The main goal of this thesis is to create a definition for mixed milk feeding clusters based on the mixed milk feeding behavior in which breast milk and formula feeding regimen are carried out on...Show moreThe main goal of this thesis is to create a definition for mixed milk feeding clusters based on the mixed milk feeding behavior in which breast milk and formula feeding regimen are carried out on the same day. Additionally, the aim is to study the relationship between these clusters and different health outcomes, specifically the microbiota composition in a baby’s gut. Although the mixed milk feeding regimen is a common practice, there is no definition for clusters of this type of feeding behavior. Hence, the first aim of this thesis is to evaluate the optimal cut-off values chosen earlier for the purpose of defining MMF clusters and to use them to determine the most important variables in describing MMF clusters. The ROC curve methodology is used to find the optimum cut-off values. The study creates different confusion matrices based on these variables and determines the best cut-off values considering clinical implications and accuracy. With this technique, we developed new simplified MMF clusters that can serve as the gold standard for identifying MMF clusters to address the lack of consensus in the literature. A number of important conclusions were drawn from the findings of the analysis. First, the results of the first study were to develop new simplified clusters that would later become the gold standard for MMF clusters in the literature. The second aim of the thesis is to examine the relationship between identified MMF clusters and microbiota composition using 16s rRNA data. Four different transformations for microbiota data were applied, including log transformation, scaled log transformation, centered log-ratio transformation (for relative abundance), and relative abundance log transformation, to create four different principal response curves. The aim is to study the change in microbiota composition within these MMF clusters at the genus level and species level over time. The second study showed that the clusters that are fed with more formula are more distant from the reference group, which is the reference breastfeeding cluster. In addition, clusters with more formula-fed infants had higher abundances of the Lachnospiraceae genus and Bifidobacterium breve species, while the abundance of Escherichia-Shigella genus and Bifidobacterium dentium species had higher in clusters with more breast milk infants. These findings have important implications for the field of MMF, providing insights into the impact of different feeding practices on infant gut microbiota.Show less
