Gut Brain Axis

Hybrid Performance Method
September 23, 2019

For the longest time, scientists and doctors have classified the body into systems, conveying the idea that for the most part, we are a bunch of different and separate parts that function nearly independently of one another, and then if you have a problem or ailment, that it’s best classified accordingly to the system affected most. Respiratory system issues, psychiatric disorders, cardiac problems, the list goes on. However, modern research is starting to debunk this method of thinking, supporting the long held belief that we are a massively complex and interconnected being, all systems linked to one another, with hormones, neurotransmitters, enzymes, electrolytes and more all carrying messages throughout the body. This ultimately means what happens in one part of the body may significantly affect other parts as well. 

With the rise of psychiatric disorders, including depression, some of the newest and most exciting research being done is on the gut-brain axis (Liu & Zhu, 2018). Put more simply, the gut-brain axis is the relationship between your digestive tract, and your mood. Sounds crazy right? But consider that 90% of the serotonin receptors in the body are in the gastrointestinal tract (Liu & Zhu, 2018). Serotonin is the body’s “feel good” hormone, and the most commonly treated neurotransmitter in cases of depression. When levels are high and things are working well, people tend to feel more happy, upbeat, positive and have more energy (Liu & Zhu, 2018.. When levels are low, people tend to be tired, lethargic, negative, and experience fatigue (Liu & Zhu, 2018). Also, consider that the gut is DIRECTLY linked to the brain via a feedback highway called the Vagus nerve. Meaning, the intestines are in constant, direct communication with the brain.

Additionally, the body is a complex biological system, home to over ONE TRILLION bacteria. Yeah, that’s one thousand million bacteria for those of you who are bad at math. That means that there are 10 times the number of bacteria present than actual cells in your body. Are you ready for this? You are MORE bacteria than you are HUMAN. Crazy right? But these bacteria are GOOD. They are responsible for a massive part of your body’s immunity. They produce neurotransmitters such as dopamine, acetylcholine, and you guessed it, serotonin. They help you digest the food you eat. In other words, if you keep these bacteria happy and healthy, your life is going to be much, much, better. You might be less sick, less often. You will likely be happier and have more energy. You will sleep better. And you will also be less bloated, less often, and have more normal bowel movements if you are properly digesting the foods you consume, assuming you are eating foods your body tolerates well.

But we typically TERRORIZE our poor gut with what we do to it on a regular basis. Want to know what your microbiome hates? It hates stress, sleep deprivation, processed food, Antibiotics, lack of fresh fruits and vegetables in the diet, and lack of fermented foods in the diet. These literally are ALL things that pretty much everyone does nowadays. Stress reduces the number of bacteria present. Processed food encourages the growth of species that are NOT good, and reduces numbers of bacteria that are good (Liu & Zhu, 2018). Many commonly used antibiotics are nonselective in the bacteria they kill, meaning that while they can kill or prevent replication of infectious bacteria, they also can do the same to healthy populations of good bacteria in your gut. A lack of fresh fruits and vegetables starves the good bacteria of the type of nutrients and prebiotic fiber they need to flourish, and not consuming fermented food literally takes away reinforcements of the same good bacteria present in your gut that exist in those foods.

Ultimately, scientists are still researching the degrees and magnitude to which the microbiome is influenced by the aforementioned factors. The majority of current research has been done in rats which can convey a high sense of confidence as to the predictions being made, but more human studies need to be done in order to learn exactly how and why these factors influence the gut so heavily.

So what do you do in the meantime? Stop eating shit food – shy away from the twinkies and pizza. Sleep more and prioritize yourself and your schedule. Don’t feel the need to make everyone happy all the time. EAT MORE FRUITS AND VEGETABLES, MORE OFTEN. Consume common fermented foods such as yogurt, kefir, kimchi, kombucha, sauerkraut, and the like. And don’t jump on a damn antibiotic every time you get a common cold or a sore throat – antibiotics don’t harm viruses anyways.

Oh, and a little exercise never hurt anyone! 😀


Liu, L., & Zhu, G. (2018). Gut-Brain Axis and Mood Disorder. Frontiers in psychiatry, 9, 223. doi:10.3389/fpsyt.2018.00223


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