When people ask how to have a healthy immune system, what they typically are looking for is a pill or supplement, something they can add to a smoothie, a food item, or behavior that will give them the security that, Ah, now I have a healthy immune system. But before we can identify what will support healthy immune function, I think it is worthwhile to understand what a healthy immune system looks like.
Typically, what people want is to be exposed to a virus and to have no symptoms. They blame their symptoms on the “bug” or the disease. That miserable, run down feeling, the sinus congestion, runny nose, fever, exhaustion, pain, cough, etc. are the symptoms people complain about and want to avoid. We’re miserable and may wonder, Why isn’t my immune system working?! The truth is, that is your immune system working. Your symptoms are actually a sign that your body is fighting back against the infection or virus. Your immune response is triggered and being expressed as those symptoms.
We refer to the immune system like it is an isolated function of the body, but it’s not. The immune system does not function independently. Rather, it is inseparably and intimately connected to other systems such as the endocrine system, nervous system, and the community of microbes that live within us. In fact it is argued that the immune system would cease to function without the microbiota. In essence, they are part of the same working crew, as we will see. What scientists have discovered is that the microbes of our body are the eyes and ears of the immune system.
When we think of who we are, we think well I’m human of course, made up of human cells, human DNA. But the composition of the human body is in actuality more microbe than human. That is who we are. It is not a them–and–us situation, as the two are really one.
The immune system would cease to exist or function without the microbiome. Consider that one of the roles of the immune system is to monitor microbes. Whether we are talking about the common cold or the coronavirus, we want the immune system to take care of these invaders in short order. But there is a problem. There are trillions of microbes all over the place inside our bodies. How does our immune system know which ones are a part of us and which ones are enemies? The amazing thing is, it often doesn’t know. Research has been conducted with mice who have no microbiome, no bacteria, or other microbes living in or upon them. When these germ-free mice are exposed to a virus, their immune system is dormant, inactive, and useless in recognizing terrorists. It would be like the TSA not recognizing the difference between a curling iron and a firearm, and allowing anyone and everything through.
Allow me to dramatize a potential scenario. A dangerous virus is inhaled. It lands safely on the warm, moist mucosal lining of my lungs where it can potentially rapidly establish itself. There is not an immune cell in sight. Surrounding commensal bacteria—which are bacteria that are a part of me—sense the newcomer as not one of us. It relays messages to the central command center in the gut where the vast majority of microbes live. The alert is received and the microbial commanding officers produce communicating molecules that inform the surrounding immune cells to dispatch troops to the lungs immediately. Meanwhile, the local lung bacteria have been doing their part to directly inhibit the growth of respiratory pathogens by directly launching ammunition against the invaders and competing for nutrients and property.[1]
Whew! Who would’ve known how involved microbes are in defending us? God did. It’s His design, after all. Thankfully, He did not leave us without an owner’s manual. His Word says, “God composed the body having given greater honor to that part which lacks it, that there should be no schism in the body, but that the members should have the same care for one another” 1 Corinthians 12:24.
[1] Khan, R., Petersen, F. C., & Shekhar, S. (2019). Commensal Bacteria: An Emerging Player in Defense Against Respiratory Pathogens. Frontiers in Immunology, 10, 1203.
