gut brain connection

Key Topic

In this episode we will explore the fascinating link between gut health and mental health. We will break down why this connection matters, how gut health relates to almost everything in the body, and why it’s such a popular topic. With a mix of science and practical insight, this episode dives into both the hype and the evidence behind the gut-brain connection.

IBS link with Mental Health

  • The connection between the gut and brain is well established, especially when it comes to IBS and other functional gut disorders.
  • Research shows that over one-third of people with IBS also experience mental health conditions like anxiety or depression.
  • We also know that stress can significantly influence gut symptoms, often making them worse.
  • But rather than focusing on how mental health affects the gut, today we’re flipping the script—and looking at how gut health and the microbiome may influence mental health.

Mechanisms

  • Gut-Brain axis – the gut and brain communicate with each other through nerves, hormones, neurotransmitters and the immune system.
  • Your gut produces neurotransmitters. One example of this is GABA which is well known for having a calming effect.
  • Poor gut health can contribute to inflammation, which we know is linked to anxiety and depression
  • The gut can produce short chain fatty acids like butyrate which play a role in inflammation and mood.

It’s an endless list. To keep it good podcast content we won’t go deeper than that haha.

Research

Part 1 

  • Certain gut bacteria—like Firmicutes (FUR-mi-CUE-tees) and Bacteroidetes (BAK-teh-roy-DEE-tees)—have been shown to play a role in mental health.
  • In simple terms, these bacteria are generally considered beneficial, but it’s not just about having them—the balance between them matters.
  • Having too much of one type compared to the other may lead to imbalances that could negatively impact mood and mental wellbeing.

Part 2

  • Other dietary components, including probiotics, prebiotic, synbiotics, postbiotics, fermented dairy products, some herbs and spices, fruits, vegetables, and so on, can potentially help by enhancing beneficial gut microbiota while suppressing harmful ones.
  • It’s hard to go through individual research since there is SO much to cover, but we’ve included a relevant review in the show notes.

Part 3

  • That review also included a list of studies finding different bacteria linked with an increased risk of mental health conditions
  • and others with a decreased risk. 

Part 4

  • Immediately that should make you wonder – “can I just take a probiotic based on that research”
  • Of course there will be individual differences, but so far the research is mildly promising.
  • A lot of lactobacillus ones in particular have evidence for helping.
  • Note that it is often only a small to moderate beneficial effect. So it’s not a treatment by itself. But it’s still interesting.

Part 5

  • The review also identified several other probiotic strains that may support mental health.
  • One surprising finding was that people who consumed more than two servings of fermented dairy (like yoghurt) per day actually showed an increase in depression symptoms.
  • The researchers noted this doesn’t necessarily mean yoghurt is harmful—factors like added sugar or sweeteners may have influenced the results.
    • They suggested that unsweetened or low-sugar options might not show the same effect, but more research is needed to confirm this.

What if we look beyond gut-health?

  • I recently saw somebody reference the SMILEs trial for depression and anxiety and link all the benefits to the gut-health changes.
  • For context, that diet involved a modified mediterranean diet.
  • The authors of that study did point to the gut aspect, but also SO much more.
  • It’s an area where it’s easy to hyperfocus on one thing, but clearly a lot matter.
  • For example, certain nutrients are often lower in those with mental health conditions. If somebody focused just on nutrients, they would come to a different conclusion to somebody who just focused on the microbiome.
  • In that specific study the authors pointed to things like inflammation, oxidative stress, gut health, nutrients and a bunch more.
  • All of the above can be true where gut health matters AND other stuff matters.

What to do with this information?

  • Start by focusing on a nutrient-rich, balanced diet—this lays the foundation for both gut and mental health.
  • Aim for a diverse fibre intake from a variety of plant foods to help support a healthy gut microbiome.
  • Including fermented foods like yogurt, kefir, kimchi, or sauerkraut is also likely beneficial.
  • There may also be value in probiotics, and potentially prebiotics and postbiotics too—but start with options that are low risk and well tolerated.
  • I’d recommend beginning with choices that overlap with the strategies outlined in the article linked in the show notes—they’re practical, evidence-informed, and unlikely to cause harm.

While the connection between gut health and mental health is complex, the takeaway is surprisingly straightforward: support your gut, and you may support your mind too. That means focusing on a balanced, nutrient-rich diet, increasing plant and fibre diversity, and including fermented foods like yoghurt or sauerkraut. For some, probiotics or prebiotics might also help, though starting with simple, well-tolerated changes is key. Ultimately, small, consistent habits can lay the foundation for better gut and mental wellbeing.

Relevant Blogs / Resources

Relevant Studies:

Relevant Blog Post: