In Episode #191 I sit down with Stanford University Professor's Dr Christopher Gardner and Dr Justin Sonnenburg to talk about fermented foods, fibre, gut health and immunity. This conversation was organised following the results of their latest randomised controlled trial 'Gut-microbiota-targeted diets modulate human immune status' which was published in Cell Press in 2021.In this conversation we cover:Dr Sonnenburg’s background and journey into studying the microbiomeDefining the terms ‘microbiome’ and ‘microbiotaThe development of technology in learning more about the microbiomeWhat defines a healthy microbiome and dysbiosisStudying the microbiomes of traditional populations such as the Hadza tribeThe benefits of microbiome diversityLack of microbiome diversityIntestinal permeabilityHow Justin and Christopher came to working togetherThe mission behind their study of fibre and fermented foodsThe methodology of the studyThe definition of fermented foodsMicrobes being added to packaged fermented foodsWhat the study found in terms of fermented foodConducting studies with humans vs animalsWhat can the study tell us about the effectiveness of probioticsSodium in fermented foodsWhat the study found in terms of fibre intakeAccuracy of stool/microbiome testingKey takeaways from the studyand plenty moreJustin Sonnenburg, PhD bio:Dr Sonnenburg is an associate professor in the Department of Microbiology and Immunology at the Stanford University School of Medicine, where he studies the gut microbiota in health and disease and co-directs the Center for Human Microbiome Studies. He and his wife Erica, are the authors of the book The Good Gut: Taking Control of Your Weight, Your Mood, and Your Long-Term Health. Their laboratory at Stanford develops and employs diverse technologies to understand basic principles that govern interactions within the intestinal microbiota and between the microbiota and the host. An ongoing objective of the research program is to devise and implement innovative strategies to prevent and treat disease in humans via the gut microbiota. Current pursuits include genetic engineering commensal bacteria to enable therapeutic delivery within the gut, as well as understanding the health impact of microbiome change that has occurred during industrialization. Justin conducted his Ph.D. in Biomedical Sciences at the University of California, San Diego in the laboratory of Ajit Varki. His postdoctoral work was conducted at Washington University in Saint Louis, Missouri in the laboratory of Jeffrey Gordon. He has received an NIH Director’s New Innovator Award and Pioneer Award. He serves on several scientific advisory boards and is a co-founder of Novome Biotechnologies.Christopher Gardner, PhD bio:Dr Gardner is the Rehnborg Farquhar professor of medicine at Stanford, the director of Stanford Prevention Research Center’s (SPRC) Nutrition Studies Group, and the director of the SPRC postdoctoral research fellow training program. His primary research focus for the past decade has been randomized controlled nutrition intervention trials (soy, garlic, antioxidants, ginkgo, omega-3 fats, vegetarian diets, weight loss diets), testing the effects of these on chronic disease risk factors that have included blood cholesterol, weight, inflammatory markers, and the microbiome. His research interests have recently shifted to two new areas. The first is to approach helping individuals make healthful improvements in diet through motivators beyond health, linking to ongoing social movements around animal rights and welfare, climate change, and social justice, and their relationships to food. The second is to focus less on trying to improve individual behaviors around food, and more on a food systems approach that addresses the quality of food provided by universities, worksites, hospitals, schools, etc., using a community-based participatory research approach and taking advantage of the many complementary disciplines represented on the Stanf