Avaliação do papel de fatores genéticos e alimentares no microbioma intestinal humano na adolescência

Abstract

The gut microbiome is characterized as a complex ecosystem of microorganism species that inhabit the intestine and modulate the relationship between the host and the processes of homeostasis and disease. The formation of the intestinal bacterial community undergoes drastic transformations during the development of the individual and substantial changes occur from early life to aging. Genetic factors influence this process, as wel as early environmental factors that determine the colonization of bacteria in the intestine, such as type of delivery, breastfeeding, diet, socioeconomic level, physical activity, among others. The main objective of this project is to investigate the association between genetic and dietary factors, specifica ly the consumption of ultra-processed foods and breastfeeding, and parameters of composition and diversity of the intestinal microbiome in a subsample of participants from the 2004 Pelotas Birth Cohort. The first original article of the thesis aims to investigate the relationship between the longitudinal consumption of ultra-processed foods (UPF) and the quantitative characteristics of the intestinal microbiome. The results suggest that UPF consumption at 11 years of age was associated with a reduction in beneficial bacteria such as the Bacteroides genus and an increase in Peptostreptococcus and Actinobacteria. The second article aims to identify genomic regions that influence quantitative characteristics (bacterial abundance and diversity) related to the intestinal microbiome in humans. We found that a variant of the SLC5A1 gene was associated with a lower abundance of the bacterium Oxalobacter, a genus potentialy involved in the regulation of oxalate metabolism. The third article of the thesis sought to evaluate the association between breastfeeding practices (exclusively breastfed, mixed breastfeeding, and non-breastfed until three months of age) on the diversity and composition of the intestinal microbiota of the participants in the subsample. No differences in alpha diversity were found between the breastfeeding patterns investigated. Modest associations were observed between breastfeeding patterns and the composition of the intestinal microbiota at 12 years of age. Non-exclusive breastfeeding and early introduction of liquids or semi-solid foods were associated with a higher abundance or presence of Ruminococcus and Eubacterium. However, these associations did not remain significant after correction for multiple testing, suggesting limited longterm effects.