This episode features Raphaela Joos from University College Cork in Ireland, speaking about efforts by the Human Microbiome Action Consortium to create an expert-led consensus around the concept of a healthy human microbiome. Ms. Joos, a PhD student who was first author of the resulting paper, notes that a healthy human microbiome can be defined at many different levels. Some parameters such as diversity and resilience are good for a microbial community, and other parameters such as antimicrobial resistance are good for the microbial community but not necessarily good for the host. Another challenge with the definition was how to define health. The group decided that the definition of healthy microbiome needed to be more inclusive than just the microbiome of a healthy person with no disease diagnoses. At present, causality is not clear so we don’t know whether disease-associated microbiomes are adaptive or are driving the disease. The main consensus that emerged from this expert discussion was that more data are needed, tracking large cohorts of people over time in many geographical areas. Only in this way will it be possible to overcome individual variability and truly identify the robust features of a healthy microbiome. Different microbiome compositions can have similar functional capacities, so possibly a functional signature will emerge. Episode abbreviations and links: Perspective paper by Human Microbiome Action Consortium, first authored by Joos: Examining the healthy human microbiome concept About Raphaela Joos: Born and bred in Germany, I obtained my BSc in Psychology with a focus on biological neuropsychology, nutrition and statistics at Leiden University and the University of Melbourne. Fascinated by nutritional science and its impact on mental health, I then pursued a MSc on the topic of Microbiome in Health and Disease at King’s College London, delving into microbiology, bioinformatics and microbiome science. After the masters I moved to Cork for a research assistant position investigating the structure and infection mechanisms of bacteriophages involved in cheese fermentation using the protein-folding software AlphaFold. Before starting my PhD, I worked as a project manager under Prof Paul Ross and Prof Aonghus Lavelle on the Human Microbiome Project, organising a workshop featuring international leaders in microbiome research to establish a roadmap to define a healthy microbiome. My PhD now focuses on investigating the role of the infant microbiome in development, applying statistical modelling strategies to integrate functional microbiome data with clinical data. Sign up for our monthly newsletter Follow us on LinkedIn, Bluesky, X, Facebook, Instagram, Threads