Towards More Sustainable Analysis of Archaeological Dental Calculus

From the 1990s, the investigation of incorporated material into dental calculus (mineralised plaque) has become an important source of direct dietary information of past people. While this started with the examination of microscopic remains, the last decade has shown a wide increase in the use of different biomolecular methods to characterise consumed material. The different sources of biomolecular and microscopic information are complementary and necessary to get a more holistic idea of ancient diets. However, current protocols often involve different extraction methods on separate samples of calculus, despite co-extractions being more sustainable and comparable. Here we present our journey towards more sustainable analysis of archaeological dental calculus, not only applicable to the more judicious use of material but also what the results can provide for modern sustainable food use. This is done through developing a co-extraction protocol that allows for lipids, proteins, and microremains to be extracted from the same sample. This approach considered the impact of previous demineralisation to lipid retrieval and potential changes in protein damage. The final tests were done on calculus from a medieval individual from modern-day Italy, in triplicate, with two different lipid extraction techniques. Finally, we apply this technique to samples from Neolithic Ireland (Carrowkeel, Dowth Hall). The transition to the Neolithic and the food producing way of life is commonly understood to be amongst the most fundamental changes in prehistory, and understanding this change is important to contextualise current foodways and the future of sustainable practices.