The Gut-Brain Connection: Why Your Mental Health Starts in the Microbiome

Mark Hyman

Mar 24, 2025

Episode description

The connection between mental health and metabolic health is far deeper than once believed, with growing evidence showing a powerful, bidirectional relationship. Inflammation, poor diet, and gut dysfunction are now recognized as key drivers of both physical and psychological illness—often hiding in plain sight. By addressing root causes such as blood sugar imbalances, nutritional deficiencies, and microbiome disruption, many chronic mental health conditions can improve or even resolve. This emerging science challenges the traditional separation of mind and body, pointing instead to an integrated approach where healing the body becomes essential for healing the brain. Recognizing this link is crucial in shifting the future of mental health care.

In this episode, I discuss, along with Dr. Chris Palmer and Dr. Shebani Sethi, why our diet is so closely related to the state of our mental health.

Dr. Chris Palmer is a psychiatrist and researcher working at the interface of metabolism and mental health. He is the Director of the Department of Postgraduate and Continuing Education at McLean Hospital and an Assistant Professor of Psychiatry at Harvard Medical School. For over 25 years, he has held leadership roles in psychiatric education, conducted research, and worked with people who have treatment-resistant mental illnesses. He has been pioneering the use of the medical ketogenic diet in the treatment of psychiatric disorders - conducting research in this area, treating patients, writing, and speaking around the world on this topic. More broadly, he is interested in the roles of metabolism and metabolic interventions on brain health.

Dr. Shebani Sethi is a double board-certified physician in Obesity Medicine and Psychiatry. She is the Founding Director of Stanford University’s Metabolic Psychiatry program and Silicon Valley Metabolic Psychiatry, a new center in the San Francisco Bay Area focused on optimizing brain health by integrating low carb nutrition, comprehensive psychiatric care, and treatment of obesity with associated metabolic disease.

This episode is brought to you by BIOptimizers.

Head to bioptimizers.com/hyman and use code HYMAN10 to save 10%.

Full-length episodes can be found here:

The Hidden Connection Between Gut Health & Mental Health That Therapy and Drugs Cannot Fix

A Harvard Psychiatrist Rethinks Mental Health As A Metabolic Disease

How Does Ultra-Processed Food Affect Our Mental Health?

Episode description

In this episode, I discuss, along with Dr. Chris Palmer and Dr. Shebani Sethi, why our diet is so closely related to the state of our mental health.

This episode is brought to you by BIOptimizers.

Head to bioptimizers.com/hyman and use code HYMAN10 to save 10%.

Full-length episodes can be found here:

The Hidden Connection Between Gut Health & Mental Health That Therapy and Drugs Cannot Fix

A Harvard Psychiatrist Rethinks Mental Health As A Metabolic Disease

How Does Ultra-Processed Food Affect Our Mental Health?

Mindsip insights from this episode:

Reframe mental disorders as metabolic brain disorders

Mental disorders can be understood as metabolic disorders of the brain, with mitochondrial dysfunction being a central cause.

#mental-health

#mitochondria

Understand mitochondria's role in hormone regulation

Mitochondria are not just the powerhouse of the cell; they are also primary regulators of key hormones like cortisol, estrogen, and testosterone.

#hormones

#mitochondria

Recognize childhood infections as risk factors for mental disorders

A serious infection during childhood can double the risk of developing a mental disorder later in life, including schizophrenia and autism.

#children

#mental-health

Recognize depression as a physical issue rooted in the body

Depression is often not a problem originating in your head, but rather a physical problem originating in your body.

#body

#depression

Address malnutrition in overweight individuals by improving diet quality

People who are overweight are often the most malnourished because their diet of ultra-processed foods lacks essential vitamins and minerals.

#nutrition

#obesity

Treat sugar as a recreational drug, not a dietary staple

Sugar should be treated as a recreational drug that is not essential for survival, rather than a staple food for every meal.

#nutrition

#sugar

Address gut inflammation to alleviate brain irritability

It's often not that anxiety causes irritable bowel syndrome (IBS), but rather that an inflamed gut from IBS leads to an 'irritable brain.'.

#anxiety

#IBS

Recognize gut microbiome's role in your blood composition

A third to a half of all the metabolites circulating in your blood are not human but are produced by your gut microbiome.

#blood-test

#microbiome

Leverage Akkermansia for natural relaxation through GABA

The beneficial gut bacteria Akkermansia produces the neurotransmitter GABA, which acts like a natural form of Valium to promote relaxation.

#GABA

#microbiome

Mark Hyman

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