Have you ever felt that churning in your stomach when you’re nervous about a situation? Have you ever realized after the fact that you should have trusted your gut? A quick look at the anatomy of your gut may give you the answer. These sensations that come from your gut suggest that your gut and brain are connected.
This connection is called the gut-brain axis, and it is through this axis that your body’s central nervous system and gastrointestinal tract communicate. Recent research shows that the gut-brain axis affects human brain function and behavior.
Exploring the Gut-Brain Connection
The gut-brain axis is used to refer to the communication network that connects your brain and your gut. The two organs are connected in several physical and biochemical ways.
The Vagus Nerve and the Nervous System
Found in the brain and the central nervous system (CNS) neurons are cells that tell your body how to behave. There are about 100 billion neurons in the human brain.
Your gut also contains between 200-600 neurons million that are connected to your brain through your nervous system. The vagus nerve is one of the largest nerves connecting your brain and your gut. The large nerve sends signals in both directions.
The brain and gut are also connected through neurotransmitters, chemicals produced by the brain to control emotions and feelings. For example, serotonin is a neurotransmitter that causes us to feel happy and helps control our internal body clock.
Many neurotransmitters are produced in your gut microbiome, including a large portion of serotonin. Gamma-aminobutyric acid (GABA), a neurotransmitter that controls feelings of anxiety or fear, is also produced here.
Neurotransmitters Aren’t the Only Game in the Gut Microbiome
Your gut microbiome also produces other chemicals that affect your brain. Including lots of short-chain fatty acids (SCFA) like propionate, butyrate, and acetate. When your gut microbes digest fiber, they produce these SCFAs, which in turn, regulate can regulate appetite and digestion.
The Gut Microbiome and Inflammation
The gut microbiome also plays an essential role in inflammation and the immune system by controlling what is passed through the body and excreted. If your immune system is overactive, it can lead to excess inflammation, which is associated with brain disorders such as Alzheimer’s disease and depression.
Prebiotics, Probiotics, and the Gut-Brain Axis
Since the gut microbiome affects brain health, you can improve your brain health by changing your gut bacteria. Many people add probiotics to their supplements for this reason. However, not all probiotics affect the brain in the same way.
Prebiotics may affect brain health. One study on healthy volunteers indicated that taking the prebiotic galactooligosaccharides for three weeks reduces the amount of cortisol in the body.
What Role Does Diet Play in the Gut-Brain Connection?
A healthy diet centered around whole foods and plenty of fruit and vegetables is one of the best ways to keep the mind, body, and gut health. However, a few food groups are particularly beneficial for the health of the gut-brain axis, such as:
- Omega-3 fats – can increase helpful bacteria in the gut and lower the risk of brain disorders.
- High-fiber food – prebiotics found in whole grains, fruit, vegetables, nuts, and seeds can reduce stress.
- Fermented foods – probiotics found in fermented foods have been shown to alter brain activity in the brain region that controls the processing of emotion and sensation.
- Tryptophan-rich foods – such as turkey, eggs, and cheese supply the amino acid that is converted into the neurotransmitter serotonin.
- Polyphenol-rich foods – such as chocolate, olive oil, green tea, and coffee increase gut microbiota and may improve cognition.
Eating a diet rich in gut-healthy foods may improve your gut health, which completes the circle by benefiting the gut-brain axis.