top of page

Gut-Brain Connection

Could your gut be causing your next anxiety attack? Could your brain be causing your digestion issues?

Have you ever felt "butterflies" in your stomach, or have a "gut wrenching" experience, or even have a "sickness" feeling in your stomach? These are just some of the many ways we describe the connection between your brain and your digestive system. It's no joke.

Your brain has a direct effect on your stomach and intestines via the Vagus Nerve. For example, the very thought of eating can release digestive enzymes before food gets there. We often don’t know why a gut feels sick until we understand that our gut is talking to us. When people experience discomfort in their gut, they are not always dealing with a problem that has a simple physical cause. People who have functional gastrointestinal disorders often experience anxiety, stress, or depression, which can result in symptoms that may feel unrelated to the intestine. This is very common and a proposed issue with patients that suffer from Irritable Bowel Syndrome.

The Second Brain

The gut is more than just digestion - the GI tract is home to many different microorganisms. Research has shown that the way the gut microbiome affects your mood and affects your body’s response to stress are linked, and that it can make a difference in your mood. Your gut bacteria also participate in digestion, so by improving your gut microbiome, you can help your gut bacteria regulate how your body responds to stress. Your gut bacteria are responsible for producing about 95% of your body's serotonin, the hormone largely responsible for stabilizing your mood and happiness. By learning how to improve your gut microbiome, you can help improve how it affects your brain and mood.


Your Gut-Brain connection is affected by inflammation mediated by the immune system. When you have inflammation that lasts for long periods of time it can lead to a number of disorders like depression or Alzheimer's disease.

Inflammation located in the gut, mediated by Lipopolysaccharide (LPS), an inflammatory toxin made by certain bacteria, can lead to a systemic immune response. LPS and inflammation have been associated with severe depression, dementia and schizophrenia.

The bottom line

Your gut and brain are connected physically through millions of nerves but also through hormones, inflammation and the immune system.


Breit S, Kupferberg A, Rogler G, Hasler G. Vagus Nerve as Modulator of the Brain-Gut Axis in Psychiatric and Inflammatory Disorders. Front Psychiatry. 2018 Mar 13;9:44. doi: 10.3389/fpsyt.2018.00044. PMID: 29593576; PMCID: PMC5859128.

Pellissier S, Dantzer C, Mondillon L, Trocme C, Gauchez AS, Ducros V, Mathieu N, Toussaint B, Fournier A, Canini F, Bonaz B. Relationship between vagal tone, cortisol, TNF-alpha, epinephrine and negative affects in Crohn's disease and irritable bowel syndrome. PLoS One. 2014 Sep 10;9(9):e105328. doi: 10.1371/journal.pone.0105328. PMID: 25207649; PMCID: PMC4160179.

Yano JM, Yu K, Donaldson GP, Shastri GG, Ann P, Ma L, Nagler CR, Ismagilov RF, Mazmanian SK, Hsiao EY. Indigenous bacteria from the gut microbiota regulate host serotonin biosynthesis. Cell. 2015 Apr 9;161(2):264-76. doi: 10.1016/j.cell.2015.02.047. Erratum in: Cell. 2015 Sep 24;163:258. PMID: 25860609; PMCID: PMC4393509.

Lucas SM, Rothwell NJ, Gibson RM. The role of inflammation in CNS injury and disease. Br J Pharmacol. 2006 Jan;147 Suppl 1(Suppl 1):S232-40. doi: 10.1038/sj.bjp.0706400. PMID: 16402109; PMCID: PMC1760754.

Kelly JR, Kennedy PJ, Cryan JF, Dinan TG, Clarke G, Hyland NP. Breaking down the barriers: the gut microbiome, intestinal permeability and stress-related psychiatric disorders. Front Cell Neurosci. 2015 Oct 14;9:392. doi: 10.3389/fncel.2015.00392. PMID: 26528128; PMCID: PMC4604320.


bottom of page