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Gut Brain Axis

Gut / Brain Axis
Enteric Nervous System
and Mental Health

The “Gut / Brain Axis, ” a medical term coined in the early 2000’s, is becoming increasing understood in medicine as a foundational connection. Your Gut and Brain are intimately connected to each other via the “Enteric Nervous System.”

The Enteric Nervous System is also known in medicine as the “Second Brain” because it is made up of millions of nerves that communicates back and forth between your Gut and your Brain.

Intestinal bacteria is responsible for alterations in emotional and mental heath of the Brain, good or bad, via direct connections through the Enteric Nervous System, which is the definition of the Gut / Brain Axis.

Gut flora irregularities:

  1. In the UPPER GI can cause: heartburn, burping, constrictions in throat (problems swallowing), changes in appetite, and stomach ulcers.
  2. In the LOWER GI can cause: diarrhea, constipation, gas, cramps, bloating and irritable bowel syndrome (IBS), amongst other illnesses.

Mental health connections resulting from within the Gut / Brain Axis can be manifested as several symptoms, a few of which include:

  1. Changes in emotions, happy and calm verses sad and depressed.
  2. Enhanced cognitive concentration, or hindering the ability to concentrate and think clearly.
  3. Mood swings can go up or down.
  4. Enhanced or subdued alertness.


CHEMICALS: Intestinal bacteria produce chemicals which are known to alter moods as well as affect physical ailments. All hormones MUST BE IN BALANCE. A few examples of these naturally produced chemicals manufactured from intestinal bacteria include:


  1. Learning, Motivation, Heart rate, Blood vessel function, Kidney function, Lactation, Sleep, Mood, Attention, Control of nausea and vomiting, Pain processing, Movement, Anxiety, Paranoia, Schizophrenia, ADHD, Obesity, and Parkinson’s Disease.

• Epinephrine (a.k.a. Adrenaline): Dopamine is converted into Epinephrine from bacteria in the gut.

  1. HIGH LEVELS: Pounding heart, Rapid heart rate, Rapid and shallow breathing, Increased sweating, Dilated pupils, Increased ability to run or lift heavy objects, Feeling shaky or nervous, Trembling or shaking, Dizziness, and Dry mouth.
  2. CHRONICALLY HIGH LEVELS: High blood pressure, Chronic headaches, Digestive problems, Weight gain, Atherosclerosis (hardening of the arteries), Memory and concentration problems, Insomnia, Anxiety, Depression, and PTSD symptoms that do not go away.
  3. LOW LEVELS: Low blood pressure, Low blood sugar, Chronic fatigue, Lack of energy / Lethargic, Muscle weakness, Nausea, Diarrhea, Dehydration, Depression, and Irregular or missed periods.

• GABA (Gamma-Aminobutyric Acid):

  1. LOW LEVELS: Anxiety or mood disorders, Epilepsy, and Chronic pain.
  2. GABA as a Supplement: Improve mood, Relieve anxiety, Improve sleep, Help with premenstrual syndrome (PMS), Treat attention deficit hyperactivity disorder (ADHD), Relieve pain or discomfort from injuries, Increase tolerance to exercise, Lower blood pressure, Burn fat, and Increase the growth of lean muscle mass. Limited research shows a possible link to lowering Blood Pressure.
  3. GABA is found in: Spinach, Sweet Potatoes, Broccoli, Kale, and Fermented foods including Tempeh and Kimchi

• Melatonin:

  1. Control sleep cycles. Is tied to the amount of light around you. Your melatonin level usually starts to rise after the sun sets and stays high during the night. It drops in the early morning, which helps you wake up. That quality — rising at night, disappearing during the day — gives melatonin its nickname: the Dracula of hormones.
  2. Shorter winter days with limited light can throw off your melatonin production. Your body also makes less of it as you age.
  3. Melatonin as a Supplement: Jet lag, Circadian rhythm disorders among blind people, Delayed sleep disorder (when you fall asleep and wake later than a normal sleep pattern), Trouble sleeping for shift workers who must rest during daylight hours. Sleep-wake cycle issues among children with disabilities.
  4. Light: Your eyes determine the amount of light. Sitting in front of a computer screen for hours on end will affect your Melatonin release cycles, the same how daylight changes from sunrise to sunset.

• Serotonin (a.k.a. 5-hydroxytryptamine (5-HT):

  1. Acts both as a neurotransmitter and hormone. 95% is produced by your gut bacteria. Gut bacteria synthesizes the amino acid Tryptophan to create Serotonin.
  2. Effects: Happiness, Sense of well being, Digestion (suppress appetite, enhance nutrient absorption, promote insulin secretion), Sleep (works with dopamine and melatonin to prepare for falling asleep, maintain circadian rhythm.), Wound healing, Sexual desire, Immunity, and Memory.

TAKE HOME LESSON: “Balanced” intestinal micro-flora is critical for hormone production, which then affects brain symptoms.



  1. Overzealous prescribing of antibiotics by conventional medicine is the fastest way to destroy beneficial intestinal microflora. A ten-day RX of antibiotics can wipe out an entire year’s worth of remaking beneficial bacteria. The bacterial diversity in any single person’s gut in so individualized, it is like a second set of fingerprints.
  2. Overzealous RXing of antibiotics is also responsible for creating antibiotic resistant bacteria like the dreaded MRSA. In the early 1990’s, the CDC sent out letters to all licensed doctors, begging them to drastically reduce writing out prescriptions for antibiotics because the evidence was already emerging of creating horrible antibiotic resistant bacteria.
  3. Overzealous RXing of antibiotics is also responsible for creating Psychiatric Illnesses by wiping out the natural production in your gut of mood altering chemicals. Rather then a doctor prescribing prescription medications, it is far better to rebuild the intestinal micro-flora, maintain it, and do NOT RX antibiotics!


FINGERPRINTS: Intestinal bacteria is also “familial”, meaning your personal fingerprint of gut bacteria was handed down to you by your mother. And she from her mother. And she from her mother. Meaning your gut bacteria finger print has been handed down from generation to generation through your mother’s side. Habitual use (acceptance) of antibiotics wipes out generations of intestinal microflora fingerprints, which are then lost forever.

BLOOD BRAIN BARRIER: Microorganisms in the gut impacts brain development and function. Microbes affect the Blood Brain Barrier, affecting the permeability of this barrier. Microbes regulate neuro-immunity. Microbes communicate along the Gut-Brain-Microbial Axis. Infants with higher levels of the microbe “Bacteroides” had better cognitive outcomes in a published trial. Microbes have an affect on the development of the Central Nervous System. A healthy gut is essential. Just as beneficial bacteria improves health, unhealthy bacteria destroys health.

MATURED GUT FLORA: Intestinal Microflora is generally established by the mid teenager years. Interestingly, this is the exact same time when teens exert their greatest independence and begin to develop poor eating habits.

IMMUNE SYSTEM: Your Immune System is directly affected by your gut flora. Some gut bacteria will cause inflammation while other bacteria will fight inflammation. This is why some people in the same group will have severe inflammatory reactions to spring time pollens, while others in the same group are spared all of those bad symptoms. The key is what makes up their individual intestinal micro-flora “fingerprint.”



  1. Autoimmune Thyroid Diseases: Intestinal micro-flora regulates the Thyroid gland. “Dysbiosis” (gut flora is out of balance), is connected to both “non-Celiac” wheat sensitivity and “Celiac Disease” and often co-occurs with Autoimmune Thyroid Diseases such as Hashimoto’s Thyroiditis and Grave’s Disease.
  2. Micro-Nutrients: Intestinal micro-flora releases micro-nutrients from the food in your gut. Of importance to the thyroid gland are: Iodine, Copper, Iron, Selenium and Zinc. The first three are needed for making the T4 thyroid hormone. Selenium and zinc are needed to convert T4 into the active thyroid hormone T3.
  3. Thyroid Hormone Binding: The bacterial flora strains of Lactobacillaceae and Bifidobacteriaceae, stabilize thyroid function.


ENDOCRINE SYSTEM: Adrenal Corticoids. It has been well established the chronic stress and anxiety can burn out the adrenal glands, called “adrenal exhaustion.” It goes deeper than that. A published study in 2021 revealed that corticosterone production is driven by intestinal micro-flora. The mechanism of action is the microbiota provokes expression of genes including steroidogenesis. Genesis is the term for creating something biological. Steroids is what is being created. Steroidogenesis is how your body makes steroids in the first place.



1) Find a doctor who understands the importance of treating gut bacteria.

Secondary, two choices:
1) Doctor takes a stool sample and prescribes individual bacterium to see what helps.
2) Doctor helps re-establish ALL gut bacterium as one great whole.

I prefer the second. Why? There might be other bacterium that are lacking but and have not become problematic YET, but may become an issue in the future.

Medical Topics
Female Hormones Demolition Ball

DISCLAIMER This information is provided for Educational Purposes Only and has NOT been designed to diagnose, treat or cure any health conditions. Please consult a qualified Health Care Professional with Nutritional Training to diagnose your health conditions and avoid self-diagnosis. The U.S. Food and Drug Administration have not evaluated statements about these health topics or any suggested product compositions.