#607: Gut Health & Microbiome Testing: What Evidence Do We Actually Have? – Emily Leeming, PhD

Gut health has become a major focus in nutrition, medicine, and consumer wellness, but the term is often used loosely. Claims about microbiome testing, probiotics, fermented foods, fibre, and "boosting" the gut microbiome are now common, yet the evidence behind these claims varies substantially.

In this episode, Dr. Emily Leeming examines what gut health actually refers to, why it cannot be reduced to the microbiome alone, and where current microbiome science is being applied before it is ready. The discussion covers the limits of commercial stool testing, the difficulty of defining a healthy microbiome, and the practical strategies most strongly supported by current evidence.

Timestamps:

• [02:48] Interview start
• [04:17] Defining gut health
• [09:03] What is a "healthy microbiome"?
• [15:25] Microbiome testing - any clinical utility?
• [24:08] Interpreting microbiome studies
• [34:39] "30 plants a week" is not evidence-based
• [39:53] Serotonin and gut brain
• [45:34] Fiber research frontier

Links/Resources:

• Go to episode page (w/ links to mentioned studies)
• Join the Sigma newsletter for free
• Subscribe to Sigma Nutrition Premium
• Enroll in the next cohort of our Applied Nutrition Literacy course
• Dr. Leeming's newsletter: Second Brain