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The bacteria living in your digestive tract have been shown to directly communicate with your brain—impacting your thoughts, emotions, and behaviours.

Find out how your gut bacteria and mental health are connected, and how restoring your gut microbiota can reduce anxiety, lower stress, and help you to feel more calm, happy, and energized.

Working to improve my digestive health and re-build the community of friendly bacteria in my gut was an essential step in my journey to managing anxiety and overcoming panic attacks. This idea may sound a little strange if you’re new to the world of the microbiome (micro-what?), so let’s take a few steps back, and I’ll explain some of the science behind your gut-brain connection.

Your microbiome: what it is, and why it matters to your mental health

There are trillions of tiny bacteria living inside you—in fact, there are more of “them” than your own human cells. Collectively, this ecosystem of bacteria in your body is known as your microbiome. The largest part of your microbiome is the community of bacteria that live in your digestive tract, called your gut microbiota.

Your gut microbiota is essential to healthy digestive function—the colonies of friendly bacteria in your gut help you to break down and absorb nutrients from your food.

But it doesn’t end there. 

Research is now showing that your gut microbiota is also essential to healthy brain function—and certain bacteria species in your gut can directly affect your mood, emotions, thoughts, and behaviours.

Sounds a little crazy, doesn’t it? Crazy, but true.

How gut bacteria “talk” to your brain

The gut-brain axis is the fancy name given to the communication pathway that exists between your gut and your brain.

Your gut bacteria communicate through this pathway in two main ways:

    1. Bacteria can signal your vagus nerve. This is a large nerve that transmits messages between your brain and your gut. Have you ever had a “gut feeling” about something? Or felt anxious “butterflies in your stomach”? Scientists have found that gut bacteria can signal your vagus nerve, sending messages to the part of your brain responsible for your emotions and your fear response.
    2. Bacteria can influence your neurotransmitters. Neurotransmitters are powerful chemical messengers that control your nervous system, and tell your body and brain what to do. For example, the bacteria in your gut can produce serotonin, the neurotransmitter that helps you to feel happy and social. Gut bacteria can also effect GABA, the neurotransmitter that helps you to feel calm and relaxed.

The take-away here is that tiny bacteria living in your digestive tract have the ability to talk directly to your brain and change the way you think, act, and feel.

I think that makes them pretty darn important, don’t you?

It’s just one of the many reasons to take care of your digestive system, and to make sure that your gut microbiota contains the right balance of healthy bacteria.

“Good guys” and “bad guys”: what happens when good bacteria go missing

In my twenties, I found out the hard way that years of chronic stress, a few rounds of antibiotics, and a diet high in processed grains, can lead to an imbalance in your gut microbiota. This is known as dysbiosis—when your “good” bacteria are missing or become outnumbered by “bad” bacteria. For me, dysbiosis significantly contributed to anxiety and panic attacks—and I’m not the only person to experience this.

Research shows that digestive problems and mood disorders go hand-in hand. Dysbiosis can lead to inflammation in the gut lining, frequent bloating, cramping, constipation, loose stools, and Irritable Bowel Syndrome (IBS), as well as increased rates of anxiety, depression, chronic fatigue, and impaired ability to cope with stress.

Some causes of dysbiosis:

  • The overuse of antibiotics, which kill good bacteria along with the bad
  • Frequent use of over-the-counter medications like anti-inflammatories, antacids, and laxatives
  • A diet high in sugar, processed oils, refined grains, alcohol, and other inflammatory foods
  • Chronic stress

Here’s the good news.  

Research also shows that restoring the balance of healthy bacteria in your gut microbiota helps to improve both digestive health and symptoms of anxiety. One way that you can put the “good guys” back into your gut is through probiotic foods and supplements.

What are probiotics?

Probiotics are beneficial bacteria found in traditionally fermented foods, or in the form of natural supplements. Consuming probiotics helps to build and maintain the balance of healthy bacteria in your gut. Studies on the gut microbiota have been flooding medical research in the past few years, and there is an ever-growing body of research to support the use of probiotics for improved health.

Some positive effects of probiotics

  • Reduced digestive issues such as bloating, gas, constipation, loose stools
  • Reduced symptoms of IBS
  • Normalized levels of cortisol, the “stress hormone”
  • Improved production of serotonin, the “happy neurotransmitter”
  • Improved function of GABA, the “calming neurotransmitter”
  • Reduced symptoms of anxiety and stress
  • Improved mood, energy, and overall health

Sources of probiotics

One of my favourite ways to get a dose of healthy probiotics each day is by eating traditionally fermented foods like sauerkraut, kimchi, yogurt, kefir, apple cider vinegar, and brine-cured pickles or olives.  You can find a selection of fermented foods in the fridge at your local health food store.

Another way to get probiotics is by taking a quality probiotic supplement. I like this approach as well, because it allows you to select a formula containing specific bacteria species based on your needs. Below I’ve listed bacteria that have been shown in studies to decrease anxiety and stress, among many other health benefits.

Bacteria for a better mood:

Lactobacillus rhamnosus – Shown to lower stress-induced anxiety, and improve the function of GABA, the “calming neurotransmitter”.

Lactobacillus plantarum – Shown to reduce anxiety-like behaviours in animals, and increase serotonin, “the happy neurotransmitter”.

Lactobacillus helvecticus – Improved stress-coping ability, reduced inflammation, and helped to offset some of the negative effects of poor diet.

Lactobacillus reuteri – Reduced symptoms of social anxiety.

Lactobacillus casei – Helped patients with chronic fatigue syndrome to reduce digestive problems and anxiety symptoms.

Lactobacillus fermentum – Reduced inflammation in animals treated with antibiotics, normalized gut microbiota, and reduced anxiety-like behavior—showing how probiotics can counter some of the negative side effects of antibiotics.

Bifidobacterium breve – Reduced anxiety and improved performance on cognitive tests. This strain is found in human breast milk, and the amount in your gut declines as you get older.

Bifidobacterium longum – Found to reduce cortisol levels and alleviate psychological distress in human volunteers.

You can search for a quality probiotic supplement that contains one or more of the above listed species. Like fermented foods, you’ll find them in the fridge at your local health food store. I prefer probiotic supplements that do not contain FOS, GOS, or inulin—these indigestible carbohydrates can lead to increased bloating or digestive upset, particularly in individuals with IBS. I also avoid any supplements that contain additives or artificial ingredients.

Here are two probiotic supplements that I personally use and love:

Garden of Life Mood Biotics – This supplement contains 16 beneficial strains, including all but two from the list above. It also contains a blend of herbs to support stress.

HCP70 Probiotic by Progressive – This is my absolute favourite probiotic supplement. It’s a high-potency probiotic containing 8 beneficial species, including from the list above: two strains of Lactobacillus rhamnosus, two strains of Bifidobacterium longum, and one strain of Bifidobacterium breve.

probiotics for healthy gut bacteria and mental health

Many people begin to notice positive changes in digestive health and mood after 3-4 weeks of use.

Microbiome and mood: some final thoughts

The connection between the microbiome, brain function, and mood, is a very exciting area of research. I believe that continued understanding of our gut microbiota, gut-brain axis, and probiotics could one day transform the way doctors treat patients with mental health disorders.

Eating a variety of probiotic foods and taking probiotic supplements were two simple, yet important steps in my own journey to restore my gut health, overcome panic attacks, and feel more calm, happy, and energized each day.

It’s important to note, however, that probiotics are just one tiny piece of a very complex puzzle. Making dietary changes to support healthy gut microbiota and brain function is another essential step to improving your mental health. Working closely with your physician, a qualified therapist, and a practitioner that specializes in gut health (such as a nutritionist, naturopath, or functional medicine doctor), will provide you with a well-rounded approach to reducing anxiety and stress, so that you can live a happier, healthier life.

We’re all beautifully complex and unique individuals—as with anything health-related, I’ll always encourage you to simply keep an open mind, explore the mind-body connection, do your research, and experiment to find out what works best for YOU.

You’ll find additional tips for improved mood in my free guide, 5 Nutritional Strategies to Reduce Anxiety & Stressif you haven’t already, you can grab a copy below!

To happiness and gut health,



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