The Dirt on Gut & Soil Health

Written by Emily Spiegelman

It can be hard to understand or care much about things we cannot see with the naked eye. That’s just human nature. It’s curious to note that, at the time of writing this, major news and culture outlets are awash with posts about gut health. You’ve probably encountered evidence of our growing obsession with the trillions of microscopic organisms that dwell in our digestive tract on grocery store shelves lined with foods and beverages touting “live cultures” and “probiotics.”

Scientific studies reveal that gut health can affect everything from digestion to quality of sleep, memory, and immunity. Though there’s still much we don’t know about our gut flora, the evidence is indisputable: A gut microbiome made up of a wide range of microorganisms is good for you. And what you eat can make a difference in the health of your gut—for better or worse. In fact, a recent study revealed that what participants ate “had a more powerful effect on the makeup of their microbiome than their genes.” That’s right: What you eat could play a bigger role in your gut health than your genetic makeup—another deeply compelling reason to care a lot about what we eat and what feeds our food.

In much the same way that we’re learning about the gut microbiome and human wellness, the agricultural community is discovering a connection between microorganisms in the soil and the health of everything that depends upon that soil—and what happens when that connection is severed.

To put it simply, plants and soil microorganisms need each other. Plant roots secrete a sugary substance that feeds a diverse array of bacteria and fungi, which in turn attract predatory microorganisms. As these miniscule predators consume the bacteria and fungi, they produce waste containing an abundance of nutrients that are now available in plant-soluble form. Think of it as the Poop Loop! Bacteria and fungi also produce “glues” that help aggregate soil particles that hold water and nutrients, making them available for plants. This symbiotic relationship is even more powerful when we think about the incredible root systems of native prairie plants. Those vast root systems (which sometimes grow to a depth of 15 feet!)—and the microbes that depend on them—are part of what makes this prairie landscape, when untouched by plows and annual cropping, so fertile and resilient against flooding and drought. 

Buffalo are an essential piece of this microbial puzzle. As a keystone species of the Great Plains, buffalo evolved to eat these prairie plants, moving over the landscape in a way that encourages new plant growth without overgrazing. And because they’re ruminants, their own gut microbiomes allow them to derive energy from the compounds abundant in plants’ cell walls. This marvel of fermentation on four legs then returns a microbe-rich manure to the prairie soil, a pivotal ingredient in keeping the circle of soil life intact.

We may not be able to see microbes with the naked eye, but the devastating ripple effects of the broken link between soil health and human health are painfully clear. Our investment in monoculture—growing annual crops such as corn, wheat, and soy (the latter two of which are key ingredients in today’s plant-based meats)—rather than a diversity of plants has allowed crop-specific disease and pests to flourish. Herbicides, fungicides, and genetically modified crops used to control those pests and plant pathogens may have permitted the continuous cultivation of annual crops (grown mostly to feed animals in confinement), but in the process, they’ve sterilized the soil by wildly upsetting the balance of microbial life. The plow—that historic symbol of productivity and progress—is an instrument of death and destruction for soil microbes. Tillage does more than loosen the soil. It breaks up soil aggregates, the porous particles that allow air and water to penetrate deep into the ground to nourish the massive, carbon-sequestering root systems of native plants. It compacts the earth, making it difficult for plant roots to grow and for soil microbes to live. Without live plant roots, fungi and microbes starve. Without fungi and microbes, plants that do grow simply can’t absorb the nutrients they need. As a result, what we grow and eat is significantly less nutritious. 

The good news is, just as we can influence the health of our own guts by changing what we eat, we can affect the health of our soil by supporting food producers whose practices restore, rather than deplete, the tiny organisms so vital to all of us.

Bringing the buffalo back to the Great Plains, following a large-landscape grazing model designed to let the buffalo live as closely as possible to what nature intended, is about more than just the label of “grass-fed meat.” Our buffalo meat is the happy by-product, not the end product, of our efforts to repair what modern agricultural practices have done to the earth and to our health. Wild Idea founder Dan O’Brien writes in his book Great Plains Bison, “My family and I are not crop farmers. We produce completely grass-fed buffalo, so we are farmers of grass.” If “grass-fed” is really supposed to mean something when it comes to the meat we eat, then the health of the soil that grass grows in is crucial.

Photos: Jill O'Brien / 1st, 2nd, and Vieo / Graphic - NRCS
Reference Sources: https://www.nytimes.com/2021/01/11/well/eat/diet-gut-microbiome.html 
https://www.bbc.com/future/bespoke/follow-the-food/why-modern-food-lost-its-nutrients/