Podcast Summary: Armchair Expert with Dax Shepard

Episode: Colleen Cutcliffe (on the microbiome)
Date: February 18, 2026

Episode Overview

This episode features Dr. Colleen Cutcliffe, a microbiome scientist and health advisory board member at Johns Hopkins, and CEO of Pendulum, a company focused on scientifically rigorous probiotics and prebiotics. Dax Shepard and co-host Monica Padman delve into the science, implications, and personal stories behind the microbiome, covering its effects on metabolism, mental health, public health, and more. The conversation is equal parts accessible science, personal anecdotes, and lively banter, making the topic relevant for anyone interested in health, aging, diet, and wellness.

Key Discussion Points & Insights

1. What Is the Microbiome and Why Does It Matter?

• Definition and Scope:
  • The human microbiome comprises trillions of bacteria, viruses, and fungi living in and on us—especially in our digestive system.
  • “We’ve really co-evolved with them from day one. … they live inside you, on you, in all your nasal passages. … For the most part, they’re actually really beneficial.” (C, 18:05)
• Critical Role in Health:
  • Microbes make up about 1–3% of a person’s body mass (2–6 lbs).
  • The microbiome’s collective DNA outnumbers human DNA by a factor of 100.
  • Loss or alteration of this ecosystem—often due to antibiotics or over-sterilization—can contribute to long-term health issues.

2. Microbiome Disruption: Antibiotics, Diet, and Modern Lifestyle

• Antibiotics:
  • Early exposure (especially under age 2) increases risk for obesity, diabetes, allergies, asthma, ADHD, and even depression.
  • “If you’re under two and you’re on a lot of antibiotics, you’re not only more prone to obesity and diabetes, you’re also more prone to allergies, depression, asthma, ADHD, Crohn's, Celiac disease.” (C, 16:31)
• Diet:
  • Lack of fiber and polyphenols (found in berries, olive oil, dark chocolate) means crucial microbes starve.
  • Modern, processed diets make it hard to rebuild or maintain a robust microbiome.
• Other Depleting Factors: Stress, aging, travel/circadian rhythm changes, and hormonal shifts like menopause.

3. Animal Microbiomes and Evolutionary Insights

• Animal Comparisons:
  • Digestive symbioses are common; eg., hyenas' mouths have evolved to chemically neutralize rancid meat.
  • Story: A scientist bit by a hyena declined antibiotics, trusting the animal’s “clean” oral microbiome—and recovered fine. (C, 21:02)
• Human Uniqueness:
  • Humans are unusually disgusted by feces compared to other primates, likely due to risks from communal living.

4. Fecal Microbiota Transplants ("Crapsules") & C. Diff

• Treating C. Diff:
  • Fecal transplants often have a >95% success rate, far outpacing antibiotics for recurrent C. diff infections. (C, 24:25)
  • “Flooding with competitors, that's the whole thing, is incredibly effective … like a 97% success rate.” (C, 25:13)
• Societal Stigma:
  • Strong cultural aversion still delays adoption of this highly effective therapy.

5. Microbiome and Metabolism: GLP-1, Obesity, Diabetes

• Mechanism:
  • Certain microbes stimulate GLP-1, the same pathway targeted by diabetes/weight loss drugs.
  • People with obesity/diabetes often lack these key strains.
  • “There are two strains that we know to date that are able to directly stimulate your body’s natural GLP-1 … that mechanism is known.” (C, 25:45)
• Why Microbes Go Missing:
  • Antibiotics, poor diet, stress, aging—all can result in critical strains disappearing, leading to lowered GLP-1 signaling and poor blood sugar control.
• Personal Relevance:
  • Dax reflects, “When I was 26, I smoked two packs … ate every meal at 7/11 … I felt pretty fucking good ... Now I have an autoimmune condition and food allergies … my microbes were banging back then.” (A, 28:07)

6. Science & Claims Around Probiotics (and Pendulum’s Work)

• Probiotic Efficacy:
  • Most over-the-counter probiotics don’t survive stomach acid or reach the lower gut.
  • Pendulum uses enteric-coated, time-release capsules so that specific strains survive to the colon.
  • Akkermansia muciniphila: a strain key to gut lining, food sensitivity, and metabolic health; mostly absent as we age, but can be supplemented.
  • “We were the first company to manufacture and bring Akkermansia to market ... only ours actually has it.” (C, 32:46)

7. The Gut-Brain Axis: Mental Health Connections

• Neurotransmitter Production:
  • The gut makes serotonin, dopamine, GABA, and more—sending signals via the vagus nerve to the brain.
  • “Your gut makes a ton of neurotransmitters ... they can literally send those through the vagus nerve to the brain.” (C, 44:51)
• Behavioral Studies:
  • Animal studies show Akkermansia supplementation rivals Prozac for improving stress/anxiety behaviors.
  • “When you give [stressed mice] Akkermansia or Prozac, they look like the healthy mouse again ... even in some cases [Akkermansia] was better than Prozac.” (C, 47:47)

8. Birth, Early Life, and Microbiome Formation

• Seeding the Microbiome:
  • Vaginal birth and breastfeeding provide critical initial microbes and prebiotics; C-sections or formula feeding may result in less diverse microbiomes.
  • “The first real seeding … is delivery through the vaginal canal … then breast milk. … If you’re born by C-section, you don’t get that first seeding.” (C, 37:51)
  • Breast milk contains prebiotics and, uniquely, Akkermansia.
• Resilience and Recovery:
  • “You are constantly changing it [the microbiome], and you can constantly change it for the better. … Not like your genes.” (C, 43:57)

9. Practical Takeaways for Listeners

• Building & Maintaining Microbiome Health:
  • Supplementation may jumpstart a depleted system, but ongoing support comes from a diet rich in fiber and polyphenols.
  • Try interventions for 90 days: “If you feel a difference (usually food cravings, sustained energy), great—if not, it's something else.” (C, 55:15)
• Mindful Consumption:
  • Most marketing around “gut health” is not backed by rigorous science.
  • “Do it for 90 days, get the strains in there, and if you can eat the food that feeds them, you’re good to go … You don’t have to take this every day for life.” (C, 53:13)

10. Microbiome in Public Health

• 88% of Americans are metabolically unhealthy—diet and current medical approaches aren't reversing these trends alone.
• Microbiome interventions—which can change metabolic, immune, and inflammatory profiles—represent a promising new tool.
• “That might be a tool … Even for someone like Halle Berry—regimented, healthy, but she benefited from microbiome intervention.” (C, 54:59)

Notable Quotes & Moments

• On Over-Sterilization:
  “It's the epitome of throwing the baby out with the bathwater. Right? You might isolate the single microbe you want to get rid of at the expense of 9,000 that are good.” — Dax (A), 18:45

• On GLP-1 and Obesity Drugs:
  “Your natural body system … that mechanism is known, it's very much linked to obesity.” — Colleen (C), 26:27

• On Resilience and Aging:
  “A healthy gut is a resilient gut. … You had the most resilient gut, then you could do all kinds of things that were assaulting it … and be fine.” — Colleen (C), 28:38

• On Shame and Health:
  “We’re a social primate, so hardwired for shame … any kind of shortcoming we have is like, it must be me. … Even this psoriatic arthritis … it’s got to be my fault.” — Dax (A), 37:13

• On Birth and Breastfeeding:
  “That’s the first seeding. Most babies … go straight to breast milk. So then breast milk becomes the second. And if you’re born by C-section, you don’t get that first seeding.” — Colleen (C), 38:03

• On Microbiome as a Changing System:
  “You can constantly change it, and you can constantly change it for the better. … The microbiome, you can change.” — Colleen (C), 43:57

• On Probiotics & Industry:
  “We’re the only probiotics company the Mayo Clinic has invested in … over 30,000 healthcare practitioners.” — Colleen (C), 62:40

Timestamps for Key Segments

| Timestamp | Topic | |-----------|--------------------------------------------| | 04:54 | Intro to Colleen, microbiome basics | | 16:31 | Antibiotics, early microbiome disruption | | 21:02 | Animal microbiomes: hyena story | | 24:02 | Fecal transplants (“Crapsules”), C. diff | | 25:45 | Microbes, GLP-1, obesity and diabetes | | 28:07 | Dax’s personal microbiome story | | 32:46 | Akkermansia: production & real vs. fake | | 44:51 | Gut-brain axis, mental health connections | | 47:47 | Akkermansia vs. Prozac (mouse study) | | 55:15 | Public health, 90-day try-and-see advice | | 62:40 | Pendulum's clinical acceptance, Mayo Clinic|

Tone & Language

• Conversational, witty, mixing science with humor and personal anecdotes.
• Dax is self-deprecating, curious, and not afraid to push for clear or “dumb” questions.
• Monica brings a relatable “everywoman” perspective.
• Colleen is knowledgeable, approachable, and practical—dispelling myths without excessive hype.

Memorable Moments

• Science story: The hyena bite (21:02) — a scientist refuses antibiotics after being bitten, confidently trusting the animal’s oral microbiome, and is fine.
• Real talk on “shit eating” in animal behavior versus human disgust (23:00).
• Dax’s comedic analogy about his former “trashcan” lifestyle and resistant youth gut (28:07).
• Monica and Colleen’s reflections on generational and cultural identity (9:00–11:00).

Actionable Takeaways

• Build gut resilience with fiber, polyphenols (berries, olive oil, dark chocolate), and (if needed) quality probiotics—especially after antibiotics.
• Don’t stress about early life “misses”: If you/your kids had C-sections, formula, or antibiotics, the microbiome can still be nurtured and improved throughout life.
• Be wary of probiotics hype: Not all products work; look for science (not just marketing) and forms that survive the stomach.
• Test interventions: Try things (like supplementation or dietary changes) for 90 days to see if you notice changes in cravings or sustained energy.

Listener Utility

This episode demystifies the microbiome, connecting it to everyday concerns (weight, mental health, childhood exposures), and arms listeners with both skepticism (about marketing) and optimism (“it’s constantly changing, and you can make it better”). The science is supported by memorable stories, clear analogies, and grounded, practical advice.

For More

• Pendulum Website: pendulumlife.com for more about the company and products
• Book Recommendation: I Contain Multitudes by Ed Yong for accessible microbiome science

All quotes attributed with speaker name and [MM:SS] timestamp where possible.