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A Journey Through My Microbiome: An Immigrant’s Perspective on a Changing Gut


Six years ago, I met my best friend Hannah as a randomly assigned college roommate.

She had driven 200 miles from Indianapolis, Indiana and I had flown 8000 miles from New Delhi, India to arrive at the very same dorm room in St. Louis, Missouri. We had a running joke in our families that we were destined to be in each other’s lives since “India” belongs in “Indiana.” True to this sentiment, I spent every break visiting her home. My community was back in India, so hers became my own.

Hannah (left) and Manasvi (right), pictured at the St. Louis Zoo, the first week they met back in September 2016. (Courtesy of Manasvi Verma)

The stories of our communities are often the stories of our food. Eating Hannah’s favorite meal: her mom’s famous chicken noodle casserole with a side of blueberry muffins, and chocolate chip cookies for dessert, tells me not only the story of her palate, but also that of her childhood. My own palate, of course, tells a different story. When I was growing up, no day was better than when I woke up to the smell of my दादी’s (Dadi or paternal grandmother) कढ़ी (kadhi) brewing in the kitchen. Kadhi is a North Indian dish made of sour yoghurt and gram flour. In my home, it was served with a heap of basmati rice and pickled lemon. The yoghurt had been left to sour over a few days, triggering a bacterial bloom, and yielding the souring lactic acid. It was mixed with a generous amount of gram flour, a host of spices, and cooked over the flame for hours. As a special treat, Dadi would batter fry chopped red onions in gram flour and add them to the piping hot kadhi. The product, a sunshine yellow plate of happiness perfectly balancing sour, spicy, and crunchy, never failed to tickle my tongue and always forced me to reach over for a second helping. I rarely eat kadhi anymore, having moved away from home, but it remains my favorite food.

Kadhi made with Dadi’s recipe. (Courtesy of Manasvi Verma)

Hannah and my favorite meals are windows into our divergent cultures, but they are more than that. They are also windows into our divergent guts. Cooking traditions back home emphasized an array of fiber-rich vegetables, spicy lentils, yoghurt, rice, and rotis. Meat was a luxury, and mangoes were compulsory. The bugs I cultured in my belly reflected what I ate. Each time I munched on something, I fed the bugs that could utilize it. On the other end of the world, Hannah did the same.

Before we met, our microbiomes were worlds apart. Most prominently, Indian guts are often richer in species that can break down complex plant-based fibers, mirroring our fiber-heavy diets. Factors such as diet and lifestyle influence which microbes thrive, and which perish. Some would argue that we can alter our own gut microbiomes just like moving around the sliders in a video game: Diversify diets! Fewer antibiotics! More exercise! Thus, the onus of building a healthy gut appears to be on the individual; if we follow the right recommendations, our gut will simply build itself. However, rarely is anything as uncomplicated as that.

Living in the U.S., I am much more likely to eat casserole than kadhi. Consequently, my microbial community now likely looks a lot more like Hannah’s. A fascinating study published in Cell in 2018 highlighted that US immigrants from Thailand witnessed drastic shifts in their resident microbial species within a matter of months, resulting in lost microbial diversity, and a specific loss of fiber-degrading microbes, the very bugs that are missing from Western microbiomes. This gets worse with obesity, and is compounded by generations.

So why not just make kadhi and restore those lost bugs? It is not that I do not know how to, or do not want to make kadhi. It is because moving to the U.S. has changed how I access food. Often, locating traditionally Indian ingredients (if they’re even available) takes a lot more effort than I can afford. I must balance my desire for kadhi with the time taken to travel often to city outskirts to obtain the ingredients, the financial cost of renting a car, paying for gas, and eventually affording the necessary ingredients.

The concept of “food deserts” is nothing new, but it’s more accurate to understand the phenomenon as “food apartheid”: a complex and intentional web of policy decisions and economic practices that lead to poor people of color disproportionately lacking access to affordable and nutritious food. In St. Louis, Black residents are in one measure 3.6 times as likely as white residents to live in census tracts where the poverty rate is over 20% and the closest grocery store is at least one mile away. This does not account for the fact that car-centric infrastructure prevents car-less residents like myself from accessing some grocery stores even if they are less than a mile away: the grocery store may be on the other side of a highway, there are no buses or sidewalks or ramps so we could get there safely and back, or just like this summer, it is just too hot and humid to be outdoors for an extended period of time without shade.

When our health deteriorates, we consult scientific recommendations because science should have the answers for how to host a healthy gut. But diet is sociological, impacted by culture and by cost, and science often shies away from society. What we are left with is a set of seemingly neutral dietary guidelines that function under the assumption that access to all foods is equal.

The high barriers of time, effort, and affordability involved in cooking meals from our home countries in the U.S. veer many immigrant diets to commonly available Western options. A 2020 survey of immigrant communities in Massachusetts, where I now live and study, found that 59% of households experienced food insecurity. If we look at households that have at least one undocumented family member, that statistic climbs to 78%. In the U.S., there has been a significant association between household income and the nutritional quality of food people purchase and subsequently their microbial diversity.

Census tracts with low-income and low access to a supermarket or a large grocery store in the Greater St. Louis metro area in 2019. (Courtesy of East-West Gateway Council of Governments)

And it’s not as if low-income Americans, who are disproportionately immigrants, are not trying to do the right thing: the U.S. Department of Agriculture (USDA) was prompted to reevaluate their Thrifty Food Plan (TFP), which serves as the basis for Supplemental Nutrition Assistance Program (SNAP) benefit allotments for low-income families, after their previous update in 2006 received criticism for failing to balance taste, convenience, variety, and societal norms. The USDA itself acknowledged that one of the main goals of the most recent TFP in 2021 was to accurately reflect the “diversity of food pathways” in the country, such as the need for us immigrants to purchase herbs and spices that form the backbone of our cuisines.

For immigrants, the inevitability of dietary acculturation is compounded by socioeconomic status. Ultimately, we change our diets, our microbes, and our guts. So, are there consequences to the Westernization of our gut microbiota? Public health statistics point to a yes. Microbial dysbiosis, a tipping of the microbial balance in our guts, is linked with an array of chronic health conditions including cardiovascular disease and Type 2 diabetes. The difference between non-immigrant and immigrant health outcomes hints at this microbial dissonance. In fact, it is understood that immigrants have a lowered risk for cardiovascular disease, hypertension, and diabetes before they touch U.S. borders. These risk factors tend to increase with time in the U.S. For Indians specifically, studies show that native, non-migrant communities still residing within India as well as in the Indian subcontinent have reportedly lower risk of coronary heart disease than their counterparts that migrated to the West. So, with time in the U.S., where dietary fibers are uncommon and processed food is king, our diets change, our microbes change, and consequently our health takes a turn for the worse.

When our health deteriorates, we consult scientific recommendations because science should have the answers for how to host a healthy gut. But diet is sociological, impacted by culture and by cost, and science often shies away from society. What we are left with is a set of seemingly neutral dietary guidelines that function under the assumption that access to all foods is equal. Because, in theory, even though this isn’t settled science, we do know that a healthy gut needs high fiber, low sugar, and increased fermentation. But, in practice, this notion of a healthy gut is not so easy for everyone to nurture.

Our food, our microbes, and our guts link all of us. With this realization, we can finally transfer the onus of building a healthy gut from the individual to the collective.

Once we realize that building a healthy gut is more than a simple biological problem, we can overcome the ever-frustrating barrage of self-help tips: grow your own vegetables, cut out red meat, be sure to walk right past the processed foods aisle in the grocery store, ferment some kombucha, skip the carbonated soda and all will be well. Then, we must really think about how to emphasize the importance of the gut microbiota without downplaying all the sociological factors that go into creating it. What kind of societal changes do we need before we can simply recommend gut-healthy foods? In the face of widening inequities, how can we describe gut microbiome research in a culturally conscious way?

Our food, our microbes, and our guts link all of us. With this realization, we can finally transfer the onus of building a healthy gut from the individual to the collective. A one-size-fits-all approach will not only be unsuccessful in improving public gut health but will only make inequalities worse. As the gut microbiome field blooms, we will continue to learn more about how our microbes influence our health, and the internet will continue to plague us with ways to hack our gut. It is up to us to know that our health is our own, and no single “hack” is going to transform it. On an individual level, we can do a lot: let go of our guilt and celebrate the blooming diversity of food that grounds us to our diverse cultures, in addition to supporting local food pantries, mom-and-pop grocery stores, and urban farms. Meanwhile, we must hold scientists and policymakers accountable to enable systemic-level change. The true revolution for equitable microbial health hinges on realizing the intersectionality of our health, practicing intentional social medicine, and remembering the complicated ways in which we are shaped by our interactions with the world.

As I moved across the globe, my microbiome changed in ways that I could not control. My microbiome tells my story of change, resilience, and integration into new communities. Now that Hannah is in my life, that story is different, it is better. Now it tells not just the story of kadhi but also that of chicken noodle casserole.

Manasvi and Hannah in a June 2023 gathering. (Courtesy of Manasvi Verma)


This piece was inspired by and is dedicated to my Dadi. Dadi, you were always a joyous, vibrant, almost boisterous cheerleader for me. Wherever you are now, I hope you know that I deeply miss you and your kadhi. Rest in infinite power and endless peace.


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Manasvi Verma

Manasvi grew up in New Delhi, and moved half-way across the world to St. Louis, Missouri to get her bachelor’s degree at Washington University in St. Louis where she majored in Biology with minors in Biomedical Physics and Gender Studies. She is now a Ph.D. candidate at Harvard University studying how gut microbes communicate with human cells.

When free of pipette, she can be found with a metaphorical pen. Passionate about science communication, she writes for WOWSTEM and MicroBites and is an organizer for ComSciCon’s Flagship Workshop. She is specifically interested in bridging the gap between science and the individuals that do the science.

When she puts down the pipette and the pen, she loves exploring Boston and its plethora of coffee shops, traveling, listening to live music, finding her way to bodies of water, and watching way too much Netflix.

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