What if I told you that your gut microbiome can influence your mood, your cognitive function, your thought clarity, and even the health of your brain?

Would you believe that your microbe friends can be the difference between having a great day or spending your day depressed or anxious? By improving your gut microbiome, you can change how you feel about things that irritate you or stress you out. You can improve your memory, your ability to think clearly, and your overall brain health.

In this article, we are going to chat about how your gut microbiome:

• Produces “feel good” or even “feel bad” messengers called neurotransmitters that influence your mood, how your brain functions, and even what you think about.
• Regulates your stress response and can cause anxiety or depression.
• Reduces or causes inflammation in your body (including your brain) which either improves or erodes your brain health and the overall health and function of your whole body.
• How you can support your gut microbiome to optimize your brain and mood health.

The Gut Microbiome and Mental Health: The Gut-Brain Axis

The gut-brain axis refers to the communication between the gut and the brain. The gut and the brain are actually able to communicate with each other through the nervous system, hormones, and the gut microbiome. This communication helps regulate your mood, your ability to think clearly, and your overall mental health.

There are also certain gut bacteria that can increase your stress response and heighten your risk for depression.

Neurotransmitter Production

One way your gut microbiome assists in the communication between the brain and the gut is by producing neurotransmitters. These directly affect your brain function and your mood. An example of this would be the neurotransmitter, serotonin. About 90% of your body’s serotonin is produced by several friendly bacteria. Serotonin is well known for influencing your mood and overall sense of well-being. This is why we have a whole classification of drugs called selective serotonin reuptake inhibitors for depression. These are medications like Prozac, Zoloft, Paxil, and other similar medications. If you do not have enough serotonin, you may struggle with mood issues like depression and anxiety. These drugs do not create MORE serotonin, they just prevent reabsorption of the serotonin. By preventing it from reabsorbing, it keeps it available to continue to be used.

What you may not know is that 95% of serotonin is made in your intestines. It is very important for your intestines to have peristalsis. Peristalsis is the contraction of the bowels that helps to move your stool through your colon so it doesn’t just sit there and get stuck. Pretty important, right?

Other important neurotransmitters produced by your gut microbiota are:

• Dopamine - Well-known for being involved in the reward center of your brain that motivates you towards certain activities, like video games and social media.
• Noradrenaline - Also known as norepinephrine - improves your overall alertness, cognitive function, as well as your ability to pay attention and deal with stress reactions. It is critical in your “fight or flight” response.
• GABA - a calming neurotransmitter that allows you to avoid being overly excited. It is important for your sleep and mood regulation.
• Acetylcholine - Influences your stomach and intestinal movement and your ability to control the muscles that allow you to control bowel movements and urination. It even affects a man’s ability to have an erection and the lordosis response in women (which is a sign of female sexual receptivity).
• Histamine - This is found in every one of your cells and influences the immune response and inflammation. It also helps regulate your sleep-wake cycle and cognitive function.

Of course, this is just a brief overview of a few things each of these neurotransmitters do. There is so much more that they do, but you can see how these neurotransmitters can influence every cell in your body.

Modulation of the Stress Response

Your gut microbiome also influences your body's stress response by regulating the hypothalamic-pituitary-adrenal (HPA) axis. Beneficial bacteria help regulate cortisol levels. This reduces the impact of chronic stress on your body.

It’s interesting to note that in addition to the gut bacteria influencing your mood, if you are stressed or depressed, your mood can reshape your gut bacteria also. This is done through stress hormones and inflammation. Alternately, the gut bacteria release neurohormones, metabolites, and toxins that can literally alter your eating behavior and mood. There are some bacterial species that may encourage poor eating habits. Have you ever felt like it wasn’t even you who wanted to eat something, you just felt compelled to eat it? That is very likely your gut microbiome influencing your behavior to eat foods you know are not good for you. By reshaping your gut microbiota, you can actually change the foods you are craving.

Reduction of Inflammation

The gut microbiome can help reduce whole-body (systemic) inflammation by producing metabolites like:

• Tryptophan - which prevents hyperinflammation and the aging that is associated with inflammation - known as inflammaging.
• Bile acids - which significantly reduce skin inflammation.
• Small chain fatty acids (SCFAs), like butyrate, propionate, and acetate - which are key regulators of the local and systemic immune response in inflammatory diseases and infections.

As you can see, these metabolites produced by our gut microbiota are crucial for reducing chronic inflammation. By improving the gut microbiota, you reduce the inflammation which can in turn reduce your risk of suffering from mental health challenges, like depression, anxiety, chronic stress, and more.

How You Can Improve Your Microbiome Health

I ran across a study I want to share with you where scientists investigated the impact on the gut microbiome of a high fiber diet and a diet high in fermented foods. They took 36 people and split them into two groups of 18 each. One group was given large amounts of fiber and the other group was given large amounts of fermented foods (like yogurt, kimchi, kefir, and kombucha).

They discovered that the high fiber diet group increased the abundance of microbiota-encoded carbohydrate active enzymes (CAZymes). These CAZymes are involved in degrading plant cell wall carbohydrates. The high fiber diet resulted in reduced inflammation.

The fermented food group significantly increased their gut microbiome diversity over the ten weeks which also reduced inflammation markers, suggesting fermented foods may help counteract inflammation and low microbial diversity common in industrialized populations.

So, what does this have to do with your brain? When you reduce inflammation and improve how your immune system functions, that has a direct impact on your brain health which influences your mood, thought clarity, and overall brain function.

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