When you think of the immune system, do you also think about the gastrointestinal (GI) tract? Usually not, but little do most of us know that the GI tract and the immune system are heavily related. Our gut wall is home to 70% of the immune cells in our body, which is why in functional medicine we focus so heavily on gut health and restoration.
In our gut, we have this unique and vital ecosystem known as the microbiome. It has gotten a ton of attention in the past few years and there are many great studies presenting more and more about our microbiome and its importance in overall health.
When you try to envision the microbiome, think about it like a coral reef, or a bustling city, something that is made up of many integral parts working together synergistically in its own ecosystem. The Microbiome consists of 100 trillion microorganisms and thousands of different species that coexist together. The microbiome is incredibly biodiverse, so much so, that no two people have the same microbiome.
Our microbiome is influenced by many factors and changes throughout our lifetime. For a healthy microbiome, we want richness and diversity in the number of organisms and the different species that are present. There is a certain balance here that can affect our overall health and wellness.
The day to day activity of these microbes plays a key role in immunoregulation. Martin Blaser, MD and author of Missing Microbes: How the overuse of antibiotics is fueling our modern plagues, states, “It is reasonable to propose that the composition of the microbiome and its activities are involved in most, if not all, of the biological processes that constitute human health and disease.”
A healthy immune system is one that is ready to act but is not overstimulated, it is known as “tolerant”. Our immune system balances our microbiome and our microbiome balances our immune system, they work synergistically with one another.
When our microbiome is imbalanced or disrupted we refer to this as dysbiosis. Think about it as too many bad organisms, not enough good organisms, or good organisms living and multiplying in the wrong place. The example here is Small Intestine Bacterial Overgrowth or SIBO for short. Dysbiosis has many causes including poor diet and stress management, genetics, early colonization of bacteria including whether you were born vaginally or via cesarean section vs breastfed or bottle-fed, overuse of antibiotics, overall hygiene level and certain diseases. The problem with dysbiosis is that it can lead to immunosuppression or activation, both of which are a problem, unwanted inflammation, and increased intestinal permeability or “leaky gut”.
Our gut lining/barrier acts as a physiological barrier between our immune system and our microbiome. We need this barrier for them to work synergistically and to stay healthy overall. When our gut barrier is breached, it can lead to a whole host of diseases such as autoimmune disease, allergies, obesity, and Inflammatory Bowel Disease.