Exercise, Gut Health, and Depression

According to the Journal of the American Medical Association, more than 20-26 per cent of women and 8-12 per cent of men suffer from depression in their lifetime. Given its prevalence, depression is something being widely studied and explored from different angles. It is commonly known that exercise can improve mental health and provide treatment for illnesses such as depression, but the precise mechanisms for how this works is something that scientists are still trying to uncover. In recent studies, researchers have discovered a new explanation as to how exercise might be working to prevent and treat depression.

You might be shocked to hear that your gastrointestinal (GI) system, or gut, is the first line of defense when it comes to having a healthy immune system and that exercise has a huge effect on preventing gut inflammation. The gut is also connected to your brain through the gut-brain axis (GBA), a system of communication where bacteria in your GI tract can activate neural pathways that impact how your brain functions, impacting your mood, stress, and mental health. The effectiveness of the GBA is determined by two things; inflammation levels in the gut, which exercise helps moderate; and gut health, which is impacted by diet and the resulting bacteria that live in the GI tract. 

Microbiota, also known as gut flora, refers to all the microorganisms (including bacteria) living in your GI tract. Commensal bacteria and probiotics provide the body with essential nutrients, whereas pathogenic bacteria cause disease in the body. All of these bacteria are significant, because the balance of good and bad bacteria significantly impacts your mental health and is what influences stress-related behaviours in the body. In addition to bacteria, the GI tract also directly impacts hormone levels. Serotonin, often referred to as the happiness hormone, is the main hormone for mood regulation in the body. Low levels of serotonin in the brain may cause depression, anxiety, or sleep trouble. Surprisingly, over 90 per cent of the body’s serotonin is made in the GI tract. Recent research shows that modifying the gut microbiota could improve symptoms of serotonin-related diseases, such as depression and anxiety, by helping regulate serotonin levels through proper diet and gut health.

Gut health is important at every age, especially in children. Borre et al.’s 2014 study shows the implications of a healthy gut in young brain development. Changes in gut bacteria early in life can lead to negative mental health implications down the road. This is why it’s crucial to have a good healthy diet at every age and promote physical activity in children and adults alike. 

These discoveries open new doors when it comes to treating and understanding mental health. Moreover, they highlight the correlation between exercise, a healthy GI system, and treatment of depression, and are the first studies pinpointing exactly how having a healthy gut through diet and exercise can lead to having a healthy mind.