How Your Gut Affects Your Mental Health: the Gut-Brain Connection

by Emily Curwood

The gut is somewhat of our bodies most underrated organ: when we develop from a clump of cells into a human being we develop from three ‘tubes’, one goes on to form the nervous system, of which the most important feature is the brain and the second forms our cardiovascular system, the main feature being the heart. The third tube is the intestinal tube and its key element is the gut, or intestine. However we often view the heart and the brain as the most essential elements to life, without the brain we wouldn’t be able to understand or conceptualise, and the heart has the pivotal role of pumping blood, and with it oxygen, around our body: the gut is never viewed of being of equal importance. But our gut is not solely responsible for digestion, like we are all taught, it has influences across the entire human body. The gut microbiome plays an important role in the well-being of our immune system: an imbalance of microbes, in addition to the myriad of ‘good’ bacteria that it contains, can contribute to weight gain, high blood sugar high cholesterol and other disorders. But beyond our immune system our gut health has a direct influence of our mental health…

There are many common expressions linking the gut to feelings in our brain; “a gut-wrenching” experience, or “butterflies” in your stomach or even something that makes you feel “nauseous”. These expressions are often seen as a myth, a common saying that viewed to not actually mean anything, but this is not true; our gastrointestinal tract is sensitive to emotion. This is due to the two-way communication present between our brain and the microbes in our gut (known by scientists as gut microbiota), referred to as the gut-brain-axis. Due to this connection being two-way, poor gut health can be the cause or product of feelings such as anger, anxiety, sadness, and elation. There have been multiple studies conducted to display this connection; in 2017 a group of people with moderate to severe depression were put into two groups. One group were told by a dietician to follow the Mediterranean diet for 3 months and the other group were given a type of counselling to act as the placebo. This study had a remarkable conclusion; those following the Mediterranean diet had a much greater improvement in happiness levels compared to placebo, moreover 30% of those in the Mediterranean diet group improved their mental health to such a level deemed as clinical remission.  However it is not just simply emotions that our gut health can influence, studies in the field of neuropsychology have also lead to strong speculation that there is an association between changes in the gut microbiome and the development of mental health problems, such as bipolar disorder or schizophrenia.

The obvious conclusion to these studies is the emphasis of the importance of gut health, especially maintaining a strong balance of beneficial bacteria in your gut biome. These main bacteria are probiotic bacteria, which is commonly found in fermented foods such as yogurt, kombucha, pickles and sourdough bread. In addition to probiotics, prebiotics are also extremely beneficial to gut health; while prebiotics do not contain living organisms, unlike probiotics, they contain indigestible fibres that are consumed by probiotic bacteria and converted into other healthful substances. Prebiotic foods include onions, oats, cabbage, and asparagus.

Most studies concerning the gut-brain axis are still ongoing, and research to support the theories of the link between gut health and mental health disorders are only being currently conducted on a small scale and in the preclinical stage. However positive outcomes that scientists have received on early research is opening the door to large scale, human clinical studies that could possibly reinvent the treatment of mental disorders and increase the understanding on the link between our gut and the brain.