Psychobiotics are intestinal bacteria with proven mental health benefits. Help reduce anxiety and depression with the right probiotics and prebiotic foods.
There’s a 3-pound part of you that affects your thoughts and feelings, and runs your life more than you would expect.
Surprisingly, it’s not your brain, it’s the total biomass of bacteria that lives in your intestines.
There’s new evidence that bacteria in the gut are integrally linked to the workings and the health of your brain.
Researchers are just beginning to learn how a class of probiotics called psychobiotics could be used to modify gut bacteria to alleviate anxiety, depression, and more.
Let’s take a look at this exciting new discovery to see why psychobiotics are being called “the new frontier” in mental health treatments.
The term psychobiotics was first coined in 2013 by Ted Dinan, PhD, at the University of Cork, Ireland. (1)
It sounds pretty high-tech but, in fact, it’s a twist on the familiar term probiotics — live microorganisms beneficial to health. (2)
Psychobiotics are probiotics that specifically bestow mental health benefits. (3)
More recently, the definition has expanded to include prebiotics, which act as food for probiotics and encourage their growth.
The Amazing Connection Between the Gut and the Brain
To fully understand how psychobiotics work, a little background on the important connection between your gut and your brain is needed.
Your intestines have their own nervous system which has been called the “second brain” or “backup brain.”
Neurons are generally associated with the brain, but your intestines contain 100 million of them. (4)
This is more than either your spinal cord or peripheral nervous system.
Our language is filled with terms that reflect the brain-gut connection — gut wrenching, gut instinct, gut feeling, and having butterflies in the stomach.
But it’s not just your intestines that have a two-way communication channel with the brain.
Weirdly, the bacteria that live there do as well.
The intestines contain 100 trillion microorganisms comprising over 1,000 species. (5)
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These microorganisms are referred to collectively as your gut or intestinal flora, microbiome, or microbiota.
Each of us has a microbiome as individual as our fingerprints.
Virtually everything you do and everything that happens to you from the moment you’re born contributes to the creation of your unique gut flora profile.
Factors that impact your gut flora include your age, gender, lifestyle, geographic location, diet, stress, and antibiotic use. (6)
Gut microbes may even play a role in personality.
Researchers have developed germ-free mice that are born with no gut bacteria and live in sterile environments.
When a germ-free mouse is exposed to the bacteria of a regular mouse, amazingly it adopts the personality of that donor mouse! (12)
The Real Benefits of Probiotics for Your Brain
How Psychobiotics Affect the Brain
Probiotics work in a wide variety of ways to improve overall health.
They crowd out “bad” bacteria, aid digestion, break down toxins, and synthesize certain essential nutrients such as folic acid and vitamin K. (13)
But to qualify as a psychobiotic, a probiotic must specifically provide mental health benefits.
There are many existing theories on how psychobiotics affect the brain.
Here’s a look at the five most likely mechanisms.
Vagus Nerve Communication
The vagus nerve is the longest cranial nerve, relaying messages between the intestines and the brain while touching many organs in between.
It is thought to be a major way that psychobiotics exert influence on the brain. (14)
Dr. Ted Dinan’s research supports this.
He and his colleagues found that when mice were given the probiotic Lactobacillus rhamnosus they showed fewer signs of stress, anxiety, and depression. (15)
But mice with a severed vagus nerve did not experience the same benefits.
GABA Supplements for Stress and Anxiety Relief
Neurotransmitters are chemicals brain cells use to communicate with each other.
But neurotransmitters aren’t found only in the brain.
The gut’s enteric nervous system (ENS) uses and produces over 30 neurotransmitters. (16)
This enables the ENS to work on its own to control digestion — with no input from the brain.
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More than 90% of your total serotonin and 50% of dopamine resides in the intestines. (19)
Here’s a chart that shows some common gut bacteria and the neurotransmitters they create.
Another way psychobiotics work is by reducing cortisol.
Some strains of psychobiotics have been shown to significantly reduce levels of this stress hormone. (20)
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Study participants who took a combination of Lactobacillus helveticus and Bifidobacterium longum for one month experienced a large drop in cortisol levels and significant improvement in mood. (25)
How to Reduce Cortisol, the Stress Hormone
Inflammation is a natural healing mechanism.
But it can get stuck “on” leading to inflammatory diseases like arthritis and allergies.
When chronic inflammation sets up in the brain, it can cause a host of brain-related disorders including depression. (26)
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New Brain Cell Formation
Lastly, psychobiotics may work by increasing levels of brain-derived neurotrophic factor (BDNF).
This important brain protein has natural antidepressant properties and stimulates the formation of new brain cells. (29)
So far, this effect has been observed only in lab animals and not humans. (30)
Brain Inflammation May Be the Cause of Your Depression
Evidence-Based Benefits of Psychobiotics
The research on the potential benefits of psychobiotics is very promising.
There’s evidence they can bring relief to some of the most common mental conditions of our times including anxiety, depression, and memory loss, as well as the effects of stress.
Here’s a sampling of research highlights on the benefits of psychobiotics.
A review of 38 studies found that probiotics effectively reduced symptoms of anxiety, depression, autism, and obsessive compulsive disorder, while improving various kinds of memory. (31)
A meta analysis of 96 trials found that probiotics were associated with a significant reduction in depression. (32)
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One bacteria, Bifidobacterium infantis, altered levels of serotonin much like the antidepressant Prozac. (33)
A mix of Bifidobacterium and Lactobacillus species reduced sadness, rumination and aggressive thoughts. (34)
Using Psychobiotics Therapeutically
The evidence is clear that psychobiotics bestow numerous mental health benefits.
But determining which strains of probiotics are the best for the many brain disorders that exist is definitely a work in progress.
The general consensus among experts is that a lot more research is needed. (37)
So far, researchers have only scratched the surface.
Most studies use species of Bifidobacterium (B. longum, B. breve, or B. infantis) or Lactobacillus (L. helveticus or L. rhamnosus) bacteria.
This means there are still 1,000 additional species of bacteria to be considered!
Dr. Emeran Mayer, author of The Mind-Gut Connection, believes clinically tested psychobiotics won’t be available for another five to ten years.
Dr. Philip Burnet, a psychobiotic researcher from University of Oxford, cautions not to expect psychobiotic supplements to become a substitute for psychotropic medications but to be a useful adjunct instead. (38)
So while your doctor won’t be prescribing psychobiotics anytime soon, here are six things you can do on your own to optimize your microbiome right now.
Balance Your Neurotransmitters to Take Control of Your Life
SUBJECT: Sharper thinking, better mood
Movies like Limitless and Lucy have fueled an interest in the power of nootropics. Nootropics are substances that claim to make you smarter, highly focused, and more productive.
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Deane & Dr. Pat
1. Take a Psychobiotic Supplement
You can take probiotic supplements that qualify as psychobiotic, but finding one that contains proven species can be a challenge.
Psychobiotic expert Dr. Tim Dinan warns consumers not to fall for false claims.
Discouragingly, he insists that few probiotics marketed as cognitive enhancers or mood boosters offer any real benefits. (39)
There are very few probiotic supplements developed specifically for mental health and not all strains used in studies are commercially available.
The label below is from a supplement with some science behind it — Mood Probiotic by InnovixLabs.
It contains two strains of probiotics, Lactobacillus helveticus and Bifidobacterium longum, which have been proven beneficial to mood.
2. Take a Probiotic Supplement for General Health
If you aren’t sure where to start, or aren’t sure you need a true psychobiotic, consider a probiotic that contains a variety of Lactobacillus and Bifidobacterium species.
These are the two best groups of probiotics to support both brain health and general health as well.
But do your homework before buying any probiotic supplements.
One study found that only one out of 17 probiotic products were accurately labeled. (40)
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One foolproof way to find quality supplements that contain these genus of bacteria is with LabDoor.com’s probiotic ranker.
LabDoor buys supplements off the shelf and then has them analyzed at independent labs.
You can easily find their highest ranking supplements in one or both of these probiotic categories.
Serotonin Foods and Mood Disorders
3. Eat Probiotic Foods
There are some drawbacks to taking probiotic supplements.
There is no guarantee they contain what is stated on the label.
There’s doubt whether these microbes make it alive past your highly acidic stomach.
And taking them over time can be expensive.
Eating probiotic foods — foods that contain microbes — is the more sustainable way to increase your good gut bacteria.
Virtually all healthy traditional diets wisely included fermented foods. (41)
Lactobacillus and Bifidobacterium, mainstays of probiotic and psychobiotic supplements, are commonly found in probiotic foods as well. (42)
Add these to your diet to boost your friendly flora naturally:
- Fermented dairy products including yogurt and kefir. Choose unsweetened products that state they contain live cultures.
- Fermented soy foods like miso, tempeh, and tamari. Stick with traditionally fermented products.
- Fermented vegetables such as pickles, sauerkraut and kimchi. Avoid vegetables soaked in vinegar. Look for those traditionally fermented and labeled unpasteurized.
For tips on finding foods that contain beneficial live cultures, see the fermented foods section in 12 Brain Foods That Supercharge Your Memory, Focus & Mood.
4. Eat Prebiotic Foods
Prebiotics provide the “food” your good bacteria needs to thrive.
Ingesting probiotics without them is like trying to grow flowers on concrete.
Some experts believe that prebiotics are even more important than probiotics for maintaining a healthy microflora. (43)
Prebiotics alone can reduce stress, anxiety, and depression. (44)
Unwisely, most of us grab unhealthy foods like pizza, chips, and ice cream as our comfort foods.
A smarter idea would be to eat foods high in prebiotic fibers including asparagus, Jerusalem artichokes, bamboo shoots, bananas, barley, chicory, dark chocolate, leeks, garlic, jicama, lentils, mustard greens, onions, and tomatoes. (45, 46, 47)
If you want to learn more about incorporating both probiotics and prebiotic foods into your diet, you’ll find everything you need to know in neurologist Dr. David Perlmutter’s cutting-edge book Brain Maker: The Power of Gut Microbes to Heal and Protect Your Brain for Life.
5. Play in the Dirt
Not all beneficial bacteria enter by mouth.
Simply inhaling Mycobacterium vaccae, a bacteria found in soil, can improve your mood by stimulating the production of serotonin.
M. vaccae activates the same neurons in the brain as the antidepressant Prozac. (48)
6. Stop Killing Your Good Bacteria
Antibiotics are the biggest danger to your microbiome since they indiscriminately kill the good bacteria along with the bad.
But less obvious factors such as stress, prescription medications, poor diet, underlying health concerns, and the widespread use of artificial sweeteners also contribute to the demise of good bacteria. (51, 52, 53, 54)
Rethinking Our War on Bacteria
The use of antibiotics against infectious diseases is arguably the most important medical advance of all time.
But there’s a lot of evidence that we’ve gone too far.
Antibiotic overuse has made antibiotic-resistant bugs a frightening reality. (55)
An alarming 70% of all antibiotics are used in livestock feed. (56)
And our collective mental health may be suffering from it.
It’s time to stop our war on microbes and accept our lifelong symbiotic relationship with them.
Bacteria have been found living in the most hostile environments on earth. (59)
Recently, live microbes were found trapped inside 50,000-year-old cave crystals in Mexico. (60)
They’ve even been found growing on the outside of the International Space Station! (61)
They are that ubiquitous and that tough.
And without them life as we know it could not exist.
In this engaging TED Talk, nutritionist, microbiologist and neuroscientist Ruairi Robertson explains that our gut bacteria is naturally as diverse as an Amazon rainforest.
Unfortunately, our war on bacteria has left our gut a barren wasteland instead.
Psychobiotics: The Bottom Line
Psychobiotics are at the frontier of advancement in mental health care.
These live bacteria impact your brain health and function in an amazing variety of ways.
They may be the next generation of treatment for anxiety, depression, and other mental disorders.
But, in the meantime, you can optimize your intestinal microflora by taking the right supplements and eating a diet that contains both probiotics and prebiotic foods.
Encouraging the growth of good bacteria may be one of the most important things you can do for your general health and mental well-being.