Jennifer Lovejoy, Arivale Chief Science Officer, PhD
The human body harbors more bacterial cells than human cells, and they live in vastly different, but equally vibrant ecosystems throughout our bodies. Comforting thought, right? It should be. Most of these microbes are actually good for us and incredibly important for our overall health.
Together, these different communities of bacteria are known as microbiomes. Our bodies have several microbiomes, each distinct and quite unlike the next. (To put it in perspective, your gut and oral microbiomes are about as similar as prairie and ocean microbiomes.)
Your body’s largest, most complex, and arguably most important microbiome resides in your gut.
While research on the gut microbiome is still new and evolving, scientists are beginning to see how the health of our gut’s ecosystems affects just about everything—from our metabolism to our immune system to our risk for diseases.
The Gut Microbiome, Explained
Your gut microbiome is the community of bacteria, fungi, viruses, and archaea that reside in your gastrointestinal tract, or your gut.
Throughout the gut, you’ll find many smaller ecosystems unique to their specific habitat. For example, certain species that thrive in your esophagus might not be able to survive in your highly acidic stomach. The gut’s biggest ecosystem lives in your large intestine, or colon.
For us visual learners, NPR has a great video that explains more about the gut microbiome’s importance for our overall health.
The Gut Microbiome’s Importance
Why is the gut microbiome more important than say, your skin microbiome?
While the skin microbiome can affect things like acne and even your attractiveness to mosquitos, it doesn’t necessarily impact things system-wide like metabolism or the immune system. In contrast, the gut permeates everywhere. How? Your blood is filled with metabolites, which travel throughout your body impacting many things including your heart health, your risk for certain diseases, your inflammatory response, and even your mood. Many of the metabolites in your blood are produced by your gut microbiome.
Impact on Immune System
The gut microbiome is especially important for our immune system. Remember, much of the bacteria in our gut are “good” germs and are crucial to our immune system.
As we grow up and our gut microbiome develops, its microbes basically function as our immune system’s favorite teacher. As the gut exposes us to new forms of bacteria, our immune system learns to identify the “good” germs it should leave alone and the “bad” germs it should attack. This takes time and exposure to the world’s many kinds of germs. So put away the hand sanitizer and let your kids play in the dirt. It’s good for them.
As our gut microbiome continues to diversify, the various species also keep each other in check. When there’s an overgrowth of one species, we run into problems. For example, while streptococcus or “strep” bacteria exists throughout our microbiomes, when too much builds up the throat, our immune system starts attacking the take-over causing the unpleasant symptoms of “strep throat.” Antibiotics easily combat overgrowth, though they also wipe out much of the good bacteria keeping the peace elsewhere.
Impact on Disease Risk
No two gut microbiomes are alike, and there’s still not a lot known about how these differences impact our health. But when it comes to the gut microbiome’s impact on disease, researchers are already finding interesting patterns.
In almost every study on the gut microbiome and disease, there were differences in the gut microbiome compositions of people with and without a disease. This was consistent, no matter what disease researchers were studying. The big question remains whether or not these differences are caused by the disease or are causing the disease, or some combination of the two.
Scientists still have a hard time defining what a “healthy” gut microbiome looks like. The differences in healthy individuals are still huge, making it difficult to identify the disease culprits just yet.
Research Into the Gut Microbiome
As we explained earlier, research around the gut microbiome is relatively new and evolving. Though scientists have long known it was important, until recently, there wasn’t a good way to profile or quantify an individual’s gut microbiome composition in order to study it.
With the invention and ever-lowering cost of genome sequencing, we can now profile a gut microbiome by sequencing the bacterial DNA. This new technology is allowing researchers to look for ways the gut microbiome can help us prevent, detect, and possibly even treat many common and rare diseases.
Science isn’t there yet, but that’s where it’s headed … full steam ahead. Stay tuned.