Leo Grady, PhD, AI and microbiome founder; Helen Messier, MD, PhD, molecular immunologist and longevity clinician; Lawrence Kosinski, MD, gastroenterologist and value-based care leader. They discuss how AI decodes microbiome signatures before disease. Conversations cover gut–brain links, microbial metabolites like butyrate, TMAO and cardiovascular risk, effects of diet, fiber and drugs on microbiome, and clinical uses of fecal testing.