Passion Struck with John R. Miles
Dr. Steven Gundry on How Your Microbiome Shapes Your Identity | EP 599
Thu, 17 Apr 2025
Imagine that your thoughts, cravings—even your emotions—aren’t entirely your own. That they’re being driven by trillions of microscopic organisms living inside you. It sounds like science fiction, but in Episode 599 of Passion Struck, Dr. Steven Gundry explains why this is scientific fact.Dr. Gundry, a former cardiothoracic surgeon turned gut health expert, joined me to discuss his new book The Gut-Brain Paradox and the profound connection between your digestive system and your mental state. As he puts it, "We are passengers on a bus driven by our microbiome—and they’ve been at the wheel a lot longer than we have."For full show notes: https://passionstruck.com/dr-steven-gundry-radically-heal-your-microbiome/Key Takeaways: Your Gut Runs the Show: Dr. Gundry explains how trillions of bacteria in your gut send messages that shape your thoughts, cravings, and emotional states. Leaky Gut Is Everywhere: If you’re battling fatigue, autoimmune disease, or mental fog, there’s a high chance you have a leaky gut—and it's reversible. Food as Medicine: Changing what you eat, including eliminating certain lectins and processed foods, can reverse chronic conditions like Parkinson’s, anxiety, and more. Microbes vs. Free Will: The bacteria in your gut may be influencing your decisions more than your conscious mind. Beyond SSRIs: Many antidepressants work by altering the microbiome, not just serotonin levels—a strong argument for gut-first mental health care. Connect with Dr. Steven Gundry: https://drgundry.com/Sponsors: Factor Meals: http://factormeals.com/factormeals50off and use code “FACTOR MEALS 50 OFF” Rosetta Stone: Unlock 25 languages for life at “ROSETTASTONE.com/passionstruck.” Prolon: Reset your health with 15% off at “ProlonLife.com/passionstruck.” Mint Mobile: Cut your wireless bill to 15 bucks a month at “MINT MOBILE dot com slash PASSION.” Hims: Start your journey to regrowing hair with Hims. Visit hims.com/PASSIONSTRUCK for your free online visit. Quince: Discover luxury at affordable prices with Quince. Enjoy free shipping and 365-day returns at quince.com/PASSION Next on Passion Struck:In the next episode of Passion Struck, John sits down with Anne Marie Anderson, an Emmy Award-winning broadcaster, sports journalist, and leadership expert. Anne Marie has spent years breaking barriers in sports media, navigating high-stakes environments, and coaching top athletes and executives on leadership, resilience, and communication. In our conversation, we'll dive into the mental frameworks of high performers, the art of storytelling, and how to build confidence in any field.For more information on advertisers and promo codes, visit Passion Struck Deals.Join the Passion Struck Community!Sign up for the Live Intentionally newsletter, where I share exclusive content, actionable advice, and insights to help you ignite your purpose and live your most intentional life. Get access to practical exercises, inspiring stories, and tools designed to help you grow. Learn more and sign up here.Speaking Engagements & WorkshopsAre you looking to inspire your team, organization, or audience to take intentional action in their lives and careers? I’m available for keynote speaking, workshops, and leadership training on topics such as intentional living, resilience, leadership, and personal growth. Let’s work together to create transformational change. Learn more at johnrmiles.com/speaking.Episode Starter PacksWith over 500 episodes, it can be overwhelming to know where to start. We’ve curated Episode Starter Packs based on key themes like leadership, mental health, and personal growth, making it easier for you to dive into the topics you care about. Check them out at passionstruck.com/starterpacks.Catch More of Passion Struck: My solo episode on The Mattering Mindset in Love – Choose the Love You Deserve Can't miss my episode with Jennifer B. Wallace on the Consequences of Prioritizing Achievements Over Mattering My episode with The Art of Listening: How to Make People Feel Like They Matter Catch my interview with Laurie Santos on How to Matter in a Busy World Listen to my solo episode on Fading into Insignificance: The Impact of Un-Mattering in Our Interconnected Era If you liked the show, please leave us a review—it only takes a moment and helps us reach more people! Don’t forget to include your Twitter or Instagram handle so we can thank you personally.How to Connect with John: Connect with John on Twitter at @John_RMiles Follow him on Instagram at @John_R_Miles Subscribe to our main YouTube Channel and to our YouTube Clips Channel For more insights and resources, visit John’s website Want to explore where you stand on the path to becoming Passion Struck? Take our 20-question quiz on Passionstruck.com and find out today!See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.
Chapter 1: Who is Dr. Steven Gundry and what is the focus of this episode?
On Tuesday, I was joined by Laura and Isabel Hoff, daughters of Wim Hoff and authors of Secrets of the Ice Women. We explored how cold exposure, mindset, and breath work can transform hormone balance, emotional resilience, and personal power. And in my upcoming solo episode, number 600, I'll be making a very special announcement that marks a major next chapter for this community.
you don't want to miss it now let me ask you this what if your thoughts cravings even your emotions weren't entirely your own what if trillions of microbes inside you were pulling the strings shaping your mood metabolism and mental health in ways you never imagined and what if Fixing your gut was the key to unlocking peak cognitive performance, resilience, and longevity.
That's exactly what we're exploring today with Dr. Stephen Gundry, renowned medical researcher, cardiothoracic surgeon, and best-selling author. In his latest book, The Gut-Brain Paradox, He challenges everything we thought we knew about mental health, cravings, weight loss, and even free will.
In today's conversation, we unpack the groundbreaking science behind how your gut microbes control your brain, mood, and metabolism, why the war on germs might be making us sicker, and what modern medicine needs to rethink.
Chapter 2: What is the gut-brain paradox and how does the microbiome influence our health?
how conditions like anxiety, depression, and even Alzheimer's may actually start in the gut, and a step-by-step roadmap to healing your gut-brain axis and reclaiming your clarity and health. This episode is a game changer for anyone dealing with brain fog, anxiety, chronic fatigue, or constant cravings. We'll see you next time.
personal mastery, and mental resilience to help you find the inspiration that meets you where you are. And don't forget to subscribe to my Live Intentionally newsletter for exclusive insights, behind-the-scenes content, and tools to live a life that truly matters. Now, let's get into this fascinating conversation with the one and only Dr. Stephen Gundry.
Thank you for choosing PassionStruck and choosing me to be your host and guide on your journey to creating an intentional life. Now, let that journey begin. I am so honored and ecstatic today to have the one and only Dr. Stephen Gundry with me on PassionStruck. Welcome, Dr. Gundry. Hey, thanks for having me, John. It's great to see you again. And I think I want to start there.
The last time we spoke, I was in a position I never thought I was going to be in. I was the editor-in-chief of this publication called Bold Business, and I had developed something called the Bold Leader Spotlight, where We looked at eight to 10 characteristics of what we thought described someone who was a bold leader. And so I interviewed you as a member of that club.
So it's been nearly six years since we last spoke. And since then your work has continued to push boundaries of what we know about nutrition, disease prevention, and now the link between gut and mental wellbeing. What inspired you to shift your focus to the gut brain connection for this book?
With each kind of passing book, since The Plant Paradox came out in 2017, interestingly, the Human Microbiome Project actually finished in 2017. And with every almost passing month, thanks to that project,
we now know who lives in our microbiome and for those who don't know yet the microbiome the microbiome that just lives in our gut probably has a hundred trillion bacteria alone not to mention fungi and molds and viruses and worms and we're now able to identify who all these creatures are and the roles they play in our health.
And because we can now identify who they are, we can start to see that the types of bacteria, the balance of good and bad bacteria really has a huge effect on personality, on
depression, anxiety, addictions, mood, and you can actually do animal experiments and human experiments showing that manipulating these groups of bacteria with food, for instance, or supplements, for instance, can have a huge impact on us. And so this book is a deep dive into the gut brain paradox that our brain is basically a good receiver for signals from the cloud of our microbiome.
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Chapter 3: How does leaky gut contribute to various diseases and how can it be treated?
And that she now tailors the food that she eats and she no longer has this problem. She's off of all drugs.
and she's actually created a business where she provides food services for people with ibs and ulcerative colitis and imagine that but the entire article was basically oh the miracles of all these modern drugs and i'm a transplant immunologist by training as a heart surgeon and a heart transplant surgeon and when i have a patient walk in on these immune suppression drugs
I go, I didn't do a heart transplant on you. You don't have a kidney transplant. You don't have a liver transplant. So what the heck are you doing on a transplant drug? And they go, yeah, you're right. What am I doing on that? The immune system is being told to look the other way. And that's not what we want to do. We want to find out what the immune system is revved up about. That's what we do.
Yeah, it reminds me of one of the interviews I did last year on the podcast with Dr. Terry Walls, who you probably know. And I think hers is a story that kind of parallels that. She was suffering from multiple sclerosis, if I have it correct, and had gotten to the point where she was actually in a wheelchair when she started to change her whole diet.
And over time, she found herself riding a bike again and exercising and living a normal life. And One of the things that I really love about her work is she does a lot of patient care in the VA system. And so veterans who have exhausted all Western medicines, she invites into her clinic, but says, if you're going to commit to it, you have to commit to exactly what I tell you to do.
And her results have been pretty fascinating.
I have a very similar philosophy here. I can show you the path, but it's you who must walk it. And we can see people who stray. We do leaky gut tests usually every three months in our patients. And we can see slip ups or we can see where they're really doing spectacular. And the fun stuff is it's measurable stuff. We can watch it.
Just actually before I got on this podcast, I have a young man who flew in from the Midwest. He's 50 years old. Had really horrible leaky gut. Had liver inflammation from his leaky gut. He had vascular inflammation from his leaky gut. And he's now six months into this and his repeat leaky gut test is, oh, 75% better than six months ago.
And his antibodies to the various forms of wheat are 75% gone compared to six months ago. And his liver inflammation is gone. His vascular inflammation is gone. And he's just sitting there going, oh my gosh, look, this works. This isn't a placebo effect. He said, oh yeah, I can see it. And it's, yeah, I didn't make this up.
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Chapter 4: What is the debate between germ theory and terrain theory in modern medicine?
It looks like.
You mentioned Dr. Mark Hyman a few minutes ago, and he's also my friend. I've had him on the show a couple times. And a couple episodes ago that I did with him, we were talking about the latest book he had published, and we were going through biological age and how to extend it compared to our chronicle age. And so we spent a lot of time also talking about the microbiome.
And one of the things you both talk about, and it's one of the most mind-blowing takeaways I think from your book is that about half of the cells in our bodies are not actually human, they're microbial. And you take this even further by suggesting that we need to rethink what it even means to be human. Can you expand on that?
My previous book, Gut Check, I introduced people to a little one cell organism called toxoplasmosis. which is a single cell parasite that has, like many parasites, has two life cycles. And many parasites have to spend some time in an intermediate host to get to their final place they really want to get to. And toxoplasmosis wants to get into a cat, and that's where it wants to go.
And its intermediate host is strangely selected to be a mouse or a rat. Now that's a really, you would think, a dumb idea because mice and rats are deathly afraid of cats. If they smell cat urine, they run the other direction. But toxoplasmosis gets into a rat or a mouse through contaminated water that a cat has pooped in. And
It basically goes to the brain and literally rewires the brain, primarily using dopamine receptors. And it makes the smell of cat urine sexually stimulating to the rat. And it also makes the sight of a cat incredibly exciting. And the rat literally runs to danger and gets eaten. Now, what's so interesting about that
is we know that great apes particularly chimps can be infected with toxoplasmosis and why because believe it or not tigers big cats chimps are one of the favorite foods and these animals become emboldened around tigers
great studies out of yellowstone park showing that most wolf pack leaders are infected with toxoplasmosis because believe it or not the predator of a wolf is a cougar a mountain lion and they become more bold take more risks and that's actually how they become leaders What's really scary is that humans can be infected with toxoplasmosis and people who are infected with toxoplasmosis.
For instance, the vast majority of motorcycle riders in fatal accidents are infected with toxoplasmosis. And at one point, the U.S. military was very interested in infecting troops with toxoplasmosis so that they would run towards danger.
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Chapter 5: How do microbes affect human behavior and what does that mean for our identity?
And so we could see it on the blood test. She knew it. And that was the contamination in her. Now people go, oh, come on, a few breadcrumbs? If you'd told me this, again, 30 years ago, I would have laughed you out of the room. But there it was. We could see it. She felt it. And again, Hippocrates was right. Just be a detective. And there it was.
That was the thing that was now stopping her green life force energy from expressing itself. And it sounds so hokey.
I mean, it does, because when you think about it, like you said, it's probably just dust on the board. It's not, it's just residual.
Just a few molecules of gluten in some of my, what I call my canaries, is enough to do this. Again, I would have told you these people are just crazy. They're not. And we can actually measure it. And it's like, son of a gun. You're right. Look, your gut is leaky again. Look, you've got antibodies to gluten. Where'd you get those from? And there it was, the sun.
I appreciate you sharing that. And I want to shift the discussion to, of all topics, free will. Because you write in the book that microbes don't just live inside of us. They actually control us. They dictate what we crave. how we think and even how we feel. And this is a radical idea. Can you explain just how much power these microbes have over our behavior?
To me, again, if I look back, this seems like a incredibly radical idea, but Deepak Chopra has been talking about the intelligence of single cells, the sentient beings. Some people now want to talk about the intelligence of mitochondria, which are the energy producing organelles in all of our cells, which are actually engulfed bacteria.
And I've come around to the way of thinking that we are truly a symbiotic organism. And that bacteria have been around for 3 billion years, the most successful life form ever. And we've only been around in our current form for about 100,000 years. And that a lot of us now think that this bacterial part of us
is driving the passengers are driving the bus and they're driving the bus for a really good reason because they've had a lot of experience with living and again i make the argument that they are sentient beings they see not with eyes like we see but they can read the barcodes on neighboring bacteria. We've known this for many years. It's called quorum sensing. They know who's in the house.
I'll give you an example. There's a keystone species in our gut that's called Ackermansia mucinophilia, and
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Chapter 6: What foods should be avoided to heal leaky gut and improve health?
Chapter 7: How can patients measure their gut health progress and what are success stories?
I'll give you a great story. You mentioned this wonderful woman who had Parkinson's that I start the book with. And I won't go into her whole story, but she had very leaky gut. She was very sensitive to gluten, a component, a lectin in gluten. Wheat, rye, barley. There's also a molecule in oats and corn that cross reacts with gluten, just as an example.
And she had antibodies to all these and we changed her diet. We took these things away. And within a year, her leaky gut was gone. And within a year, her Parkinson's symptoms really completely abated. She was back running again. She didn't have a tremor anymore. And I saw her and her husband about a month and a half ago for her two-year follow-up. And she still looked really good.
And she said, I don't know. I think I'm slipping. I can feel myself slipping. I don't know what it is. but are just not as good the last few months. And I said, well, let's look at your blood work. Let's look at your leaky gut. And sure enough, her leaky gut was still pretty good, but it was not as good as six months ago. Then she had some antibodies to gluten that she didn't have.
And I said, I know you so well by now, but are you eating out more? Are you going to restaurants? Are you cheating? She said, oh no, I wouldn't cheat. Why would I? And I said, well, something's different. I said, you're getting exposed to gluten. And her husband perks up and he said, would sharing a cutting board with somebody who's cutting bread, regular bread on a cutting board do this?
And I said, what do you mean? He says, well, our son who's 30 moved in with us about four months ago and he doesn't follow our diet. And every day he cuts bread on the cutting board. And then we have our bread that is safe and we use the same cutting board. And I said, Son of a gun. And when did you start noticing you were changing? And she said, it's when our son moved in with us.
And so we could see it on the blood test. She knew it. And that was the contamination in her. Now people go, oh, come on, a few breadcrumbs? If you'd told me this, again, 30 years ago, I would have laughed you out of the room. But there it was. We could see it. She felt it. And again, Hippocrates was right. Just be a detective. And there it was.
That was the thing that was now stopping her green life force energy from expressing itself. And it sounds so hokey.
I mean, it does, because when you think about it, like you said, it's probably just dust on the board. It's not, it's just residual.
Just a few molecules of gluten in some of my, what I call my canaries, is enough to do this. Again, I would have told you these people are just crazy. They're not. And we can actually measure it. And it's like, son of a gun. You're right. Look, your gut is leaky again. Look, you've got antibodies to gluten. Where'd you get those from? And there it was, the sun.
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