Dr. Hasinika Gamage is a postdoctoral research fellow at the Facilitated Advancement of Australia's Bioactives (FAAB) in the School of Natural Sciences at Macquarie University in Sydney, Australia. In this episode, we begin exploring the meta theme of Gut Health, a crucially important subject of our time. Feeling good? Feeling down? Lend me your ears, 'cause I got news for ya: serotonin is produced in the gut! Are you in prison and feeling violent (I hope not! On both counts!); but if so you might want to take some probiotics, as they have been proven in peer-reviewed studies to reduce violent tendencies (prisoners have been shown to have deficient microbial allocations). Rapidly becoming cliché is the notion that the gut is the second brain, a concept borrowed from Ayurveda; so, so many of our feelings emanate from the complex brew stirring up in the depths. The gut is fundamentally the place where mood origination happens; we are coming to realise it is the interface to everything; and we couldn't be with a better guest today to help us understand the contours of this fascinating (and still much unknown) space.

As a non-physician, Dr. Hasinika is clear to disclaim any statements that suggest medical advice; which is an important footnote. However, as she she uses molecular microbiology, sequencing, bioinformatics, and various coding and data analysis tools to do her work, there is a very important emergent theme here. That is, the gut is so complex, that nothing less than a multidisciplinary approach, perhaps one that uses combinatorial methods and/or is comfortable with large data sets and maths, is suitable to make any sweeping statements. Dr. Hasinika reminds us that at play are microbial communities, each with computationally vast oceans of interactions between them. This is wild!

We quickly learn from Dr. Hasinika that balance is an important metaphor when thinking about our microbiomes. We walk through the literal human "viscera" with Dr. Hasinika, who makes notes about the varying pH levels at different stages of the human digestive system, noting that different bacteria and even fungus populate different specialised nodes, for example, in the stomach and the large intestine the pH gets extremely acidic, limiting the potential candidates (bonus points for puns about candida? Haha, no!). Our diet, lifestyle, and even the timing of our meals shapes these microbial communities, and as a result, our overall health. From the role of the intestinal mucus layer (sexy, I know) and dietary fibre, to the emerging science of prebiotics, probiotics, and "postbiotics" (a new one for us, too,) we explore how different microbes thrive and interact.

Dr. Hasinika explains why diverse, whole-food diets are crucial for microbial balance, how modern processed foods can reduce gut diversity, and why extreme diets may have unintended consequences. We also discuss the influence of circadian rhythms and meal timing on gut health and metabolism, showing that it’s not just what we eat, but when we eat it. All of the strict science is held in tension at certain moments, where Dr. Hasinika also reveals that she has an Ayurvedic family background, and shares some personal vignettes of her "healer" relatives in Sri Lanka. We explore "common sense" as an idea in light of imperfect knowledge in a very complex field.

Get some kimchi and sauerkraut juice, kick back and enjoy this episode!