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The Brain/Gut Connection Influences Well Being and Mental Health

by Temecula psychologist Linda Comin, Psy.D.

How many of us over the years have heard the saying two brains are better than one?  Would you be surprised to find out that we do have two brains in our own body?  Yes it turns out that the gut does have a mind of it’s own and it is known as the “enteric nervous system”.   Just like the brain, which we identify as the mind, there is also a brain in our gut that is located in the tissue lining of our esophagus, stomach, small intestine and colon.  According to, Dr. Michael Gershon, author of “The Second Brain”, “the connection between the two can be unpleasantly clear.”  In fact, we can all relate to this statement “butterflies in the stomach”, before giving a speech, or the first time we kiss someone, anytime we have to make an important decision that involves risk, or the night before a significant examination a bout of diarrhea.  This is a direct experience of the action between our two nervous systems.

Many of you may be surprised to hear that there are 100 million neurons in the gut, and that this is greater than what we have in our spinal cord.  Furthermore, there are major neurotransmitters like serotonin (95% of serotonin is produced in the gut), as well as, dopamine, glutamate, norepinephrine, and nitric acid.  Not to mention the presence of two-dozen small brain proteins, called neuropeptides, as well as major cells of from the immune system.  The presence of Enkephalins (a member of the endorphin family) is also found in the gut.  Endorphins are small protein molecules that are produced by cells in your body and their goal is to relieve pain with an analgesia type effect.  This is experienced by some as the natural high experienced in running or some other form of exercise.  It is also one of the sited reasons why soldiers continue to fight in war when they have been injured.  Benzodiazepines an anxiolytic medication (anti-anxiety medication) is also abundantly found in the gut, from the popular psychoactive chemicals known as Valium and Xanax.

The brain and the enteric nervous system (gut) are connected by the vagus nerve.  The vagus nerve is the major communication network between the two brains.  Messages between the two brains run up and down this network and are supported by other neural networks such as the “myenteric plexus and the submucosal plexus, which command and control neurons in the gut.
According to the current research, there is a plethora of evidence that is coming to light regarding the circuitry between the two brains.  Scientists, psychologists and nutritionists are beginning to understand why people act and feel the way they do.  It has long been known by psychology the connection between fight and flight and that the response is initiated by a fearful situation, which in turn results in the release of stress hormones that prepare the body to flee or fight.  If the body prepares to fight like on the battlefield the higher brain communicates to the gut and tells it to shut down.  However, fear can also result in the opposite result whereby the vagus nerve turns up the volume of the serotonin circuits in the gut resulting in overstimulation and diarrhea.


Current research is clearly making a connection between the gut and the brain and how digestive imbalance and mental health are highly correlated.  Therefore, if we balance the gut, issues like depression, anxiety, and digestive issues, autoimmune illnesses, and arthritis, fatigue, eczema, migraines, and attention deficit disorder come into balance.

There is an old saying, “we are what we eat” and it is never truer than now.  It is time to pay attention to what we eat.  It is true that some people eat all the right foods but for some reason they cannot digest them or absorb the necessary nutrients.  In these cases the result is diarrhea, constipation or irritable bowel syndrome (known as IBS).   Below are some of the stats on what the current research is finding with gastrointestinal diseases:


• 84% of state anxiety (chronic anxiety) is related to small intestine bowel disorders, such as h-pylori and ulcerative colitis.

• 67% of trait anxiety (periodic anticipation of something happening in life) is related to irritable bowel syndrome (IBS).

• 27% of depression is related to celiac and irritable bowel syndrome.

• IBS affects 10-20% of the adults in the U.S.  According to Dr. Gershon more than a two million Americans are afflicted with IBS, which arises in part from too much serotonin in the gut, and may well be regarded in the future as the mental illness of the gut.


• 70-90% of patients who seek treatment for IBS have a psychiatric co-morbidity such as a mood disorder or anxiety disorder.

• 19% of population has schizophrenia.

• 29% of IBS patients have Major Depressive Disorder.

• 46% of IBS patients have a panic disorder.

• 40-80% are at high risk for having migraines, and fibromyalgia.

• 91% of children with autism have a gastrointestinal issue.

In my practice I focus on an integrative approach between all factors, body (food, supplements, water, breath, rest and sleep), mind (stress management, yoga, meditation and automatic negative thoughts), relationships (important connections with others in our lives), and spirit (our connections to something beyond the physical).  The client is asked to keep a thorough food diary (including how they feel after they eat certain foods) and activity log (detailing how much exercise and how they feel after they exercise).   All ingested materials are looked at included prescription drugs and supplements.   The philosophy I take is that food and exercise are our best medicine and when everything in our lives is balanced we will feel better.

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