Studies across the globe have linked intestinal microbes with protection from diseases; India may be sitting on a mine of information
THERE IS a surge across the world in studies on human microbiome — the community of microorganisms, mostly bacteria, that lives in intestines. Gut microbiome is essential for digestion, nutrition, immune system maturation and the overall health of an individual, and there have been several studies that link changes in gut flora with almost all major diseases.
Sample these: A study published online in Clinical Gastroenterology and Hepatology, the clinical practical journal of the American Gastroenterological Association, in October 2018 says that gut bacteria have an impact on an individual’s brain. It finds that there is a communication channel with neural, endocrine and inflammatory mechanisms between a person’s gut and brain. A major part of this channel gets established in the first three years of life but can get influenced later by diet, medication and stress.
Another study, published online in the same journal in July 2018, says that environmental conditions affect the health of the microbiome which can, in turn, lead to colorectal cancer. Alterations in the microbiome induce changes in the expression of genes, the process of metabolism and the immune response of an individual. All these are crucial for the development and propagation of the cancer.
Another report published in a supplement of Nature in March 2018 says that poor gut health of a baby can be linked with the onset of diseases like diabetes later in life. It says that without the microorganisms that are transferred from a mother to her newborn and the ones that it picks up after birth, the baby’s very survival could be in jeopardy.
The second genome
The high variability in the composition and characteristics of gut microbiome — which vary on the basis of age, gender, genetics, diets and environmental conditions — have led experts to call gut microbiome the second human genome. Owing to India’s ethnic and geographical diversity, the gut flora of the people here should be a mine of information. Studies have also indicated that microbiomes of different communities are different and the effectiveness of therapies depends on knowing the unique gut bacteria profile of the individual. But little is known about the gut microflora of Indians. The most expansive research on Indian gut microbiome, published in October 2018 in Nature, found 993 microorganisms unique to the Indian population. The researchers studied 1,004 individuals in 18 geographical locations across the major regions of the country. It shows the high diversity of gut flora in the Indian population.
Such differences are crucial because even within the country there are differences that need to be understood. For example, a paper published in Nature in July 2018, talks about gut microbiomes in people living in rural and urban areas of Ballabhgarh in Haryana and Leh and Ladakh regions of Jammu and Kashmir. It says that the gut bacteria of people in high altitude regions like Leh have less diversity but a greater number of beneficial anti-inflammatory bacteria as compared to the people living in the plains. It also says that the gut microbiomes of people in rural areas are much more diverse and similar to each other as compared to people living in urban areas.
This understanding can help in identifying ideal subject donor for faecal microbiome transplants which are now picking up pace in India. “The ideal donor should have minimum number of inflammatory bacteria which was seen in the people of rural Leh,” says Bhabatosh Das, lead author of the paper and senior scientist at the Translational Health Science and Technology Institute, Faridabad, Haryana. Das’ group is now working on isolating indigenous Indian probiotic bacteria from gut, vaginal and stomach samples. The lack of knowledge of indigenous probiotic bacteria has led to the Indian market getting flooded with probiotic drinks such as Yakult, based on bacteria from other countries like Japan.
However, research establishments have recently taken steps to address this. The Council of Scientific and Industrial Research (CSIR) is seeking government’s approval to create a representative healthy Indian gut microbiome at a cost of Rs 150 crore. “The project proposal has undergone two rounds of review and is expected to be cleared in the current financial year,” says Yogesh Shouche, lead coordinator of the project and senior microbiologist at the National Centre for Cell Science, Pune.
The project will also involve some ethnic groups in the tribal areas which have not been exposed to modern lifestyles and environments. Studying their microbiomes will throw light on what an Indian microbiome would look like without the impacts that the modern world has accorded us.
“Most of the modern human diseases have been linked to human microbiomes, especially the ones present in the human intestines or the gut. The research conducted in the last 10 years has thrown up correlations between various diseases and the microbes in the gut. These include metabolism-related diseases like irritable bowel syndrome, heart disorders and even brain-related diseases like Alzheimer’s and schizophrenia,” says G Rajamohan, senior scientist at the Institute of Microbial Technology, Chandigarh. “The microbiome in the gut could even turn out to be the master regulator that controls diseases or the main switchboard that is controlled by diseases,” Raja-mohan adds.
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