In this episode of the Vibrant Wellness Podcast, Dr. Alex Carrasco sits down with Dr. Karan Rajan to explore why the gut microbiome may be one of the most powerful yet misunderstood systems in the body. From mood and energy to sleep and immune function, the microbiome’s impact extends far beyond digestion. Dr. Rajan brings clinical insight and personal experience to a conversation that’s both science-backed and deeply practical.
Dr. Rajan shares how his own gut health challenges and passion for education led him to investigate the science of fiber, fermentation, and microbiome diversity. He breaks down why most prebiotic supplements miss the mark, feeding only part of the colon, and why feeding the “back of the line” with slow-fermenting fibers is key. Dr. Carrasco and Dr. Rajan also discuss why many people mistakenly believe they can’t tolerate fiber and how to gently reintroduce it through foods like beans, berries, seeds, and resistant starches. They emphasize that restoring microbiome balance doesn’t require perfection; it starts with consistency, movement, stress regulation, and rediscovering the lost art of cooking.
In a world of overprocessed foods and “quick-fix” health products, this episode brings the conversation back to fundamentals: nourish your gut, and the rest follows. Dr. Rajan also shares the inspiration behind LOAM, his meticulously formulated prebiotic fiber blend designed to mimic ancestral diets, enhance gut-brain signaling, and support long-term cognitive and metabolic health. Whether you're a clinician or just fiber-curious, this episode offers clear steps to reconnect with your microbiome—and feel more vibrant every day.
Key Topics Covered
🧠 The gut microbiome as a second brain — influencing cognition, mood, and even dementia risk
🌾 Why most people are “fiber naive” and how to reintroduce it without discomfort
💥 The difference between fast, medium, and slow-fermenting fibers—and why diversity matters
🥦 How ancestral diets rich in tubers, beans, and seasonal plants shape microbial resilience
🚶♂️ Movement, stress reduction, and social connection as essential tools for gut motility
🧪 The case for prebiotics over probiotics—and the problem with inulin and fiber sodas
🩺 Practical clinical tools: using food and poop diaries to uncover gut patterns
🧬 How postbiotics like urolithin A are made in the body—and why prebiotics come first
Timestamps
00:00 – Dr. Karan Rajan, NHS
03:05 – The Gut: Your Second Brain
06:14 – Feed Your Microbiome, Not Just Yourself
09:24 – The Fiber Deficiency Crisis
12:05 – The Secret Life of Tubers
15:13 – Beans, Berries & Seeds: The Big 3
18:31 – Brain Fog Starts in Your Gut
20:57 – You’re Not Fiber-Intolerant — You’re Fiber-Naive
25:10 – The Gut-Brain Connection Explained
29:42 – Poop: Your Body’s Daily Report Card
33:15 – Why We Need to Cook Like Our Ancestors
38:00 – Processed Food & Microbiome Collapse
41:30 – Personalized Health & Testing with Vibrant Wellness
47:53 – The Missing Piece: Data-Driven Gut Testing
52:13 – How to Have the Best Poop of Your Life
55:40 – Realistic Habits for Longevity
58:22 – Stay Curious About Your Health
Resources Mentioned
🌐 Explore more from Dr. Karan Rajan on his official website
🔗 Connect with Dr. Karan Rajan on Instagram
📱 Connect with Dr. Alex Carrasco on Instagram
🥦 Learn more about Loam, Dr. Rajan's prebiotic fiber blend
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Limitations
Please note the information provided by Vibrant Wellness is intended solely for research and informational purposes to help inform lifestyle choices aimed at potential risk mitigation. The information is not intended to be used by the patient for any diagnostic purpose and is not a substitute for medical advice by a healthcare practitioner. Please consult a licensed healthcare practitioner for any questions regarding diagnosis, prevention, or treatment of any disease or health assessment.