The Gut Brain Connection 101

By: Clara Wisner

May 13, 2016


The gut brain connection is one of my favorite new topics. There is an incredible amount of new research coming out on this subject daily, and all of it is super interesting (especially if you are a gut-health nerd like me!).

Therefore, I wanted to give a general overview about this topic, so that the person who won’t spend tons of time pouring over the research can still make educated decisions about their gut and brain health.

First off, there are few concepts you need to be familiar with.

The Gut: small intestine

- actually located where we generally refer to our stomach

- a part of the GI tract, which also includes the large intestine, stomach, and colon.

- the gut is our interface between the outside and inside world, separated by one-cell-thickness. These cells are called “enterocytes".

- The resident microorganisms in our gut, outnumbering by 10:1 our human body cells, develop an ecosystem through postnatal exposures, in the vaginal canal, through breastfeeding, and the immediate environment.  This means we actually contain more bacterial DNA than human DNA!

Fight or Flight vs Rest and Digest

- Body has two key systems:

- Fight or Flight (sympathetic nervous system): our body diverts all its resources towards immediate survival.  It is ready to fight or flee. Digestion doesn’t happen, our body is ready to use any energy it has on the task at hand, not more long term health tasks like reproduction, digestion, or rebuilding immunity.

- Rest and Digest (parasympathetic nervous system): Should be the dominant state. Digestion happens, we detoxify, we build and circulate hormones, rebuilding or immune system and structures, etc.

- This is huge for the gut brain connection because, as we’ll see, when we are in a fight or flight response, our brain and gut don’t communicate well, and problems arise.

The gutbrain axis refers to the biochemical signaling taking place between the GI tract and the nervous system, often involving intestinal microbiota, has a lot to do with healthy brain function. 

Vagus Nerve:

- The vagus nerve is the tenth cranial nerve, and runs from the spinal chord into the digestive tract.

- Connects with the ‘rest and digest’ control of the heart and digestive tract.

Leaky Gut

AKA Intestinal permeability.

When the “tight junctions” in the gut’s single cell layer get inflamed and loosen allowing junk to get through and into the blood stream, causing a whole host of health issues.

(refer to picture)


Enteric Nervous System:

- The gut has a mind of its own, the "enteric nervous system". 

- Sometimes it’s hard to imagine having a brain in our gut, since we’re used to thinking of the brain in our head, but really the brain is a complex web of nerve impulses, neurons, neurotransmitters, etc., not the structure necessarily.

- The gut's brain or the "enteric nervous system" is located in the sheaths of tissue lining the esophagus, stomach, small intestine and colon.

- it is a network of neurons, neurotransmitters and proteins

- it zaps messages between neurons' support cells like those found in the brain proper

- a complex circuitry that enables it to act independently, learn, remember and, as the saying goes, produce gut feelings.

  • Your enteric nervous system would function completely if severed from the spinal chord.
  • The gut contains 100 million neurons, more than the spinal cord
  • Major neurotransmitters like sertonin, dopamine, glutamate, etc. are in the gut and made in the gut
  • The gut is rich source of natural benzodiazepines- the family of psychoactive chemicals that includes xanax and valium,
    • Could have to do with why high anxiety is related to gut health.


The Gut-Brain Axis: How the Gut Affects the Brain

  1. When there is destruction of beneficial microbes– from antibiotics, birth control, processed foods, chemicals, stress, etc. leads to an increase in pathogenic yeasts and bacteria. This leads to:
  • Leaky gut
  • Chronic low grade inflammation
  • Inflammatory cytokines and other toxins damaging and crossing the blood-brain barrier
  • Inflamed brain
  • Decreased nerve conductance
  • Depression and reduced vagus nerve communication
  • And the whole cycle begins again….
  1. Dairy and Gluten– These contain opiate like substances that come from the improper break down of the gluten and casein proteins found in grain and dairy products. These can replicate the symptoms of a drug addiction in both children and adults and affect the functioning of the brain.

- When we are struggling with leaky gut or any neuro issues, these should be the first to get cut out of the diet.


What can we do to make sure our gut-brain communication is healthy:

  • Limit/Remove inflammatory foods: gluten and dairy, in particular
  • Drink bone broth daily to heal the one-cell layer lining your gut
  • Eat sauerkraut/fermented veggies daily to support good bacteria growth
  • Mitigate the amount of toxins we are taking in to minimize the destruction of beneficial bacteria. Avoid: NSAIDS (Tylenol, IBprofen), toxic cosmetics, toxic cleaning products, plastics of all kinds, do not cook on Teflon pans, etc.
  • Stimulate the vagus nerve by:
    • Gargling
    • Laughing
    • Deep breathing/Meditation
    • Singing
    • Spending time in uncomfortably hot or cold environments has been shown to stimulate the vagus nerve. So go outside without a coat on a chilly morning or opt to not turn the AC on in the car.
  • Address digestive issues ASAP because, as you can see from this article, digestive issues can quickly lead to neurological issues.

This is a very basic overview of the gut brain connection, but I hope it guides you to make healthier decisions in your every day life.

If you are curious about your digestive or neurological symptoms and how they might be healed through nutrition and lifestyle, feel free to book a complimentary 30 minute health breakthrough phone session with me by clicking the link [ ].


Clara Wisner is a Certified Nutrition Therapy Practitioner and Lifestyle Coach. She attended school at the Nutrition Therapy Institute in Denver, CO from 2012 to 2015. Clara Wisner is also a Certified Primal Expert and a Certified Sugar Detox Coach. She has a B.S. in Resource Conservation and a B.S. in Economics from the University of Montana. She specializes in helping women ditch toxic habits and release the self-sabotaging beliefs that keep them from creating the health and happiness they desire with her unique approach that addresses mental, physical, spiritual, and emotional health. She is a world traveler and is working on cookbook tentatively called Global Superfoods: 10 Traditional Recipes for Cutting Edge Health. Clara organizes the Paleo Pop Events in Denver, helping to create a healthier, stronger, more connected community. She currently lives in Denver, CO with her husband and the paleo puggle, Ooli. In her free time she Crossfits, cooks, writes poetry, walks dogs (other peoples’ and her own), listens to A LOT of podcasts, reads fantasy novels and also loves to read about biology, neurology, and marketing. 

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