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When we think about our gut, or our “gastrointestinal (GI) tract”, we know that it is responsible for helping food travel through our body, allowing us to break food up and get the nutrients we need to fuel our body. We may feel as though we have no control over the processes regulated in the gut since it happens without the need for us to consciously control it, but that does not mean that there is no connection between our mind and gut.

It’s important to note that all over the world, rates of depression and anxiety have been on the rise. It is interesting to look at the connection between our gut health and the intensity of depression and/or anxiety disorders [4]. Recent research has emerged showing a link between a bad diet and negative effects on our mental health. The key connector between these two factors may be our gut microbiome [4].

Our gut microbiome, also referred to as gut flora is made up of trillions of microorganisms, mainly different types of bacteria, that live in our intestines. These bacteria are very important in helping us digest food and absorb the nutrients we need from them [8]. They also help with other processes in the body, like metabolism, body weight, immune regulation, and as mentioned, are now being found to have a link to mood and other brain functions [8].

Everyone’s gut microbiome is unique, although we may share some characteristics with people of similar body types. Our microbiome is believed to start developing from the womb and continues to develop throughout life [8][9]. Many factors can influence the appearance of the microbiome. Whether you were breastfed, your genetics, and more controllable factors, such as your diet can all modify aspects of the microbiome.

Your gut microbiome is like a fingerprint, or a snowflake; each one is distinctive from others, no two look the same [8][9]. A healthy gut is one that does the job well, and in this sense, a healthy gut microbiome should do its jobs of: stopping undigested food products from leaving the GI tract, as well as fight off infections, and absorb nutrients. A healthy gut doesn’t have a specific set of bacteria needed, rather it should just be able to get the job done [9].

When we think about if there is a connection between the gut and mind, let’s think to times one has influenced the other [7]. For instance, when you were nervous to give a presentation (mind), did you ever start to feel butterflies in your stomach (gut)? Or, when under a lot of stress, were you hit by pain in your stomach? These are all examples of the mind and gut influencing one another [7].

When looking specifically at the gut in connection with mood disorders, research had indicated a link between gut issues, like irritable bowel syndrome (IBS) being a result/symptom of depression [2]. However, newer research is now finding that connection may work both ways, and illnesses, like IBS, can actually cause depression as well. This can be seen by the fact that people with IBS and other functional bowel issues develop depression and/or anxiety as well [2].

As mentioned, based on previous studies, mood disorders are thought to be linked to your gut health, but what exactly are the mechanisms behind this connection?

Research is currently working on answering this. One thing that is still uncertain is which one came first? It is a chicken or egg situation where it is unclear if the mood disorders cause poor gut health or the other way around [5]. Based on this knowledge gap, there are two big hypotheses behind this connection. There is evidence that some people with major depressive disorder (MDD) have gut flora that are lacking in diversity, making the gut less healthy. For this reason, the first hypothesis is that MDD and other mental health illnesses are the causes of poor gut diversity [5][10]. Another hypothesis is that lacking specific gut flora contributes to more severe depression, as evident through rodent studies [10]. One of the most supported hypotheses is that bacteria in our gut can trigger the nervous system and this acts as the mediator between our mind and gut connections [6][10].

It may sound daunting that this connection clearly exists, but the mechanism behind it is still not clear. However, from what we do know, there is some form of a connection present and therefore what we can focus on is how to ensure our gut flora is healthy [6].

The Canadian Digestive Health Foundation provides us with many ways we can ensure our guts are thriving [1]. The first is making sure we eat our vegetables! Especially dark, leafy, green ones. Vegetables (and fruits!) are high in fibre, which we may not be able to digest but the healthy bacteria in our gut can! A diet high in fruits and vegetables helps to make sure we don’t grow any unhealthy bacteria in our guts. As you can see, what we eat also feed the bacteria in our gut, these kinds of foods are called prebiotics [1]. In addition to fibre, other foods high in prebiotics are whole grains, garlic, red wine extract, and lentils. Prebiotics is also the reason you want to limit processed sugar. Processed sugar is digested so quickly in our body that our gut flora doesn’t get a chance to eat any, which starves them and makes them die! Instead, you can try natural sugars like those found in honey, dark chocolate, mangoes, and others (but remember everything is fine in moderation, you never have to completely cut foods for a healthy diet!) [1]. Another food you can introduce into your diet are probiotics [6]. Probiotics are full of live, healthy bacteria that will help your gut flora flourish. You can get these from the grocery stores, and lots of yogurts commonly have some added into them. You can typically find probiotics in many fermented foods, yogurt as mentioned, as well as kombucha, pickles, kimchee, and kefir, which are all great sources and will keep your gut healthy and happy [1].

Turning away from food, something that affects your gut flora is taking antibiotics. Antibiotics are a very necessary part of healthcare as they eliminate harmful bacteria from your body, but they do not know the difference between good and bad bacteria and work by also wiping out the bacteria in your gut. To help our microbiome against anti-biotics, try eating meat without added antibiotics, and when you are sick and need to take antibiotics, add a probiotic to your day as well [1].

In addition to diet, it is important you get enough sleep! Studies have provided evidence that people with irregular sleep schedules are at risk of disrupting their gut flora and causing inflammation in the gut because of it. Try to get in your 7-9 hours a night [1].

Also, don’t forget to get that workout in! People who are physically active in the week, have been found to have healthier and more diverse gut flora [1]. Aim for the Canadian guidelines of 150 minutes of physical activity a week. Try to incorporate an active lifestyle into your daily to do list to meet this goal, like starting off with a light walk everyday [3]!

Lastly, as we talk about mood disorders and mental health in general, it is important to explore your own mental health and try to make time for yourself. Life can be crazy and hectic, and trying methods like yoga or mindfulness, can provide some avenues to work on your mental health [1]. Prioritize your health physically, and mentally, to provide yourself time to re-energize for the next day!

Author: Javaria Bhatti

References

[1] 10 ways to strengthen your microbiome. Canadian Digestive Health Foundation. (2022, February 11). Retrieved April 1, 2022, from https://cdhf.ca/health-lifestyle/10-ways-to-strengthen-your-microbiome/

[2] The brain-gut connection. Johns Hopkins Medicine. (n.d.). Retrieved April 1, 2022, from https://www.hopkinsmedicine.org/health/wellness-and-prevention/the-brain-gut-connection

[3] CanGov. (n.d.). Canadian 24-hour movement guidelines: 24Hour Movement Guidelines. Retrieved April 1, 2022, from https://csepguidelines.ca/

[4] Dash, S., Clarke, G., Berk, M., & Jacka, F. N. (2015). The gut microbiome and diet in psychiatry. Current Opinion in Psychiatry, 28(1), 1–6. https://doi.org/10.1097/yco.0000000000000117

[5] Evrensel, A., & Ceylan, M. E. (2015). The gut-brain axis: The missing link in depression. Clinical Psychopharmacology and Neuroscience, 13(3), 239–244. https://doi.org/10.9758/cpn.2015.13.3.239

[6] Foster, J. A., & Neufeld, K.-A. M. V. (2013, February 4). Gut–Brain Axis: How the microbiome influences anxiety and depression. Trends in Neurosciences. Retrieved April 1, 2022, from https://www.sciencedirect.com/science/article/abs/pii/S0166223613000088

[7] The gut-brain connection. Harvard Health. (2021, April 19). Retrieved April 1, 2022, from https://www.health.harvard.edu/diseases-and-conditions/the-gut-brain-connection

[8] Jacka, F. (2016, July 4). What is the gut microbiome? Food and Mood Centre. Retrieved April 1, 2022, from https://foodandmoodcentre.com.au/2016/07/what-is-the-gut-microbiome/#:~:text=Your%20’gut%20microbiome’%20is%20made,to%20your%20health%20and%20wellbeing

[9] Malan-Muller, S., Valles-Colomer, M., Raes, J., Lowry, C. A., Seedat, S., & Hemmings, S. M. J. (2018). The gut microbiome and mental health: Implications for anxiety- and trauma-related disorders. OMICS: A Journal of Integrative Biology, 22(2), 90–107. https://doi.org/10.1089/omi.2017.0077

[10] Winter, G., Hart, R. A., Charlesworth, R. P. G., & Sharpley, C. F. (2018). Gut microbiome and depression: What we know and what we need to know. Reviews in the Neurosciences, 29(6), 629–643. https://doi.org/10.1515/revneuro-2017-0072