Gut-Brain Axis: The Ultimate Communication Channel – Part 1

Written by Anil Bajnath, MD
Posted February 9, 2021

Dear Longevity Insider,

Ever wonder what causes "gut feelings" and "butterflies" in your stomach?

Or why your stomach gets upset when you’re worried or fearful? There is an elaborate and intriguing system in our bodies that connects and communicates without any effort on our part!

Our microscopic friends

In a previous article, we pointed out that your unique microbiome is so important that it is considered a hidden organ by some researchers. It started as soon as you were born, if not before, and is continually influenced by your diet, your experiences, what you’ve been exposed to and where you live. We also illustrated how vital it is to keep your microbiome healthy, and what can happen when this community of microorganisms gets tipped out of balance.

We depend on these complex social networks of microorganisms to help break down nutrients and produce important vitamins and enzymes in our digestive system, which in turn strengthens our immune system. And although it might seem strange, it has been shown that our microbiome is intricately linked to our central nervous system (CNS) through neural, hormonal, metabolic, and immunological signaling pathways.

Another brain?

Just as fascinating is that hidden in the walls of our digestive systems is our enteric nervous system (ENS), referred to as the "second brain," due to its ability to operate independently of the central nervous system. While researchers are still learning exactly how the ENS works and the full extent of its functions, we do know that the ENS plays a significant role in disease and mental health.

The main role of the ENS is to control digestion from start to finish. But because of its ability to also communicate with our brain through the central nervous system and autonomic nervous system (ANS), researchers are now finding that people with gastrointestinal symptoms may experience mood changes as a result. We outlined the ANS and its two branches, the sympathetic and parasympathetic nervous systems, in our last article on stress.

Our communication channel

Our microbiome, central nervous system, autonomic nervous system, enteric nervous system, immunological and neuroendocrine systems all interact to comprise what’s called our gut-brain axis. An essential role of this multidirectional interaction is to help the body maintain metabolic homeostasis.

Signals are sent back and forth between the gut and the CNS, which causes the hypothalamus and brain stem to regulate how your body consumes and uses energy. In addition, since roughly 70% of our immune system is in our gut, the gut-brain axis also allows our brain to monitor the interactions taking place between our immune cells and our microbes, hormones, and neuronal cells in our gut so it can respond to changes if needed.

Our multi-tasking wonder nerve

A special and significant part of our parasympathetic nervous system, and ultimately our gut-brain axis, is the vagus nerve. On page 165 in my book, The Longevity Equation, I mention that “The vagus nerve is the longest cranial nerve in the body. It runs through the brain stem, esophagus, lungs, heart, digestive tract, and all the way down to the colon.” 

When we are not stressed, the vagus nerve serves as a communication superhighway, sending sensory information from the peripheral system to the brain so it can monitor function, and transmitting motor signals from the brain to the rest of the body.

The vagus nerve has immunomodulatory properties, and, therefore ,it “plays important roles in the relationship between the gut, the brain, and inflammation.” It stimulates muscles in the heart, almost like a natural pacemaker, where it helps to lower resting heart rate. In the gut, the vagus nerve can even let our brains know the status of our microbiome!

A healthy vagus nerve helps us to access parts of the brain responsible for creativity, higher cognition, and complex decision making. As you can see, this nerve has a critical place in our bodies, affecting our thoughts, many internal organs, and our gastrointestinal system. Some say it is the key to our well-being.

On Thursday, let's uncover what all of this means and how you can restore the gut-brain axis.

To your longevity,

Anil Bajnath MD
CEO/Founder, Institute for Human Optimization
Chief Medical Officer, Longevity Insider HQ