Biting into the Truth: Connecting oral pathology and stable isotopes through the paradigmatic example of a hyper-specialized marine diet in Medieval Pontevedra (NW Iberia)

Abstract

Human feeding patterns have been reconstructed in Archaeology by analysing either oral pathology or stable isotope ratios in human skeletal remains. However, no clear agreement has been developed between these two methodologies. The main objective of this study is to determine if we can establish a link between them when analysing a population with a hyper-specialized diet, in this case marine resources. To reach this goal we developed a conjoined multi-isotope analysis in collagen and bioapatite (δ13Ccol, δ15Ncol, δ13Ccar and δ18Ocar) and a detailed study of oral health (caries, antemortem loss, periapical lesions, periodontal disease, calculus, and wear). All available skeletons with at least one preserved tooth from two cemeteries of the medieval town of Pontevedra (n = 34) were researched. The buried individuals belonged to the guild of fishers and artisans, professions which were dominant among the families of medieval Pontevedra. The evidence of δ18Ocar indicates that most people seem to have local origins. The diet was based on marine fish protein with contributions of millets (e.g. δ13Ccar -11.87 ± 1.79‰) that seems to be slightly higher in individuals linked to artisanal guilds. Oral pathology study shows severe dental wear from an early age, including hypercementosis due to compensatory eruption, as well as moderate-high presence of caries and dental calculus. Both the oral pathology and the isotopic signal differ from that observed in other areas of the Iberian Peninsula. This study points to the existence of connections between findings of the two methodologies, and specifically an association between intense dental wear and high consumption of marine resources. At the same time, this analysis implies the necessity of caution in estimation of age by dental wear in populations linked to the sea.