What? Do we have a second brain?
Yes, you read that right. Your gut has a brain of its own!
Have you ever experienced changes in your mood after having your favourite meal? Or sensed butterflies in your stomach when you are too excited or anxious? Also, you must have noticed how your tummy rumbles when you are hungry and your mouth waters just by the sight of your favourite food.
Well, these are not merely illusions created by your mind. Science is now catching up to reveal what might be causing these sensations in your stomach. There exists a bidirectional communication system between your brain and your gut. This is termed as the Gut-Brain Axis (GBA). In simple terms, GBA is the communication network that connects your gut to your brain. Thus, our gut has a direct influence on our brain and vice versa.
What causes this bi-directional communication to occur?
Well, perhaps a better question would be – who causes this bidirectional communication to occur? And the answer lies in the trillions of microbial cells (even outnumbering our own human cells), collectively known as the Human Microbiota. The human gut microbiota forms an essential component of human gut. It has been reported that the gut microbiota composition of an individual considerably influences how their brain functions, thereby creating an impact on the overall health.
You might think, how can a microbe send and even receive signals? Well, let’s dive into the basics to understand this.
Neurons, the cells present in your Central Nervous System (Brain), instruct your body how to behave by sending and receiving information to and from all parts of the body. The human brain is thought to have approximately 100 billion such neurons. Interestingly, 500 million neurons are found to be present in the ‘Gastro-Intestinal Tract’ or gut. These neurons connect the gut to the brain, through nerves present in your nervous system. This is specifically termed as the Enteric Nervous System (ENS). In other words, it is the nervous system of the gut. One of the biggest nerves of ENS that connects the brain and the gut physically as well as biochemically is the Vagus Nerve. It has the ability to send signals in both directions at the same time. The ends of the Vagus nerves that are spread on to the gut wall can sense certain chemicals called ‘Neurotransmitters’ and ‘Hormones’. These form chemical connections between the brain and the body parts.
Interesting! Isn’t it? Voila! Now it must be clear how the gut and the brain swap messages.
But what do they talk about? And is it important?
The gut wall encloses a complex environment and contains millions of neurons, hormone producing cells (endocrine cells) and most of our immune cells. That being so, the gut becomes central to hormone production and a place where most of the body reactions ensue. The gut, being the part of our digestive system is also involved in digestion of food and absorption of nutrients. While this is happening, the brain on the other hand, needs to direct and co-ordinate the sequence of activities taking place there. Accordingly, the brain and gut continuously exchange information and influence each other’s performances.
What’s the role of gut microbiota then?
Well, most of the hormones and neurotransmitters are made in the gastro-intestinal tract by the gut microbiota. For example, the neurotransmitter called gamma-aminobutyric acid (GABA) produced by gut microbes is the main regulator of emotions such as fear and anxiety. Similarly, several neurotransmitters like serotonin, dopamine, norepinephrine, acetylcholine etc. that communicate with the brain to stimulate and regulate other set of emotions are also produced by the gut microbiota.
Profuse right!!
We will reflect over these compounds and their cycle of production and regulation in our upcoming articles.
Disclaimer: The content of this article is meant for educational and creative purposes only, and will not be directly used for generation of profits. All rights and responsibilities, including the authenticity of the information presented in this article belong to the original authors and their publications (listed below in the Bibliography section), and there is no copyright infringement intended.
Bibliography
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