The roles of genetic variation and exercise on dietary patterns among sedentary young adults
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Researchers from health care to basic science are interested in determining how people can improve their overall eating patterns. This dissertation concerns the roles of genetic variation and exercise in influencing dietary patterns, with three specific aims. 1. Characterize dietary patterns using sparse latent factor models, addressing the methodological shortcomings of the current dietary pattern approach. 2. Examine the influence of a 15-week aerobic exercise training protocol on dietary patterns among young adults. 3. Examine the contribution of genetic variation to the variability of dietary patterns using genome-wide single nucleotide polymorphism (SNP) data. Since foods and beverages are consumed in a variety of combinations under free-living circumstances, analysis performed on a per-food or per-nutrient basis can be misleading. Thus, it is important to consider not only research related individual dietary component, but also research that examines dietary patterns that represent the real-life manner in which foods are consumed in a variety of combinations. With this idea in mind, dietary pattern analysis was performed to identify habitual dietary patterns among young adults. In this research project, sparse latent factor modeling was applied to dietary pattern analysis an alternative approach to overcome the methodological shortcomings of the current dietary pattern methods in which several steps are performed sequentially, and each step involves in an arbitrary decision rule. Once dietary patterns were identified, the influence of exercise on patterns of food consumption was evaluated. Changes in dietary patterns among young adults after 15 weeks of exercise training were examined using the time-varying factor scores of dietary patterns. The results suggest that engaging in regular exercise may motivate individuals to regulate overall food intake as well as pursue healthier dietary preferences. Finally, the SNP-based heritability of dietary patterns was examined using genome-wide SNP data. The proportion of variance in dietary patterns accounted for by genetic variation was calculated, which produced estimates of SNP-based heritability. The heritability of both the Snacking and Western patterns was greater than that of the Prudent pattern, suggesting a stronger biological underpinning for preference of foods high in fat and sugar. Dietary patterns are more than the sum of their part; they represent what people habitually eat and drink in daily lives, and these dietary components act synergistically to affect health. Understanding the roles of exercise and genetic variation in influencing dietary patterns as a whole would be a significant step toward the goal of providing a robust behavioral and biological basis for healthy eating patterns that both reduce risk of preventable chronic disease and promote overall health.