Gut Health and Depression

While associations between one’s mental health and their physical health have been widely studied and discussed, recent studies on how depression is linked to gut health have thrust their mutual influences into the spotlight. Read on to find out how they interact.

Gut health and depression

What’s Love Gut to Do with It: On Mood Disorders and Digestion

Gut health refers to the state of the gastrointestinal tract. It focuses on the gastric tract’s food processing functions, which are:

  • Food transport and breakdown.
  • Extraction and absorption of nutrients and energy.
  • Waste removal.

Various gut functions are made possible through the use of trillions of bacteria, which act to process foods.

Gut health is determined by a number of factors, including one’s genetics, choices of food, exposure to medication, and stressful experiences.

In addition to its crucial role in the digestive system, recent years have found gut health to play a decisive role in certain types of cancer and adult-onset diabetes. Gut health also seems to be associated with mental health issues, and particularly those of anxiety and depression. The current article will be taking a closer look at the connection between gut health and depression.

Eat Your Heart Out: How Gut Health and Depression Interact

So how does gut health affect depression, and is there such a disorder as gut health depression?

While gut health depression is not a considered mental health disorder, the reciprocal effects of the digestive system and mood disorders have been recognized. A Finnish study from 2002, for example, found that an increased number of two types of microbes in the gut, called morganella and klebsiella, can cause the appearance of depression.

Patients with depression were also found to have stronger immune responses, such as inflammation, to morganella and a number of other bacteria produced in the gut. Colonic barrier dysfunction has similarly been linked to the increased release of cortisol and eventual increase in depressive symptoms. And stress-induced inflammation stemming from the gut has generally been shown to cause depressive symptoms.

The correlation between depression and gut health has been made clearer through studies on irritable bowel syndrome (IBD) and mental health. Depression prevalence was found to be higher among patients with IBD, as well as a lower quality of life and an increased mortality rate.

The literature on gut health and depression has already solidified a clear connection between the two. While causality has yet to be fully proven, animal studies have found that fecal transplants from patients with depression did lead to rodents exhibiting depressive symptoms. Conversely, rodents that experienced stress and depression presented a reduction in gut microbiome content number and diversity.

The Gut-Brain Axis

The gut-brain axis refers to the bidirectional communication carried out between the central nervous system of the brain and spinal cord, and the enteric nervous system of the gastrointestinal tract. The mutual messaging along this axis also appears to rely on the microbiota that exist within the gut.

The brain has direct connection to the intestinal tract, and vice versa: therefore, just as the thought of a certain food can cause the secretion of digestive juices, a malfunctioning intestine can send its own signals to the brain.

Gut health depression

(B)Eat It: What Can Be Done to Improve Related Well-Being

The gut-brain axis has been shown to influence one’s state of well-being through their ability to manage stress. As a result, the way one’s body, and specifically their digestive system, respond to stressors, has been associated with greater emotional stress levels and levels of depressive symptoms, with persistent neuroinflammation affecting mood and behavior-related brain functions.

The proliferation of beneficial bacteria in the gut also appears to contribute to greater durability in the face of depression. Incorporating probiotics into one’s diet have particularly been found to help improve one’s mental health. A Mediterranean diet, which includes high intakes of olive oil, whole grains, fruit and vegetables, fish, low-fat dairy products, and antioxidants, has been shown to help avoid physical inflammation.

A Western diet, however, with its focus on processed and red meat, high-fat dairy products, refined grains, potatoes, saturated fats, and candy, causes an increase in inflammation, thereby indirectly contributing to the increase in the prevalence of depression.

Highlighting the benefits of probiotic supplements, a study from 2015 found that certain probiotics that are a central player in healthy gut functions, and are also conducive to decreased levels of cortisol—a stress-related hormone shown to play a part in the appearance of depression. Somewhat similarly, fecal transplants containing healthy microbiomes have also been found to facilitate symptom alleviation among patients diagnosed with depression.

In addition to the consumption of certain microbiotics, a balanced diet and regular exercise has been proven to help alleviate gut-related inflammatory stressors, and through this, protect one’s mental health.

Another factor affecting gut health appears to be quality of sleep. Both a lack of sleep and unhealthy eating habits have been connected to gut leakiness, inflammation, and immune dysfunction (immunosenescence).

Minimizing one’s exposure to inflammatory-causing medication can also help promote their own mental health. Proton pump inhibitors (PPIs), for example, are commonly used to treat acid reflux or peptic ulcers. PPIs, however, are the drugs most associated with a decrease in gut microbiome diversity, and an overall change in their makeup. The use of PPIs was also linked to an increase in IBD prevalence and one’s immune system.

It should also be mentioned that studies have also found that psychotherapy can also lead to improved gut health, which in turn can favorably affect one’s mental health. A more stable approach to life and its stressors can therefore eventually provide greater well-being when faced with destabilizing factors, in cases of physical health scares, anxiety-inducing relationship experiences, or emotional triggers.