Tag Archives: ARA

Visual Acuity and LCPUFA

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Long-chain polyunsaturated fatty acids (LCPUFA) have been examined due to their potential to affect infant cognition (Long–chain polyunsaturated fatty acids, breastmilk … – gutsandgro).  A recent meta-analysis has reviewed 19 studies with regard to LCPUFA supplementation and infant visual acuity (Pediatrics 2013; 131: e262-72 -thanks to Mike Hart for sharing this reference).

Since 75% of U.S. infants are formula fed by 1 year of age and there is widespread dependence on formula for nutritional completeness, these formulas have been designed to mimic breast milk composition.  Docosahexaenoic acid (DHA) and arachidonic acid (ARA) are the two main LCPUFAs and are integral to  the structural membranes of cells in the central nervous system and retina.  DHA comprises >50% of the phospholipid content of the retinal membrane bilayer.

These 16 studies (in the abstract it erroneously states 19 studies), identified by a literature search, involved 1949 infants.  Overall, a significant benefit of LCPUFA supplementation on infants’ visual acuity was noted at 2, 4, and 12 months of age when assessed by visual evoked potential.  A benefit was also seen at 2 months of age by using behavioral methods.  Studies were included if they were randomized control trials comparing LCPUFA supplementation to unsupplemented formula.  Initially, 286 citations were identified but most did not meet inclusion criteria.

This study findings differ from two recent Cochrane reviews on the effect of LCPUFA on visual acuity.  The Cochrane reviews failed to combine trials that  measured “visual acuity in logMAR and cycles/degree and assessed preterm and term infants separately.”  The authors state that this reduced the Cochrane reviews power to detect potential benefits of LCPUFA supplementation.

While this study demonstrates improvement during the first year of life, there is a scarcity of data beyond this time point.  Limitations of this review included heterogeneity in the study results, varying doses of LCPUFA supplementation, variable DHA/AA ratio supplied, and variability in maternal diets.

Related blog post:

Low levels of LCPUFA in Premature Infants … – gutsandgrowth

Low levels of LCPUFA in Premature Infants Associated with Intravenous Lipids

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Low levels of the long-chain polyunsaturated fatty acids (LCPUFA) docosahexanenoic acid (DHA) and arachidonic acid (ARA) in premature infants are correlated with an increased risk of developmental, respiratory, and infectious morbidities in premature infants.  A new report suggests that prolonged exposure to intravenous lipids exacerbates these low levels and could contribute to poor neurodevelopmental outcomes (J Pediatr 2013; 162: 56-61).

This study followed 26 extremely low birth weight premature infants with serial blood draws during the first two months of life using a prospective cohort design.  Infants who received more than 28 days of intravenous lipid emulsion had significantly decreased DHA levels compared to infants with shorter duration of parenteral lipid exposure; at 8 weeks, the DHA levels were 2.7 ± 0.6 compared with 4.2 ± 1.9 (all levels reported as g/100 g).  DHA levels at birth were 5.5 ± 1.4.

ARA levels decreased in a similar fashion in both groups, though values were mildly lower in the prolonged lipid group.  At 8 weeks, the ARA values were 9.4 ± 1.6 and 11.5 ± 2.5 respectively.  Thus, with a larger study group, this could be a significant finding as well.

These lower LCPUFA (especially DHA) levels may reflect a suboptimal intravenous lipid emulsion.  Alternatively, the underlying reason for the prolonged lipids, like sepsis and NEC , could result in these lower levels.  Perhaps attention to LCPUFA in parenteral formulations can improve neurodevelopmental outcomes in this vulnerable population.

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