Dietary history of two human individuals at the Yingpanshan site, Sichuan Province, revealed by carbon and nitrogen isotope analysis of serial samples of dentinal collagen

Abstract

AbstractInstead of the conventional approach to sectioning tooth dentine horizontally for isotope analysis, a new serial sampling strategy has been developed recently. This new method considers the developmental direction of growth lines in dentine when samples are sectioned. It can therefore provide more precise and detailed information about an individual's dietary history, including breastfeeding/weaning patterns, infant feeding experiences, and dietary shifts throughout the early life of an individual. In order to enhance our understanding of human groups in ancient Sichuan, it is practical and necessary to apply this new technique to archaeological samples from this region.In this study, carbon and nitrogen isotope compositions of bone and serial dentinal collagen from two Yingpanshan human individuals (M32 and M40) were analysed and compared, in order to reveal the dietary history during their lifetime. Results indicate that their long‐term averaged diets after childhood consisted of both C3 and C4‐type foods, predominantly the former. The contribution of animal protein to the childhood diet of individual M40, between the ages of 3.0 and 7.5, was similar to his long‐term averaged diet after childhood. He had also consumed more millets during the childhood. By comparison, individual M32 consumed more animal protein and likely also more C3‐type foods between the ages of 4.5 and 13.5 than after childhood. Little variations in δ15N dentinal collagen of each individual suggest that the relative consumption of animal to plant foods in their respective diets was more or less consistent in their childhood. However, the larger variations in the δ13C values of dentine samples show that the proportion of C3 and C4‐plant foods in their respective diets varied at different phases in their childhood. The variations are probably related to environmental factors and/or human behaviour. The dietary history and weaning practices revealed by using this technique also indicate that the two individuals might have been non‐locals or received some foods that originated from the outside.