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  • Joan Rothchild Hardin

Psychobiotics for Anxiety and Depression


Source: Gut Health Project

It may strain the imagination to hear that several pounds of organisms live inside your gastrointestinal tract and that they are in constant communication with your brain, but it’s true. Actually, the communication is two way – gut to brain and brain to gut – and operates via biochemical signaling. This process is called the gut-brain axis. The gut microbiome is so so important to the body’s functioning it’s often now referred to as our second brain.

Recent research has also demonstrated that our mood is greatly affected by certain bacteria living in our gut microbiome. These bacteria profoundly influence how anxious or depressed we are. Having lots of friendly probiotic bacteria in there exerts anxiety-reducing and antidepressant effects on our emotions and physical bodies.

Fortunately for us, there is an emerging field of neuroscience called psychobiotics that is studying how changing the bacterial composition in the gut affects the brain. (Atlay, 2016)

Psychobiotics researchers are beginning to identify which probiotics have psychotropic (mind-altering) effects – boosting mood and cognitive function; decreasing stress, anxiety, and depression.

Functional Medicine doc Kelly Brogan, along with numerous others, is convinced that mood disorders and many other psychiatric problems are the results of imbalances and chronic inflammation in the gut microbiome and that psychobiotics will become the treatment of choice for mood disorders and will also be used to prevent them. She wrote:

“For two decades now, pioneering researchers have been substantiating inflammatory models of mental illnesses such as depression, bipolar disorder, and schizophrenia.  Research has focused on markers that indicate immune distress in an important subset of patients, many of whom are labeled “treatment-resistant.” Through this body of literature, we have identified that depression can be induced, in animals and in humans through inflammatory agents, that it is correlated with blood levels of inflammatory markers, in a linear way (more markers = worse depression), and that symptoms can be reversed through pharmaceutical anti-inflammatories.” (Brogan, 2014)

Source: Mercola

The well respected scientists who authored an article called Psychobiotics and the Manipulation of Bacteria–Gut-Brain Signals published a few months ago in Trends in Neurosciences believe that prebiotics (nondigestible plant fibers that nourish our probiotics) should also be included as actors in the gut-brain communication process and propose the diagram below to show how it all works (Sarkar, 2016): Systems-Level Overview of Psychobiotic Action


Source:Trends in Neuroscience

If you’re interested in a deeper understanding of how the process works, take a look at this explanation of the diagram provided by the authors:

“Probiotics directly introduce beneficial bacteria such as Lactobacilli and Bifidobacteria into the gut. Prebiotics (e.g., galacto-oligosaccharides) support the growth of such bacteria. SCFAs and gut hormones: Both probiotics and prebiotics increase the production of short-chain fatty acids (SCFAs), which interact with gut mucosal enteroendocrine cells and catalyse the release of gut hormones such as cholecystokinin (CCK), peptide tyrosine tyrosine (PYY) and glucagon-like peptide- 1 (GLP-1). Prebiotics may have stronger effects in this regard in comparison to probiotics. SCFAs and gut hormones enter circulation and can migrate into the central nervous system. Gut hormones are also secreted by tissues other than enteroendocrine cells. Neurotransmitters: psychobiotics enhance neurotransmitter production in the gut, including dopamine (DA), serotonin (5-HT), noradrenaline (NA), and γ-aminobutyric acid (GABA), which likely modulate neurotransmission in the proximal synapses of the enteric nervous system. Vagal connections: the vagus nerve synapses on enteric neurons and enables gut–brain communication. Stress, barrier function, and cytokines: barrier dysfunction is exacerbated through stress-induced glucocorticoid exposure. This enables migration of bacteria with pro-inflammatory components, increasing inflammation directly and also triggering a rise in pro-inflammatory cytokines via the immunogenic response. These cytokines impair the integrity of the blood–brain barrier and permit access to potentially pathogenic or inflammatory elements. Pro-inflammatory cytokines (red circles) also reduce the integrity of the gut barrier. Psychobiotic action restores gut barrier function and decreases circulating concentrations of glucocorticoids and pro-inflammatory cytokines. They also increase concentrations of anti-inflammatory cytokines (blue circles), which enhance the integrity of the blood–brain barrier, the gut barrier, and reduce overall inflammation. Cytokines clustering at the brain represents cytokine interaction with the blood–brain barrier. Central lymphatic vessels: cytokines may interact more directly with the brain than previously appreciated through the recently discovered central lymphatic vessels.” (Sarkar, 2016) THE GUT-BRAIN AXIS AND MOOD The gut microbiome and the brain, working together via the gut-brain axis, are jointly responsible for maintaining health in the body – including mental health. If a body has an unbalanced gut microbiome containing too few or unbalanced probiotics and prebiotics (dysbiosis) – because its owner consumes a nutritionally impoverished diet, has taken antibiotics that have killed off many probiotics in the gut, has been exposed to toxins, and/or isn’t doing a good job managing stress, the body’s intestinal lining may become too porous (a condition called leaky gut), creating chronic inflammation in the body and eventually a series of autoimmune diseases – and apparently mood disorders too.

In the diagram above from the Sarkar article, blue arrows indicate psychobiotic processes and effects, while red arrows indicate processes associated with leaky gut and chronic inflammation. RESEARCH FINDINGS ON PSYCHOBIOTICS FOR ANXIETY & DEPRESSION

Source: Organic Sunshine

Here are some intriguing results from research studies on probiotics’ and prebiotics’ effects on anxiety and depression:

A 30-day human study found these two probiotics helpful for reducing anxiety as compared to a placebo (Sarkar, 2016)

  • Lactobacillus helveticus R0052

  • Bifidobacterium longum


A mixture of these probiotics compared to a placebo, taken for four weeks, substantially reduced depression in human subjects (Sarkar, 2016)

  • Bifidobacterium bifidum W23

  • Bifidobacterium lactis W52

  • Lactobacillus acidophilus W37

  • Lactobacillus brevis W63

  • Lactobacillus casei W56

  • Lactobacillus salivarius W24

  • Lactococcus lactis W19 and W58


In a study of academic stress, healthy medical students took either this probiotic or a placebo for eight weeks before an exam. The day before the exam, plasma cortisol was substantially lower in the probiotic group  compared to the placebo group. (Sarkar, 2016):

  • Lactobacillus casei Shirota


In another study, student athletes who were given this probiotic had elevated mood and reduced natural killer cell activity after strenuous exercise, relative to placebo:

  • Lactobacillus gasseri OLL2809 LG2809

When the probiotic was taken along with this protein in milk,

  • Alpha-lactalbumin

the students also experienced less fatigue. (Sarkar, 2016)


Irritable bowel syndrome is known to be associated with disturbances in the gut-brain axis and composition of the gut microbiome. IBS is a chronic inflammatory condition and is  often accompanied by anxiety and depression. After human study participants with IBS consumed this probiotic,  their level of inflammation was reduced (as measured by the ratio of interleukin-10 to interleukin-12), compared to those who took a placebo  (Sarkar, 2016):

  • Bifidobacterium infantis 35624


In a clinical trial of people with major depressive disorder, patients were given these probiotics:

  • Lactobacillus acidophilus (2 billion CFUs)

  • Lactobacillus casei (2 billion CFUs)

  • Bifidobacterium bifidum (2 billion CFUs)


Compared with placebo, the people who took the probiotics were less depressed at the end of the eight week study  and also had significant decreases in systemic inflammation, reduced insulin resistance, and a significant rise in glutathione (the body’s master anti-oxidant). (University Health News, 2016) A study looking at the effects of these probiotics (given as Probio’Stick®) on anxiety, depression, stress, and coping strategies in healthy human volunteers found a reduction of psychological distress (particularly depression, anger/hostility, and anxiety) and improved problem solving ability at the end of the 30 day study (University Health News, 2016):


  • Lactobacillus helveticus R0052

  • Bifidobacterium longum R0175

Harrington states, “For anyone experiencing anxiety and/or depression, regular supplementation with this probiotic combination seems a natural and worthwhile practice. It is conceivable that such supplementation could reduce reliance on prescription medications and deliver freedom from the burdens of these common mental illnesses.” (Harrington, 2016)

Patients with chronic fatigue syndrome were given either this probiotic or a placebo daily for two months. The people who took the probiotic experienced a significant decrease in anxiety (University Health News, 2016):

  • Lactobacillus casei strain Shirota (24 billion colony forming units)

Animal studies have shown that this probiotic reduces depression by increasing dopamine and serotonin. This same probiotic decreased cortisol and increased dopamine and serotonin, normalizing the stress response system in depressed mice subjected to early-life stress  (University Health News, 2016):

  • Lactobacillus plantarum strain PS128


These two probiotics have been shown to reduce anxiety-like behavior and improve performance on cognitive tests in anxious mice (University Health News, 2016):

  • Bifidobacterium longum 1714

  • Bifidobacterium breve 1205


The same probiotic shown to help people with chronic fatigue syndrome has also been shown to help humans and lab animals undergoing other kinds of stress. This probiotic (consumed as kefir, a fermented milk drink that’s loaded with a variety of probiotics) prevented stress-related cortisol increases and raised serotonin levels in stressed medical students. The kefir also decreased stress-related physical symptoms such as abdominal pain and colds (University Health News, 2016):

  • Lactobacillus casei strain Shirota


Animal studies have also identified other probiotics that reduce stress-related depression and anxiety by affecting serotonin, cortisol, and other neuroactive compounds. These two, in combination, normalized anxious behaviors along with learning and memory impairments in immune-deficient rats (University Health News, 2016):

  • Lactobacillus helveticus R0052 combined with Lactobacillus rhamnosus R0011


This probiotic was more effective than the SSRI citalopram (Celexa) in reducing stress-induced anxiety, depression, and cognitive dysfunction in rats. It lowered their cortisol and restored their serotonin and other brain neurochemical levels back to normal (University Health News, 2016):

  • Lactobacillus helveticus NS8


Prebiotics, like probiotics, have also been identified as regulators of mood and brain function. A recent study found that this prebiotic decreased the secretion of the stress hormone cortisol and improved emotional processing and lowered anxiety in healthy human volunteers (University Health News, 2016):

  • Bimuno-galactooligosaccharides, B-GOS


A study of people with IBS, who typically have decreased microbial diversity in their gut microbiomes and often suffer from anxiety, found that daily consumption of this prebiotic mixture for four weeks reduced their anxiety (University Health News, 2016):

  • a galactooligosaccharide-containing prebiotic mixture in powder form


An informative article called 10 Best Probiotics For Depression & Anxiety: Gut-Brain Axis Modification names the following as the most helpful probiotics for mood regulation, describes their functions in the body, presents relevant research results from studies in which they were used as psychobiotics, and recommends some specific probiotic products. The first nine in the list are probiotics; the 10th is a prebiotic:

  • Bifidobacterium longum

  • Lactobacillus rhamnosus

  • Lactobacillus helveticus

  • Lactobacillus plantarum

  • Bifidobacterium animalis

  • Lactobacillus casei

  • Bifidobacterium infantis

  • Bifidobacterium breve

  • Lactobacillus acidophilus

  • Transgalactooligosaccharides


The article also discusses pathogenic bacteria that may CAUSE anxiety and depression:

  • Citrobacter rodentium

  • Campylobacter jejuni

  • Clostridium

  • Enterococcus faecalis


Interestingly, these pathogenic bacteria have also been found to be associated with other serious physical problems, including GI disease, stress-induced memory dysfunction, autism, chronic fatigue syndrome, and heart valve damage. COMMERCIAL PSYCHOBIOTIC  SUPPLEMENTS

If your interest in the relationship between the probiotics in your gut microbiome and your mood has been piqued, perhaps you want to pick out one or more of the probiotics mentioned above to experiment with. Start with the one that interests you most and take it for a month so it has a chance to colonize in your gut.

If deliberately encouraging a strain of bacteria to colonize your gut sounds too much like a scary science fiction movie, please remember that we’re talking about GOOD (probiotic) bacteria, ones that create health in the body, not HARMFUL (pathologic)  bacteria that create illness.

Source: Happy Oligo

Here are a few commercially available probiotic supplements that provide  psychobiotic and other benefits: Life Extension Florassist Mood Capsules

This supplement contains 3 billion colony-forming units (CFUs) of a blend of two probiotic strains demonstrated to improve mood, reduce perceived stress, and promote relaxation in humans.

  • Lactobacillus Helveticas strain R0052

  • Bifid bacterium longum strain R0175


“Research suggests specific probiotics positively influence biochemical signaling between the gastrointestinal tract and the nervous system- resulting in positive effects on mood.” (Amazon.com, 2017)

Contains milk and soybeans. The ingredients may be from GMO sources.

Life Extension  says this about the GMO issue:

“Q. Should I be concerned with the usage of genetically modified plants (GMOs)?

“A. Soybeans are an example of a crop that has used extensive genetic engineering to increase crop yield. The reality is that soybean oil and soy lecithin are highly processed derivatives of soy … far removed from their soy origin. Genetic modification doesn’t alter the entire plant… only a specific gene. Thus, specific molecules like soy lecithin are the same whether they come from a GMO or non-GMO soy source. However, due to our sensitivity to customer concerns, products with corn and soy-based active ingredients are in process of having the labels updated to list when soy and corn-derived active ingredients have been certified to be from non-GM food crops. As the labels are updated the information will be transferred to the product descriptions on our website and directory. Currently Life Extension already offers several premium quality non-GMO soy isoflavone extract products.” (Life Extension, 2017) Hyperbiotics PRO-15 Probiotics Time-Release Micro-Pearls

At time of manufacture, contains 5 billion Colony Forming Units per BIO-tract pearl,  equivalent to 75 billion CFU. Contains a minimum of 1.5 CFU at time of expiration date.

The 15 Group, B. (2015). biotic strains in this  supplement are:

  • Lactobacillus plantarum – Secretes the oxidant hydrogen peroxide which acts as a weapon to protect your body and must be present for your immune system to function correctly. Creates a healthy barrier in your colon and helps lower luminal pH, creating an unfavorable environment for the growth of pathogens including molds, yeasts and bacteria.

  • Lactobacillus fermentum –  highly antimicrobial and antioxidative. Helps inhibit the growth of harmful bacteria, yeast and other pathogens and has demonstrated clinical efficacy within immune health.

  • Lactobacillus acidophilus – Creates a fortress of good colonies that helps keep unwanted organisms out of your gut. Studies show that L. acidophilus helps to reduce occasional diarrhea and enhances your immune system and may help to reduce cholesterol levels. Studies have shown that those taking L. acidophilus experienced significantly more relief from their gastrointestinal discomfort than did those taking a placebo.

  • Bifidobacterium Infantis – Has been shown to reduce the major symptoms of GI disorders, including diarrhea, flatulence, bloating, cramping and constipation. It is particularly popular as a means of combating Irritable Bowel Syndrome (IBS) and has been shown to improve digestion and the body’s ability to absorb and process nutrients.

  • Lactobacillus casei – Along with L. Acidolphilus, converts lactose into lactic acid, helping those who are lactose intolerant. Helps to encourage the growth of other beneficial bacteria.

  • Bifidobacterium longum – Assists in breaking down carbohydrates and fighting free radicals. Provides potent antioxidant support and helps reduce the effects of seasonal allergens.

  • Lactobacillus rhamnosus – Helps reduce occurrences of traveler’s diarrhea and food poisoning.

  • Bifidobacterium lactis – Helps decrease H. pylori (a bacterium associated with the majority of stomach ulcers) and helps the production of the front line cells in your immune system.

  • Lactobacillus reuteri – Improves cholesterol levels, reduces H. plyori, protects female urinary tract and vaginal health and aids infants’ GI health.

  • Lactobacillus salivarius – Helps with GI problems (especially diarrhea caused by antibiotics), helps lactose-intolerant people digest dairy. It may lower cholesterol and blood pressure, maintain dental health, help with IBS, and boost the immune system.

  • Lactobacillus paracasei – Is key for digestive function, boosts the immune system, and energy levels, resolves infant diarrhea. It may help fight infections and relieve symptoms of chronic fatigue syndrome.

  • Lactobacillus gasseri – May speed up metabolism and encourage weight loss, protect against harmful organisms, lower cholesterol, reduce allergic response, ease symptoms of asthma in children, and lessen menstrual pain in women with endometriosis.

  • Bifidobacterium bifidum – Protects the intestinal lining from damage from toxins and pathological germs. Produces important vitamins like B12, biotin, and K2. Helps digest sugar and reduces incidence of colds and flu.

  • Bifidobacterium breve – Protects colon function, alleviates constipation, reduces gas and diarrhea. Stimulates the immune system, inhibits E. coli and suppresses the fungus Candida. Ferments sugars and produces acetic and lactic acids. Helps digest plant  fibers typically thought of as undigestible. May reduce intestinal irritation and allergic responses.

  • Streptococcus thermopholus – Breaks down lactose into lactic acid and helps boost the immune system. May lower the risk of colon cancer. May protect intestinal tissues from irritation during chemotherapy . Correlates with better growth in children.

plus 25 mg of prebiotic:

  • Fructooligosaccharides (FOS)