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D'Aloisio, Leah

University of British Columbia

The growing immigrant population in North America are experiencing westernization at a rapid rate. Amidst the backdrop of rising immigration, health disparities are emerging in immigrants, including several modern diseases linked with the westernized lifestyle. Young Indian immigrants and Indo-Canadians face a significantly higher risk of inflammatory bowel disease (IBD) in westernized countries. While the root causes of IBD are not entirely understood, a main characteristic is an imbalanced gut microbiome no longer in symbiosis with its host. However, Indian populations are underrepresented in microbiome studies, making it challenging to determine the influences of their gut microbiome in this increased IBD risk. To understand why Indians are more vulnerable to IBD in Canada, it is essential to first investigate their gut microbiome. This thesis explores the gut microbiome transition in Indian migrants in Canada by characterizing their microbial composition, and the impact of their dietary patterns on the microbiome. Using 16S and shotgun sequencing data obtained from stool samples of healthy subjects, our study compares the microbiome of Indians residing in India, Indian immigrants, and Indo-Canadians, with Euro-Canadians and Euro-Immigrants as westernized controls. Our findings reveal significant differences in microbiota composition among these groups, with Indian residents showing a distinctive gut microbiota rich in Prevotella spp., whereas Indo-Canadians resembled more of an industrialized gut, with higher Bacteroides spp. abundance. While Indo-Immigrants had a gut microbiota that was distinct from Indians and westernized cohorts, some subjects displayed moderate levels of Prevotella spp. abundances, which may be due to their mixed diet that included both traditional Indian and westernized foods. This study concludes that Indo-Canadians undergo a marked transition towards an industrialized microbiome within just one generation, both through functional changes and the loss of Prevotella spp. This microbiota transition was associated with a large change in dietary habits, in particular a decrease in a high carbohydrate, high fibre diet, and an increase in ultra-processed foods. Overall, the data shown offers insight into how migration and lifestyle changes affect both microbial composition and functions in the gut, and their implications for understanding immigrant-health outcomes.

Text

2024-04-02

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/87669

Biology

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/