We are not alone.
Since the beginning of human existence we’ve been in a complex dance with the microbial world. Thanks to new technology we now understand that our lives and theirs are crucially and intimately bound together.
“Whether you have balanced, well fed gut bacteria that positively affect your health, or poorly fed, unhealthy bacteria that make you sick, it’s not a stretch to say: “You are what THEY eat.”
Human beings contain an astonishing ten trillion cells, but we host ten times that amount of microbes. That’s 100 trillion! Further, for every one of our genes, we contain one hundred microbial genes.
We are seemingly more microbial than human.
The microbes living inside of us have been called “our hidden organ.” They’ve also been referred to as “our second genome.”
This simultaneous, entwined existence leads to the idea that we don’t contain a single human genome. Rather we have a meta-genome, a combined genome of our own and our microbes’ genetic material.
Most populous and most influential to our health are our gut microbes. A diverse array of gut microorganisms performs multiple functions and evolves more quickly than we can, giving us resiliency to changing environments.
For those gut microbes to live, they must be fed. Whether you have balanced, well fed gut bacteria that positively affect your health, or poorly fed, unhealthy bacteria that make you sick, it’s not a stretch to say: “You are what THEY eat.
Here’s how it works.
We absorb most of our food in the small intestine. What we’re not able to absorb goes to the large intestine, and here, the microbes ‘eat’ (ferment) what we can’t.
The foods that best promote the growth of healthy gut bacteria are non-digestible carbohydrates. That includes fiber, lignin, and complex chains of sugars and resistant starch. These are widely distributed in the plant kingdom: fruits, vegetable, beans, legumes, nuts seeds, and whole grains.
Prebiotic supplements contain this optimal microbial food source, but relying on fiber bars or supplements is less beneficial than eating a diversity of these compounds via whole plant foods.
The goal is to support a variety of beneficial microbial populations rather than relying on one habitual source. We’ve learned that a diversity of gut bacteria is key to health. In fact many disease states are specifically marked by the loss of diversity. A multiplicity of bacteria produces a multiplicity of beneficial compounds and promotes healthy immune and nervous systems.
Unfortunately, the common American diet only feeds the small intestine. A diet limited to fat, protein and simple carbohydrates is easily digested by the small intestine, but it leaves beneficial bacteria with no food to ferment and actually promotes a disease-state. Some of these bacteria then make harmful products that can cause cellular damage and disrupt the complex immune, nervous, and metabolic systems in the body.
The role these bacteria perform in our health is monumental. New research is being added to this understanding daily. These bacteria make or activate vitamins, produce anti-cancer molecules, modulate blood sugar, and have hundreds of other beneficial effects.
It may be that the main reason eating lots of fruits, vegetables, beans, and whole grains is good for us, is because it is good for Them.
Dr. Sally Fisher specializes in evidence-based integrative and nutritional medicine and is Sunrise Springs’ Medical Director.