In this article:
- What’s the connection?
- The Gut-Brain Axis
- What can you do?
You needn’t be a scientific scholar to know that maintaining a healthy gut microbiome is one of the keys to vibrant overall health and wellbeing. A diverse and balanced gut supports everything from optimal digestion to glowing skin to a strong immune system.
But more recently, science says that a healthy microbiome is actually key to a healthy, happy brain, too.
What’s the connection?
Think about it: Do you ever experience “butterflies” in your stomach or a strong feeling in your belly telling you to do or not to do something? Those phenomenons that we call “gut feelings” suggest that your microbiome and your brain are connected.
Research speculates that psychological disorders such as bipolar disorder, schizophrenia, and depression may be linked to alterations in the microbiome. Researchers believe that any disruption to the balance of bacteria and fungi in your microbiome can lead to inflammation — and not just in your gut, but throughout your entire body and brain.
The Gut-Brain Axis
This system of connections between your digestive tract and your brain — the system that allows our brains and guts to “talk” to each other — is referred to as the “gut-brain axis.” These two organs are connected in several physical and biochemical ways, all of which have the potential to impact your mental health.
Here are five ways your gut health influences your mood:
1. Your brain and gut communicate via nerves.
Your brain contains billions of neurons (nerve cells) that essentially tell your body how to behave. Your gut contains hundreds of millions of nerve cells that communicate with your brain. The two organs constantly send signals up and down your nervous system, likely through one of your body’s largest nerves called the vagus nerve.
In animal studies, researchers found that stress keeps the vagus nerve from working properly, and those findings coincided with gastrointestinal issues. In people with Crohn’s disease and irritable bowel syndrome (IBS), vagus nerve function seems to be dampened, which could explain their digestive symptoms.
2. Your diet can make you depressed.
Consider this: roughly 90 percent of serotonin receptors are located in the gut. Well-known for its happiness-inducing qualities, serotonin is a neurotransmitter (or chemical) that relays messages from certain parts of your brain to others. This includes brain cells related to your mood, sexual desire, sleep, appetite, memory, and some social behavior. When serotonin production is impacted or reduced, it may manifest as a lack or change in any of those things.
Some research suggests that eating a healthy, balanced diet that avoids inflammation-inducing foods can prevent or treat depression. The Antidepressant Food Scale describes 12 antidepressant nutrients, many of which are found in shellfish, leafy greens, cruciferous vegetables, and mildly acidic fruits such as strawberries.
When your gut becomes inflamed, you leave your brain at risk for inflammation, too, and an inflamed brain is not a happy brain. Inflammation in the brain can alter the messages it sends and receives.
3. Your gut health impacts your hormones.
Ever feel “bleh”? That weird, in between, not-depressed-but-not-happy state of being could be attributed to your gut health. If your gut is imbalanced, you stand to lose proper production of some pretty critical hormones, including thyroid hormone and estrogen.
Basically, your gut bacteria are the big boss of your hormones, and some scientists even refer to the microbiome as an endocrine organ (an organ that produces hormones). If you experience mood swings, longer-than-normal periods of low mood, or unexplained fatigue, your gut microbiome could be to blame.
4. The state of your gut affects your immune system.
And your immune system affects your mood. All the tiny colonists in your digestive tract contribute to the functioning of your immune system and your body’s inflammation levels by controlling what passes through your body, and what doesn’t.
If your immune system doesn’t like what’s going on in your gut, it’ll stay switched on. When your immune system never shuts off, you’re at risk for increased inflammation, which is linked to a whole range of brain disorders and diseases, including depression. Remember: an inflamed brain is not a happy brain.
5. Cortisol can set up shop in your gut.
Ever hear of the “stress hormone”? That’s cortisol, and when you’re stressed out, cortisol can encourage the growth of certain microbes. And you don’t want cortisol to determine what kinds of bacteria and fungi grow in your belly. The strains and species that thrive in a high-cortisol environment can heighten stress and anxiety even more.
Essentially, stress can result in more stress through the gut-brain axis — take this as your sign to recommit to your daily meditation practice or even just a walk!
What can you do?
Now that you know how your gut health affects your mood, it’s time to take action on that knowledge. The shortlist: eat gut-friendly foods, exercise regularly, and keep stress levels as low as possible. Taking care of your gut is taking care of your brain.
Editor’s note: This post has been updated for relevancy. Its first publish date was September 16, 2019.