Gut microbiota in relation to diet-induced metabolic worsening and improvements in overweight and obese adults : toward prediction of personalized dietary response
Year: 2021
Type: dissertation
Abstract: It has been estimated that one in five adults is affected by metabolic syndrome globally, characterized by obesity concomitant with several metabolic derangements such as insulin resistance or non-alcoholic fatty liver disease. The current treatment options for metabolic syndrome-associated conditions are mainly based on lifestyle modification, such as dietary strategies. However, there is substantial interindividual heterogeneity in dietary response. A wealth of evidence derived from animal models suggests that the gut microbiota, i.e., the collection of intestinal microbes is causally involved in the diet-induced metabolic alternations. In contrast, the diet-microbiota-host interplay is still poorly understood in humans. In the present dissertation, the gut bacterial microbiota was characterized and compared by qPCR and Illumina sequencing of the 16S rRNA gene amplicons before and after two dietary intervention studies, overfeeding and calorie restriction, that induced metabolic alternations in opposite directions in overweight and obese adults. The associations between dietary response and the pre-intervention gut microbiota were explored. In addition, a qPCR-based experimental quantitative approach for microbiome profiling was developed. The results showed that overfeeding was associated with macronutrient-specific changes in individual bacterial taxa, but not the overall community. The baseline levels of genus Bilophila were positively associated to overfeeding-induced liver fat increases independently of the macronutrient composition. On the other hand, caloric restriction by a low-energy diet was associated with remodeling of the gut microbiota, with large decreases in the relative abundances of butyrate-producing bacteria and Bifidobacterium and an increased proportion of mucus-utilizing Akkermansia. These changes in the gut bacterial microbiota correlated with changes in host metabolic variables. Importantly, the pre-intervention gut bacterial microbiota was predictive of diet-induced metabolic worsening or improvements. Quantitative microbiota profiling was shown to be easy to perform and palliate the caveats to data interpretation when using relative abundance data. The present work identified alterations in the human gut bacterial microbiota associated with quantity- and quality-specific dietary changes that may have context-dependent effects on host metabolic health. The present findings also suggest that pre-intervention participant stratification based on the gut microbiota holds potential for improving intervention response.
Source: Työväentutkimus Vuosikirja
Author: Jian, Ching
Language: English
Topic: Gut microbiota and health
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7038123358