Feeling down? Maybe not eating right is part of the culprit. The connection between gut health and brain health is known as the gut brain axis. For anyone dealing with depression, mood disorders, or anxiety, eating foods that help promote a healthy gut microbiome may play a big role in boosting your mood.

This article provides a systematic review of how your gastrointestinal tract affects your mood (and vice versa). And, you’ll learn what types of foods to eat and how they can potentially make you feel happier!

Illustration of the gut brain axis with a photo of a woman and text overlay:

The gut and brain are interconnected more than we previously thought—recent research is proving the crucial role of the microbiome in controlling the brain-gut axis. These discoveries have huge potential to help people with gut issues with help from their brains. And help people with brain or mood issues with help from their gut.

Imagine if eating differently could elevate your mood or improve your brain function and mental health. (It can.) Or if reducing stress can also reduce gut symptoms. (It does.)

Sounds interesting? Learn all about the gut brain axis and how you can leverage this new research to improve your gut health AND your brain health.

The gut brain connection

Functional GI disorders, like IBS, can cause pain, bloating, & other digestive discomforts. They impact over 35 percent of people at some point in life—affecting women more than men. Many times, these gut issues don’t have an apparent or easily diagnosable physical cause, so they can be difficult to treat and find relief from.

We already know that our brains control some of our digestive processes. Research has found that even thinking about eating can cause the stomach to release digestive enzymes. Your gut is also sensitive to emotions-many of us can recall a time feeling anxious or nauseous with“knots” or “butterflies” in our stomachs.

Indeed, several studies show that stress may be an important—often overlooked—reason for gut issues. According to Harvard Health…

Stress can trigger and worsen gastrointestinal pain and other symptoms, and vice versa.

Harvard Health

This is why it’s so important to look at your stress and emotions if you have gut issues. Many studies have found that stress reduction techniques can lead to greater improvement in gut symptoms compared to conventional medical treatment alone.

Before we go over how to do this, let’s look at a bit more of the biology behind the microbiota-gut-brain axis and the important role it plays in depression and anxiety disorders.

Nervous system 101

Photo of the nervous system in pink, purple, and orange colors.
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There are two main parts of your “main” nervous system. The somatic nervous system is the part that we can consciously control, like when we move our muscles to walk around, chew our food, or swim laps.

The autonomic nervous system regulates our body’s functions, such as digestion, heart rate, and respiratory rate, by either speeding things up or slowing them down. It includes both the sympathetic and parasympathetic nervous systems.

The sympathetic nervous system speeds things up, allowing our “fight or flight” reactions to kick in. We feel this happening when we sense danger (real or not) and get stressed. Our heart beats faster and we breathe heavier. We’re preparing to fight or flee, so our body focuses on ensuring our muscles get enough blood and oxygen to work hard.

On the other hand, the parasympathetic nervous system slows things down. The vagus nerve is the main component of the parasympathetic nervous system, and is able to sense intestinal microbiota metabolites (i.e. short-chain fatty acids, bile acid metabolites, and tryptophan metabolites). This happens when we’re relaxing or after the danger has passed and we start to calm down.

When our heart, lungs, and muscles rest, our digestive systems do their jobs much better. In this phase, we’re secreting more digestive juices to break down food, we’re absorbing more nutrients, and we have lower levels of inflammation in our gut. That’s why this is called the “rest and digest” phase.

Both of these arms of the autonomic nervous system—the sympathetic and parasympathetic—interact with the gut. This means that when our body is stressed we can experience digestive symptoms. And, when we’re relaxed, our digestion does what it’s meant to do.

The Enteric Nervous System

In addition to your “main” nervous system, your gut has its own nervous system called the enteric nervous system. The enteric nervous system spans your whole digestive tract from your esophagus, along your stomach, intestines, and colon. This nervous system is sometimes referred to as the second brain because it works in the same way that the “main” one does. It has 100 million nerve cells (called neurons) that communicate with each other using biochemicals called neurotransmitters.

Your enteric nervous system gets input from both the sympathetic and parasympathetic nervous systems, so it can speed up or slow down when it has to. It also has a “mind” of its own and can function independently of them.

This complex system is important because of how complex our digestive processes are. For example, after we eat, the neurons in our enteric system tell the muscle cells of the stomach and intestines to contract to move food along to the next part. As our gut does this, our enteric nervous system uses neurotransmitters to communicate with the central nervous system.

Your enteric nervous system is also very closely linked to your immune response. This is because pathogenic bacteria can enter the body through the mouth and end up in the gut. You have a large immune presence there to help fight them off before they become a larger problem and infect other parts of the body.

Immune cells provide another path for the gut to communicate up to the brain. They relay information like when they detect an infection or when your stomach is bloated, so your brain knows, too.

Even the friendly gut microbes (gut microbiota) that help us digest food and make certain nutrients play a role in communicating with the brain. They make neurotransmitters such as serotonin and GABA (gamma-aminobutyric acid) which are known to influence our moods.

What is the microbiome gut brain axis?

This intimate and complex connection between your gut and brain is called the gut brain axis. And we now know that the signals go in both directions: from your brain down to your gut, and from your gut up to your brain.

This is where we see the link between digestive issues and brain, stress, and mood issues.

When someone is stressed enough that they get into the “fight or flight” reaction, digestion slows down to allow the muscles to fight or flee. The same physical reaction appears whether the stress is from a real threat or a perceived one.

This means that your body reacts the same whether you’re facing a real life-threatening situation or whether you’re super-stressed about a looming deadline. This disruption of the digestive process can cause gastrointestinal symptoms including pain, nausea, or other related issues.

Meanwhile, it’s known that experiencing strong or frequent digestive issues can increase your stress levels and moods. People with psychiatric disorders, including depression and anxiety, tend to have have more GI symptoms, and vice versa.

How stress and emotions affect your gut

Gut brain axis infographic showing how stress leads to brain-gut dysregulation and altered intestinal motility.

Because of this direct connection between the gi tract and brain, it’s easy to see how stress and other emotions can affect your digestive system. Indeed, the gut “feels” moods and emotions including fear, sadness, anger, anxiety, and depression.

When they cause our digestive systems to speed up (or slow down) too much, this can influence pain and bloating. It can also allow germs to cross the lining of the gut and get into the bloodstream, activating our immune systems. It can increase inflammation in the gut or even change the microbiota.

This is why stress and strong emotions can contribute to or worsen a number of GI issues such as inflammatory bowel disease (i.e. Crohn’s disease & ulcerative colitis), irritable bowel syndrome (IBS), gastroesophageal reflux disease (GERD), or food allergies or sensitivities.

Then, these gut issues are communicated to the brain, increasing the stress response and affecting our moods and brain processes. This loop of stress and gut issues and more stress and more gut issues becomes a vicious cycle.

It’s thought that the gut brain axis is also impacts additional neurological disorders, including alzheimer’s disease, autism spectrum disorders, and parkinson’s disease.

Recent studies show that changes to the gut microbiota composition can strongly affect many other parts of the body as well—not just the brain and mood. They’re also associated with depression and heart disease.

How do you fix the gut axis of the brain?

What you eat can have a huge impact on your health. This is particularly true when it comes to the microbiome. Your gut health improves when you eat a prebiotic rich, higher-fiber, plant-forward diet. That’s because it provides your friendly gut microbes with their preferred foods to produce healthy short-chain fatty acids and thrive.

Probiotic rich foods that include health promoting gut bacteria are also recommended. Reducing the amount of sugar and red meat you eat can also help. These foods promote a healthier microbiome by helping to maintain a diverse community of many species of microbes to maximize your health.

They can also lower levels of gut inflammation, improve intestinal permeability (aka leaky gut), and reduce the risk of depression and heart disease.

(Learn more: The Best Foods with Probiotics and Prebiotics to Boost Your Health)

What to Eat for a Healthier Gut & Happier Mood

Plant-Based Breakfast Ideas with a heart shaped bowl of granola and fruit.

Eat more…

  • Fruits and Vegetables
  • Beans and Legumes
  • Nuts and Seeds
  • Whole Grains (gluten free if needed)
  • Fermented Foods (yogurt, kefir, miso, sauerkraut, kimchi, tempeh, kombucha)

Eat less…

  • Foods high in sugar
  • Red meat
  • Foods high in saturated and trans fats

(Learn more: The Best Mood Boosting Foods to Eat Everyday)

How Does Stress Affect The Gut Brain Axis?

What about stress? There is a growing body of evidence suggesting that some stress reduction techniques or psychotherapy may help people who experience digestive issues. These interventions can lower the sympathetic “fight or flight” response, enhance the parasympathetic “rest and digest” response, and even reduce inflammation.

Some stress-reduction techniques I love are:

Have you heard of gut-directed hypnotherapy?

There’s exciting research showing gut-directed hypnotherapy can reduce IBS symptoms by up to 70%. During gut-directed hypnotherapy a therapist guides you into a focused state of awareness using suggestions aimed to calm your digestive tract while feeling deeply relaxed.

I am just starting to recommend gut-directed hypnotherapy to my clients, as there is significant research suggesting effective and long-lasting results from treatment. If you are interested in giving it a try, you can search for a gut-directed hypnotherapist near you.

Or, you can also try Nerva, a new online app for self-guided gut-directed hypnotherapy. Nerva is currently offering a free 7-day trail, so it’s definitely worth giving it a try!

Start Boosting Your Mood Today!

Colorful fruits and vegetables on a white background with text overlay-Eat More Plants.

I know first hand, that when I eat a high quality diet, and practice regular self care, my mood gets a boost as well! I also know that it’s important to make small, gradual changes, if you want to see lasting results.

You might start working on your gut health by adding more plant based foods into your diet. Or perhaps you might try stress reduction through mindfulness meditation. Whatever the case may be, make sure to do these things regularly so you can feel better soon!

To help you get started, I’ve created a challenge to help you eat 30-40+ plants per week. It’s fun, easy, and delicious! When you sign up, you get a 40 page guidebook, a one week meal plan with grocery list, and a colorful tracker that will definitely motivate you to eat more plant based meals. I’m right here ready to answer any questions as they come up, so sign up now and let me know how it goes!

Gut Brain Axis References

Let’s Chat! Did you learn anything new about food, mood, and stress today? Have you made a correlation between what you eat and your moods? Any follow-up questions? I’d love to hear from you! And, if you enjoyed this post, please share. Thank you!

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