Document Type

Thesis - Open Access

Award Date

2019

Degree Name

Master of Science (MS)

Department / School

Health and Nutritional Sciences

First Advisor

Moul Dey

Keywords

bile acids, fatty acids, gut microbiome, metabolites, resistant starch type 4

Abstract

The human gastrointestinal tract is populated by a diverse and mutualistic microbial flora that has profound effect on human health. Identification and characterization of microbial-metabolites produced in response to human dietary intakes may provide insights into host-microbiota interactions to better understand the role of the microbiota in human health and diseases. However, much of this interaction is poorly understood as many metabolites remain unidentified or understudied at the present time. Starch is ubiquitously present in human diet and is a major energy source to all living cells. Resistant starch (RS) is the starch portion that is not absorbed in the small intestine of healthy individuals but is fermented in the gut by the gut microbes. Recent advances in the fields of metabolomics and microbiome analyses have resulted in the newly identified functional roles of short chain fatty acids in the context of health benefits of resistant starches. This thesis encompasses a retrospective examination of the effects of resistant starch type 4 on medium and long chain fatty acids and bile acids on individuals with metabolic syndrome. Study samples were obtained and used from a completed/published 2-arm crossover, placebo controlled, double blind, human dietary intervention trial that reported several immunometabolic health benefits and gut-microbial alterations after resistant starch consumption. Eighteen fecal and plasma samples were subjected to methylation and analyzed with gas-chromatography, for the medium and long chain fatty acids, and liquid chromatography for the bile acids followed by mass-spectrometry measurements. Differential changes in the test and control groups post intervention in 46 fatty acids and 23 bile acid species were compared and presented in this thesis. Further research is needed to determine how these changes correlated with the previously reported microbiome changes in the participants from this study to meaningfully interpret the implications of the changes reported here. To conclude, this work presents novel changes in the fatty acid and bile acid profiles after resistant starch consumption that were previously unknown in the literature and opens up new direction for future investigations within the rapidly growing discipline of microbial metabolomics.

Library of Congress Subject Headings

Digestive organs -- Microbiology.
Starch.
Fatty acids.
Bile acids.

Format

application/pdf

Number of Pages

112

Publisher

South Dakota State University

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Rights Statement

In Copyright