The gut-brain connection is complex and bidirectional. Signals pass both ways between your digestive system and central nervous system, and health or disease in one can affect the other. Key players in this connection include your enteric nervous system, your vagus nerve and your gut microbiome.
Your brain talks to your gut, and your gut talks back. If you’ve ever had a “gut feeling,” you’ve experienced this communication. It’s how the thought of an exciting event can make you feel “butterflies in your stomach,” while the thought of something dreadful might be “gut-wrenching.” And it’s how the feeling in your gut can influence your decision-making, as in “going with your gut”.
Your brain communicates with all of your body through nerves (your nervous system). But your brain and your gut are like besties. They talk about all kinds of things, from practical, physical matters to emotional ones. More information passes between your brain and your gut than any other body system. In fact, there are more nerve cells in your gut than anywhere else in your body outside of your brain.
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy
Our brains and digestive systems have evolved together to help us survive. What we eat is crucial to our overall health, and it has also varied a lot throughout history, depending on what was available. Our brains and guts needed to stay in close contact to make sure we got the nutrients we needed. And if we ate the wrong thing, or we needed to put the brake on digestion, we had to have a good alarm system in place.
This alarm system includes the emotional part of your brain. After a physical injury, your emotional brain kicks in to help you remember to avoid that injury in the future. Emotion can make physical sensations in your gut seem more intense. Intense physical sensations can also raise your stress levels and your emotional response. This feedback loop is especially strong between your brain and gut.
Studies suggest that crosstalk between your gut and brain may influence your:
What healthcare providers refer to as the gut-brain axis is the network of nerves that connect your brain and gut and send signals back and forth. But your nervous system also works closely with your endocrine system, which produces hormones that communicate things like hunger, fullness and stress. And it works closely with your immune system to respond appropriately to injury or disease in your gut.
Within this network, some of the key players in the gut-brain connection include:
Your enteric nervous system is the neural network that operates within your gastrointestinal (GI) tract and controls its digestive functions. With more than 500 million neurons, it’s the most complex neural network outside of your brain. It’s also unique in that it can operate somewhat independently from your brain and central nervous system. This has led some scientists to refer to it as a “second brain”.
Your enteric nervous system is a special division of your autonomic nervous system, which governs the automatic functions of your internal organs. It operates as part of your overall autonomic nervous system, but also on its own. It can gather information about the conditions inside your GI tract, process that information locally and generate a response without sending it back to your brain.
Your vagus nerve is the main link between your enteric nervous system and your brain. It’s one of your 12 cranial nerves, which begin in your cranium and travel down through your body, branching out along the way. Your vagus nerve conveys sensory information about the conditions inside your gut from your enteric nervous system to your brain. In response, it conveys motor signals from your brain to your gut.
The vagus nerve mediates various reflexes that operate within your gut in response to changing conditions, like chemical changes or the presence of food. These are called vagal reflexes. Intrinsic vagal reflexes operate within your enteric nervous system without involving your brain. Extrinsic reflexes operate through communication between your enteric nervous system and central nervous system.
Believe it or not, the bacteria that live in your gut are also involved in your gut-brain connection. Gut microbes produce or help produce many of the chemical neurotransmitters that convey messages between your gut and brain. They also produce other chemicals that can affect your brain through your bloodstream. Your brain and gut, in turn, can affect your gut microbiome by altering its environment.
Recent studies have shown that the gut microbiome may be involved in various neurological, mental health and functional gastrointestinal disorders. Functional disorders are those that cause persistent symptoms but don’t have any obvious physical cause. There’s a significant overlap among people who have functional gastrointestinal disorders, like IBS (irritable bowel syndrome), and who have mental health disorders, like anxiety.
Disorders related to the gut-brain axis may include:
Healthcare providers are experimenting with treating some of these disorders by treating your gut microbiome. Animal experiments have suggested that a healthier diversity of microbiota in your gut may help to relieve gastrointestinal, neurological, inflammatory and emotional stress symptoms. Results in humans are still mixed, but intriguing. They might treat your gut microbiome in several ways, including:
People with certain functional gastrointestinal disorders may benefit from mind-body therapy with a behavioral medicine specialist. Several different types of therapies may be beneficial in relieving persistent GI symptoms, or at least learning to cope with them. They can also help improve your overall mood and stress levels, which may help your gut indirectly. Some of these therapies include:
The best way you can take care of your gut health on a day-to-day basis — and maybe your brain health, as a result — is by maintaining a healthy, balanced diet. You can also take care of your brain health — and maybe, through it, your gut health — by doing what you can to manage your stress. Here are some ways to manage stress during intense times, and ways to relieve stress in your day-to-day life.
A good rule of thumb to improve your gut health naturally is to eat a good variety of whole foods, emphasizing plants. More diversity in your diet leads to a more diverse gut microbiome, which is good for your overall gut health. Whole foods and plants also pack more nutrition per calorie than processed foods, leaving less room for harmful additives, sweeteners and saturated fats. Instead, they offer:
A note from Cleveland Clinic
Your gut and brain are in constant communication through nerves and chemical signals. They’re so close that they can feel each other’s pain. If you have a condition that affects your digestive system or nervous system, it may also involve the other. Healthcare providers are beginning to approach these conditions from both sides of the gut-brain axis. You can, too, by taking care of your mental health and gut health.
Last reviewed by a Cleveland Clinic medical professional on 09/20/2023.
Learn more about our editorial process.