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Title: The effect of fermentable carbohydrates on diabetes & obesity
Author: Fountana, Sofia
ISNI:       0000 0004 7427 7475
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2018
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Fermentable carbohydrates have been shown to exert beneficial effects on dysregulated metabolic conditions such as obesity and diabetes by improving insulin sensitivity and glucose homeostasis, independent of weight loss. Short-chain fatty acids produced by the fermentation of these carbohydrates are considered the primary mediators of these beneficial effects. This thesis aims to evaluate the effect of fermentable carbohydrates on metabolic profiles of pre-diabetic individuals at high risk of developing diabetes and the effect of colonic propionate on glucose and lipid homeostasis in obese individuals. The work presented in this thesis comprises of two axes. The first one is centered on the development and validation of an analytical approach of quantifying SCFAs in human plasma, serum and urine. The applicability of the assay in nutritional studies is also assessed in the second aim. The second part explores the metabolic profiles of pre-diabetic and obese individuals with the employment of 1H nuclear magnetic spectroscopy and mass spectrometry analysis. Concentrations of SCFAs and alteration of the lipid profile were also assessed. The responses to dietary interventions were compared using multivariate statistics. The fermentable carbohydrate inulin increased the production of postprandial SCFAs in pre-diabetic individuals but did not exhibit a significant effect on the overall metabolic profile. Colonic propionate improved the postprandial lipaemia in obese individuals and exerted higher microbial derived metabolites suggesting a role for propionate in the lipid homeostasis in obesity. Propionate levels in the circulation were not affected but systemic acetate significantly increased during the meal test. Finally, the controlled intervention with the non-fermentable carbohydrate cellulose improved lipid profiles in pre-diabetic and obese individuals.
Supervisor: Nicholson, Jeremy ; Frost, Gary Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral