A phylogenetic approach to bridge the food-medicine continuum at the continental scale

The relationship between food and medicinal plants is longstanding and complex, with many species serving both roles. This study explores the food-medicine continuum at a continental scale, analysing phylogenetic patterns of plants used for food, medicine and condiments across three ecologically and culturally distinct Eurasian regions: Iberian Peninsula, Caucasus and West Himalaya. We applied an adapted phylogenetic hot node analysis to identify plant lineages significantly rich in useful species across each use category and region, thereby revealing cross-cultural patterns of plant use and enlarging the potential of the method beyond bioprospecting. We found overlap between lineages used for food and medicine, and between condiments and medicine, both across and within regions. Condiments, often classified as food, had a higher overlap with medicinal plants, reinforcing the idea that they play a critical role in bridging nutrition and health. Our results indicate that the food-medicine continuum transcends cultural boundaries and is grounded in shared history. Our study highlights the value of integrating phylogenetic and ethnobotanical approaches to understand multifunctional plant lineages, an approach that can support food security and healthcare amid global environmental and health challenges.