The Fascinating Link Between Gut Flora And Anxiety And Depression

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Depression is a devastating illness affecting 20% of the world’s population. ^1,2 By 2030, it will be the most common illness worldwide. ⁷

“Can you believe that 1 in every five people around you feels down, has poor self-confidence, and lacks interest in life?”

A patient’s tendency to depression has always been put down to nature and nurture.

A combination of underlying genetics and
their environment. ¹

Recently, a new area of research has shown a third factor, the bowel microbiome. In this article, I will discuss the link between gut flora and anxiety and depression.

Limited resources in many countries mean underdiagnosed and undertreated anxiety and depression. Antidepressant medications are often expensive. They may mask the underlying emotional triggers. They also have side effects.

Antidepressants are essential and lifesaving for some patients. Others do not respond well to these medications; about 35% of patients are treatment-resistant. ⁷

The link between gut flora and anxiety and depression is fascinating and might lead to innovative and unusual treatment options for mental illness. ¹

Table of Contents

Your bowel bacteria

Approximately 1000 bacterial species live in your gut; that is 100 trillion bowel flora cells. ^1,2,6

Your pattern of commensals is as unique as you are. It is one of a kind and referred to as a stool signature. ¹Even identical twins’ signatures vary more than 50%. ⁹

Genetics plays a role in your early stool signature. As does your birth method, hospital environment, and feeding method as a baby. ^1,3

Changes in your gut flora signature

These bacteria usually live in harmony. Various triggers can send them into an unhealthy, unbalanced state. ^1,3

Antibiotics
Obesity
High-fat and high-sugar diets
Pesticides and heavy metals
Social stressors
Gut infections

Also read: 4 Tips On How to Increase Good Bacteria in Your Gut and Be Happier

Your gut microbiome’s purpose

Your gut microbes have many functions.

Assisting bowel movement
Aiding digestion and nutrient absorption
Helping with metabolism
Boosting immune function
Allowing the gut to talk to the brain

The last point is the topic of this post.

How your bowel bacteria chat to your brain

Gut microbes speak to the brain in three ways.

Along nerves,
via hormones and chemicals, and
through immune system cues.⁴

I know it sounds unbelievable; you must trust me on this. The details of the research are outside the scope of this post.

I will list some of the substances your gut flora produces that affect your brain: gamma-aminobutyric acid (GABA), noradrenaline, serotonin, dopamine, and acetylcholine. ⁶Doesn’t that blow your mind?

It works both ways.

The brain can influence gut flora by changing the intestine’s movements and fluid absorption. This alters the microbiome home environment with stool consistency and transit time.⁴This, in turn, favors differing bacterial species.

This backward and forward communication is called the brain-gut-microbiome axis.

Interruptions of these pathways at any point can cause illness.⁴

Brain and mental disorders like depression or anxiety
Gut problems like irritable bowel syndrome (IBS)

Gut flora and anxiety and depression

Both anxiety and depression are associated with changes in the gut flora.⁶

By analyzing stool signatures of patients, studies have been able to identify differences between the microbiomes of depressed, anxious patients and healthy counterparts.¹

“There were more Enterobacteriaceae and Alistipes in chronically depressed patients’ microbiomes and fewer Faecalibacterium, Coprococcus, and Dialister.” ²

You don’t need to know those names; it is more to illustrate the point.

Antidepressants and your gut flora

Studies have proved that antidepressants help to improve the number of good bacteria in your gut. ^2,7

Possible new depression treatment options

Fecal microbial transplantation (FMT)

You read that correctly, a poop transplant.

A healthy individual donates gut flora to replace the disrupted microbiome in an ill patient. ⁹

This has proved a successful therapy for chronic bowel disease and gut infections. Studies suggest it might be a unique option for the treatment of depression. ^2,7

Psychobiotics

“Psychobiotics are defined as probiotics that confer mental health benefits to the host when consumed in a particular quantity through the interaction with commensal gut bacteria.” ⁶

90% of the body’s serotonin is produced in the gut from something called tryptophan. Tryptophan can also be broken down into kynurenine, which is bad news. Kynurenine’s breakdown products suppress the immune system and are brain-toxic. ^2,8

Serotonin makes you feel good. Kynurenine increases depression symptoms.

Psychobiotics stimulate the serotonin pathway. ²

There are many promising studies on lactobacilli psychobiotics and the treatment of depression.

Lactobacillus plantarum 299v is one of these. ² It’s available over the counter in South Africa to treat irritable bowel syndrome.
Lactobacillus plantarum JYLP-326 is another probiotic that, in a trial, reduced test-anxiety in students writing exams. ⁵
Lactobacillus rhamnosus JB-1 has proved valuable in depression and anxiety treatment. ²

“This does not mean that you should stop your antidepressants.”

As mentioned above, your antidepressants help restore your gut microbiome’s balance.

Psychobiotics need more research, but adding one might benefit your treatment.

Next, read 4 Tips On How to Increase Good Bacteria in Your Gut and Be Happier

References

Limbana, T., Khan, F., & Eskander, N. (2020). Gut Microbiome and Depression: How Microbes Affect the Way We Think. Cureus, 12(8), e9966. https://doi.org/10.7759/cureus.9966
Irum, N., Afzal, T., Faraz, M. H., Aslam, Z., & Rasheed, F. (2023). The role of gut microbiota in depression: an analysis of the gut-brain axis. Frontiers in behavioral neuroscience, 17, 1185522. https://doi.org/10.3389/fnbeh.2023.1185522
Capuco, A., Urits, I., Hasoon, J., Chun, R., Gerald, B., Wang, J. K., Kassem, H., Ngo, A. L., Abd-Elsayed, A., Simopoulos, T., Kaye, A. D., & Viswanath, O. (2020). Current Perspectives on Gut Microbiome Dysbiosis and Depression. Advances in therapy, 37(4), 1328–1346. https://doi.org/10.1007/s12325-020-01272-7
Martin, C. R., Osadchiy, V., Kalani, A., & Mayer, E. A. (2018). The Brain-Gut-Microbiome Axis. Cellular and molecular gastroenterology and hepatology, 6(2), 133–148. https://doi.org/10.1016/j.jcmgh.2018.04.003
Zhu, R., Fang, Y., Li, H., Liu, Y., Wei, J., Zhang, S., Wang, L., Fan, R., Wang, L., Li, S., & Chen, T. (2023). Psychobiotic Lactobacillus plantarum JYLP-326 relieves anxiety, depression, and insomnia symptoms in test anxious college via modulating the gut microbiota and its metabolism. Frontiers in immunology, 14, 1158137. https://doi.org/10.3389/fimmu.2023.1158137
Toro-Barbosa, M. D., Hurtado-Romero, A., Garcia-Amezquita, L. E., & García-Cayuela, T. (2020). Psychobiotics: Mechanisms of Action, Evaluation Methods and Effectiveness in Applications with Food Products. Nutrients, 12(12). https://doi.org/10.3390/nu12123896
Kumar, A., Pramanik, J., Goyal, N., Chauhan, D., Sivamaruthi, B. S., Prajapati, B. G., & Chaiyasut, C. (2023). Gut Microbiota in Anxiety and Depression: Unveiling the Relationships and Management Options. Pharmaceuticals (Basel, Switzerland), 16(4), 565. https://doi.org/10.3390/ph16040565
Dantzer, R. (2017). Role of the kynurenine metabolism pathway in inflammation-induced depression – Preclinical approaches. Current Topics in Behavioral Neurosciences, 31, 117. https://doi.org/10.1007/7854_2016_6
Guinane, C. M., & Cotter, P. D. (2013). Role of the gut microbiota in health and chronic gastrointestinal disease: Understanding a hidden metabolic organ. Therapeutic Advances in Gastroenterology, 6(4), 295-308. https://doi.org/10.1177/1756283X13482996