Ricostruzione dei pattern alimentari e delle pratiche di allattamento e svezzamento dal Neolitico alle età dei metalli tramite analisi multi-isotopiche della dentina incrementale e del collagene osseo

This study analyses changes in breastfeeding and weaning practices, diet, and residential mobility in Liguria (Italy) from the Neolithic to the end of the metal ages. The stable isotopes of carbon, nitrogen, and sulphur from dentine microsections provided information on early diet during development in seven individuals dated to the Neolithic, Copper, Bronze, and Iron Ages, unearthed from nearby caves in the Finalese area. Although it is difficult to pinpoint the exact timing of the introduction of supplementary food and of the end of breastfeeding, results show a marked difference between the Neolithic and metal age individuals. Neolithic children appear to have breastfed for a longer period, possibly at the longer end of the variability in traditional agriculturalists (ranging 2-4 years) and their diet included animal protein food; conversely, post-Neolithic children had a shorter breastfeeding period, and were weaned using plant resources. Sulphur isotopes highlight diachronic changes in mobility, suggesting a local origin of Neolithic and Copper Age children, and movement from the inland for Bronze and Iron Age children. One adolescent, who died with skeletal signs of tuberculosis, shows a sharp increase in δ15N in the last 2-3 years of life, suggesting intense catabolism. This indicates that, by the Neolithic, tuberculosis already had the potential to manifest as a chronic and long-lasting infection, which is typical of diseases with a long history of host-pathogen coevolution. We suggest that the shortening of breastfeeding and weaning practices in the metal ages may have been facilitated by socioeconomic and technological improvements, including the introduction of new agricultural practices and new crops. Neolithic delayed practices, although shorter than the ones shown by hunter gatherers, may have been influenced by a highly infectious environment. Indeed, prolonged breastfeeding is common in marginal contexts, where the maximization of the immune potential transmitted by breast milk is perceived as a priority. However, due to methodological limitations, this study could only include individuals who did not survive into adulthood. It is possible therefore that the analysis highlights the pattern shown by the fragile subset of the populations under exam, rather than successful breastfeeding and weaning practices.