The gut is said to be the "second brain," but it may actually be the "first brain."
Points out the main reasons why the gut is called the 'second brain':
It has its neural network. The gut has around 100 million neurons, second only to the brain.
It has Autonomy. The gut can operate independently without commands from the brain.
The intestine makes its own decisions and controls its autonomic movements.
Digestion, absorption, and excretion carry out important functions. They are essential for the survival of the organism.
The gut and brain are made from the same nerves during development and influence each other through the autonomic nervous system.
It is involved in the production of neurotransmitters. Over 90% of serotonin, which is important for mental states, is produced in the gut.
These characteristics have led to the gut being referred to as a 'second brain', as it is not just a digestive organ but is recognised as an organ with its own 'brain-like' functions.
A)
"Gut stand(I'm angry)," "Fat stomach(generous)," "Stomach decided," "Stomach's bags can't fix(I can't get over it)," "Stomach is black colour(black-hearted)," "Stomach split and speaking(speaking frankly)," "Stomach doesn't fall(it doesn't make sense)"...
We use words that connect the mind (brain) and the stomach (intestines) without realising it. Still, we don't know the connection between the brain and the intestines, and we have only noticed it from experience. Before a public presentation or an exam, we get stomach pains and diarrhoea, and when we travel, we get constipated.
When we worry about going to the toilet, we become irritable, have headaches and insomnia, and our autonomic nervous system becomes unbalanced, causing constipation, diarrhoea and stomach pain, leading to a vicious circle. This condition is commonly referred to as irritable bowel syndrome.
Still, we often go to the doctor and have a colonoscopy, only to be told there is nothing wrong, and then endure it with over-the-counter medications. This is because the brain, the autonomic nervous system, the endocrine system and other systems are all involved, and this relationship is called the brain-gut correlation. In other words, "the gut is a mirror of the mind" and at the same time "the mind is a mirror of the gut".
For this reason, the gut has been called the "second brain," but recently, many findings have been reported suggesting it may actually be the "first brain," we will present some of the most interesting findings here.
B)
1. Our bodies are made up of intestines!
The outside of the fertilised egg is depressed, its opening closes and the "intestine" forms. The intestine stretches to form the "mouth" and the "anus". The 'liver', which stores nutrients, then forms the 'lungs', which store oxygen, and the upper part expands to create the 'brain'. This suggests that the brain evolved as an outpost of the gut.
When the brains of germ-free mice are examined, they have no learning ability, are passive and behave recklessly. Without gut bacteria, the brain cannot develop.
Similarly, in the evolutionary process, there are creatures without brains but no creatures without guts. Jellyfish and sea anemones have guts but no brains. In the evolution of living things, the intestines form first, the nervous system develops around them, and the brain (central nervous system) develops later. It is no exaggeration to say that for living things, "the intestines are the origin of life".
C)
2. The gut has an independent nervous system
The gut has over 100 million nerve cells, second only to the brain, more than the spinal cord and peripheral nervous system, and it functions independently of the brain (hence the name autonomic nerves).
In other words, the intestines perform the essential functions of digestion, absorption and excretion without waiting for signals from the brain, and this seems reasonable when you consider that intestinal function is maintained without any problems even in the neonatal brain (a helpless brain).
D)
3. The gut sends emotional and personality signals to the brain
The gut is embedded in a thick, large nerve called the vagus nerve, and it has been shown that up to 90% of its fibres carry information from the gut to the brain. In other words, the brain interprets and expresses signals from the gut as emotions.
The sixth sense is called "gut feeling" in English, but the "gut" here refers to the intestines, and, interestingly, the intestines feel the sixth sense. Also, dopamine (pleasure hormone), noradrenaline (stress hormone) and serotonin (happiness hormone) are said to be representative neurotransmitters in the brain that control emotions (personality).
Still, most of them are produced in the gut. In particular, serotonin, which also suppresses the escape of dopamine and noradrenaline, is made in the intestines (in collaboration with intestinal bacteria). Ninety per cent of the serotonin in the body is present in the intestines and is involved in the peristalsis of the intestinal tract.
Too much causes diarrhoea, and too little causes constipation. Only 2% of serotonin is found in the brain. It is said that people with depression have low levels of serotonin in the brain and that increasing serotonin makes them feel happy. Intestinal bacteria (certain intestinal bacteria have been identified) are deeply involved in increasing serotonin, so adjusting your "gut" will improve your "mind".
E)
4. Immune cells in the gut protect us from disease
The gut contains many immune cells, 70% of the body's total, known as gut-associated lymphoid tissue, which fights off invasions from external bacteria and food toxins.
We can only tell what bacteria is in the food we eat and whether it harms the body by its appearance and smell; our brains cannot tell this by sight or smell, so they command 'eat'. However, when dangerous food enters the gut, nerve and immune cells make the judgement and cause vomiting or diarrhoea. The intestines work hard (wisely) to prevent illness (known as a biological defence mechanism).
F)
From the above, you may have realised how superior the gut is to the brain and perhaps even thought of the gut as the "first brain." In any case, we need to listen to the "voice of the gut," regulate our gut, and take care of it so that it can have a positive effect on the brain.
The gut is said to be the "second brain", but maybe the "first brain".
Add info)
We talk to Nobuko Nakano about the true nature of intuition.
https://www.vogue.co.jp/lifestyle/article/2020-02-15-nobuko-nakano-interview
When you hear the word intuition, you might imagine someone who is always clear-headed and can make the right decisions instantly. But is that true? And what exactly is intuition? Brain scientist Nobuko Nakano explains its mechanism. She also introduces people good at intuition and specific ways to train it. Cultivate your intuition with a correct understanding and face your true nature again.
