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
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