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The Gut-Brain Connection: How It Works + How to Support It

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Gut-brain connection - Dr. Axe

You’ve probably used the phrases: “I have butterflies in my stomach,” “I have a gut feeling about this,” or “there’s a pit in my stomach.” Have you ever wondered why so many of these sayings involve our brains and tummies? The answer is the gut-brain connection.

As it turns out, your nervous stomach isn’t such a coincidence. In fact, the more we learn about the human gut, or our gut microbiome, the more it’s clear that it really is our “second brain.”

You’re probably already aware that leaky gut syndrome is linked to serious conditions and diseases. Turns out, science is discovering that the connection between our guts and our emotions is just as strong.

What Is the Gut-Brain Connection?

The microbes in the gut play a significant role in human body function. The gut microbiome is responsible for everyday functions, including digestion and the nutrient absorption.

The gut and brain work in a “bi-directional manner,” which means that gut health can impact stress, anxiety, depression and cognition.

Scientific studies show that the gut is home to the enteric nervous system (ENS). Separate from the central nervous system, the ENS is made up of two thin layers with more than 100 million nerve cells in them — more than the spinal cord.

These cells line the gastrointestinal tract, controlling blood flow and secretions to help the gastrointestinal tract digest food. They also help us “feel” what’s happening inside the gut, since this second brain is behind the mechanics of food digestion.

While the second brain doesn’t get involved in thought processes like political debates or theological reflection, studies suggest that it does control behavior on its own. Researchers believe this came about to make digestion more efficient in the body. Instead of having to “direct” digestion through the spinal cord and into the brain and back, we developed an on-site brain that could handle things closer to the source.

Because this second brain is so complex, scientists aren’t convinced that it was designed as just a way to aid in digestion. So while it isn’t capable of thoughts, it does “talk” to the brain in major ways.

Impact on Depression

The gut microbiome appears to play a role in depression. The microflora has proved to benefit mental health by enhancing the microbiome content in our GI systems.

Researchers have learned that healthy gut microflora transmits brain signals through pathways that are involved in brain neuron formation and behavioral control. They also proved that inflammation affects the brain and how someone thinks, which explains why more than 20 percent of inflammatory bowel disease patients exhibit depressed behaviors.

One study illustrated how the gut and brain are connected through studying the effects of probiotics on patients with irritable bowel syndrome and depression. Researchers found that twice as many patients saw improvements from depression when they took a probiotic as compared to the other patients who took a placebo.

Again, with an improvement of the gut came an improvement of mental well-being. Patients in this study took the probiotic Bifidobacterium longum NCC3001 daily. 

Studies show that patients with inflammatory diseases are prone to depression. The theory is that a dysregulation of the pathways involved in the gut-brain axis is responsible for this phenomenon. Research indicates that inflammation leads to depression, and depression worsens cytokine responses, so it’s really just a vicious cycle.

Impact on Anxiety

Research shows that stress is intimately tied to our guts — thereby proving the gut-brain connection. We know that gut health influences anxiety and the body’s response to stress as part of the brain-gut connection.

Our bodies respond to stress with a “fight or flight system,” related to our cortisol levels and which we know is ruled by the hypothalamic-pituitary-adrenal axis. When something scary or worrying happens, like someone unexpectedly jumps in front of you, you have a physical reaction: Your palms might get sweaty, and you might feel your heartbeat quicken.

Typically, if you’re in a stressful situation that is then diffused, your body goes back to normal. However, if you’re constantly stressed, your body is stuck in that fight or flight phase over an extended period of time.

The critical part is that our bodies are unable to distinguish between physical and mental stress. Thus your body responds the same way if a bear shows up in your home as it does when you realize you hate your job — it tries to combat the stress.

This constant state of stress causes chronic inflammation. The body reacts to the stress as a type of infection and tries to overcome it.

Because inflammation is at the root of many diseases, this exposure to prolonged stress can have serious consequences for your health, ranging from high blood pressure to autoimmune disorders. The types of bacteria found in the gut — “good bacteria” — play a role in how our immune responses are regulated.

Related: Mythbusters: Mood Plays Little Role in Your Health

Natural Ways to Improve Your Gut-Brain Connection

While there’s still much to uncover about the mystery of the gut and all it affects, we are sure of a few things you should do to improve your gut-brain connection.

1. Avoid Processed Foods

For starters, a whole foods-based diet leads to a gut with a much different makeup than one that’s been fed mainly refined and processed foods. Even worse, ultra-processed foods — like white bread, chips and snack cakes — make up nearly 60 percent of the average American’s diet.

The added sugar found in these foods, often disguised as different types of artificial sweeteners, are responsible for a variety of health conditions, from obesity to type 2 diabetes to migraines.

2. Eat Probiotics

Eating probiotic-rich foods, like kefir and sauerkraut, can also cause your gut and mood to thrive. Probiotics are good bacteria that primarily line your gut and are responsible for nutrient absorption and supporting your immune system.

3. Swear Off Gluten

For many people, limiting gluten will also have positive effect on their gut microbiomes. The traditional methods of soaking, sprouting and souring grains in order to make them digestible and nutritious have been abandoned for a fast and convenient method of mass producing food.

How to support the gut-brain connection - Dr. Axe

4. Eat Healthy Fats

Healthy fats are essential for brain development. Olive oil, for instance, includes a high amount of antioxidants that protect your cells from damage. It also helps improve memory and cognitive function, and works as an anti-inflammatory.

Avocado benefits range from protecting your heart to helping with digestion, but it’s also a great pick for improving your mood.

5. Consume Mushrooms

The shiitake mushroom contains plenty of vitamin B6. Because vitamin B6 impacts the production of serotonin and neurotransmitters, healthy B6 levels are associated with a positive mood and reducing stress naturally.

It’s also been shown to effectively treat mood disorders like depression in animal research.

6. Eat Nuts

Have a small handful of nuts, like almonds, cashews, walnuts and Brazil nuts. Why? Research shows they’re full of serotonin, a feel-good chemical that’s in short supply when you’re depressed.

7. Have Sesame Seeds

Sesame seeds benefits stem from tyrosine, an amino acid that boosts the brain’s dopamine levels. It kicks the feel-good hormone into high gear while balancing out the others.

We don’t have all the answers on the gut-mood link just yet, but one thing is certain: Our bodies and minds are much more connected than you believe. Taking care of one part will reap benefits for the rest of you.

Final Thoughts

  • The microbes in the gut play a significant role in human body function. They are responsible for everyday functions, including digestion and the nutrient absorption, and gut health has a significant impact on mental health. This is known as the gut-brain connection.
  • Research shows that there’s a connection between gut microbiota and mental health disorders like depression and chronic anxiety or stress.
  • The key is to improve gut health, which will reduce systemic inflammation and improve mental health thanks to the gut-brain connection.
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