How Microbiome Health Might Contribute to Depression

Depressed? Your Gut Health Could Be the Answer!

The relationship between the gut microbiome and the brain—the Gut-Brain Axis—has come into the spotlight in recent years and is reshaping our understanding of mental health conditions and treatment. As research related to this “gut-brain axis” continues to grow, the connections between changes in the gut microbiome and certain mental health conditions like depression are strengthening.

While no definitive cause-and-effect relationships have been proven yet, multiple studies have found correlations between our gut bacteria and its impact on brain function.

How Do You Know If You’re Depressed?

Everyone experiences feeling the blues occasionally. But how do you know if you are suffering from Major Depressive Disorder (MDD)?

Here are the 5 most common symptoms of depression:

• Persistent feelings of sadness
• Loss of interest in enjoyable activities
• Fatigue
• Appetite changes
• Thoughts of death or suicide.

And the 2 most common treatments for depression:

• Psychotherapy, specifically cognitive-behavior therapy
• And/or psychiatric medications

The medications used to treat depression can cause many patients to experience unpleasant side effects, such as:

• Weight gain
• Fatigue
• Irritability

While these treatments are helpful for some people, the reality is that many people continue to struggle with symptoms of depression even with these interventions in place.

How Does the Microbiome Relate to the Brain?

The Gut-Brain axis (GBA) is a bidirectional link between the central nervous system (the brain) and the enteric nervous system (the gut). It is made up of pathways between the cognitive and emotional sections of the brain and certain intestinal functions.

The GBA allows the brain to influence intestinal function, and vice versa, through the immune cells, enteric neurons, smooth muscle cells, and by the bacteria living in the gut.

This means that the gut microbiome impacts the intestinal functions, which then influence the brain through the gut-brain axis. Recent research has proven the existence of this gut-brain connection by showing that there are microbial imbalances present in both central nervous disorders such as depression and gastrointestinal issues such as irritable bowel syndrome (IBS).

So, How Does an Imbalanced Microbiome Contribute to Depression?

Let’s Look at The Science! One recent study found that certain bacterial compositions of the gut microbiome can induce major depressive disorder-like symptoms in mice.

Researchers sampled bacteria from patients with MDD as well as from healthy patients in a control group. They found that patients with MDD had a very different microbiome than the control group. When they transplanted the two different microbiomes into germ-free mice (which would have been a clean slate before), they found that the mice with the “depression microbiota” exhibited depressive-like behaviors compared to germ-free mice with the control microbiota. A review of several large studies looking at the impact of the gut microbiome on the gut-brain axis concluded that many different organisms in the gut can activate the immune and central nervous systems. This includes both good and bad types of bacteria.

Since some organisms in the gut microbiome produce or block neurotransmitters such as serotonin (which act on the gut-brain axis), it only makes sense that the absence or presence of those specific organisms would have an impact on the brain. Serotonin is important because it is known as the “feel good” brain chemical that helps regulate our mood and is thought to be a piece of the depression puzzle.

This is important: These studies acknowledge the potential for using probiotics to treat depressive symptoms, meaning that an increase of good bacteria in the gut microbiome could potentially help to reduce or eliminate depression and related disorders. A similar review also came to many of the same conclusions. Researchers have discovered that in animal models, depression and chronic stress are associated with drastic alterations to the gut microbiome. In addition, they are often present at the same time as gastrointestinal issues such as irritable bowel syndrome (IBS), suggesting that the condition of the gut microbiome is linked with brain health. A very recent study analyzed the gut microbiomes of over 1,000 people from the Flemish Gut Flora Project in Belgium and associated different bacterial compositions with participants’ quality of life (based on both personal and physician diagnoses).They then did the same thing with even more people from the LifeLines DEEP project in the Netherlands to validate their results. They found that two groups of bacteria

(Faecalibacterium and Coprococcus) that are responsible for producing butyrate (a short-chain fatty acid important for gut health) were consistently associated with a higher quality of life, whereas a lack of Coprococcus as well as another group of bacteria called Dialister was correlated with a lower quality of life.

This means that specific types of bacteria, or a lack thereof, have the potential to be directly linked to cognitive issues such as depression. In addition, the researchers found a positive correlation between quality of life and the gut microbiome’s ability to produce a product of the neurotransmitter dopamine, which is associated with happiness.

What Can You Do to Create a Healthy Microbiome & Reduce Depression?

While the studies done so far do not prove a concrete cause-and-effect relationship between the gut microbiome and depression or other mental health disorders, they make it clear that there is much to be gained by continuing to study these links.

In the meantime, since we know the gut and the brain influence each other, you should do everything you can to create a healthy microbiome so that the brain can function as it should.

Here are 4 easy ways to balance the gut and heal the brain:

• Take high-quality, 100% spore-based probiotics to balance your microbiome.
• Eat a healthy, high-fiber diet. Try including fermented foods like yogurt or kefir, which feed the good bacteria in your gut.
• Move your body. Exercise is a depression buster. Even just 30 minutes a day of walking does wonders for the body and the brain.
• Practice mindfulness and meditation.