PhD Defence Mônica Maurer Sost

Keywords: Dietary fibres, Gut microbiota, Short-chain fatty acids, Obesity

"A Journey into the Gut Bacterial Profile and Functionality in Obesity and Health - From Dietary Fibres & Polyphenols to Sweeteners"

This thesis investigated how different foods and food components influence the bacteria in the human gut and their activity, with a focus on supporting people with obesity or at risk to develop type 2 diabetes. Using both in vitro models and clinical trials, this thesis tested asparagus, citrus fruit extracts, non-caloric sweeteners, and complex dietary fibre mixtures. The results show that parts of asparagus, usually considered waste, could support bacteria linked to better metabolic health. Citrus extracts were found to increase the production of beneficial compounds in the gut and showed positive effects in people at risk of metabolic syndrome. Studies on non-caloric sweeteners demonstrated that replacing sugar with these alternatives could aid in maintaining weight loss and encourage favourable bacterial changes. Finally, personalised mixtures of dietary fibres led to higher production of beneficial gut compounds, though responses varied between individuals. Overall, the research suggests that targeted food choices may support healthier gut function and metabolic health.

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