The gut-brain connection: How it works

Your gut and brain are in constant communication through a complex network — and understanding this connection could change how you think about your health.

Written by Calocurb • January 9, 2021 • 1 min read

Key Takeaways

The gut and brain are connected through a complex network called the gut-brain axis.

The vagus nerve is one of the key physical links between the gut and the brain, helping move food and supporting gut immunity.

Many neurotransmitters, including serotonin and dopamine, are produced in the gut and influence mood and emotions.

Trillions of gut bacteria, known as the microbiota, produce compounds like short-chain fatty acids that can directly affect brain function.

Scientists believe gut health may be linked to mental health conditions such as anxiety and depression.

Have you ever wondered why you can always trust your gut?

It's likely because your brain and gut are constantly communicating with each other.

What's more, this back-and-forth plays an important role in your health and wellbeing.

This article explains the different ways your gut and brain are connected.

How are they connected?

The gut and brain are constantly communicating with each other.

They do so in many ways through a complex network called the gut-brain axis (¹).

Here are some of the different ways your gut and brain communicate with each other.

Through your nervous system

The nervous system is a network that relays messages between your brain and body.

It's made up of nerves and special cells called neurons, which control many important processes such as your reflexes, muscle contractions, heartbeat, and much more.

Millions of these nerves are located in the gut and relay messages to and from the brain.

This includes one of the largest nerves in the body called the vagus nerve, which helps move food down your digestive tract and plays a key role in your gut immunity (², ³).

Through neurotransmitters

Neurotransmitters are chemicals that help the brain communicate with the body.

They play important roles, like controlling your feelings and emotions.

Surprisingly, a lot of neurotransmitters are made in your gut, like GABA — which controls fear and anxiety, and both serotonin and dopamine — feel-good hormones (⁴, ⁵).

That's a big reason why some scientists believe there's a connection between gut health and many mental health conditions such as anxiety and depression (⁶, ⁷, ⁸).

Through your gut bacteria

Did you know that trillions of bacteria live inside your gut? (⁹)

Collectively, these bacteria are called your microbiota and they are crucial to your health.

For starters, these bacteria make chemicals that affect how your brain works (¹⁰).

This includes short-chain fatty acids, such as butyrate, propionate, and acetate (¹¹).

Research shows that short-chain fatty acids can affect your brain in several ways such as influencing your appetite and strengthening your brain's natural defense systems (¹², ¹³).

They also help with making hormones in the gut, like the happy hormone serotonin (⁵, ¹⁴).

Summary

Your gut and brain are connected physically through nerves. They also relay messages through chemicals called neurotransmitters, and by the gut bacteria, which make compounds that can affect your brain health.

References

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Margolis, K. G., Cryan, J. F., & Mayer, E. A. (2021). The microbiota-gut-brain axis: From motility to mood. Gastroenterology, 160(5), 1486–1501. ⤴

Silva, Y. P., Bernardi, A., & Frozza, R. L. (2020). The role of short-chain fatty acids from gut microbiota in gut-brain communication. Frontiers in Endocrinology, 11, 25. ⤴

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Yano, J. M., Yu, K., Donaldson, G. P., et al. (2015). Indigenous bacteria from the gut microbiota regulate host serotonin biosynthesis. Cell, 161(2), 264–276. ⤴

The gut-brain connection: How it works