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Do you ever feel butterflies in your stomach when you’re excited? How about that pit of dread when you forget something? There’s a reason people say to trust your gut — and it’s not just an expression. Science agrees that your digestive tract can affect your mood and mental health.1
“If something is affecting your body, it’s also going to affect your overall mental health,” says Kaiser Permanente psychologist Margot Green, PhD. In fact, “people have been wondering about where the connection is between our mind and our body since at least the Renaissance.”
What is the gut-brain connection?
Like your brain, your gut is full of nerve cells — more than 100 million of them. This is your enteric nervous system, sometimes called your “second brain.”
You might mainly think of your gut for its role in digestion. But its nerve cells also send signals to your brain — and your brain sends signals back — to help keep your body working properly. “It’s the ultimate mind-body connection,” says Dr. Green.
The vagus nerve’s role in gut-brain communication
Your head and your gut talk to each other mainly through your vagus nerve. One of the longest nerves in your body, it stretches from your brainstem to your intestines. It plays a big role in the gut-brain connection.
The vagus nerve sends the chemical signals made in your gut up to your brain. These signals tell your brain what’s going on in your gut, which can affect your mood and mental health. It also works the other way. Your thoughts and feelings send messages through the vagus nerve that can cause problems in your gut.2
“Typically, it’s hard for us to realize that our thoughts and feelings can affect our physical bodies,” says Dr. Green. “Yet the gut-brain connection shows that our mental and physical processes work together in a 2-way biochemical process.”
How gut bacteria affects mental health
Trillions of bacteria, viruses, and fungi live in your gut, mainly in the intestines. Together they’re called the gut microbiota, or microbiome. They make chemicals that help your body function properly. These chemicals affect the way your mind functions, too.
- Neurotransmitters like serotonin and dopamine regulate your appetite and sleep. They also play key roles in controlling your mood and emotions. And about 90% of your body’s serotonin and 50% of dopamine is produced in your gut, not your brain.3
- Hormones like insulin signal when you’re hungry or full. They’re also linked to your emotions and response to stress.4
- Postbiotics like amino acids, glucose, and fatty acids help fight infections and inflammation, especially in the brain. They can also help with stress, anxiety, and depression.5
How to improve your gut health
Improving your gut health can also improve your mood. And what we eat is key in keeping our gut healthy. Dr. Green recommends feeding your gut microbiome a range of nutrients. This can include fiber-rich, fermented, and probiotic-rich whole foods and a rainbow of fruits and vegetables.
“That’s the common wisdom,” says Dr. Green. Too much saturated fat, sugar, salt, or not enough fiber can make your microbiome imbalanced — leading to various physical and mental health problems.6
Some powerful nutrients that help promote good gut health include:
- Probiotics: Live bacteria and yeasts found in things like yogurt, kefir, kimchi, kombucha, and other fermented foods. They increase good bacteria and decrease bad bacteria in your microbiome. This can lower inflammation and improve digestion.7
- Prebiotics: Fiber found in things like fruits, vegetables, whole grains, legumes, nuts, and seeds. Prebiotics are important for digestion, support your immune system, and help probiotics work better.8
- Polyphenols: Antioxidants found in plants like green and black tea, coffee, cocoa, certain spices, and colorful fruits and vegetables. Polyphenols can help prevent or reduce cell damage and inflammation. And when they break down, they can help release neurotransmitters and hormones.9
- Omega-3s: Fatty acids found in fatty fish like salmon, mackerel, and sardines or plant-based foods like flaxseeds, chia seeds, and walnuts. Omega-3 helps balance the gut microbiome’s bacteria, provide gut cells with energy, and produce chemicals that are anti-inflammatory.10
Can supplements help with gut health?
Sometimes a diet of whole foods may need extra help in keeping your gut microbiome well balanced. That’s when taking supplements may make sense. Think of them as a complement — not a replacement — to whole foods. Supplements should provide the additional nutrients you may need but aren’t able to get from your diet.
Before taking any supplements, talk with your doctor first. They can help you figure out if you need them at all. If you do, they can tell you which ones to take and how much. It’s especially important to talk with your doctor if you’re taking prescription drugs. You’ll want to make sure the supplements won’t cause any bad side effects with your medication.
Getting started with a gut-healthy diet
When it comes to healthy eating, the key is finding food that fits your lifestyle. Don’t feel like you need to spend a lot of money or make any big changes. Small, consistent choices can make all the difference. And just knowing what foods are good for your gut is the best place to start.