The Gut-Brain Connection: Summer Highlights with Dr. Will Bulsiewicz and Dr. Trisha Pasricha

How fiber, the microbiome, stress, and the aging gut shape brain health. In this Summer Highlights episode, Dr. Annie Fenn and Jenny Shilling revisit key moments from two season-one conversations about the gut-brain connection. Gastroenterologist and microbiome expert Dr. Will Bulsiewicz explains how fiber feeds the gut microbiome, which then produces short-chain fatty acids with anti-inflammatory effects throughout the body and brain. He also describes how the microbiome helps maintain the gut barrier, regulate the immune system, and transform polyphenols from colorful plant foods into compounds the body can use. Neurogastroenterologist Dr. Trisha Pasricha explains why the gut is much more than a digestive organ. It has its own nervous system, communicates constantly with the brain, and may even offer early clues about neurodegenerative diseases such as Parkinson’s. Together, these conversations explore how stress affects digestion, why gut symptoms are never simply “all in your head,” what happens to the gut as it ages, and why constipation, sleep changes, and loss of smell may deserve attention when they occur together. You’ll also learn why many of the same habits that support the brain—eating more whole plants, exercising, managing stress, and limiting ultra-processed foods—also support the gut. Chapters 00:00 The gut-brain connection 03:48 Why a gastroenterologist studies Parkinson’s 06:24 How fiber feeds the microbiome 09:50 Stress, digestion, and the two-way gut-brain loop 15:26 The gut barrier, immunity, and inflammation 21:45 The aging gut and early Parkinson’s clues 31:44 Fiber, polyphenols, and eating the rainbow 34:22 What this means for brain health Links Mentioned Dr. Will Bulsiewicz Dr. Trisha Pasricha Full episode with Dr. Will Bulsiewicz Full episode with Dr. Trisha Pasricha Brain Health Kitchen Substack NeuroReserve. Our founding sponsor NeuroReserve has a special discount code that can be applied to their brain health nutrition products: Relevate, Revanta creatine, and the new release of BHK EVOO Order here and use code BHKPODCAST at checkout for 10% off. BetterBrain. If you are curious about having a brain health check-up, our founding sponsor BetterBrain is offering BHK Podcast subscribers a special deal: use code AFENN50 for $50 off your assessment, which includes key biomarkers for brain health. Check them out at BetterBrain.com/annie.