When we eat, the food moves into the gut, where millions of tiny single-celled organisms help break it down and absorb nutrients. These unicellular organisms, known as microbes, are present in incredibly large numbers.
One mindblowing fact about microbes is that our gut is home to trillions of microbes. This entire ‘gut-universe’ is constructed by the symbiotic relationship spanning millions of years that primarily benefits us. Research showed that it not only affects our digestion but also other systems.
Gut microbes are also linked to our immunity, mental health, genetics and other body systems. And hence, it is believed that food rich in good bacteria is good for our gut health.
Humanity’s thousands of years of practice of eating fermented food actually means to strengthen gut microbial health.
For instance, yogurt, a common Indian ‘Dahi’, is good for digestion, even our mothers and their mothers know this. And we all know that. However, a recent study by an Indian scientist shows that fermented food doesn’t always support our gut health in all seasons.
This is the story of Dr. Kumaraswamy Jeyaram and his extensive research on fermented food and its significance.
Key Topics:
Meet the Scientist:
Dr. Kumaraswamy Jeyaram is a scientist-F at the Regional Centre of the Institute of Bioresources and Sustainable Development (IBSD), Gangtok, Sikkim, India. He completed his PhD in Biotechnology from Tamil Nadu Agricultural University.
However, his love for microbes encouraged him to go one step further. In 2012, he joined the Laboratory of Microbiology, Wageningen University, The Netherlands, for his postdoctoral research.
After returning to India, he joined IBSD. He also won various national awards, including the Dr. S. K. Ballal award and the Dr. Gurudev S. Khush award for the best student in Biotechnology during his PhD.
He is also a lifetime member of BRSI- Biotech Research Society of India and PAi- Probiotic Association of India. As per Google Scholar, he has published 51 peer-reviewed articles in national and international journals.
Dr. Kumaraswamy Jeyaram is highly interested in understanding the microbial ecology of traditional fermented food and beverages, particularly in North India.
His groundbreaking research:
India’s North-East is home to fermented food and beverages. Including the popular Indian fermented milk- Dahi (yogurt) and butter milk, fermented soybean products- tungrumbai, Hawaijar, fermented fish- ngari and other products, which are very popular in this part of India.
Dr. Kumaraswamy Jeyaram is deeply interested in understanding whether these food products and beverages are indeed beneficial to our gut health. He understood the cultural impact of food choices, beliefs and rituals around fermented food, and started his fascinating research endeavor at the Regional Centre of the Institute of Bioresources and Sustainable Development (IBSD), Gangtok, Sikkim, India.
His research, entitled “Fermented food affects the seasonal stability of gut bacteria in the Indian rural population,” was published in Nature Communications this January 2025. His team preliminarily focused on the two most prevalent gut microbes – Bifidobacterium and Prevotella.
Related story: Why These Two Genetic Techniques Are Game-Changers in Studying Host-Microbe Interaction.
Techniques Dr. Kumaraswamy Jeyaram used:
The main objective of the present research was to understand the seasonal effect of fermented food on gut health. Dr. Kumaraswamy Jeyaram never compromised on technology. He selected state-of-the-art techniques such as 16S rRNA gene array, quantitative PCR, HITChip, liquid chromatography‐high resolution mass spectrometry (LC-HRMS) and short-chain fatty acid (SCFA) quantification by high-pressure liquid chromatography (HPLC).
This entire and highly technical research project was backed by extensive statistical analysis. Guess what?
The results were actually shocking.
Fermented food doesn’t help gut microbes in all seasons:
The outcomes of this highly ambitious research project were also outstanding, shocking and pathbreaking. Fermented food, which likely contains ‘good bacteria,’ isn’t always beneficial to the gut microbes in all seasons.
Dr. Kumaraswamy Jeyaram and team reported that people who regularly consume fermented foods showed lower bacterial load and diversity. The change was substantial during particular seasons, for instance, summer.
In addition, the imbalance between the two gut microbes, Bifidobacterium and Prevotella, was also notable. It means the load of gut bacteria (Bifidobacterium), the beneficial one, substantially reduces during a particular season. Other outcomes show how this change affects metabolic and health-related traits later on.
Future aspect:
These research outcomes are indeed groundbreaking and meaningful for understanding our culturally rooted dietary habits linked with common beliefs. The present research will significantly help researchers understand the health of people living in rural areas.
It also challenges common dietary recommendations and helps design and advise on personalized diet and nutrition plans.
In addition, the present research also benefits in understanding seasonal diseases and infections and their association with gut microbes and health. He also showed scopes to develop more seasonal probiotics and probiotic supplements.
Further to this, the present research also helps understand the gut microbiota and their link to our genetics and gene expression in a better way.
Next story: From 20,000 Human Genes, This Indian Scientist Found One — And Many More Are Yet to Come.
Wrapping up:
Science is not about challenging our beliefs, rituals and cultural habits; rather, scientists like Dr. Kumaraswamy Jeyaram and their research contributions make them clearer and beneficial.
India needs more scientists like him, who understand our culture and blend science with it to understand it even at a deeper level. We congratulate Dr. Kumaraswamy Jeyaram and team for their outstanding research work.
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Resources: Jeyaram, K., Lahti, L., Tims, S. et al. Fermented foods affect the seasonal stability of gut bacteria in an Indian rural population. Nat Commun 16, 771 (2025). https://doi.org/10.1038/s41467-025-56014-6.
Disclaimer: The information presented in this article is based on publicly available online sources and, when possible, direct communication with the scientist. While every effort has been made to ensure accuracy, Genetic Education does not take responsibility for any errors, misinterpretations, or outdated details. All scientific information is referenced from peer-reviewed research and credible academic publications.
