Your gut and its link with depression & anxiety

Gut link depression and anxiety

This is the first post in a series on some of the physiological (non-psychological) causes of depression and/or anxiety.

First on the list is the gut.

Our digestive system (or gut) is the epicentre of our physical and mental health, and very often, gut issues go hand-in-hand with mood problems, such as anxiety and depression.

Our gut is where the food we eat is broken down and absorbed. What we eat provides the building blocks for many chemicals in our bodies, including neurotransmitters related to mood and well being, such as serotonin, dopamine, gamma-amino butyric acid (GABA), to name just a few.

In addition, our good gut bacteria is involved in the production of B vitamins, neurotransmitters, fatty acids and amino acids all of which positively affect our mood. In addition, our gut bacteria play a critical role in mood via the communication between our gut and brain (called the "gut-brain axis"). Without enough of the good bacteria to keep the bad ones in check, our mood can be significantly affected. A poor balance in gut bacteria can lead to symptoms of anxiety such as panic attacks and low mood. Ever noticed how, at times following a tummy bug or antibiotic therapy, we may be more prone to low mood or high anxiety states? This can be due to certain pathogenic bacteria that produce substances or toxins that in turn affect mood negatively.

There are several ways in which things can go wrong with our gut, and thus set up an environment where an individual will be at an increased risk for depression and/or anxiety symptoms:

Gut inflammation, for example due to food intolerances/allergies, pathogenic bacteria or yeast, diverts the amount of tryptophan (an amino acid that is used for serotonin and melatonin synthesis) away from the serotonin pathway. This then leads to decreased levels of serotonin both in the gut and the brain and can lead to symptoms of depression and insomnia. Gut inflammation can also negatively affect levels of hormones such as testosterone and oestrogen in both men and women, which will in turn affect neurotransmitters and mood.

Another instance where things can go wrong is when there is insufficient production of stomach acid (symptoms include, but are not limited to, gastric reflux, burping, bloating, and constipation). We need sufficient stomach acid to break down our food. An impairment in proper digestion results in amino acid, vitamin and mineral deficiencies, which then impact our ability to once again make neurotransmitters, thus affecting mood.

Lastly, poor liver function, and/or an imbalance in our gut bacteria, can impair thyroid hormone activation. Not having enough active thyroid hormone has a profound effect on how our bodies function overall, and can also cause depression.

If you have any gut or digestive issues, and suffer from depression and/or anxiety, there may be a connection. Correcting digestive issues will often have a profound effect on our mood.

If you would like an individual naturopathic health consultation to address these or any other health issues that may be impacting on your mood or wellbeing, contact me to make your appointment.

Stay tuned for my next post in this series on the link between hormonal imbalance and anxiety & depression.


Yours in Health,




Bercik, P., Verdu, E.F., Foster, J.A., Macri, J., Potter, M., Huang, X., Malinowski, P., Jackson, W., Blennerhassett, P., Neufeld, K.A. and Lu, J., 2010. Chronic gastrointestinal inflammation induces anxiety-like behavior and alters central nervous system biochemistry in mice. Gastroenterology, 139(6), pp. 2102-2112.

Birdsall, T.C., 1998. 5-Hydroxytryptophan: a clinically-effective serotonin precursor. Alternative Medicine Review: a journal of clinical therapeutic, 3(4), pp.271-280.

Cryan, J.F. and Dinan, T.G., 2012. Mind-altering microorganisms: the impact of the gut microbiota on brain and behaviour. Nature Reviews Neuroscience, 13 (10), pp. 701-712.

Gropper, s, Smith, J, Groff, J 2009, Advanced Nutrition and Human Metabolism, 5th edn., Wadsworth Cengage Learning, CA.

Jackson, J.R., Eaton, W.W., Cascella, N.G., Fasano, A. and Kelly, D.L., 2012. Neurologic and psychiatric manifestations of celiac disease and gluten sensitivity. Psychiatric Quarterly, 83(1), pp.91-102.

Kharrazian Datis 2010, Why Do I Still Have Thyroid Symptoms When My Lab Tests Are Normal?, Morgan-James, NY.

Mass, M., Kubera, M. and Leunis, J.C., 2008. The gut-brain barrier in major depression: intestinal mucosal dysfunction with an increased translocation of LPS from gram negative enterobacteria (leaky gut) plays a role in the inflammatory pathophysiology of depression. Neuroendocrinology Letters, 29(1), pp. 117-124.

Rhee, S.H., Pothoulakis, C. and Mayer, E.A., 2009. Principles and clinical implications of the brain–gut–enteric microbiota axis. Nature Reviews Gastroenterology and Hepatology, 6(5), pp. 306-314.