In this episode of The Mind-Gut Conversation, Dr. Emeran Mayer speaks with Dr. Martin Picard, Professor of Behavioral Medicine in Psychiatry and Neurology at Columbia University, where he holds the Endowed Chair in the Science of Energy and Health. Martin has spent his career studying mitochondria, and his research program brings together mitochondrial biology, bioenergetics, aging science, and psychosocial research in an effort to build what he calls a science of healing. His book, Energy, is expected in early 2027.

The conversation begins with the basics. What are mitochondria, and where did they come from? Martin describes them not as static components but as small living organisms with a life cycle of their own, dividing, fusing, repairing, and being recycled inside every cell in the body. Their origin is an evolutionary merger roughly 1.5 billion years ago, when an oxygen-using bacterium ended up inside a larger cell that could not use oxygen. About a thousand genes moved from one to the other, and neither can now survive alone. Martin argues that this single event is what made complex multicellular life possible.

Dr. Mayer draws the parallel to his own field immediately, and the two spend time on it. Mitochondria and gut bacteria are evolutionary cousins, and there is at least one well-established pathway by which they still communicate. When gut microbes ferment dietary fiber they produce short-chain fatty acids, and butyrate functions as fuel for mitochondria in much the same way the ketone bodies made by the liver do. Martin notes early evidence that the relationship runs in both directions, with changes in mitochondria appearing to shift microbiome composition and diversity.

The second half turns to stress. Martin’s working hypothesis is that stress damages health because it costs energy. The body operates on a fixed energy budget, and a perceived threat redirects a large share of that budget toward defense, which is exactly what it should do in the short term. When the threat never resolves, energy spent on vigilance is energy unavailable for maintenance and repair. He reframes the familiar stress-to-inflammation pathway as a stress, energy, disease cascade, with mitochondria in the middle.

They also discuss why Martin believes the serotonin hypothesis of depression hardened into dogma despite never being confirmed, what his Columbia group means by intrinsic health, and why most biomedical funding studies what goes wrong rather than what keeps people well. The conversation turns philosophical in places, and Martin is the first to point that out. He closes on a problem he thinks has eroded public trust in medicine: clinical evidence is built on averages, and nobody is the average.

Key Topics Covered:

• Where mitochondria came from and why endosymbiosis mattered
• How butyrate connects the gut microbiome to cellular energy
• Why chronic stress leaves you depleted and what a fixed energy budget means in practice
• The difference between generating energy and transforming it
• Research linking mood, purpose, and social connection to mitochondrial biology
• Why the serotonin-deficiency model of depression never held up
• Intrinsic health as a framework, and the problem of measuring it
• Why average-based clinical evidence fails individual patients

This is a wide-ranging, science-grounded conversation for anyone who has wondered why chronic stress is so exhausting, or why the advice to move, sleep, and eat plants works better than it has any right to.

Chapters:

0:00 – Introduction
2:17 – What mitochondria are and where they came from
7:00 – The gut microbiome, butyrate, and mitochondrial fuel
11:34 – What energy actually is
19:59 – Mitochondria as a portal between matter and energy
25:33 – Mood, purpose, and mitochondrial biology
28:00 – The serotonin hypothesis and how it became dogma
32:18 – Intrinsic health and the science of health
40:15 – Measuring intrinsic health, biophotons, and light
44:20 – Trust, individuality, and average-based evidence
49:40 – Allostatic load and the stress, energy, disease cascade

FAQ:

What are mitochondria?

Mitochondria are structures inside nearly every cell in the body that transform energy from food into a usable form. Martin describes them as small living organisms rather than static parts. They divide, fuse, repair themselves, and get recycled, which gives them a life cycle of their own. He also makes a point about language: mitochondria do not generate energy, since energy is never created or destroyed. They transform it.

Where did mitochondria come from?

About 1.5 billion years ago an oxygen-using bacterium ended up inside a larger cell that could not use oxygen, through a process called endosymbiosis. Roughly a thousand genes moved from the bacterium to the host nucleus, and the two became genetically and metabolically interdependent. Martin argues that this merger is what allowed single cells to organize into complex life.

Is there a connection between the gut microbiome and mitochondria?

Yes, and the clearest known pathway runs through short-chain fatty acids. Gut bacteria ferment dietary fiber and produce butyrate, which mitochondria can use directly as fuel, much like the ketone bodies the liver makes and releases for mitochondria elsewhere in the body. Martin also points to early evidence that the relationship works in reverse, with changes in mitochondria shifting microbiome composition and diversity.

Why does chronic stress make you tired?

Martin’s hypothesis is that stress is expensive. The body has a finite energy budget, and a perceived threat redirects a large share of it toward defense and vigilance. That response is protective in the short term. When it never switches off, the energy spent staying prepared is energy unavailable for maintenance, repair, and recovery, which may help explain why chronic stress raises the risk of so many different conditions.

What is allostatic load?

Allostatic load is the cumulative wear that comes from a stress response that stays switched on too long. Martin’s group has proposed reframing the familiar stress-to-inflammation pathway as a stress, energy, disease cascade, and has tested that model in several ways.

Can emotions affect mitochondria?

Martin’s lab has published research pointing in that direction. A 2018 study with Elissa Epel at UCSF found that how people felt on a given day predicted aspects of their mitochondrial biology the next day. Later work using donated brain tissue found that people who reported more positive experience, stronger sense of purpose, and more social connection had brain mitochondria that appeared better set up for energy transformation. These are associations from a young field rather than proof of cause.

Is depression caused by a serotonin imbalance?

Martin argues that the serotonin-deficiency model was a reasonable hypothesis decades ago that was never confirmed, and that it hardened into dogma partly because a physical explanation relieves uncertainty. He is clear that antidepressants help some people and that medication has a place. His concern is with telling patients their brain is broken and needs a chemical fix, which he thinks steers attention away from other approaches. This remains an active debate in psychiatry, and anyone taking an antidepressant should raise it with their prescriber rather than act on a podcast conversation.

What is intrinsic health?

The concept came out of Columbia’s Science of Health program, launched with geriatrician Linda Fried. The group concluded that health has too many dimensions to quantify as a single thing, so they divided it in two. Realized health is what a person can actually do in daily life. Intrinsic health is the underlying capacity beneath the skin, which Martin describes as emerging from the interaction of energy, structure, and communication, and which gives rise to resilience, robustness, and adaptability.

How would you measure something like intrinsic health?

Not easily, and Martin says so. His comparison is to gravity: you cannot observe the field directly, so you drop something into it and watch what happens. He expects progress to come from perturbation-based and energy-based methods rather than from measuring more molecules, and he is watching ultra-weak photon emission and light-based approaches, including recent findings on red light and glycemic control. He presents this as a direction for research, not as established science.

What can I do to support mitochondrial function?

Nothing exotic. Regular physical activity, adequate sleep, a diet with plenty of fiber-containing plant foods to feed the microbes that produce butyrate, and finding real ways to interrupt chronic stress. The advice has not changed. What this conversation offers is a better explanation of why it works.

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