There is an unravelling complex relationship between our gut and immunity. The interactions between our gut bacteria colonies within our intestines determine how well our bodies respond to oxidative stress, illnesses, viruses, and diseases.
Today we’re going to dive a little deeper into the relationship and correlation between our immune system and gut health.
Our immune system is essentially the surveillance system of the body. Just like how a bouncer is at a club! It’s our natural defence mechanism that is supposed to protect the body, organs and healthy tissues from foreign invaders. The immune system’s job is to identify and detect something abnormal and then call in to guard all the natural defence mechanisms!
Before we begin it is important to go over the fundamentals and the importance of our HPA-Axis on the immune system. Now you’re probably thinking HPA-What? Let me explain….
The Hypothalamus-Pituitary-Adrenal (HPA-Axis) organs regulate the fight or flight reaction (sympathetic state) and regulate balance in our body and mind (parasympathetic state). When under chronic stress, any one of these glands can demonstrate dysfunction leading to hindered metabolism and immune system distress.
The fight or flight mode is an active up regulation of stress hormones that puts the body’s metabolism on hold as it focuses on survival and often leads to cravings, increased fat storage and difficulty with weight loss. Rest and Digest mode is focusing on relaxation of the muscles, nerves, blood vessels and promoting surges of digestive enzymes aiding the body’s ability to metabolize, absorb nutrients and effectively burn fuel!
Defining the HPA-Axis
The hypothalamus gland’s primary role is keeping homeostasis (keeping balance through the body). It also plays a role in satiety, regulates body temperature and impacts caloric burn at rest. It also plays a role in our circadian rhythms, sleep cycles, fatigue and thirst regulation!
The pituitary gland plays a significant role on the thyroid which is a major metabolic organ. The pituitary gland releases many hormones that regulate fluid, sexual function, growth, mood instability/anxiety, pain management and caloric burn.
The adrenals are our primary stress agents. They are two shaped walnut glands located above the kidneys that release cortisol and stress chemicals both epinephrine (adrenaline) and norepinephrine. The adrenals also produce DHEA which is a hormone-building precursor for estrogen and testosterone that aids in stress resilience.
Immune and Gut Relationship
We can look at the immune system in two ways; over-reactive and under-reactive and in both of these states our immune system is out-of-balance. Why does this happen? It becomes out of balance when glands from our HPA-axis stop working synergistically. It can also occur when there is an excess or too little of cortisol in the body, when our natural production of feel-good neurotransmitters are hindered and due to poor food choices/ overconsumption of inflammatory foods.
When the immune system is in overdrive our bodies are starting to overact. An overactive immune system can lead to many autoimmune disorders and cases of chronic inflammation. The body has a hard time detecting or can’t tell the difference between your healthy normal cells versus invaders. In essence, your immune system turns against you. On the other hand, we can be under-reactive. This means the surveillance system has shut down. This is where we would be more susceptible to things like the cold, flu, viruses, and unwanted things like cancer.
Almost 70% of our immune system is in our gut! The reason why their interactions are so important is that “our immune system has co-evolved along with a diverse gut flora, not only to create defenses against pathogens, but also to develop tolerance for beneficial microbes. Consequently, the immune system and the gut microbiota developed a mutualistic relationship, regulating one another and cooperating to support each other. The dialogue between the immune system and the microbiota starts the moment our body gets in contact with microbes—at birth. As we grow, the microbiota shapes the development of our immune system, and the immune system shapes the composition of the microbiota” states the website Neurohacker.
Therefore, a healthy interaction between our gut microbes and our immune system is crucial for the maintenance of homeostasis. Imbalances in the gut may cause immune dysfunction and dysregulated immune responses and lead to the development of chronic inflammation and autoimmune diseases.