The Mind-Gut Conversation Podcast

Millions of people take a daily probiotic without ever asking a basic question: does any of it survive long enough to do anything?

In this episode of The Mind-Gut Conversation, Dr. Mayer is joined by Kiran Krishnan, a research microbiologist and Chief Scientific Officer at Microbiome Labs who has spent his career studying the human microbiome and the science behind probiotics. Kiran is best known for popularizing spore-based probiotics and for his work on metabolic endotoxemia, the mechanism behind what many people call leaky gut.

The conversation opens with a hard look at what happens to probiotics in the stomach. Kiran describes testing 40 of the leading probiotic brands under standard gastric conditions and finding that none of the strains survived the passage intact. From there they examine why CFU counts have become the industry's main marketing lever despite telling consumers almost nothing, why multi-strain formulas can cause individual strains to cancel each other out, and why some probiotic strains may trigger an inflammatory response rather than calm one.

They also address one of the most persistent myths in the field, the idea that probiotics colonize the gut and reseed the microbiome. Kiran explains why nearly all probiotics, including spores, are transient, and what that means for how these products should actually be evaluated.

The second half turns to the missing microbes hypothesis: the argument that modern agriculture has stripped soil-derived spore-forming bacteria out of our food supply, along with the tilling, monocropping, and synthetic fertilizer practices driving that loss. Dr. Mayer and Kiran connect the health of the soil to the health of the gut, and close with practical guidance on how an ordinary consumer can evaluate a probiotic in an unregulated market.

Topics discussed include:
Why most probiotics do not survive stomach acid
What CFU counts really tell you, and what they do not
Why multi-strain formulas can work against themselves
The myth of probiotic colonization and reseeding the microbiome
How modern agriculture changed the soil microbiome
How to evaluate a probiotic before you buy it

This is a candid, evidence-based conversation for anyone interested in gut health, the microbiome, and separating probiotic science from probiotic marketing.

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This episode is brought to you by Mayer Nutrition. Use code MINDGUT to save 10% on your first order of Synaptic Bloom.

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Chapters:
0:00 - Introduction
2:23 - The Missing Microbes Hypothesis and the Role of Spores
11:51 - Why Most Probiotics Don't Survive the Stomach
20:24 - The Problem With Multi-Strain Formulas
27:41 - How Modern Agriculture Changed Our Soil
43:14 - Colonization, Survival, and What the Evidence Shows
50:03 - How to Choose a Probiotic That Actually Works

Menopause isn't just hot flashes — it's brain fog, bone loss, sleep, mood, and your gut. In this solo episode of The Mind-Gut Conversation, Dr. Emeran Mayer unpacks the ~34 symptoms of perimenopause and menopause, the 2002 hormone-therapy scare that still shapes care today, and what current science says about estrogen and HRT.

Then he turns to the part almost no one is talking about: the estrobolome — the gut microbes that recycle estrogen as part of the brain-gut microbiome system. It may explain why symptom severity varies so widely between women, and why fiber, phytoestrogens, soy isoflavones, and equol point toward a new generation of non-hormonal menopause treatments.

A myth-busting, hopeful look at what we get wrong about menopause — and the science finally setting it right.

Key Topics Covered:
The ~34 symptoms of perimenopause and menopause
The 2002 WHI study and the hormone-therapy backlash
What current science says about estrogen, HRT, and vaginal estrogen
The estrobolome and how the gut recycles estrogen
Phytoestrogens, equol, and fiber as non-hormonal levers
Why there's real reason for hope

Chapters:
0:00 – How many symptoms does menopause really have?
2:21 – Why menopause care was abandoned for a generation
4:40 – The 2002 scare & what we know now about hormone therapy
7:05 – The estrobolome: how your gut recycles estrogen
7:50 – A non-hormonal approach: phytoestrogens & Dr. David Meriwether's research
10:25 – Fiber, ultra-processed foods & the probiotic myth
11:45 – The reframe & the equity gap in menopause care
14:05 – Reasons for hope

Connect with Dr. Mayer:
Website: https://www.emeranmayer.com
Instagram: https://www.instagram.com/emeranmayer/
X: https://www.x.com/emeranmayermd
Facebook: https://www.facebook.com/EmeranMayerMD/
LinkedIn: https://www.linkedin.com/in/emeranmayer/

This episode is brought to you by Mayer Nutrition. Use code MINDGUT at checkout to save 10% on your first order of our polyphenol blend, Synaptic Bloom, at https://www.mayernutrition.com.

The health of our soil and the health of our gut may be expressions of the same crisis — and healing one may depend on healing the other.

In this episode of The Mind–Gut Conversation, Dr. Mayer continues his conversation with Sadhguru, recorded at the Isha Foundation in Tennessee, turning from consciousness and inner intelligence to the ground beneath us — quite literally. Sadhguru has spent years leading the Save Soil movement, one of the most far-reaching environmental campaigns in recent history, reaching nearly four billion people in a hundred days.

In this conversation, they explore why the collapse of microbial life in our soil, the chlorination of our water supply, and the devitalization of our food may be driving a slow, generational deterioration in human health — one that science is only beginning to measure. Sadhguru argues that the soil crisis and the gut health crisis are not separate problems, but deeply intertwined expressions of the same disconnect from the living systems that sustain us. Dr. Mayer traces how that impoverishment travels from the earth to the root, to the gut, to the brain.

Topics discussed include:
Why soil degradation and gut health are part of the same crisis
How the loss of microbial life in soil, water, and food affects human biology
The gut-soil continuum and what ancient yogic science understood about the microbiome
Whether the Save Soil movement can outpace the speed of environmental decline
Why Sadhguru believes science and spirituality are searching for the same truth
What it means to live at full capacity — from microbe to human being

Connect with Dr. Mayer:
Website: https://www.emeranmayer.com
Instagram: https://www.instagram.com/emeranmayer/
X: https://www.x.com/emeranmayermd
Facebook: https://www.facebook.com/EmeranMayerMD/
LinkedIn: https://www.linkedin.com/in/emeranmayer/

Chapters:
0:00 - Introduction
1:45 - Is the Save Soil Movement Enough to Turn the Tide?
5:30 - Human Well-Being Is What's in Peril
9:00 - The Gut-Soil Continuum
13:00 - What Ancient Yogic Science Knew About Microbial Life
16:30 - Chlorinated Water, Devitalized Food, and Generational Health
19:30 - You Are a Walking Lump of Soil
22:00 - Where Science and Spirituality Meet

Neuroscience is built on an assumption most scientists never examine: that the brain is the seat of consciousness, intelligence, and everything that makes us human. Sadhguru thinks that’s like a child staring at a phone while a sunset unfolds right in front of them.

In this episode of The Mind-Gut Conversation, Dr. Emeran Mayer sits down with Sadhguru — yogi, mystic, and founder of the Isha Foundation — for a conversation recorded at the Isha Foundation’s retreat center in Tennessee.

Sadhguru draws a sharp distinction between intellect — the data-gathering, pattern-finding capacity that AI now replicates — and intelligence, which he sees as something far more fundamental, distributed across all living systems from microbes to complex organisms. He argues that consciousness is not a product of the brain, but something far wider, and that our current scientific frameworks are designed for manipulation of the world rather than understanding of it.

Topics discussed include:
• Why the brain may be evolution’s newest gadget, not its crowning achievement
• Intelligence vs. intellect: what the distinction reveals
• The phenomenal intelligence of microbes and living systems
• Why AI leads to more certainty, not more understanding
• Memory as a boundary and the concept of Samskara
• What consciousness actually means when used precisely

Dr. Mayer engages critically throughout, bringing a scientist’s perspective and pushing back where he sees tension with evidence from his own decades of research. The result is a rare, unscripted exchange across very different worldviews — science, mysticism, and the gut microbiome all at the table.

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Connect with Dr. Mayer:
Website: https://www.emeranmayer.com
Instagram: https://www.instagram.com/emeranmayer/
X (Twitter): https://www.x.com/emeranmayermd
Facebook: https://www.facebook.com/EmeranMayerMD/
LinkedIn: https://www.linkedin.com/in/emeranmayer/

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Chapters:
0:00 – Introduction
1:26 – Does the Brain Deserve Its Central Role?
6:14 – Intelligence vs. Intellect
10:49 – AI, Data, and the Limits of the Analytical Mind
15:39 – What Is Consciousness, Really?
22:25 – Memory, Samskara, and the Boundaries of Perception

Most of us know overwork isn't good for us. But the research on just how damaging it can be, and how quietly the damage accumulates, is more sobering than most people realize.

In this episode of The Mind–Gut Conversation, Dr. Emeran Mayer reflects on his own experience of sustained overwork throughout his career. We're talking 80-hour weeks, chronic sleep disruption, borderline hypertension, and eventually atrial fibrillation. He also digs into what the science says about why this pattern is so common and so easy to miss.

Drawing on findings from the World Health Organization, the Cleveland Clinic, and Harvard Business Review, he explores the biological and behavioral mechanisms through which chronic overwork damages the body over time, identifies six key warning signs that your work-life balance is already off, and makes a practical case for reconnecting with physical signals that most of us have learned to override.

Topics discussed include:
Why working more than 54 hours a week is linked to measurable increases in stroke and heart disease risk
What allostatic load is and how chronic stress accumulates invisibly
Six red flags that signal your work-life balance is off
Dr. Mayer's personal experience with atrial fibrillation and what prompted a rethink
The role of mindfulness, movement, and nature in nervous system recovery
Why your body keeps the score, even when you're not paying attention

This is a candid, evidence-based episode for anyone who has normalized pushing through exhaustion and wonders what it may be costing them.

Connect with Dr. Mayer:
Website: https://www.emeranmayer.com
Instagram: https://www.instagram.com/emeranmayer/
X: https://x.com/emeranmayermd
Facebook: https://www.facebook.com/EmeranMayerMD/
LinkedIn: https://www.linkedin.com/in/emeranmayer/

Chapters:
0:00 – Introduction
0:35 – The Science of Overwork
1:06 – Dr. Mayer's Personal Experience
3:00 – Six Warning Signs
4:55 – Reconnecting with Your Body