Background:The second an individual is born, the gut microbiome starts acquiring unique characteristics, including microbial richness and evenness. In addition, it has been found that during infancy, the mode of delivery, antibiotic exposure, feeding patterns, and environment play a role in such development. However, infancy is still an understudied population related to the gut microbiota, specifically its’ connection to two modifiable factors-sleep-wake patterns and its’ interconnection with feeding practices in the first year of life. Methods: This secondary data analysis from a randomized longitudinal intervention study assessed the efficacy of a home-based education program in preventing the onset of childhood obesity. A convenience sample of 40 Hispanic mother and infant dyads were recruited to participate in an additional collection of fecal samples to evaluate associations between lifestyle/behavioral factors in infancy and gut microbiome composition in toddlerhood. Total sleep duration and feeding practices (breastmilk and formula) were assessed at one, six, and twelve months. In addition, alpha and beta diversity metrics were assessed from infant stool samples collected at 36 months. Results: This study found some significant and trending values for pairwise comparisons of alpha (Shannon Diversity Index) and beta (Bray Curtis and Jaccard Distance). Sleep-wake adequacy consisted of 14-17 total hours of sleep in 24 hours at one month and 12-16 hours for six and twelve months of age. No significant values were identified at one month of age. However, six and twelve months demonstrated significant observations for gut microbial richness and evenness. Trending differences (p=.06, Shannon Diversity Index) persisted in infants receiving adequate sleep at six months but for different feeding modalities. Faith’s PD, Pielou’s measure, and observed OTUs were three additional alpha-diversity metrics performed in all groups. Observed OTUs (p=.03) and Faith’s PD (p=.03) were significant at twelve months, demonstrating an increased microbial feature in infants receiving adequate sleep. Conclusion: The findings from this study may show how different timestamps in the first year of life may create gut microbial milestones. However, the interrelation between sleep-wake patterns, feeding modalities, and gut microbiome development is limited; further investigation is needed to monitor close changes and potentially create a criterion

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.