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Stress: Gut Brain Connection

Updated: Aug 25, 2021

“The brain-gut axis is a bi-directional between the brain and the gastrointestinal tract, linking emotions and cognitive centers of the brain with peripheral control and function of the gut." -Emeran Mayer, MD

The Gut and Brain Connection! What’s the big deal!!!

Ever notice when you are anxious or about to speak in public that all of sudden boom! Nausea, queasiness or gotta run to the restroom!! That is your GUT signaling to your BRAIN that things aren’t right!!!

Stress means physical, mental and emotional stress, which includes the intake of crap food. The gut signals our brain that we will then show up as symptoms of nausea, queasiness, or diarrhea. Now, if the distress signals are ignored, then we can see worsening symptoms from brain fog, fatigue, aches and pain.

Our gut, often referred as the "second brain" sends a lot of signals to our brain through various interconnected mechanisms from chemical messengers called our neurotransmitters, nervous system and our microbiome.


First, our gut produces chemicals called neurotransmitters, such as serotonin and dopamine. Approximately 90% of serotonin and 50% of dopamine are produced in the gut. We usually associate serotonin and dopamine as brain hormones that affect our mood and emotions. Dopamine is sweetly named our “happy hormone”. In addition, dopamine controls our muscle, ability to focus and helps with our memory. Serotonin helps with mood but pain control, digestion and appetite. Stressful stimuli will negatively affect our gut, causing inflammation in the gut and neurons that produce the neurotransmitters. The neurons (and microbiome. Further info below) can affect the production and action of serotonin and dopamine.


Next, our nervous system plays a role in our gut and brain communication system, most especially our enteric nervous system. The enteric nervous system has been called the "first brain" because of evidence that it was developed before the central nervous system. The enteric nervous system works almost independently from the central nervous system, which means the gut has its own communication nervous system with the brain. The enteric nervous system has 90% of the information going from the gut to the brain via the vagus nerve!! The gut does a lot of talking to the brain. Our central nervous system via the sympathetic and parasympathetic system affects our digestive system. If we are stressed, the sympathetic nervous system (flight/fight mode) takes over and halts our digestion, absorption, and peristalsis. Our body needs to be in a parasympathetic, rest mode to properly digest our food.


Lastly, our microbiome in our gut. Our gut’s microbiome houses trillions of microbes that affect the health of the gut. We can associate an unhealthy microbiome with many gut associated illnesses (like irritable bowel syndrome and constipation) and links to systemic illnesses (asthma, allergies, hypothyroidism and anxiety/depression). The microbiome also plays a role in producing and metabolizing neurotransmitters. Then the health of the gut is communicated to the brain by the enteric nervous system.

What have we learned?

The gut and brain connection is a big deal!

The health of our gut is important as the gut and brain communicate constantly and affect our digestive, mental health, and total body health. Crap food and stress affect our health, but we can help our gut by maximizing having healthy, nutritious whole foods and minimizing stress and crap food and prioritizing rest and relaxation.

In a functional medicine practice, the focus is on the health of the gut and how it has affected our body systematically. The increasing scientific information is showing the body’s interconnectedness from how the immune, nervous, endocrine (hormone) and other systems interact, communicate and affect each other. Very fascinating!

Remember to limit crap food, toxins and stress.

You are not what you eat. You are what you eat, digest, absorb, and eliminate.

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