First paleoproteomics evidence of Panicum miliaceum consumption in human dental calculus

Ancient proteins provide a direct window into past diets by enabling the identification of consumed foods through the analysis of dental calculus. While previous studies have reliably detected animal-derived proteins such as milk, plant-derived proteins remain markedly underrepresented, leaving a significant gap in our understanding of the role of plants in past human diets. Here, we show how the reanalysis of open-access paleoproteomics datasets can reveal previously overlooked plant proteins by revisiting two archaeological dental calculus datasets spanning the Eneolithic to Iron Age from the Pontic-Caspian region and the Levantine coast (n = 63 individuals). We identify 60 unique peptides derived from 60 distinct proteins of broomcorn millet (Panicum miliaceum) in 39 individuals. All peptides are unique to Panicum miliaceum and their taxonomic assignment was confirmed using a stringent multi-tier validation strategy, providing the first paleoproteomics evidence of its consumption preserved in dental calculus and extending beyond current protein database annotations. Combined with existing radiocarbon chronologies, these findings represent the earliest paleoproteomics evidence of broomcorn millet consumption, substantially revising its chronology and geographic pathways of dispersal across Eurasia. More broadly, this study demonstrates the untapped potential of dental calculus proteomics and open-access data to directly trace plant consumption, opening new avenues for investigating crops that remain underrepresented in archaeological and proteomics research.