The Gut Brain Connection
Eleni Chechopoulos  |  Sep 25, 2018

You might not be aware of it, but you’re probably already in tune with your gut-brain connection. Have you ever felt sick to your stomach? Had a gut feeling about something? Felt butterflies before a presentation? Told someone to trust her gut?

Your gut, or your enteric nervous system, is your second brain, and researchers are now paying more attention to the link between the gut and the brain. The connection between the central nervous system, the autonomic nervous system, and the enteric nervous system seems to be undeniable.

Experiencing gut reactions to emotional and mental stress is due to the connection between the brain and the gut by way of the vagus nerve. The vagus nerve, a cranial nerve that runs from the brain stem to the colon, consists of fibers that detect internal bodily sensations and links the heart, brain, and gut. Your brain sends signals to your gut, and your gut sends just as many, if not more, signals back to your brain through this nerve. Not only that, but about 90% of your serotonin, an important chemical and neurotransmitter that helps regulate appetite, mood, sleep, memory, and social behavior, is made in your gut.

By now you probably know that it is important not to eat when stressed. When you are stressed, you are operating in a sympathetic state. Your sympathetic nervous system is what activates the fight or flight response. When you are in a state of stress or panic, you are not thinking about food, and digestion shuts down. Imagine being chased by a lion. All of your blood and energy is going to your muscles so you can run for your life. Stress physically alters the composition of good bacteria and bad bacteria in your gut. This isn’t such a big deal when fleeting moments of stress happen, but when you are chronically stressed the composition of your gut changes, which impacts the way you feel mentally, physically, and emotionally.

Aside from the scientific explanation, digestive issues, gut issues, and food sensitivity reactions can also simply mimic symptoms of an anxiety attack—rapid heart rate, shallow or difficult breathing, increased perspiration, lightheadedness, and dizziness, to name just a few. If you are already prone to anxiety, experiencing these very real symptoms in your gut can trigger an anxiety attack. The quickest way to experience an anxiety attack is to worry about having one and adding the physical symptoms you’d typically experience during an anxiety attack compounds the issue.

Researchers now believe that there is a link between depression, autism spectrum disorder (ASD), and the gastrointestinal tract[1]. Individuals with depression and ASD often exhibit imbalanced gut flora, or too much of the “bad” bacteria and/or not enough 

enough of the “good” bacteria. These individuals also often experience an increase in intestinal permeability, otherwise known as “leaky gut”.

This imbalance of bacteria is also seen in individuals with IBD, obesity, cardiovascular disease, and it affects social behaviors, emotional behaviors, anxiety, and brain development[1].

What’s even more interesting is that through dietary adjustments, stress management, and even fecal transplants, improving gut health and digestion often leads many people to experience an improvement in the state of their mental health. This is due to the bi-directional interaction between the brain and the gut. One study showed that participants who consumed yogurt (a probiotic-rich food) regularly had lower levels of activity in the part of the brain associated with emotion and pain, and higher levels of activity in areas associated with decision making[2]. Another study found food addiction and eating for pleasure rather than hunger more prevalent in people who had higher levels of the metabolite indole (a product of metabolism produced by intestinal bacteria) in their gut microbiome[3], indicating that the gut microbiome plays a large role in behavior patterns.

But what causes a dysbiosis that’s dramatic enough to alter one’s behavior and state of mind? There are a few things:

  • Stress
  • Illness
  • Antibiotics
  • A diet high in sugar
  • A highly refined diet
  • Consuming foods you are sensitive to

If you struggle with anxiety, depression, mood swings, or any sort of psychological distress, one piece of the puzzle is likely tending to the health of your gut and vagus nerve. Making some dietary and lifestyle changes can help not only your digestion, but your mood as well.

  1. Eliminate sugary and processed food.

Foods that are processed and full of sugar increase inflammation in the body. Sugary and processed foods also cause blood sugar spikes and dips, eventually causing insulin resistance and increasing the rate of glycation in the body. Glycation happens when glucose reacts with proteins, resulting in “sticky proteins” that accelerate the aging process and impact everything from gut health to brain health. This leads to a reduction in GABA, a neurotransmitter that inhibits anxiety, dopamine (which gives the brain vitality) and serotonin (which helps regulate mood, appetite, sexual desire, sleep, and memory).

  1. Take a probiotic or consume probiotic-rich foods.

Probiotics help crowd out the bad bacteria and increase the good bacteria in your gut. This delicate balance of good and bad bacteria plays a large role in dictating your moods and emotions. Good sources of probiotic-rich foods include cultured vegetables such as sauerkraut and kimchi, grass-fed and organic yogurt, apple cider vinegar, pickles, beet kvass, and kombucha. 

  1. Consume healthy fats

Every cell in your body is made up of fats. If your diet is made up of poor quality fats, or is lacking dietary fat in general, the health of each cell in your body suffers. Sources of cell-friendly fats include animal fats from pasture-raised and grass-fed animals, unrefined coconut oil, grass-fed butter and ghee, organic and sprouted nuts and seeds, olive oil, avocado oil, wild-caught fish, MCT oil, and pasture-raised eggs. 

  1. Practice deep diaphragmatic breathing.

If you’ve ever been in a nervous panic and had someone tell you to relax and take a deep breath, that person did so because deep breathing stimulates and strengthens your vagus nerve. This decreases stress and improves heart rate variability. Any sort of breathing that allows you to visualize filling your lower lungs with air and then exhaling slowly will help stimulate this nerve[5].

  1. Hum or chant daily.

Humming and chanting activates the vagus nerve, which is connected to the vocal chords and inner ear. The vibrations of humming and chanting stimulate the vagus nerve and increase vagal tone, decreasing stress and improving heart rate variability.

[1& 2] Hsiao, E. Y., McBride, S. W., Hsien, S., Sharon, G., Hyde, E. R., McCue, T., . . . Mazmanian, S. K. (2013, December 19). Retrieved from

[3] Hall, M. (2013, May 30). Eating probiotic yoghurt relieves anxiety, says study. Retrieved September 16, 2018, from

[4] Hatoum, R. (2018, August 23). Researchers identify link between gut bacteria and eating for pleasure, as opposed to hunger. Retrieved September 16, 2018, from

[5] Diaphragmatic Breathing Exercises and Your Vagus Nerve. (n.d.). Retrieved September 16, 2018, from


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