Effects of soluble corn fiber on cognition in older adults: Integrating clinical, in vitro, and bioinformatics approaches to explore gut-brain interactions

Alvarado, David Anthony

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https://hdl.handle.net/2142/129751 Copy

Description

Title

Effects of soluble corn fiber on cognition in older adults: Integrating clinical, in vitro, and bioinformatics approaches to explore gut-brain interactions

Author(s)

Alvarado, David Anthony

Issue Date

2025-05-01

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

Holscher, Hannah D

Doctoral Committee Chair(s)

Swanson, Kelly S

Committee Member(s)

• Khan, Naiman A
• Miller, Michael J

Department of Study

Food Science & Human Nutrition

Discipline

Food Science & Human Nutrition

Degree Granting Institution

University of Illinois Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Gut-Brain
• Parabacteroides: Soluble Corn Fiber
• Attentional Inhibition
• Microbiome

Abstract

The gut microbiome is a critical mediator in the optimization of human health through diet. Although robust evidence links dietary fiber consumption to improvements in gastrointestinal and metabolic outcomes, its potential to enhance cognitive function via gut–brain axis pathways remain underexplored. To address this gap, we integrated data from a human clinical trial, in vitro experiments, and multi-omics analyses to elucidate the interconnections among dietary fiber intake, gut microbial dynamics, and cognitive health. For our investigation (Chapter 2), we conducted a randomized crossover clinical trial to evaluate the effects of daily consumption of soluble corn fiber (SCF) for 4 weeks on cognitive function in older adults (45-75 years) and to assess the mediating and moderating influence of the microbiota using 16S rRNA gene-sequenced fecal data on these cognitive outcomes. Next, we sought to further understand if gut bacterium differentially enriched by the intervention could metabolize the SCF in isolation or if the enrichment observed in the clinical trial stems from cross-feeding interactions within the colon. Finally, we examined the microbiome profiles on a subset of participants, categorized as responders and non-responders, using shotgun metagenomic sequencing on their fecal samples to capture snapshots of their microbial functional capacity before and after the intervention, thereby reinforcing the concept of nutrition as a personalized intervention. We discovered that daily consumption of SCF numerically increased fecal acetate, improved attentional inhibition measured by their reaction time, and induced an enrichment of Parabacteroides that exerted a moderating effect. Furthermore, we observed that Parabacteroides distasonis was capable of metabolizing SCF when provided as its sole substrate for growth following an adaptation period, as evidenced by its diauxic growth pattern. In addition, the predicted imputed metagenome of the full cohort suggested increased functional capacity resulting from SCF consumption, and the quantified metagenome demonstrated distinct profiles between responders and non-responders. Together, this integrative approach not only deepens our understanding of the multifaceted roles of SCF but also underscores the importance of incorporating dietary fibers into the diet of older adults as a strategy for harnessing their potential cognitive benefits within personalized nutritional interventions.

Graduation Semester

2025-05

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/129751

Copyright and License Information

Copyright 2025 David Anthony Alvarado

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