Overview of The Model Health Show — The Shocking Truth About Microplastics, Microbes, & Pollution: Why Colon Cancer Is on the Rise (with Dr. Emeran Mayer)
In this episode Shawn Stevenson interviews Dr. Emeran Mayer — gastroenterologist, neuroscientist, and gut‑brain/microbiome pioneer — about the rising incidence of early‑onset colorectal cancer, the roles of diet/industrialized food, environmental exposures (microplastics, pesticides, additives), the mind‑gut connection, and emerging microbiome‑based therapeutics (including the estrobolome). The conversation blends epidemiology, prevention strategies, practical screening guidance, and near‑future innovations that target the microbiome to influence hormones and inflammation.
Key takeaways
- Colon cancer screening has reduced incidence/complications in older adults, but colorectal cancer is rising rapidly in younger people (even 30s–40s). Genetics alone cannot explain this—environmental and lifestyle factors are major suspects.
- Ultra‑processed food intake is strongly linked to increased early‑onset colorectal cancer risk. A recent JAMA Oncology analysis found ~45% greater odds of early colorectal cancer among younger women in the highest quintile of ultra‑processed food consumption.
- The colon houses the highest concentration of human microbes; microbiome changes that promote low‑grade inflammation are a leading mechanistic hypothesis linking modern exposures to colon cancer.
- Environmental exposures (microplastics, glyphosate, pesticides, food additives) are increasing and understudied; their long‑term effects on the gut and cancer risk are poorly understood but concerning.
- Screening options: stool‑based molecular/genetic tests (non‑invasive, increasingly sensitive) vs colonoscopy (diagnostic + therapeutic but resource‑intensive). Non‑invasive tests can improve early detection and access; colonoscopy reserved for positive/ high‑risk cases.
- The mind (stress, trauma) influences gut inflammation and microbiome composition; chronic stress can exacerbate inflammatory bowel disease and likely contributes to low‑grade inflammation relevant to cancer risk.
- The estrobolome (microbes producing beta‑glucuronidase) recycles estrogens/testosterone from biliary excretion — an important, underappreciated source of sex hormones, especially post‑menopause. Microbiome engineering may one day provide hormone modulation without external hormone replacement.
- Emerging biotech: engineered fibers (to broaden prebiotic diversity), bioengineered probiotics that home to inflamed tissue, and designer microbes that alter hormone recycling — all promising but still early.
Topics discussed (concise list)
- Epidemiology: falling older‑adult rates vs rising early‑onset colorectal cancer
- Screening: stool occult blood → advanced molecular stool tests → colonoscopy
- Healthcare incentives: colonoscopy volumes and financial drivers; need for better patient education
- Ultra‑processed foods: composition, prevalence (≈40% of U.S. diet; higher in children), and links to cancer
- Microplastics and nanoplastics: growing exposure; unknown long‑term effects on gut/microbiome
- Pesticides/chemicals (glyphosate, chlorpyrifos): impact on microbiome and systemic health
- Mind‑gut‑immune axis: stress effects on microbiome, inflammation, IBD recurrence, and cancer risk
- Estrobolome and hormone recycling: beta‑glucuronidase activity and implications for menopause/andropause
- Microbiome therapeutics: engineered fibers (OneBio), engineered probiotics, personalized microbiome interventions
- Nutrition: plant‑forward (“ancestral”) diets, fiber diversity, polyphenols, organic/regenerative agriculture
- Practical prevention vs system‑level change: individual actions and the need for policy/top‑down changes
Actionable recommendations (what listeners can do now)
- Screening and testing:
- Talk to your provider about stool‑based molecular screening options (sensitivity approaching colonoscopy for screening) — earlier and more frequent non‑invasive testing is an option for younger adults, especially with risk factors.
- Reserve colonoscopy for positive non‑invasive tests, strong family history, or when tissue biopsy is required.
- Diet:
- Reduce ultra‑processed foods (sugars, refined fats, additives, low fiber).
- Shift toward a largely plant‑based, diverse diet — emphasize many different vegetables, fruits, whole grains, legumes, nuts, seeds (diversity → diverse fiber → diverse microbiome).
- Limit frequent red/processed meat and deep‑fried/charred foods.
- Prioritize polyphenol‑rich foods (olive oil, berries, tea, herbs) where possible.
- Reduce environmental exposures:
- Minimize plastic use with food (avoid microwaving in plastic, reduce packaged produce/ready meals, use glass/ceramic).
- Choose organic/regenerative produce when affordable to reduce pesticide exposure and support healthier soil microbiomes.
- Microbiome support:
- Focus on prebiotics (fiber diversity) rather than expecting long‑term colonization from over‑the‑counter probiotics.
- Consider fiber supplements that provide diverse glycans when dietary diversity is limited (new products are emerging).
- Stress and lifestyle:
- Manage chronic stress (sleep, mindfulness, therapy, exercise) — stress modulates gut inflammation and microbiome.
- Maintain physical activity and other healthy lifestyle habits that support homeostasis.
- Advocacy and education:
- Push for policies that reduce ultra‑processed foods in institutional settings (hospitals, schools) and limit harmful environmental chemicals.
- Encourage clinicians to include nutrition counseling as part of post‑screening care.
Notable insights & memorable quotes (paraphrased)
- “The colon is the habitat of our highest concentration of microbes — it’s the ecosystem where much of the disease process happens.”
- Ultra‑processed food is not one nutrient: it’s a package (high sugar, saturated fat, salt, additives, low fiber) that shifts microbiome and promotes low‑grade inflammation.
- “Screening has been successful — but we are seeing a surprising and tragic rise in young people, so non‑invasive testing earlier can help catch cases without overusing colonoscopy.”
- On the estrobolome: microbes can ‘rescue’ hormones the liver intended to excrete, meaning the gut becomes a major regulator of circulating estrogen and testosterone.
- “Health is systems biology — multiple interacting exposures (genetics, diet, stress, chemicals) shape personalized risk; there’s no single magic bullet.”
Emerging science & clinical outlook
- Estrobolome therapeutics: probiotic or microbial engineering to modulate hormone recycling — potential non‑hormonal approach to perimenopausal/menopausal symptoms and male androgen regulation.
- Bioengineered probiotics: examples that home to inflamed tissue by feeding on inflammatory mediators — could treat IBD locally and transiently.
- Engineered fibers (glycopedia concept): synthetic/modified fibers offering broad microbiota nourishment, approximating the benefits of a highly diverse plant diet — useful when dietary change is impractical.
- These innovations are promising but early; clinical translation, safety, regulation, and access will take time.
Practical resources & further reading
- Dr. Emeran Mayer:
- Website: emranmayer.com — podcasts, newsletters, resources
- Mayer Nutrition: mayernutrition.com — curated polyphenol products and high‑polyphenol extra virgin olive oil
- Books: The Mind‑Gut Connection (10‑year anniversary edition forthcoming), The Gut Immune Connection
- Screening context:
- Ask your clinician about stool‑based molecular tests (often called FIT‑DNA or other molecular stool assays) and appropriate intervals based on age/risk.
- Recent studies referenced:
- JAMA Oncology paper linking ultra‑processed foods to higher early‑onset colorectal cancer risk (nearly 30,000 female nurses under 50).
- Scientific Reports and other emerging literature on microplastics and colorectal risk (area of active research).
Bottom line
Early‑onset colorectal cancer is rising and likely driven by a combination of diet (ultra‑processed foods), environmental contaminants (microplastics, pesticides, additives), microbiome‑mediated low‑grade inflammation, and stress/exposome interactions. Prevention and early detection should emphasize accessible, non‑invasive screening, broad dietary shifts toward diverse plant‑based foods and fiber, reduced plastic/chemical exposure where possible, stress reduction, and awareness of forthcoming microbiome‑based therapies that may reshape hormone and inflammation management.