By studying the faecal samples of over 100 healthy people from Madhya Pradesh and Kerala, researchers from the Indian Institute of Science Education and Research (IISER) Bhopal have decoded the Indian gut microbiome and have created a gene catalogue. Constructed using multiple omics approaches such as genomics and proteomics, the catalogue contains details on the different genes coded by the gut bacteria and the functions carried out by the bacteria.

Comparitive analysis

This study also compared the gut microbiome of Indians with people in China, the U.S. and Denmark. The Indian gut microbiome showed higher levels of Prevotella bacteria compared to the other populations. “The presence of these species in high abundance in Indian gut microbiome correlates with the food habits and the diet of the Indian population, which is very different from the other western populations,” says Prof. Vineet K. Sharma from the Department of Biological Sciences at the Institute in an email to The Hindu. He is the corresponding author of a paper recently published in GigaScience.

Faecal samples from 53 people from Madhya Pradesh and 57 from Kerala were used to construct the microbial gene catalogue. The catalogue contains 1,551,581 genes and 943,395 genes out of them were identified as unique to the Indian population. “So about 9% (almost one million) microbial genes were found unique to our population, and were not identified in the integrated microbial gene catalogue constructed from other populations across the globe,” adds Prof. Sharma.

The study also highlighted the differences in microbiome composition between the two states. Samples from Kerala had a higher abundance of short-chain fatty acid producing bacteria such as Faecalibacterium and Roseburia, in addition to Prevotella.

This may be due to the fact that they consumed an omnivorous diet containing rice, fish and meat. Prevotella, the key species in Indian gut was comparatively higher in the Madhya Pradesh population.

This group consists mostly of people eating a plant-based diet and also showed an enrichment of branched-chain amino acid and lipopolysaccharide biosynthesis pathways.

Faecal metabolites

Using large-scale metabolomics, the study also identified the different faecal metabolites (end products after microbial metabolism) of the Indian samples and mapped their association with the gut microbial species.

“If we have a data of the faecal metabolites, we can compare how it changes during some metabolic disorders and this can serve as simple signatures,” says Mr. Darshan Dhakan, PhD scholar at the institute and the first author of the paper. “The results of this study will also help develop pre and probiotics according to our needs.”

According to Mr. Dhakan, a drug made and tested in the U.S. may not work for the Indian population. So understanding the gut microbiome will help customise drugs and also develop new strategies for tackling the metabolic diseases by correcting the imbalance in the gut microbiome.