The gut-brain connection is bidirectional and intricate, involving pathways of the central nervous system and the digestive system.
Gut-Brain Connection Explained
The communication system shared by the brain and the gut is known as the gut-brain axis. These two are biochemically and physically connected in various ways. They could even affect each other in terms of health.
While the brain communicates with the entire body via nerves, the brain and the gut are like inseparable best friends. More information moves through the brain and the gut compared to any other system in the body. The number of nerve cells is the highest in the gut compared to anywhere else in the body that is outside of the brain.
The digestive system and the brain of humans have evolved alongside each other to aid in human survival. What people consume is important to their general health. Throughout history, diets have varied, largely depending on available resources.
The gut and the brain need to closely stay in contact to ensure that the body gets necessary nutrients. If a person ends up eating the wrong thing or if a digestion brake needs to be implemented, the body has an alarm system in place for this.
This system includes the brain's emotional part. Following a physical injury, the emotional brain works to help a person remember to avoid the said injury in the future.
Emotions are capable of making the gut's physical sensations stronger. Intense sensations can also boost emotional response and increase stress levels. Such a feedback loop shared by the gut and the brain is quite strong.
A Physical and Biochemical Connection
As mentioned earlier, both the gut and the brain are biochemically and physically connected in various ways. For one, the gut contains as many as 500 million neurons that are linked to the brain through the nervous system's nerves. One of the biggest nerves that connects the gut and the brain is the vagus nerve, which bidirectionally sends signals. This vagus nerve has been suggested to play a crucial role in the gut-brain axis and in stress.
Moreover, neurotransmitters also connect the brain and the gut. These neurotransmitters that the brain produces control one's emotions and feelings. Interestingly, the gut cells and the trillions of microbes within them also produce several neurotransmitters. In fact, a significant amount of serotonin is gut-produced.
The gut microbes also produce the GABA neurotransmitter, which stands for gamma-aminobutyric acid. This helps control anxious or fearful feelings.
Aside from this, the trillions of gut microbes also produce other chemicals that can affect brain functioning. The gut microbes make several of SCFA (short-chain fatty acids) through the digestion of fiber. SCFA can affect the brain in various ways, such as in appetite reduction.
Gut microbes also metabolize amino acids and bile acids to produce chemicals that could also impact the brain.
The gut-brain axis is also linked to each other through the immune system. The gut and its microbes could play a crucial role in the immune system and in inflammation. It does so by handling what the body excretes and what is passed into the body.
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