Dietary patterns and neurocognitive potential: Examining the intersection of carotenoid status, metabolic health, and executive function

Holthaus, Tori Ann

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https://hdl.handle.net/2142/129737 Copy

Description

Title

Dietary patterns and neurocognitive potential: Examining the intersection of carotenoid status, metabolic health, and executive function

Author(s)

Holthaus, Tori Ann

Issue Date

2025-04-30

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

Khan, Naiman A

Doctoral Committee Chair(s)

Holscher, Hannah D

Committee Member(s)

• Burd, Nicholas A
• Aguinaga, Susan

Department of Study

Nutritional Sciences

Discipline

Nutritional Sciences

Degree Granting Institution

University of Illinois Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Cognition
• metabolic syndrome
• lutein
• avocado
• food matrix
• dietary protocols

Abstract

Background: Executive functions are crucial for various aspects of daily life, and executive dysfunction often represents one of the earliest signs of cognitive decline, making it a valuable marker for early detection and intervention. Further, obesity and metabolic syndrome due to poor diet quality are significant risk factors for early or accelerated cognitive decline. This research aimed to understand the relationships between neuroprotective dietary patterns and whole foods on behavioral and neuroelectric indices of executive function and explore their associations with changes in cardiometabolic health markers and neuroprotective nutrients (i.e., carotenoids). Specific objectives included investigating the association between degree of adherence to the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) dietary pattern and 1) cognitive control, 2) cardiometabolic risk markers; and 3) carotenoid intake relative to adherence to the Mediterranean, Dietary Approaches to Stop Hypertension (DASH), and Healthy Eating Index (HEI) 2015-2020. Objectives also included: 4) prospectively testing the effects of daily whole avocado consumption on markers of attentional inhibition in adults with overweight and obesity relative to the isolated macronutrients within an avocado; and 5) examining the feasibility of a 12-week randomized controlled MIND intervention using a remotely implemented meal delivery service and its effects on carotenoid status, cardiometabolic health, and cognitive function in middle-aged adults. Methods: For studies 1 through 3, cross-sectional data were analyzed from healthy adults aged 19-82 y. Dietary data was collected using the National Institute of Health Dietary History Questionnaire. A priori diet pattern indices were used to assess adherence to the MIND, Mediterranean, DASH, and HEI. Study 4 utilized a randomized-controlled crossover complete feeding design with three, 4-week dietary conditions among weight-stable, non-diabetic adults (25-74 y) with overweight or obesity (BMI > 25 kg/m2). The dietary conditions included: average American base diet (AA), avocado-containing condition (AV), and oleic oils and fiber condition (OF). Relative to the AA group, the AV and OF provided greater MUFAs and dietary fiber in the form of an avocado or a snack that mimics the MUFA and fiber profile of avocados, respectively. For Study 5, 48 healthy adults (45-64 y) were enrolled in a 12-week, single-blind, randomized controlled trial. The intervention consisted of a daily meal containing key MIND foods (e.g., berries, greens) shipped to homes. The control group received isocaloric meals aligned with the Dietary Guidelines for Americans. Both groups received dietary education. Participant baseline dietary intake for study 5 was collected using 7-day diet records. Executive function was assessed using a modified Eriksen flanker paradigm. Neuroelectric function was assessed using the P3 event-related potential (ERP). Cardiometabolic risk markers included waist circumference, blood pressure, and fasting blood glucose, HDL, and triglyceride concentrations. Visceral adipose was assessed using dual-energy X-ray absorptiometry. Carotenoid status was assessed using reflection spectroscopy to measure skin carotenoids as a marker of fruit and vegetable intake and heterochromatic flicker photometry to measure macular carotenoids as an index of neural lutein concentration. Feasibility was assessed using retention, compliance, safety, and acceptability rates via questionnaire. Results: For studies 1-3, greater MIND adherence was inversely associated with P3 peak latency during incongruent flanker trials, blood pressure, visceral adiposity, waist circumference, triglycerides and glucose concentrations and positively associated with HDL. MIND adherence was the strongest predictor of lutein, zeaxanthin, and β-carotene intake relative to the Mediterranean, DASH, and HEI. For study 4, a total of N=40 participants (50% female) aged 40 ± 9 y with a BMI of 31 ± 5.4 kg/m2 were included in the analyses. There was a significant effect of condition for accuracy interference during the flanker task wherein the AV condition resulted in lower interference than the AA. For study 5, 39 participants (MIND=21, control=18) aged 53.2 ± 4.9 y completed the study. The intervention showed high feasibility and acceptability, and there was a significant time x group interaction effect for skin carotenoids with only the MIND group increasing. There was a time x group interaction effect for flanker accuracy interference, however, post hoc testing revealed no significant differences between MIND and control groups. Conclusions: Greater MIND diet adherence was selectively associated with faster information processing speed and was beneficially associated with each marker of cardiometabolic risk in adults. MIND adherence was disproportionately related to carotenoid intake, indicating the MIND index places greater emphasis on carotenoid-rich foods, particularly those containing lutein, zeaxanthin, and β-carotene, relative to other diet indices. Daily avocado consumption improved accuracy-based interference control relative to a standard American diet in adults with overweight and obesity, and findings suggest that whole avocado intake may offer cognitive benefits beyond isolated nutrients. Likewise, the MIND remote meal randomized controlled trial was feasible and acceptable to middle-aged adults. The MIND intervention also exhibited benefits to skin carotenoids and trend-level benefits for accuracy-based interference control relative to a control diet. Additional research is necessary to further elucidate the effects of neuroprotective dietary patterns and whole foods on executive function during this understudied life period toward the prevention of age-related cognitive decline.

Graduation Semester

2025-05

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/129737

Copyright and License Information

Embargo requested for 3 years.

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