Is the Indian Gut Microbiome Different? What a Study of 575 Adults Found

Research suggests that the Indian gut microbiome can differ from patterns often described in Western studies. A July 2026 study in Gut Microbes analysed 575 adults from ten communities in India and Sri Lanka. Their gut bacteria differed from four global comparison groups, and rural and urban participants showed differences that varied by community. Geography and community membership mattered strongly. These findings do not define a single ‘Indian gut’, prove that city life harms everyone’s microbiome, or tell us which diet would improve it.

If you have moved away from home, you may recognise how quickly familiar meals give way to whatever is available near the office, hostel or PG. Whether those changes affect your gut is a reasonable question. This study offers useful clues, while reminding us to ask who was studied before treating any bacterial pattern as ‘normal’ for everyone.

What is the gut microbiome?

The gut microbiome is the community of microorganisms living in the digestive tract. The SAMBAR study focused on bacteria, examining which groups were present in stool samples and their relative proportions.

Gut microbial diversity describes the variety of microbes in a sample and how evenly they are distributed. It is one way researchers compare samples; a diversity number alone cannot tell you whether your digestion is healthy.

Why the Indian gut microbiome needs its own research

Much of the evidence behind familiar gut-health headlines comes from people in Europe and North America. Their findings can be useful, but South Asian populations need better representation too.

The SAMBAR authors point to one version of the Human Microbiome Compendium, a large research collection. Only 3.3% of its 168,464 samples came from South Asia, and most of those were from infants and children. That percentage describes a particular database, rather than every microbiome study ever conducted.

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For researchers trying to understand adults across India and Sri Lanka, it leaves a substantial gap. Food habits, ancestry and surroundings differ both between countries and within them. More local data can help scientists work out which findings travel well and which need testing in a different population.

What did the SAMBAR study actually do?

Published online on 14 July 2026, the study in Gut Microbes was supervised by Dr Niraj Rai of the Birbal Sahni Institute of Palaeosciences in Lucknow and Dr Maanasa Raghavan of the University of Chicago, with collaborators across India, Sri Lanka and the US.

SAMBAR stands for South Asian MicroBiome ARray. Its name also nods to the familiar lentil-and-vegetable dish.

The final analysis included 575 adults. The Indian participants came from the Spitian, Gond, Kolam, Koya, Kani, Mizo and Pochury Naga communities. The Sri Lankan participants were Adivasi, Sinhalese and Sri Lankan Tamil people.

Within each Indian community, researchers compared village residents with members who had lived in a nearby town or city for more than a year. Comparing people with similar ancestry helps reduce some differences that might otherwise complicate the results. In Sri Lanka, the comparison was different: rural Adivasi participants were compared with urban Sinhalese and Sri Lankan Tamil participants, rather than urban members of the same community.

Participants supplied stool samples and answered questions about food and lifestyle. Researchers also recorded measurements such as blood glucose, blood pressure and body mass index. A technique called 16S sequencing used a bacterial gene to identify groups of bacteria, rather like reading a barcode.

Crucially, researchers took a snapshot of different people. They did not follow the same participants’ guts before and after moving to a city. Most participants belonged to Indigenous or tribal communities, and none of the Indian urban groups were sampled in the country’s ten largest cities. This was not a survey of the average Delhi or Bengaluru household.

What did the researchers find?

South Asian samples differed from the global comparison groups

The researchers compared SAMBAR with 575 adult samples from each of four other world regions, including a combined European and North American group. The South Asian samples showed a distinct overall bacterial composition.

For example, Holdemanella was more abundant in SAMBAR than in all four comparison groups. Collinsella was almost absent in SAMBAR but more abundant elsewhere.

Those findings identify regional patterns. They do not establish that everyone should try to increase one bacterium or eliminate another. The paper itself notes mixed findings about the health associations of some bacterial groups.

Village and city differences depended on the community

Geography and community membership had a stronger relationship with bacterial composition than the study’s measured diet and lifestyle variables did. Differences between rural and urban participants also varied considerably.

Gond participants and the Sri Lankan comparison showed relatively pronounced differences. Koya participants, whose urban settings were generally smaller, showed less separation. Kani participants also showed relatively small differences, which the authors suggest may reflect greater access to industrialised foods among rural members.

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Several bacterial groups were more abundant in rural participants, including Holdemanella and Succinivibrio. Other groups were more abundant in urban participants. This does not mean every villager had greater microbial diversity than every city resident.

Familiar foods were associated with particular bacterial groups

Greater wheat and yoghurt consumption was associated with more Bifidobacterium. Both foods were markers of changing diets in some communities, while Spitian participants had a longstanding pattern of consuming wheat and dairy.

The finding does not prove that a particular atta or yoghurt improves gut health, or that eating dairy becomes comfortable for everyone.

Among Pochury Naga participants, Bacillus stood out. Many reported eating axone, Nagaland’s fermented soybean preparation, which other research has found to contain abundant Bacillus. That is a plausible food connection, rather than proof that axone caused the pattern or that its bacteria permanently settled in participants’ guts.

One bacterial group was linked to higher blood glucose

Megamonas was more abundant in some urban groups. Across SAMBAR, it was associated with higher blood glucose and lower microbial diversity, after researchers accounted for several other measured factors.

An association means the measurements occurred together. The study cannot establish that Megamonas caused the higher blood glucose, or that reducing this bacterial group would improve a person’s health. It is a finding for further investigation, rather than a reason to buy a supplement targeting a named microbe.

What the study means for everyday gut-health advice

SAMBAR helps broaden the evidence used to understand South Asian gut microbes. Its most useful message for readers is to be cautious about a universal picture of a ‘healthy microbiome’.

The study did not test a diet, probiotic or treatment. It also did not validate a commercial stool test or provide a personal bacterial target. Its sequencing method could not reliably distinguish every species or strain, and participants reported their own food habits.

Researchers will need further studies to understand what the observed bacteria were doing, whether the patterns change over time and how they relate to health. A regional bacterial difference is not, by itself, a diagnosis.

If city life has changed your meals, start with the plate

You do not need to recreate someone else’s microbiome. If a move or a busy schedule has narrowed your meals, improving variety is a practical place to start. This is general dietary guidance, separate from what SAMBAR tested.

ICMR-NIN’s Dietary Guidelines for Indians 2024 encourage variety across food groups, including whole grains, pulses, vegetables, fruit, nuts and milk or curd. An Indian kitchen already offers plenty of ways to keep those foods in the day.

• If lunch is usually rice or roti with one accompaniment, consider adding dal or another pulse and a vegetable you enjoy.
• If snacks regularly replace meals, keep a familiar option available, such as fruit, roasted chana or plain curd, according to what suits you.
• If you are adding more fibre, increase it gradually and keep fluids adequate. Follow any individual dietary instructions you have been given.

For more kitchen-level ideas, read our practical guide to increasing fibre in an Indian diet.

Fermented foods can be part of that variety if you enjoy and tolerate them. In a separate, small 2021 Cell trial involving 36 adults, the group assigned to eat more fermented foods increased microbial diversity over a ten-week intervention. That result does not promise the same effect from a daily bowl of dahi, nor does it turn every fermented food into a clinically proven probiotic.

Want ideas that fit the food you can actually get? Ask Happy Tummy GPT: “I live in a PG and usually eat rice, dal and one sabzi. Suggest three affordable ways to add variety during the week.”

SAMBAR’s name is a pleasing reminder of how much variety can fit into familiar food. You can keep the dal, vegetables and meals you enjoy without needing to turn dinner into a microbiome experiment.

Sources

• Ramachandran SL, Pasupuleti N, Abdill RJ, et al. Distinct trajectories of urbanization shape the human gut microbiome across South Asia. Gut Microbes, published 14 July 2026.
• Department of Science and Technology, Government of India: announcement of the SAMBAR findings, via the Press Information Bureau, 25 August 2026.
• ICMR-NIN: Dietary Guidelines for Indians 2024
• Wastyk HC, Fragiadakis GK, Perelman D, et al. Gut-microbiota-targeted diets modulate human immune status. Cell, 2021
• US National Institute of Diabetes and Digestive and Kidney Diseases: guidance on adding fibre gradually and keeping fluids adequate.

Disclaimer: This article provides general information based on published research and is not personal medical or dietary advice. Follow individual guidance from your healthcare professional, including for children, during pregnancy or for older adults. Do not change prescribed medicines or a medically directed diet based on a research headline. Speak to a doctor if digestive symptoms persist, become severe or keep returning. Unexplained weight loss, blood in the stool, severe or persistent pain, or difficulty swallowing need prompt medical attention.