MA, YIWEI2024-01-052024-01-052021-08https://hdl.handle.net/11299/259769University of Minnesota Ph.D. dissertation.August 2021. Major: Nutrition. Advisor: Chi Chen. 1 computer file (PDF); xii, 183 pages.Functional foods, including whole, fortified, enriched, or enhanced foods, provide variety of health benefits beyond the basic function of supplying essential nutrients. The consumption of functional foods has been commonly linked with the lower risks of metabolic diseases, including cardiovascular disease, type 2 diabetes (T2DM), and certain types of cancer. However, not all these health claims on marketed functional foods are supported by solid experimental evidence and mechanistic investigation. With more complex chemical constituents than nutraceuticals or dietary supplements, functional foods can affect diverse targets in humans and animals, including both host cells and microbes, through different reactions and pathways. All these features of functional foods pose challenges in defining their bioactivities and underlying mechanisms as well as the recommended doses of intake in practice. Therefore, comprehensive examination on the metabolic effects of functional foods is needed to address those questions. In this project, the influences of Scenedesmus algae, functionalized wheat bran (FWB), and Konjac mannan-oligosaccharides (kMOS), which are whole, fortified, and enriched functional foods, respectively, on animal performance were determined in mouse trials. Their metabolic effects were examined by the comprehensive liquid chromatography-mass spectrometry (LC-MS)-based metabolomics and biochemical analysis. The results are summarized as follows: (1) Scenedesmus feeding promoted the growth at the low dose through the elevation of antioxidants, the expansion of purine nucleotide cycle, and the modification of microbial metabolism, while inhibited it at the high dose through oxidative stress, disrupted urea cycle and lipidome, and the upregulation of fatty acid oxidation. (2) FWB feeding yielded beneficial effects on cholesterol, microbial metabolism, and purine metabolism, while it also negatively affected the nutritional status by decreasing the bioavailability of essential amino acids and choline. (3) The remodeling of microbiota- derived intestinal metabolome only occurred under the high-dose MOS feeding, while the changes of hepatic metabolites in glycolysis and TCA cycle occurred in all doses. Therefore, kMOS induced different dose-dependent responses in the gut microbiome and the hepatic metabolome. Overall, double-edged and dose-dependent metabolic effects were observed in the feeding studies of these functional foods. All these information warrant further investigation on the functions of individual constituents of functional foods as well as their combinatorial effects in the biological systems in order to disentangle the “harmful” from the “beneficial” effects of functional foods for their usages in humans and animals.enThesis or Dissertation