Microbiome Medics

About Microbiome Medics

Dr Siobhan McCormack and Dr Sheena Fraser are the Microbiome Medics, two GPs who believe that the rapidly emerging science of Human Microbiomes presents a paradigm shift in the way medicine is perceived, researched, and practiced. The Microbiome Medics Podcast is the place where clinicians, scientists and anyone else can learn about Human Microbiomes, Lifestyle Medicine, how they connect and how they can be harnessed to improve health outcomes. Join our two intrepid Microbiome explorers as they unearth the evidence and present the multiple ways in which the trillions of microbes living in and on you can impact your physiology and health. This podcast will escort you through the basics, explain the research, introduce you to the experts and package the latest evidence into actionable, bite-sized chunks that you can use today to improve your own health and the health of your patients. Our only declaration of interest is that we have co-created "the gut microbiome for clinicians", an online course for busy health professionals with over 30 hours of learning available at http://bslm.org.uk/

Publisher

British Society of Lifestyle Medicine

Category

health & fitness · health & fitness · health & fitness

Language

en

Explicit

No

First episode

18 Dec 2022

Latest episode

19 Aug 2026

Latest episodes

43 episodes in the feed.

1. 

   19 Aug 2026

   Beyond Probiotics: Unlocking the Science of Postbiotics with Alastair Jessel

   What are postbiotics, and why might they be the next massive breakthrough in gut health? In this episode of the Microbiome Medics Podcast, Dr. Sheena Fraser is joined by Alastair Jessel, founder of The Postbiotic Company (AYA BIOME™), for an eye-opening dive into the world of post-fermentation microbial science. Using a clever "beer factory" analogy, Alastair breaks down exactly how postbiotics differ from prebiotics and live probiotics, explaining why these stable, inanimate metabolites might bypass the common pitfalls of live probiotic supplements—like dying on the shelf or in stomach acid. The conversation explores the patented fermentation of turmeric, sharing compelling insights from clinical trials regarding inflammation, weight management, and systemic health, alongside striking anecdotal evidence for skin conditions like rosacea. Dr. Fraser grounds the discussion with clinical nuance, emphasizing the foundational importance of a whole-food, plant-based diet and natural fermented foods, while exploring how targeted postbiotic supplements could support patients recovering from antibiotic use or managing chronic metabolic issues. Tune in to learn: The fundamental differences between prebiotics, probiotics, and postbiotics. Why shelf stability and bioavailability are the biggest hurdles for gut supplements. The clinical evidence behind fermented turmeric and its 550+ active metabolites. The potential role of postbiotics in post-antibiotic gut recovery, skin health, and metabolic function. Why Dr. Fraser advocates for a "food first" approach alongside emerging microbiome therapies. (Guest Info: Alastair Jessel is the founder of AYA BIOME™ and publishes commentary on the gut health industry via his Substack, @amanofkent.) Scientific References & Further Reading: Braga, J. D., et al. (2024). Gamma-aminobutyric acid as a potential postbiotic mediator in the gut-brain axis. Science of Food, 8(16). Higova, E. (2024). Postbiotics as metabolites and their biotherapeutic potential. International Journal of Medical Sciences, 25, 5441. Liang, B., & Xing, D. (2023). The current and future perspectives of postbiotics. Probiotics and Antimicrobial Proteins. Ma, L., et al. (2023). Postbiotics in human health. Nutrients, 15, 291. The Postbiotic Company. Research, Clinical Studies & Trials (https://thepostbioticcompany.co.uk/pages/research-clinical-studies-trials). This podcast is brought to you in collaboration with the British Society of Lifestyle Medicine. Disclaimer: The content in this podcast is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or qualified healthcare provider. Never disregard professional medical advice or delay in seeking it because of something you have heard on this podcast.

2. 

   15 Jul 2026

   Defining Gut Health: Moving Beyond the Buzzwords with Prof. Maria Marco

   While "gut health" is a ubiquitous buzzword in the wellness industry, it has historically lacked a clear scientific definition. In this episode, host Dr. Siobhan McCormack sits down with world-renowned expert Professor Maria Marco from UC Davis and the International Scientific Association for Probiotics and Prebiotics (ISAPP). They discuss the new scientific consensus defining gut health, the crucial differences between fermented foods and probiotics, and what we can actually learn from direct-to-consumer stool tests. Plus, Siobhan gets a behind-the-scenes look at a rigorous clinical trial investigating the health impacts of kimchi. What We Cover: Defining Gut Health: How a global expert panel established the first consensus definition, moving beyond just the microbiome to include six complex domains. Symptoms vs. Biomarkers: Why you can still achieve "gut health" even with a chronic but well-managed gut disorder. The Microbiome Testing Reality Check: The limitations of commercial stool tests and why they currently lack the clinical utility to guide personalized medical treatment. Fermented Foods vs. Probiotics: The true distinction between foods fermented for taste and preservation, versus specific live microbial strains proven to deliver targeted health benefits. Inside the Marco Lab: A look at the complexities of nutritional science, including an ongoing clinical trial comparing the physiological effects of kimchi to unfermented cabbage. Scientific References & Further Reading: Marco, M., et al. (2025). Consensus panel definition of gut health. Nature Reviews. Marco, M., et al. (2026). 'The impact of fermented dairy on gastrointestinal health and associated biomarkers'. Nutrition Reviews. Bischoff, S. (2011). "Gut health": a new objective in medicine? Perspective Paper. This podcast is brought to you in collaboration with the British Society of Lifestyle Medicine. Disclaimer: The content in this podcast is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or qualified healthcare provider. Never disregard professional medical advice or delay in seeking it because of something you have heard on this podcast.

3. 

   17 Jun 2026

   Eat to Sleep: The Power of Chrononutrition and Circadian Rhythms

   While we often think of sleep and diet as separate pillars of health, our internal biological clocks and gut microbiome intricately connect them both. In this episode, co-hosts Dr. Siobhan McCormack and Dr. Sheena Fraser dive into the fascinating, bidirectional relationship between circadian rhythms, sleep quality, and gut health. They discuss how our physiology adapts to 24-hour light and dark cycles, the metabolic havoc caused by social jet lag and shift work, and how our gut microbes actually operate on their own daily schedules. Plus, Siobhan and Sheena share practical, evidence-based chrononutrition strategies and explore how targeted dietary patterns, probiotics, and fermented foods can significantly boost your mood and sleep architecture. What We Cover: The Circadian Symphony: How light, dark, and our body's internal peripheral clocks orchestrate everything from hormone release (like cortisol and melatonin) to digestion. Sleep Architecture & Mental Health: The critical role of REM and deep sleep, and how just one night of sleep deprivation increases impulsivity and degrades mood. Chrononutrition: Why when you eat is just as important as what you eat, and how meal timing acts as a major environmental cue for your gut microbes. Social Jet Lag & Shift Work: The metabolic consequences of disrupted sleep cycles, including increased risks for Type 2 Diabetes, and actionable strategies to regain circadian balance. Nutrients & Microbes for Sleep: Exploring the science behind specific dietary protocols, the power of Lactobacillus, and how fermented foods support restorative rest. Scientific References & Further Reading: Conti, F. (2025). ‘Dietary protocols to promote and improve restful sleep: A narrative review’. Nutrition Reviews Dobielska, M. et al. (2025). ‘Association between fermented food consumption and sleep quality under psychological stress: Prospective cohort study’. Food Science & Nutrition. Scott, A.J., Webb, T.L., Martyn-St James, M., Rowse, G., & Weich, S. (2021). 'Improving sleep quality leads to better mental health: A meta-analysis of randomised controlled trials'. Sleep Medicine Reviews Hepsomali, P., & Groeger, J.A. (2021). 'Diet, sleep and mental health: Insights from the Uk Biobank Study'. Nutrients Reid, M., Omlin, X., Espie, C., Sharman, R., Tamm, S., & Kyle, S. (2022). 'The effect of sleep continuity disruption on multimodal emotion processing and regulation'. Journal of Sleep Research Marx, W., Manger, S.H., et al. (2023). 'Clinical guidelines for the use of lifestyle-based mental health care in major depressive disorder'. World Journal of Biological Psychiatry Vetter, C. et al. (2018). 'Night Shift Work, Genetic Risk, and Type 2 Diabetes in the UK Biobank'. Diabetes Care This podcast is brought to you in collaboration with the British Society of Lifestyle Medicine. Disclaimer: The content in this podcast is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or qualified healthcare provider. Never disregard professional medical advice or delay in seeking it because of something you have heard on this podcast.

Who has been a guest on Microbiome Medics

Names identified in recent episode analyses. Showing up to five guests.

• Michael Cox
• Chris Stewart
• Emily Leeming
• Anastasia Theodosiou
• Natalie Bennett

Reach and audience

Public platform figures. Ratings count people who left a rating, not total listeners.

Apple Podcasts (US)

4.5 / 5

8 ratings

Spotify

4.9 / 5

31 ratings

Podcast Authority Score: 35 / 100

A composite of feed quality, social presence, YouTube performance and engagement. Read the methodology.

Quality

36

Social presence

0

YouTube

0

Engagement

85

Contact Microbiome Medics

Guest appearances

Books guests

Based on episode analysis; this does not confirm that the show is currently accepting guests.

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