Dietary and adiposity influences on relational memory and attentional inhibition

Cannavale, Corinne Nancy

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https://hdl.handle.net/2142/114069 Copy

Description

Title

Dietary and adiposity influences on relational memory and attentional inhibition

Author(s)

Cannavale, Corinne Nancy

Issue Date

2021-12-01

Director of Research (if dissertation) or Advisor (if thesis)

Khan, Naiman A

Doctoral Committee Chair(s)

Khan, Naiman A

Committee Member(s)

• Barbey, Aron
• Johnson, Rodney
• Hassevoort, Kelsey

Department of Study

Neuroscience Program

Discipline

Neuroscience

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Cognitive Function
• Hippocampus
• Prefrontal Cortex
• Nutrition
• Diet
• Adiposity
• Carotenoids
• Inflammation
• Biomarkers

Abstract

Objectives The United States is among some of the highest across the globe for the prevalence of obesity, with about 40% of adults and 20% of children and adolescents having obesity. While it is known that elevated BMI is associated with a variety of metabolic and physiological health complications (i.e. cardiovascular disease, type II diabetes mellitus), our understanding of how obesity may impact cognitive health has gained more interest within the last few decades. This is even more pertinent as obesity earlier in life has been shown to impact risk of dementia over three decades later. However, a large gap in the literature remains in our understanding of how obesity may impact the brain. Although factors such as inflammation, gastrointestinal microbiota, and hormone dysregulation are hypothesized to play a role, few studies have been completed to assess these mechanisms in more detail. Thus, this dissertation aimed to understand the interrelationships between adiposity, nutrition, and cognitive function. Aim 1, utilized cross-sectional analyses to understand how lutein status can impact hippocampal functioning in adults with obesity. In aim 2, we examined the interrelationships between components of body composition and their impact on memory and cognitive control. Aim 3 assessed the impact of consuming a fermented dairy beverage containing probiotics on behavioral and physiological markers of stress, cognitive function, gastrointestinal microbiome utilizing a randomized crossover trial approach. Aim 4 examined how inflammation may mediate the relationship between adiposity and cognitive control. Finally, Aim 5 examined relationships between lutein status, inflammation, and cognition function among school-aged children. Methods We utilized both cross-sectional and clinical intervention trials in order to elucidate how lifestyle behaviors and health factors can impact the cognitive function. Aims 1 and 2 utilized baseline data collected prior to enrollment in multiple studies completed in our laboratory, specifically the Persea Americana for Total Health (PATH) study, the Effects of Probiotics On Cognition and Health (EPOCH) Study, and the Gut-Brain study. Secondary outcomes analyzed within these studies were relational memory performance and macular, self-reported, and serum lutein and zeaxanthin. In aim 1, adults aged 25-45 years completed a spatial reconstruction task. Dietary carotenoids were assessed using 7-day diet records. Serum carotenoids were measured using high-performance liquid chromatography. Macular carotenoids were assessed via customized Heterochromatic Flicker Photometry (cHFP). Aim 2 was conducted among a sample of adults aged 25-45. Dual x-ray absorptiometry was used to assess height-adjusted lean and fat mass. Memory was assessed via two cognitive assessments. Aim 3 was assessed via the EPOCH trial. Adults (25-45 yrs) free of gastrointestinal and mental illness were enrolled in a single-blind, randomized, controlled, crossover trial. Participants completed testing prior to and after 4-week consumption of: 1) 8 oz of a dairy-based fermented beverage containing 25-30 billion colony forming units of live and active cultures; or 2) 8 oz isocaloric, non-fermented, 1% low-fat lactose-free dairy-based control beverage. Hippocampal-dependent relational memory was assessed using a spatial reconstruction task. Pooled 24-hour urine samples were analyzed using an enzyme-linked immunosorbent assay to determine urinary free-cortisol (UFC) concentrations. Fecal microbiota composition was assessed using 16S rRNA sequencing. Aim 4 utilized a cross-sectional sample of adults (25-45 yrs) where visceral adiposity was assessed via DXA, cognitive control was assessed via the Eriksen Flanker task while collecting event-related potentials (ERPs), and serum inflammation was assessed utilizing ELISA. Aim 5 utilized cHFP for assessment of macular carotenoids, the Eriksen flanker task to assess cognitive control while collecting ERPs, assessment of memory utilizing a spatial reconstruction task and the Woodcock-Johnson tests of Cognitive Abilities, and whole-blood CRP was assessed via ELISA. Results Analyses for Aim 1 revealed that although initial correlations indicated that dietary lutein and beta-carotene and serum beta-carotene were positively associated with memory performance, these relationships were not sustained following adjustment for age, sex, and BMI. Serum lutein remained positively associated with accuracy in object binding and inversely related to misplacement error after controlling for covariates. Macular carotenoids were not related to memory performance. Aim 2 found linear regression modelling controlling for sex, age, IQ, and income revealed that Lean Mass Index (LMI), and not Fat Mass Index (FMI), accounted for a significant proportion of variance in lure discrimination (R2=.120, p<.001). No significant associations were observed between body composition and relational or recognition memory following adjustment of covariates. Aim 3 found that Lactobacillus was increased by 235% following fermented dairy consumption compared to the control (p<0.01). Furthermore, the fermented dairy beverage improved performance on two metrics of relational memory, misplacement (p = 0.043) and object-location binding (p = 0.027). UFC and DASS-42 scores (all p’s > 0.08) were not significantly changed by either arm of the intervention. No correlations were observed between the change in Lactobacillus and memory performance. Aim 4 utilized mediation modelling while controlling for diet quality and education level which revealed that CRP concentrations significantly mediated the relationship between VAT and incongruent trial accuracy (indirect effect 95% CI {-0.24, -0.01}). Further, IL-6 concentrations did have a significant mediation effect on the relationship between VAT and incongruent P3 peak latency (indirect effect 95% CI {0.05, 1.39}). Aim 5 findings revealed that CRP and MPOD were negatively correlated (rho=-0.43, p=0.001) after controlling for age, sex, and body mass index (BMI). Neuroelectric, but not behavioral measures of attentional inhibitory control were associated with CRP and MPOD however these correlations did not maintain significance after controlling for age, sex, and BMI. Conclusion This dissertation contributed evidence on the role of nutrition and adiposity and the influences on cognitive function among adult and child populations. The cross-sectional findings revealed that variance in cognitive function among adults can be explained by lutein status as well as body composition and chronic inflammation. Additionally, a dietary intervention utilizing consumption of a fermented dairy beverage containing probiotics improved relational memory performance. Finally, the cross-sectional findings in children revealed that chronic inflammation is negatively associated with macular lutein status in children. Future longitudinal and prospective research designs are necessary to addresses the importance for healthy diet in supporting cognitive function, while accounting for the explanatory factors of weight status and metabolic risk. This work has relevance to human health due to the persistently elevated prevalence of obesity in the US population.

Graduation Semester

2021-12

Type of Resource

Thesis

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© 2021 Corinne Cannavale

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