic acid (DHA), an omega-3 (n-3) long-chain polyunsaturated fatty acid (LCPUFA).
  
  
  METHODS
  Electronic biomedical reference database (Medline and Health Star from 1965 to July 1999) searches with index terms omega-3, n-3, infant, vision, acuity, and human. Current review article, monograph, and book chapter bibliography/reference section hand searches.
  
  
  METHODS
  A total of 5 original articles and 4 review chapters were reviewed for details on study design, conduct, and outcome. Four prospective trials of EFA/LCPUFA supplementation were included in these analyses. For behaviorally based outcomes, there were 2 randomized comparisons each at </=1, 2, 6, 9, and 12 months of corrected age and 4 randomized comparisons at 4 months of corrected age. For electrophysiologically based outcomes (visual-evoked potential), there were 2 randomized comparisons each at </=1 and approximately 4 months of corrected age.
  
  
  METHODS
  Dietary composition and EFA/LCPUFA balance, study design, and analytic characteristics (duration of feeding, source of EFAs/LCPUFAs, number of subjects in study population, number of subjects analyzed, and basis for estimating age), and experiment-based characteristics (location, number or sites, design, vision tests employed, testing protocol, and ophthalmic examination) were recorded independently by 2 researchers with a standardized protocol.
  
  
  RESULTS
  The relative difference in visual resolution acuity between groups of infants who received a source of dietary EFAs/LCPUFAs and groups who did not was computed and then analyzed with the DerSimonian and Laird random-effects method.
  
  
  RESULTS
  Analysis of the randomized comparisons (DHA-supplemented formula vs DHA-free formula) showed significant differences in visual resolution acuity at 2 and 4 months of age. Combined estimates of behaviorally based visual resolution acuity differences at these ages were.47 +/-.14 octaves and.28 +/-.08 octaves, respectively. A 1-octave difference is a reduction in the width of the stimulus elements by 50%.
  
  
  CONCLUSIONS
  These results support efficacy of n-3 LCPUFA intake in early visual system development, although supplementation safety issues still must be addressed through larger randomized trials. Whether n-3 intake confers lasting advantage in visually based process development across the life-span is still to be determined.
authors.affiliation: Department of Maternal and Child Health, Harvard School of Public Health, Boston, Massachusetts, USA. jpsangio@post.harvard.edu
authors.forename: J P
authors.initials: JP
authors.lastname: SanGiovanni
authors.forename: S
authors.initials: S
authors.lastname: Parra-Cabrera
authors.forename: G A
authors.initials: GA
authors.lastname: Colditz
authors.forename: C S
authors.initials: CS
authors.lastname: Berkey
authors.forename: J T
authors.initials: JT
authors.lastname: Dwyer
mesh_terms: D019587:Dietary Supplements; D005228:Fatty Acids, Essential / Q000008:administration & dosage*; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D014792:Visual Acuity
chemical_list: D005228:Fatty Acids, Essential; D005231:Fatty Acids, Unsaturated