The effects of nondigestible carbohydrates, prebiotics, and probiotics on gastrointestinal health and the microbiota-gutbrain axis in adults

The gastrointestinal microbiota are substantially impacted by diet, and there is promise for incorporating dietary components such as nondigestible carbohydrates (NDCs), prebiotics, and probiotics to support and improve health outcomes. Additionally, it is clear from the literature that additional high-quality research trials are needed in healthy adults investigating these dietary measures to draw thorough conclusions regarding health effects. Therefore, this project aimed to conduct further trials in healthy adults to add to the body of literature on dietary measures impacting the gastrointestinal microbiota and effects on health, particularly digestive well-being and the microbiota-gut-brain axis. First, we aimed to synthesize the literature on gastrointestinal effects and tolerance of NDCs classified as dietary fibers in adults without gastrointestinal disease and to provide tolerable intake dose recommendations likely to result in no more than minimal intolerance symptoms. This comprehensive review examined 103 clinical trials with doses ranging from 0.75-160 g/d and durations from a single-meal tolerance test to 28 weeks. Tolerance was NDC specific, and we recommended intakes of 3.75 g/d for alginate to 25 g/d for soy fiber. We also highlighted the importance of studies using standardized protocols to specifically measure gastrointestinal effects and tolerance as outcome measures in NDC and other dietary trials. Second, we aimed to determine the impact of prebiotic FOS + GOS consumption on the primary outcomes of biological markers of stress and inflammation and mental health symptoms and secondary outcomes of fecal microbiota and volatile fatty acids, emotion, sleep quality, and digestive symptoms and function in healthy adults. This randomized controlled crossover trial determined that our prebiotic combination did not affect biological markers of stress and inflammation or mental health symptoms in healthy adults; however, FOS + GOS did enrich Bifidobacterium. Third, we aimed to determine the efficacy of honey added to yogurt on the primary outcome of intestinal transit time and secondary outcomes of probiotic abundance, gastrointestinal health, mood states and cognitive function, and gastrointestinal microbiota in healthy adults. In this controlled crossover trial, honey supported probiotic enrichment, but did not reduce transit time or affect gastrointestinal health or mood and cognition in healthy adults.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Food Science & Human Nutrition

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2023

Author dc:creator

• Mysonhimer, Annemarie Rose

Contributors dc:contributor

• Holscher, Hannah D
• Donovan, Sharon M
• Khan, Naiman A
• Dilger, Ryan N

• Nondigestible Carbohydrates
• Prebiotics
• Probiotics
• Tolerance
• Microbiome
• Cognition
• Microbiota-gut-brain Axis
• Bifidobacteria

Statement dc:rights

• ©2023 Annemarie Rose Mysonhimer

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/121256

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F121256