Resiliency and Individuality Influence the Gut Microbiome Through Nutritional and Feeding Behavior Pressures

The microorganisms that colonize the gastrointestinal tract have been recognized over the last several decades to have a significant bearing on the health trajectories of the hosts that harbor them. The collection of these gut microbes display links with acute and chronic disease, garnering substantial interest in leveraging the microbiome for improved health states. How these microbes assemble as a complex community and interact with each other, and the host depends on a multitude of factors. In adulthood, diet is one of the main moderators, having a significant influence on community composition and the functional output captured in the metabolites produced and/or modified by the gut microbiome. Thus, the assembly of microbes in the gut are tightly intertwined with health. In this dissertation, I examine the impact of diet and feeding behaviors on the gut microbiome and what features may be grounding or responsive under such pressures. Specifically, I first explore the avian gut microbiome as a barometer of nutritional and environmental influence on host health. Birds have continually displayed robust physiology under dietary pressures, placing them in an important, though underutilized, position within the translational science framework. Second, I describe the association of food insecurity on gut microbiome and metabolome profiles in a diverse college-based sample. Food insecurity provides its own set of unique pressures, such as unintentional calorie restriction, and inconsistent dietary intake and access to healthy food options. Third, I examine the effect of a one vs. two-consecutive days of intermittent fasting on the gut microbiome, the plasma metabolome, and associated clinical outcomes in overweight and obese adults. Growing in scientific and lay popularity, dietary fasting has been noted to induce changes in the diversity of gut microflora and gut motility, though different fasting lengths have not been assessed in the context of the human microbiome. Overall, this collection of work underscores that the community of microbes in the gut are individualized, resilient, and baseline composition and functioning are germane to how an individual may react to a particular dietary intervention.