Fibre-rich diet cuts Indians' risk of crohn's disease, colitis: IISER

Bhopal: Indians eat more fibre-rich plant-based diet than people in the Western countries, reducing their risk of gut-related problems such as inflammatory bowel diseases like Crohn's disease, Irritable Bowel Syndrome (IBS), colitis, and colon cancer, according to research on Tuesday.

The international study, including researchers from the Indian Institute of Science Education and Research (IISER)- Bhopal, sought to understand the relationship between gut bacteria and inflammatory diseases.

"Increased intake of carbohydrate in the form of fibre such as wheat, vegetables, fruits and lentils, mostly found in Indian diet lowers the incidence of IBD, Crohn's disease, colitis, colorectal cancer, etc., than western diets that are generally meat-based," lead author Dr Vineet K. Sharma, Associate Professor, Department of Biological Sciences, IISER Bhopal, told IANS.

The human gut contains 300-500 types of bacteria that are necessary for our survival. These bacteria help in digestion, protect us from infections and even produce essential vitamins and neurochemicals.

Depending on the kind of bacteria that dominates the gut, human beings are generally classified into three "enterotypes" -- Prevotella, Bacteroides or Ruminococcus.

The study included 586 healthy samples from western and non-western populations including 200 samples from India, and 189 IBS samples from western populations.

The 200 gut samples from India were taken from people from several locations in -- Madhya Pradesh, Delhi-NCR, Rajasthan and Maharashtra, Bihar, and Kerala. It is also the largest gut metagenome study from India, as most such studies are largely based on the Western population.

The findings, published in the Nature's Biofilms and Microbiomes journal, showed that the Indian gut microbiome has the highest abundance of the Prevotella genus of bacteria, in particular, a species called Prevotella copri (P.copri).

This bacterium was also found to dominate the guts of other populations that consume a carbohydrate and fibre-rich diet, such as the Italian, Madagascarian, Peruvian, and Tanzanian. But, the gut microbiomes of people from Western countries like the US are dominated by Bacteroides.

Further, they found that P. copri is significant in the metabolism of complex polysaccharides and dietary fibres in non-western populations.

It is thus logical that this type of bacteria predominates the gut microbiome of the healthy Indian and non-western population that consumes a diet rich in plant carbohydrates and fibres, Sharma explained.

"The proportion of P.copri in Indians is 30 per cent and can reach up to 60-70 per cent. Of the more than 1200 species of Prevotella, P.copri is the most abundant in Indian human gut," Sharma told IANS.

On the other hand, the guts of the Western population were found to have other Prevotella species such as P. intermedia and P. nigrescens. These bacteria are usually found in the mouth, which points to a mouth-gut axis. These bacterial species are inflammatory and have high virulence and antibiotic resistance genes, making the Western population more susceptible to gut inflammatory diseases.

"Our insights would help in the development of new probiotics and prebiotics for different health-related conditions associated with the gut which is much needed for non-western populations," Sharma said.