An international study published in npj Biofilms and Microbiomes by UBC Okanagan researchers shows that South Asian immigrants in Canada, particularly Indo-Canadians, experience notable shifts in their gut microbiome as their diets become more Westernized changes that may explain their higher risk of inflammatory bowel disease (IBD). The study analyzed stool samples and dietary data from over 170 participants, including Indians in India, first-generation Indian immigrants, Indo-Canadians, Euro-Canadians, and Euro-immigrants, revealing that while both immigrant groups showed microbiome and dietary transitions, the most pronounced changes were seen in Indo-Canadians. According to first author Leah D’Aloisio, these findings highlight the importance of studying underrepresented populations to understand how quickly the gut responds to dietary shifts and its implications for chronic disease prevention.

The findings show that while Indians residing in India maintain gut bacteria linked to a high-fibre, plant-based diet, Indo-Canadians display a transitional microbiome marked by the loss of beneficial Prevotella species and increased signs of a westernized gut ecosystem. 

Globally, Indians show some of the steepest rises in IBD after migration, with South Asians in Canada experiencing rates more than six times higher than in India. UBC Okanagan researchers attribute this to dietary acculturation shifting from fibre-rich traditional foods to ultra-processed, sugar- and additive-heavy diets driving gut microbiome changes. As senior author Dr. Deanna Gibson explains, the Indo-Canadian microbiome is caught between two worlds adapting not just to environment but to diet, which may explain the heightened disease risk among those born in Canada to Indian parents.

The study underscores how immigration, globalization, and industrialized diets shape gut health and long-term disease risk, with implications far beyond Indian populations. As collaborators from Canada, India, the UK, and the U.S. note, the gut microbiome is becoming a key marker of how health risks evolve with migration and cultural change. With rising global mobility and shifting diets, the researchers call for culturally relevant dietary guidelines and immigrant-focused health strategies, emphasizing that the rapid emergence of IBD in immigrant communities offers a unique opportunity to identify disease drivers while helping preserve protective food traditions.

Source: https://news.ok.ubc.ca/2025/09/22/from-spice-to-sugar-westernized-diets-reshaping-immigrant-gut-microbiomes/