The Connection Between Gut Health and Anxiety

February 26, 2024   •  Posted in: 

What is the connection between the gut and mental health conditions like anxiety? This article gives an insight into how the gut-brain axis can influence anxiety levels and mental well-being and how improving gut health has the potential to alleviate symptoms.

The mind-gut connection

Increasingly, researchers have been exploring the remarkable link between the brain and the gastrointestinal tract, commonly known as the “gut.” This connection is referred to as the “gut-brain axis,” which serves as a communication network between the central nervous system (the brain and spinal cord) and the enteric nervous system (a mesh-like system of neurons that governs the function of the gastrointestinal tract)[1].

The gut houses a complex nervous system with 500 million neurons and 40 neurotransmitters. The enteric nervous system is often dubbed the “brain of the gut” or “the second brain” because it functions independently from the central nervous system. It forms an extensive network of nerve cells that regulate various processes, including digestion and even the familiar sensation of “butterflies” in your stomach when feeling anxious.

Think of the gut-brain axis as a conversation between two people. Each side interacts and responds based on the other’s actions. One example is how thoughts of eating can trigger your stomach to initiate the digestive process[2]. Conversely, when you haven’t eaten for an extended period, your stomach signals the release of ghrelin, a hormone that increases appetite and prompts you to eat.

The microbiome is the term for the collection of microorganisms residing in the gut. The gut microbiome influences both sides of the gut-brain axis.

When studying anxiety and depression, scientists have investigated the gut microbiomes of animals with intriguing results. In one study, researchers transferred the gut microbiomes from rats displaying signs of major depression into healthy rats with no signs of depression[3]. Remarkably, the previously healthy rats began to exhibit signs of depression.

Such findings suggest the gut microbiome may significantly influence mental health. The ongoing research in this area offers exciting possibilities for understanding and potentially treating mental health conditions.

What is the gut microbiome?

Until recently, the vast galaxy of 100 trillion bacteria, viruses, fungi, yeasts, and parasites in our bodies (especially within the digestive system) was relatively unknown to most of us. This community of more than a thousand species of invisible microbial passengers collectively weighs as much as a small bag of potatoes.

These microorganisms tirelessly work day and night on your behalf, breaking down foods, eliminating toxins, and taking charge of your gut health. They hold sway over your brain through the microbiome-gut-brain axis.

Numerous studies are uncovering the intricate ways in which these microbes interact with your brain, influencing your thoughts, feelings, and behavior. The growing body of evidence leads scientists to re-categorize this microbiome as a significant player in shaping your overall well-being.

Through the microbiome-gut-brain axis, these invisible inhabitants exert their impact, underscoring the vital connection between gut health and mental well-being.

Understanding the gut’s impact on mental health

While earlier studies dating back to the 19th and early 20th centuries demonstrated the influence of the brain and emotions on gastrointestinal function[4], recent research has shifted its focus on how the gut can affect mental health, such as anxiety and depression. One exciting line of inquiry is how, when, and why the gut acts autonomously and sends messages to the brain through the vagus nerve, influencing behavior.

While the gut may have an impact on a range of mental health issues, the interplay between anxiety and stomach pain is a particularly intricate one. When experiencing nervousness or excitement, you might have noticed the stomach’s response, often described as having a “knot in the stomach” or “butterflies.”

The sympathetic nervous system, also known as the “fight or flight” response, triggers these physical sensations, which prepares us for action during perceived threats. Adrenaline – the stress hormone – floods our bodies, increasing heart rate and breathing while slowing down gut activity as digestion becomes less crucial for survival in dangerous situations[5].

Usually, the parasympathetic nervous system counteracts the stress response, bringing us back to a state of calmness where heart rate and breathing return to a steady baseline.

For some individuals, the stress response can be triggered by non-life-threatening situations, meaning the calming reset doesn’t occur, thus leading to constant feelings of anxiety. This might result from trauma, but not always.

Interestingly, 50% of dopamine, responsible for reward and motivation, is produced in the brain and gut. Additionally, a staggering 95% of serotonin, a mood-stabilizing neurotransmitter that influences sleep, is produced in the gut.

However, neither dopamine nor serotonin can cross the blood-brain barrier[6], and research continues to be conducted into its role in the gut. The relationship between anxiety and stomach pain is complex and requires further understanding to address its impact on overall well-being.

How to support the gut microbiome and improve mental health issues

Your brain health has significant roots in early childhood and can be influenced, in part, by genetic factors inherited from your parents. However, emerging research is shedding light on the impact of the food you eat and the microbes in your stomach and intestines.

Some of these microbes play a vital role in affecting your mental health, shaping your thought processes, behaviors, and even your susceptibility to certain mental illnesses. Recent findings have linked anxiety, depression, ADHD, and memory issues to imbalances in the gut flora.

By studying the microbes in your gut, in the future, it may be possible to pinpoint specific conditions and, through targeted interventions like introducing new microbial species, restore balance and positively affect these illnesses.

While altering your genes is beyond your control, the latest research promises to put the fate of your mind within your own hands in a simple and cost-effective manner. With the advent of specially designed “brain biotics”, you may be able to change your brain’s chemical balance, ushering in a new era of brain medicine at the cutting edge of science.

What are psycho-biotics?

The term “psycho-biotics” was introduced in 2013 by Ted Dinan from the University of Cork. Initially, it referred to specific live microbes that, when consumed in sufficient quantities, could positively alter the gut’s bacterial composition, subsequently beneficially impacting mental health. Essentially, these were probiotics with brain-changing properties.

Over time, the definition of psycho-biotics has expanded to encompass any approach that influences brain function and behavior by modulating the gut microbiome. This includes specific probiotics and prebiotics and certain foods and exercise, which have demonstrated substantial effects on mood and mental activity. By increasing the presence of these psycho-biotics (sometimes known as “brain-biotics”) in the gut, the harmful bacteria-causing issues can be reduced, leading to improved digestive health.

The link between gut health and conditions like anxiety, depression, psychiatric, and neurodegenerative illnesses has been well-established. Our modern lifestyles expose us to numerous factors that can negatively impact gut health, such as excessive antibiotic and prescription medication use, pesticides in food and air, and chemicals found in our homes, beauty products, and clothing.

The discovery of psycho-biotics offers a degree of control over our brain’s health. However, it is crucial to note that not all psycho-biotics are beneficial. Antibiotics, anti-psychotics, and antidepressants have been shown to permanently alter the gut’s terrain, causing neurochemical and behavioral changes that negatively affect the brain. Therefore, being mindful of the impact of various psycho-biotics is essential to promote overall well-being.

Harnessing the power of psycho-biotics for mental health

The following psycho-biotics are believed to impact a range of mental health issues[7], including anxiety, with specific strains offering specific benefits.

Be patient with psycho-biotics for optimal results, as positive effects may take around two to three weeks to manifest. A daily dose of at least 10 billion CFUs (colony-forming units) is generally recommended.

Find out more about prebiotics and probiotics, as well as delivery and dosage information, in our article on Understanding prebiotics and probiotics.

Lactobacillus rhamnosus: A game changer

One prominent psycho-biotic, Lactobacillus rhamnosus, can be easily found on health food store shelves and is a crucial component of many probiotic supplements.

Again, different strains offer specific benefits. The GG strain has shown promise in reducing obsessive-compulsive disorder (OCD) behavior, performing as effectively as fluoxetine, an antidepressant used for OCD treatment[8].

Certain yogurts, semi-hard cheeses, and fermented milk also contain this beneficial psycho-biotic.

Bifidobacterium longum: Easing anxiety and depression

Bifidobacterium longum, through various strains, has demonstrated its potential to alleviate anxiety and depression[9]. It can also impact paranoia, compulsions, and obsessions.

Some strains travel via the vagus nerve, leading to reduced anxiety-like behavior and normalized responses. Moreover, specific strains reduce cortisol levels and enhance memory.

Lactobacillus plantarum: The anxiety-reducer

Though research on Lactobacillus plantarum mainly involves mice, it has shown effectiveness in reducing anxiety[10].

Strain PS128 increases serotonin and dopamine levels while also reducing inflammation (inflammation can also have adverse effects on the central nervous system, which could contribute to depression).

Furthermore, Lactobacillus plantarum has been found to decrease cortisol, normalize the stress response system, and alleviate depression in depressed mice subjected to early-life stress.

This psycho-biotic is present in fermented foods like sauerkraut, pickles, and kimchi.

Lactobacillus helveticus: The calming agent

Lactobacillus helveticus, strain R0052, works wonders in reducing cortisol levels and minimizing paranoid and obsessive-compulsive thoughts[11].

Other strains, like NS8, exhibit anti-inflammatory effects in the brain and alleviate anxiety. In fact, strain ND8 outperformed the well-known antidepressant citalopram in reducing stress and depression levels while boosting serotonin levels (in rats)[12].

Lactobacillus helveticus is found in cheeses such as Emmental, Cheddar, Parmesan, Romano, provolone, and mozzarella.

Lactobacillus reuteri: The inflammation controller

Lactobacillus reuteri, discovered in the 1980s, is an excellent probiotic for controlling inflammation. It reduces stress hormones and modifies GABA receptors for the better.

For those who have autism or social awkwardness and anxiety, strain 23272 can be highly beneficial[13].

Lactobacillus casei: The mood booster

Lactobacillus casei is known for its anti-inflammatory properties and ability to enhance antioxidant levels. Taking it daily can help reduce exhaustion, digestive issues, and anxiety. Lactobacillus casei has also been demonstrated to positively impact HDL cholesterol levels[14].

A strain of Lactobacillus casei called Shirota was found to substantially decrease anxiety symptoms in patients with chronic fatigue syndrome and digestive problems[15].

Lactobacillus fermentum: The calming ally

Lactobacillus fermentum, present in fermented vegetables like kimchi and sauerkraut, is an ideal choice for treating anxiety as it reduces inflammation and promotes a calm mind[16].

Bifidobacterium breve: Focusing the mind

Bifidobacterium breve, strain 1205, effectively reduces anxiety-like behavior in animals, making it suitable for calming excessive anxiety and enhancing focus[17].

Bifidobacteria infantis: Elevating mood

This strain boosts tryptophan levels, the precursor to serotonin (the so-called “happy hormone”[18]). Additionally, Bifidobacterium infantis helps reduce inflammation levels.

Galacto-oligosaccharides: The mind’s ally

Galacto-oligosaccharides (GOS) serve as prebiotics, stimulating the growth of beneficial gut bacteria. Prebiotics can reduce stress, anxiety, and depression.

GOS has been shown to decrease cortisol secretion and enhance focus on positive information[19].

Seeking anxiety treatment

Feeling anxious or stressed occasionally is normal, but if constant worry impacts your daily life, it may indicate an underlying issue.

If you suspect that anxiety is affecting your well-being, it’s essential to consider anxiety treatment and consult with a professional counselor, psychologist, or psychiatrist. These professionals have access to therapeutic tools and medications that can effectively address anxiety.

The gut-brain connection reveals how stress and anxiety can influence the gastrointestinal system. Managing stress and incorporating gut-friendly foods can be beneficial.

However, it’s essential to recognize that the relationship between the gut and brain works both ways. Gut issues might result from stress or anxiety, making it crucial to address the underlying anxiety to improve gastrointestinal health.

Nevertheless, if similar symptoms persist, consulting a doctor is essential to rule out other potential gastrointestinal issues.

Whole Person Care at The Center • A Place of HOPE

At The Center • A Place of HOPE, we deeply understand the intricate connection between the mind and body. Our founder, Dr. Jantz, pioneered the Whole Person Care approach in the 1980s, focusing on holistic health encompassing mental, physical, spiritual, nutritional, intellectual, relational, and spiritual aspects.

When you participate in our treatment programs, we address each facet of your well-being, identifying how they may contribute to your condition. Healing occurs at every level with our comprehensive approach.

To learn more about our admissions process or our anxiety treatment options, reach out to us or schedule a call to begin your journey toward improved well-being.


1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4367209/
2. https://pubmed.ncbi.nlm.nih.gov/3940915/
3. https://pure.rug.nl/ws/portalfiles/portal/34658674/Transferring_the_blues_Depression_associated_gut_microbiota_induces_neurobehavioural_changes_in_the_rat..pdf#page=10&zoom=100,0,0
4. Cannon, W., 1909. The Influence Of Emotional States On The Functions Of The Alimentary Canal. The American Journal of the Medical Sciences, 137(4), pp.480-486.
5. https://www.health.harvard.edu/staying-healthy/understanding-the-stress-response
6. Bektaş A, Erdal H, Ulusoy M, Uzbay IT. Does Seratonin in the intestines make you happy? Turk J Gastroenterol. 2020 Oct;31(10):721-723. doi: 10.5152/tjg.2020.19554. PMID: 33169710; PMCID: PMC7659911.
7. Davenport, S. (2020) Brain biotics, ReBoot Health. Available at: https://www.reboothealth.co.uk/blog/brain-biotics.
8. Kantak, Pranish A.; Bobrow, Dylan N.; Nyby, John G.. Obsessive–compulsive-like behaviors in house mice are attenuated by a probiotic (Lactobacillus rhamnosus GG). Behavioural Pharmacology 25(1):p 71-79, February 2014. | DOI: 10.1097/FBP.0000000000000013
9. Pinto-Sanchez, M.I. et al. (2017) ‘Probiotic Bifidobacterium Longum NCC3001 reduces depression scores and alters brain activity: A pilot study in patients with irritable bowel syndrome’, Gastroenterology, 153(2). doi:10.1053/j.gastro.2017.05.003.
10. Meng X, Gao Y, Qi H, Ding Y, Sun Y. Clinical Application Value of Lactobacillus Plantarum PS128 in Patients with Anxiety Disorders. Clin Psychopharmacol Neurosci. 2022 Aug 31;20(3):560-566. doi: 10.9758/cpn.2022.20.3.560. PMID: 35879040; PMCID: PMC9329101.
11. Messaoudi, M. et al. (2011) ‘Beneficial psychological effects of a probiotic formulation (lactobacillus helveticusR0052 andbifidobacterium longumR0175) in healthy human volunteers’, Gut Microbes, 2(4), pp. 256–261. doi:10.4161/gmic.2.4.16108.
12. Liang, S. et al. (2015) ‘Administration of lactobacillus helveticus NS8 improves behavioral, cognitive, and biochemical aberrations caused by chronic restraint stress’, Neuroscience, 310, pp. 561–577. doi:10.1016/j.neuroscience.2015.09.033.
13. Duque, A.L. et al. (2021) ‘Effect of probiotic, prebiotic, and synbiotic on the gut microbiota of autistic children using an in vitro gut microbiome model’, Food Research International, 149, p. 110657. doi:10.1016/j.foodres.2021.110657.
14. Front. Microbiol., 10 September 2018, Sec. Food Microbiology, Volume 9 – 2018 | https://doi.org/10.3389/fmicb.2018.02107
15. Kato-Kataoka, A. et al. (2016) ‘Fermented milk containing lactobacillus casei strain Shirota prevents the onset of physical symptoms in medical students under academic examination stress’, Beneficial Microbes, 7(2), pp. 153–156. doi:10.3920/bm2015.0100.
16. Liu, Y.-W. et al. (2019) ‘Lactobacillus fermentum PS150 showed psychotropic properties by altering serotonergic pathway during stress’, Journal of Functional Foods, 59, pp. 352–361. doi:10.1016/j.jff.2019.05.043.
17. Savignac, H.M. et al. (2014) ‘bifidobacteriaexert strain-specific effects on stress-related behavior and physiology in BALB/C Mice’, Neurogastroenterology & Motility, 26(11), pp. 1615–1627. doi:10.1111/nmo.12427.
18. O’Mahony, S.M. et al. (2015) ‘Serotonin, tryptophan metabolism and the brain-gut-microbiome axis’, Behavioural Brain Research, 277, pp. 32–48. doi:10.1016/j.bbr.2014.07.027.
19. Torres, D.P.M. et al. (2010) ‘Galacto-oligosaccharides: Production, properties, applications, and significance as prebiotics’, Comprehensive Reviews in Food Science and Food Safety, 9(5), pp. 438–454. doi:10.1111/j.1541-4337.2010.00119.x.

Dr. Gregory Jantz

Pioneering Whole Person Care over thirty years ago, Dr. Gregory Jantz is an innovator in the treatment of mental health. He is a best-selling author of over 45 books, and a go-to media authority on behavioral health afflictions, appearing on CBS, ABC, NBC, Fox, and CNN. Dr. Jantz leads a team of world-class, licensed, and...

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