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Title:Macular pigment optical density and academic achievement among preadolescent children
Author(s):McCorkle, Sasha M
Advisor(s):Hillman, Charles H.
Department / Program:Nutritional Sciences
Discipline:Nutritional Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Macular pigment optical density
academic achievement
Abstract:Lutein has been shown to preferentially accumulate in the macula of the neural retina as macular pigment and across all brain cortices of infants and adults. This preferential accumulation in the brain has led to the hypothesis that lutein may positively impact cognition, possibly through its anti-inflammatory and/or antioxidant properties. Both macular pigment optical density (MPOD) – a non-invasive measure of retinal lutein and correlate of brain lutein – and dietary lutein supplementation have been associated with better cognitive function among adult populations. However, the reliability of heterochromatic flicker photometry (HFP) to measure MPOD has only recently been demonstrated to be a moderately reliable technique in preadolescent children. Therefore, to date, the relationship between MPOD and cognitive performance has not been directly investigated in children. Accordingly, the main objective of this thesis was to investigate the relationship between MPOD, assessed and averaged over two time points using HFP, and academic performance among 8-10-year-olds (N = 56). Additional objectives were to investigate how MPOD relates with dietary intake of lutein and zeaxanthin, and to determine if lutein and zeaxanthin intake would mediate the relationship between MPOD and academic performance. Academic performance was assessed using the Kaufman Test of Academic and Educational Achievement II (KTEA). Habitual dietary intake of lutein and zeaxanthin was measured using the average of 3-day food records. The results for the main objective of this thesis indicated a significant correlation between MPOD and the KTEA composite measures of achievement (r = 0.40, P < 0.01), reading (r = 0.28, P = 0.04), math (r = 0.35, P < 0.01), and written language (r = 0.41, P < 0.01), but not with reading fluency (r = 0.22, P = 0.11). Further analysis with stepwise hierarchical regression models was conducted with sex, intelligence quotient (IQ), whole body percent fat, and fat free mass VO2max included in the initial step. Subsequent addition of MPOD into the model was conducted to determine the contribution to the academic measures following adjustments of related variables. The addition of MPOD did not statistically improve the explained variance for the reading or reading fluency composite scores. However, the adding of MPOD in the model did explain additional variance for the achievement composite standard scores (ΔR2 = 0.10, P < 0.01), math composite standard scores (ΔR2 = 0.07, P = 0.02), and the written language composite standard scores (ΔR2 = 0.15, P < 0.01). Further, the composite measures were decomposed to investigate whether the subtests all had similar relations with MPOD as their composite scores. The results indicated that all subtests were consistent with their composite measures. For the additional objectives the results showed the dietary consumption of lutein and zeaxanthin was positively correlated with MPOD (r = 0.39, P = 0.02). Lutein and zeaxanthin intake was significantly related with the written language composite score (r = 0.53, P < 0.01), but not with any of the other academic composite scores. Stepwise regressions completed in a subset of children to assess if lutein and zeaxanthin intake would mediate the relationship between MPOD and academics, showed that MPOD’s relationship to academics still remained following adjustment for dietary intake. The accumulation of this evidence indicates that macular lutein is associated with superior performance on academic measures, particularly in math and written language while dietary intake had weaker relationships. This is the first study to demonstrate that retinal lutein and zeaxanthin, measured as MPOD, is related to academic achievement in children. This has implications as the macular pigment can be influenced by the diet in most of the population. However, this conclusion is tenuous and should be investigated further by conducting placebo-controlled interventions.
Issue Date:2016-04-12
Rights Information:Copyright 2016 Sasha McCorkle
Date Available in IDEALS:2016-07-07
Date Deposited:2016-05

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