Dietary Protein Interacts with Prebiotic Fiber to Modulate Energy Balance and Body Composition
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2021-01-05
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Abstract
Background: Incidence of obesity is increasing throughout the world. Dietary supplementation of protein and fiber have been individually demonstrated to promote weight loss. However, less is known, about the underlying mechanisms by which diets containing a combination of protein and fiber interact to improve energy balance and promote weight loss. Objectives: The overall objectives of this dissertation were: 1) to determine the interactive effects of dietary protein and fiber on energy balance, body composition and gut microbiota in obesity prone (OPCD) rats; 2) to determine combined effects of protein and fiber enriched diets along with exercise training on energy balance, body composition, gut microbiota in OPCD rats. Methodology: In experiment-1, rats were randomized into four treatment groups- Egg albumin + Cellulose (EC), Egg albumin + Inulin (EI), Whey protein concentrate + Cellulose (WC), and Whey protein concentrate + Inulin (WI) groups. In experiment 2, the effects of identical treatment groups along with exercise were studied. Food intake, energy expenditure, respiratory quotient, and body composition were measured using CLAMS® metabolic chambers and magnetic resonance imaging. The mRNA abundance of tissue markers and gut microbiota composition were measured using qPCR technique. Results: The primary findings were: 1) supplementation of dietary egg or whey protein with inulin fiber promoted greater hypophagia, in conjunction with an increase in fat oxidation. Whey-inulin group increased cholecystokinin (CCK) and peptide YY (PYY) mRNA abundance in the gut, and CCK-1 receptor antagonist attenuated the hypophagic response of the diets. Egg-cellulose and inulin enriched diets (EI, WI) decreased weight, adiposity gains and selectively modulated gut microbiota by specifically increasing Bacteroidetes or Bifidobacterium and decreased Roseburia. 2) Diets containing egg or whey protein and inulin fibre together with exercise transiently decreased energy intake. Egg-cellulose and inulin enriched diets combined with exercise decreased body weight gains, liver fat and improved glycemic control partly through modulations in plasma concentrations of insulin, leptin and selective gut microbiota. Conclusion: Collectively, our findings provide evidence that consuming diets containing egg or whey protein and inulin fiber together with exercise improves energy balance and body composition with significant implications for preventing and treating obesity.
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Avirineni, B. S. S. (2021). Dietary Protein Interacts with Prebiotic Fiber to Modulate Energy Balance and Body Composition (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.