South Asian gut microbiome differs from western populations, study finds

Much of the existing microbiome research has focused on European and North American populations, leaving South Asia, home to nearly one-fourth of the world's population, comparatively underrepresented

A large-scale study spanning India and Sri Lanka has found that South Asian gut microbiomes are distinct from those reported in other parts of the world and are strongly shaped by local diet, culture, geography and lifestyle. 

The findings, published in Gut Microbes, could provide a foundation for developing microbiome-based diagnostics, personalised nutrition and precision healthcare approaches for South Asian populations, particularly for lifestyle-associated conditions such as obesity, diabetes and cardiovascular disease. 

The study comes as South Asia undergoes rapid urbanisation alongside a growing burden of cardiometabolic disorders. While urbanisation is known to influence the gut microbiome, researchers said it was previously unclear whether those changes occur in similar ways across the region's diverse populations. 

Much of the existing microbiome research has focused on European and North American populations, leaving South Asia, home to nearly one-fourth of the world's population, comparatively underrepresented.

Scientists from the Birbal Sahni Institute of Palaeosciences (BSIP), an autonomous institution of the Department of Science and Technology (DST), the University of Chicago and collaborating institutions in India, Sri Lanka and the US investigated how changing lifestyles affect gut microbial communities across different cultural, dietary and ecological settings.

The researchers collected stool samples along with dietary, lifestyle and health information from 575 healthy adults across 10 culturally and geographically distinct South Asian communities in India and Sri Lanka.

Using the South Asian MicroBiome ARray (SAMBAR), researchers analysed the gut microbiomes using high-throughput sequencing of bacterial 16S rRNA genes, followed by bioinformatic analysis. 

The team compared rural and urban participants within individual communities and also assessed their microbiome profiles against global datasets. 

The study found that each community followed its own distinct microbiome trajectory, reflecting differences in local culture, food habits, geography and lifestyle. At the same time, the researchers identified common microbial changes associated with urbanisation and metabolic health.

The international project was led by Dr. Niraj Rai, Group Head, Ancient DNA, BSIP, Lucknow, with field teams working closely with local communities to recruit participants and collect biological and lifestyle data. The researchers also adopted a community-engaged approach, sharing findings with participating communities.

The research team, including Shreya L. Ramachandran, Nagarjuna Pasupuleti, Richard J. Abdill, Niraj Rai and Maanasa Raghavan, identified both community-specific microbial signatures and broader patterns linked to urbanisation and metabolic health.

According to the researchers, the findings highlight the limitations of applying microbiome-based interventions developed primarily from Western populations to South Asian communities. The different responses observed across communities suggest that future microbiome-based therapies, nutrition interventions and diagnostic approaches may need to be tailored to regional populations.