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Title:The independent and interactive influence of lutein and choline on cognitive control
Author(s):Edwards, Caitlyn
Director of Research:Khan, Naiman
Doctoral Committee Chair(s):Dilger, Ryan
Doctoral Committee Member(s):Barbey, Aron; Holscher, Hannah
Department / Program:Nutritional Sciences
Discipline:Nutritional Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Abstract:Objectives Diet quality plays a role in progressive physical, as well as mental, co-morbidities, particularly among those with elevated weight status. Therefore, research exploring cost-effective, practical, and sustainable strategies to promote healthy weight status as well as healthy cognitive and mental health status are of great interest to public health agencies and individuals alike. Dietary intake as well as serum and cortical accumulation of the dietary components lutein and choline have been linked with benefits for cognition across the lifespan. This Dissertation work utilized three aims to investigate the impact of both independent and interactive dietary consumption and biomarker concentrations of these components in a young-to-middle aged sample of adults with overweight or obesity. Aim 1 utilized a cross-sectional sample as well as a randomized controlled trial to examine the impact of dietary, serum, and retinal lutein concentrations on cognitive control. Aim 2 examined the impact of dietary choline intake on cognitive control. Lastly, Aim 3 examined the interactive nature of dietary intake of lutein and choline, serum lutein concentrations, and choline metabolites on cognitive control. Methods The Persea Americana for Total Health (PATH) Study was a 12-week randomized controlled trial aimed at assessing the impact of avocado consumption on primary outcomes of visceral adiposity and glycemic control. Secondary outcomes analyzed within this work were behavioral and neuroelectric indices of cognitive control, specifically selective attention, response inhibition, and cognitive flexibility. Adults with overweight and obesity (Body Mass Index [BMI] ≥ 25.0]) between the ages of 25-45 years completed 7-day diet records, venous blood draws, heterochromatic flicker photometry for assessment of macular pigmentation (MPOD), the Kaufman Brief Intelligence Test–2 (IQ), the Eriksen Flanker task, Oddball/No-go task, and a Switch task while undergoing electroencephalographic recording for event-related potential extraction (ERP). For intervention analyses, participants were randomized to a treatment group (N = 47) that received a 12-week daily meal with fresh Hass avocado or a control group (N = 37) that received an isocaloric meal (, NCT02740439). Baseline data, prior to randomization, was utilized for cross-sectional analyses. Cognitive outcomes included behavioral (accuracy and reaction time [RT]) as well as the N2 and P3 ERP components. Results Aim 1-a utilized partial correlations between MPOD and behavioral and neuroelectric outcomes of an Oddball Task to examine the impact of retinal xanthophyll accumulation (MPOD) on cognitive control. These cross-sectional analyses revealed that after controlling for sex and dietary lutein/zeaxanthin intake, higher MPOD was associated with lower N2 mean amplitude (ρ=−0.21, p=0.04) and P3 peak latency (ρ=−0.27, p<0.01) during target trials, as well as lower P3 peak amplitude (ρ=−0.22, p=0.03) during standard trials. Improvements in behavioral outcomes were not observed (all p’s > 0.05). Aim 1-b utilized intervention data from the PATH study to examine the impact of 12-week avocado consumption on behavioral and neuroelectric outcomes of a modified Eriksen Flanker, Oddball, and No-go task. These analyses revealed significant time x group interactions (F(1,79) = 26.98, p < 0.001, ηp2 = 0.26) for serum lutein concentrations as well improvements in accuracy in both the congruent (change: 1.3%, p=0.05; 95% CI:−3.02 to 2.3) and incongruent (change: 3.0%, p< 0.01; 95%CI: 1.1 to 5.0) Flanker task conditions, indicating that the group consuming avocado exhibited increased concentrations of serum lutein as well as overall improvement on a selective attention task. Improvements in MPOD, on other cognitive tasks, and neuroelectric indices of cognitive outcomes were not observed (all p’s>0.05). Aim 2 utilized hierarchical linear regression analyses to examine the impact of dietary choline intake on behavioral and neuroelectric outcomes of a modified Eriksen Flanker Task. These cross-sectional analyses revealed that after controlling for age, sex, BMI, IQ, and overall diet quality, higher choline intake was associated with lower P3 peak amplitude (β=−0.25, p <0.01) during incongruent trials. Relationships with behavioral outcomes were not observed (all p’s>0.05). Aim 3 examined the independent and potentially interactive effects of dietary lutein, dietary choline, serum lutein concentrations, MPOD, plasma phosphatidylcholine (PC) and free choline concentrations on cognitive control. These analyses utilized hierarchical linear regression analyses controlling for sex, age, IQ, BMI, and household income. A multiplicative interaction term of dietary lutein and dietary choline intake improved models for RT in all trials of a cognitive flexibility task: NonSwitch RT (ΔR²=0.10 p=0.03), Switch RT (ΔR²=0.10 p=0.05), and Global Switch Cost (ΔR²=0.08 p=0.05) during the switch task. Plasma PC independently was associated with accuracy during a Switch task (β=0.24, p=0.04). Conclusion The dietary components lutein and choline have been hypothesized to play a protective role in cognitive health across the lifespan. This dissertation work demonstrated that independent as well as interactive consumption of both lutein and choline was associated with neurocognitive benefits for adults with overweight or obesity in middle-adulthood. This work represents additional evidence suggesting that foods high in lutein and choline may offer neuroprotective effects among persons with overweight and obesity.
Issue Date:2020-05-06
Rights Information:Copyright 2020 Caitlyn Edwards
Date Available in IDEALS:2020-08-26
Date Deposited:2020-05

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