Role of Gut Microbiota in the Metabolism of Young AdultsNovel Insights and Potential Intervention Strategies

Resumo

The gut microbiota refers to the microorganisms that colonize the gastrointestinal tract. It has emerged as a pivotal transducer of environmental influences to exert protective or detrimental effects on several host tissues and systems, and as a major player in the maintenance of human health and the pathophysiology of cardiometabolic diseases. Therefore, understanding the role that gut microbiota might play in the development and treatment of cardiometabolic diseases is of great scientific and societal interest. It has been speculated that the potential benefits of exercise and cold therapies on cardiometabolic health can be explained through their impact on the host’s gut microbiota. The aims of this International Doctoral Thesis were to study whether novel markers of cardiometabolic health are related to fecal microbiota composition in young adults (section I); and to investigate the impact of exercise and cold on fecal microbiota and cardiometabolic health, respectively, in young adults (section II). To unravel these aims we conducted two cross-sectional studies (section I), and a systematic review, a 24-week exercise-intervention study and a novel short-term mild cold intervention in young adults (section II). The results of the present International Doctoral Thesis showed a unique relationship between plasma levels of omega-3 and omega-6 oxylipins and fecal microbiota composition in young adults (study I). We also showed that specific bacteria species were related to plasma levels of primary and secondary bile acids (study II). We provided the available scientific evidence on the effect of exercise on human fecal microbiota composition (study III) and showed that a 24-week moderate-exercise intensity program modified the fecal microbiota composition in young adults (study IV). Lastly, we demonstrated that a novel mild cold regimen is able to decrease distal skin temperature in both hands after 3.5 days of activation, yet other metabolic parameters were not affected (study V). Altogether, the results of the present International Doctoral Thesis suggest that novel markers of cardiometabolic health (i.e., oxylipins and bile acids) are associated with fecal microbiota in young adults, and that exercise of moderate intensity is able to modify fecal microbiota composition. Preliminary findings on our cold intervention will pave the way towards new experiments understanding the role of cold exposure in gut microbiota composition in humans.