Honors Program

[Honors-in-Discipline (Choose below)], Honors in Nutrition

Date of Award


Thesis Professor(s)

Michelle Johnson

Thesis Professor Department

<--College of Clinical and Rehabilitative Health Sciences-->

Thesis Reader(s)

Michelle Johnson, W. Andrew Clark


Introduction: The gut microbiome is believed to have a significant impact on health throughout the lifespan, and the influence of infant nutrition and other environmental factors are of particular interest in its development. The aim of this research project was to learn more about the microbiome and short chain fatty acid (SCFA) composition of toddlers of differing weights, considering birth history, environment, and diet. In East Tennessee, opioid misuse is a growing issue, and a number of participants in this study were exposed in utero. We also hoped to identify related effects on infant’s SCFA composition. Finally, it is known that twins share a variety of traits, but much about their microbiome is unknown. With several pairs of twins in the sample, we aimed to identify any associations with SCFAs in this group.

Methods: With informed consent, the child’s history was obtained, including age, birth length and weight, delivery type (C-section or vaginal), and feeding method (breast, bottle fed, or both). The child’s current weight, height, and BMI percentile were determined. Caregivers completed a 90-question Block Questionnaire for Ages 2-7 Kids food frequency questionnaire, and results were analyzed by Berkeley Analytics Inc (dba NutritionQuest). Participant-provided stool samples were freeze-dried and ground, and SCFAs were extracted and analyzed by content area % and concentration ppm. Data analysis was generated using SAS software, Version 9.4 of the SAS System, Copyright © 2013 SAS Institute Inc.

Results: Nine SCFAs were measured in duplicate, and the concentrations averaged. Statistical analysis included comparisons of SCFAs related to factors including weight status, infant feeding modality, twin status, and intrauterine drug exposure, and significance determined with a p value < 0.05. Results did not identify significant differences in individual SCFA concentrations between obese and non-obese toddlers, however concentrations of isobutyrate, isovaleric acid, and octanoic acid were greater in toddlers who were formula fed as infants versus toddlers who were breastfed, and those fed a combination of breastmilk, and formula. Analysis further revealed a higher mean concentration of caproic and propionic acid in twin subjects. Of particular interest, toddlers with a history of opioid exposure had higher mean concentrations of isovaleric and octanoic acids, but less isocaproic acid when compared to those who were not drug exposed. Further analysis will help determine if these findings may be related to nutrient intake, in particular dietary fiber intake.


East Tennessee State University

Document Type

Honors Thesis - Withheld

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