Researchers at UBC Okanagan say that Indo-Canadians experience changes in their gut microbiome as their diets become westernized.

A new international study led by researchers at UBC Okanagan has found that Indo-Canadians, or Canadians who were born in Canada with Indian descent, experience major shifts in their gut microbiome as their diets become more westernized.

Researchers say these changes may help explain why South Asian immigrants in Canada face a higher risk of inflammatory bowel disease (IBD).

“Many non-European populations are underrepresented in microbiome research,” says Leah D’Aloisio, a Master of Science graduate at UBC Okanagan and the study’s first author.

“By studying Indo-Canadian immigrants, we can better understand how quickly the gut responds to dietary transitions, and how this influences chronic disease prevention.”

The study, published innpj Biofilms and Microbiomes, compared stool samples and dietary data from more than 170 participants across India and Canada, including Indians living in India, first-generation Indian immigrants (“Indo-immigrants”), Indo-Canadians, Euro-Canadians and Euro-immigrant controls.

When compared to Indians living in India, both Indo-Canadians and first-generation Indian immigrants showed a change in their gut microbiomes and dietary patterns; however, this transition was most prominent in Indo-Canadians.

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.

Westernization and health risks

Globally, Indians experience some of the sharpest increases in IBD after migration. In Canada, the incidence of IBD among South Asians is more than six times higher than in India.

Researchers say dietary acculturation—shifts toward ultra-processed foods high in sugar and additives, and away from fibre-rich traditional diets—is a major driver of microbiome change.

“Our study shows that the gut doesn’t just adapt to where you live, it adapts to what you eat,” said Dr. Deanna Gibson, Professor of Biology at UBC Okanagan and senior author.

“For Indo-Canadians, that means a microbiome caught between two worlds—traditional and western—which may help explain why disease risk increases when you are born here in Canada despite parents being from another continent like India.”

What the study found

• Indians in India had gut bacteria enriched withPrevotella, known for breaking down complex plant-based carbohydrates and dietary fibre.
• Indo-Immigrants and Indo-Canadians showed a decline in these bacteria and a rise in microbes common in western populations, such asBlautia andAnaerostipes.
• Dietary analysis revealed that ultra-processed foods made up more than 60% of Indo-Canadians’ daily calories, compared to just 12% in Indians. Fibre intake was highest in India and lowest among Indo-Canadians. “Indians living in India should take note: stick with the traditional dietary patterns,” says Dr. Gibson.

“The rapid development and industrialization of food systems in India will mean the adoption of westernized guts and therefore disease risks like IBD. Indeed, IBD is on a massive uptick over the past few years in India, and there’s no doubt it is related to the increased westernization of Indian diets.”

Western diets, global implications

These results highlight how immigration, globalization and the food environment shape health and long-term disease risk.The researchers stress that these findings are not limited to Indian populations.

As diets industrialize worldwide, the gut microbiome is emerging as a powerful marker of how health risks travel with migration and cultural change.

The project involved collaborators in Canada, India, the UK and the U.S.

As the global population becomes more mobile and diets continue to industrialize, the researchers call for more culturally relevant dietary guidelines and immigrant-focused health strategies.

“The exact causes of IBD are still unclear,” D’Aloisio added. “But seeing risk emerge so quickly in immigrant populations gives us a unique opportunity to pinpoint the factors driving disease, and to support communities in keeping protective food traditions alive.”