How You Can Harness Psychobiotics To Soothe Stress (specific strains that help)

Are you feeling confused about the latest gut health trending buzzword “psychobiotics”? 

Wondering where the word came from or what psycho-biotics actually are? [Hint it’s nothing to do with scary movies, full-moon antics or otherwise crazy behaviour]. 

Maybe you’d like to know the difference between a regular probiotic from a psychobiotic or even a prebiotic for that matter….

…With the fast-tracked advances in microbiome research happening globally – it can be hard to keep up with all the new terminology (and the epic discoveries).

So here I’d like to talk you through the basics of psychobiotic science, clear up the confusion and empower you with the knowledge to face the probiotic shelf with confidence…

…To help you conquer stress, anxiety, memory problems and cognitive or learning challenges.

Yes…psychobiotics can affect all that!

Let’s talk – about my favourite topic – your gut bacteria!

What are Psychobiotics?

Psychobiotics are defined as “beneficial bacteria (probiotics) or support for beneficial bacteria (prebiotics) that influence bacteria-brain relationships”. 

To understand this statement better, let’s have a look at the definitions of both pro- and pre- biotics.

Probiotics: live microorganisms that offer a health benefit (specific bacteria)

Prebiotics: a substance that is selectively used by microorganisms offering a health benefit (specific food for probiotics)

In a nutshell, you can think of psychobiotics as…

… both probiotics (specific bacteria) AND prebiotics (specific food for probiotic bacteria) that offer a health advantage *specifically* to the brain and nervous system.

If you’ve been following us for a while, you’ll know that the gut is like your second brain – and it’s intimately linked with your actual brain. 


How Psychobiotics Work

This connection is commonly known as the gut-brain axis. We will just go over the basics here…

…As I talk about the gut-brain axis at length in our article Gut-Brain Connection and How It Affects Your Mood – you can read more about our fascinating gut-brain connection here.

Fundamentally, your gut-brain axis includes your:

  • Central Nervous System (CNS) – your brain, spinal cord and nerves
  • Endocrine System – hormones that affect the brain and nerves
  • Immune System – immune functions affecting the brain
  • Sympathetic and Parasympathetic Nervous Systems (from Autonomic Nervous System – ANS) – “fight or flight” and “rest and digest” respectively
  • Enteric Nervous System (ENS) – your gut brain
  • Gut Microbiome
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The general mechanism is that gut microbial by-products (like short-chain fatty acids and neurotransmitters), immune cells and hormones can enter the bloodstream from the gut and ultimately reach the brain via the vagus nerve. 


[And vice versa – it’s a (complex) two-way street]

Psychobioitcs are thought to work on the various gut-brain signalling pathways:

  • Bacteria-nervous systems signalling: Bifidobacterium longum and Lactobacillus rhamnosus have been shown to influence the excitability of gut nerve cells
  • Vagus nerve connection: studies show that psychobiotic effects are transported via the vagus nerve to the brain
  • SCFAs & bacterial by-products: prebiotics increase the production of SCFAs, SCFAs influence secretion of important satiety (feeling full) hormones which act on the brain
  • Bacteria-immune interactions: reductions in pro-inflammatory cytokines have been reported due to prebiotics – similarly B.infantis and L.rhamnosus GG can increase anti-inflammatory cytokines
  • Stress hormones & the gut lining: Bifidobacterium and Lactobacillus have helped restore gut lining integrity in animal studies

Ultimately these mechanisms affect how your cognition (your ability to think clearly), learning, mood, emotions and stress are all affected or dictated.

Simply put, psycho-biotics affect your psychological processes.

Now that we’ve introduced the ways psychobiotics work on the gut-brain axis, let’s have a closer look at how your body registers and responds specifically to stress triggers.

How Your Body Responds to Stress

Stress affects everyone differently. And different people respond to stress in different ways.

But one thing we all have in common is the pathway that mediates our stress response.

The HPA.

Your HPA or Hypothalamic-Pituitary-Adrenal axis  is your primary pathway for a stress response.

And your Sympathetic Nervous System (SNS), our “fight or flight” nerve network, works together with our HPA to determine how we react to stress.


To illustrate this connection, their coordinated response to a stress triggers looks a little like this:

  1. Stress hormones (adrenalin etc.) are released into your bloodstream and tissues – by your SNS
  2. At the same time, CRF (corticotropin releasing factor) emerges from your brain – via your hypothalamus 
  3. CRF stimulates the release of ATCH (adrenocorticotropic hormone) – from your pituitary gland
  4. ATCH travels through your blood and triggers the synthesis (and release) of cortisol – by your adrenal glands

So it goes … stress hormones > hypothalamus (CRF) > pituitary (ATCH) > adrenals (cortisol).

How You Can Harness Psychobiotics To Soothe Stress specific strains that help

Don’t worry there’s no test at the end of this article.

I simply want to show you the pathway stress takes – there are many more steps, but these are the basics.

And that the purpose of this stress response cascade, is to increase blood glucose levels, suppress the immune system and increase metabolism of fats and proteins.

It’s your body getting you ready for an incoming threat – preparing to “fight” or “fly- run away fast”.

And the antidote…?

In order to calm this response, neurotransmitters like serotonin, noradrenaline and endorphins are needed – as well as removing the physical or psychological stress triggers of course.

So what does all this have to do with psychobiotics?


While we can’t always remove modern day stressors, we can definitely influence the gut bacteria that produce the calming hormones.

For example, some common gut bacteria produce the stress-busting serotonin. Streptococcus, Enterococcus and E.coli have all been shown to make serotonin as part of their normal metabolism.

We can supplement or encourage these helpful species.

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Additionally, well known probiotics like Lactobacillus and Bifidobacteria have also been shown to produce stress busting hormones – like GABA and others.

These are all psychologically-supportive species – as well as being helpful in many other ways too.

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Did you know… 90% of our serotonin (a master calming hormone) is stored by specialised cells in our gut –  called ECCs

Another important probiotic bacteria Lactobacillus reuteri has been associated with production of the serotonin precursor tryptophan. Tryptophan is an essential amino acid (meaning humans don’t produce it). 

In general our gut microbes are thought to contribute to tryptophan availability from the food we eat.

More tryptophan means more serotonin = less stress!

Prebiotics have also been shown to have beneficial stress response effects –  because they directly feed the bacteria that have these beneficial effects.

This is why prebiotics are included in the definition of a ‘psychobiotic’.

How are Psychobiotics Different From Probiotics?

By now I’m sure you’re starting to wonder…what’s the difference between a regular probiotic and a psychobiotic.

The answer…their researched effect. 

Psychobiotics are probiotics or prebiotics that are found to act on the Gut-Brain Axis..

To clarify, historically probiotic research focused mostly on gastro-intestinal issues. Which is why so much more is known about how gut infections and gut-specific conditions, like IBS respond to probiotic treatment.

There’s purely been more research on these topics.

For example, it is well known that infectious diarrheal illnesses respond well to specific probiotics like L.rhamnosus, Saccharomyces boulardii, Lactobacillus casei, Bifidobacterium lactis, Streptococcus thermophilus … and many others.

The aim of psychobiotic research is to conduct studies on specific probiotics and find whether they significantly improve psychological outcomes. 

It’s an exciting and brand new field of microbiome science.

but the reality is that many (perhaps most) probiotic bacteria would be classed as both a psychobiotic and a probiotic. 

For instance, L.rhamnosus (effective in diarrohea infections) is also linked with calming the HPA response to stress in animal studies AND also linked with affecting nerve excitability.

So it crosses both definitions.

I suspect many probiotics will have the same (exciting) fate.

Which Conditions Can Benefit?

So while research is still in the early stages, psychobiotic effects are beginning to emerge for some well studied probiotic bacterial species and some prebiotics too.

A handful of the human studies conducted to date are outlined in the table below…I’ve already mentioned some of the animal studies above.


L.rhamnosus GG + B.animalis lactis
Higher levels associated with improved anxiety, depression and sleep 
Supplementation reduced hospital visits in patients with mania
StressB.longum 1714

L.casei Shirota

Supplementation lowered cortisol levels, anxiety and stress. Memory improvements were also noted.
Lower academic stress and cortisol levels, higher serotonin post examination
Athletic fatigue reduction, elevated mood post exercise
MoodL.helveticus + B.longum

B.bifidum, B.lactis, L.acidophilus, L.brevis, L.casei, L.salvarius + L.lactis
Reduced stress (cortisol) and improved mood.
Reduced rumination and aggressive thoughts
Anxiety + Depression (with IBS)B.infantisReduction in pro-inflammatory markers
Negative emotionsGOSAnti-depressant effects

As you can see there have definitely been some positive connections made but there is still much research that needs to be done.

So how can you harness the power of psychobiotic probiotics and prebiotics to help you manage stress?

How Can We Harness Psychobiotics to Manage Stress?

There are a number of simple ways you can tap into the positive effects of psychobiotics.

  1. Take Probiotic Supplements: good quality probiotics, with multiple strains may support you in times of stress – my clients take high quality practitioner only probiotics selected specifically based on their gut microbiome profile
  2. Gut Microbiome Testing: knowing exactly which probiotics you are lacking – or which non-beneficial bacteria you may have in abundance is a great tool for enhancing general health (and harnessing those psychobiotic benefits too)
  3. Eat Fermented Foods: naturally fermented foods like, Kimchi, Sauerkraut, fermented vegetables, sauces and more are all great food-based sources of probiotic (and psychotropic) bacteria
  4. Fill Up With Fibre: with brain boosting SCFA production in mind, eating more fibre or resistant starch for that matter is always a good idea. We share plenty of delicious high fibre recipes – you can find some fibre-full meal ideas here.
  5. Eat More Plants: vegetables and fruits naturally contain many different prebiotic fibres all packaged conveniently together – they make for an easy prebiotic and fibre boost whilst supporting health and mood improvements in general too

And don’t forget to include stress-busting lifestyle habits in there too – like exercise, meditation and regular sleep patterns.

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Putting It in Perspective

Eating well and supporting a healthy gut microbiome is the most powerful way you can manipulate your health. What our grandmother’s grandmother knew intuitively, we now have science to support – food truly is medicine.

Whether it be in the form of prebiotic vegetables feeding probiotic psychobiotics or simply nourishing your body on a deeper level – taking charge of your health is always in your hands (and on your plate).

If you are looking to restore your health (and gut) from the inside out I offer a number of powerful (and successful) gut health programs. You can access them here.

We also regularly update our many free recipes and meal ideas – our gift to you.

Alternatively, if you’d like to keep learning about gut health with practical tips to get you started here are a few of our popular articles you may find useful:

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