Interindividual variation in infant and child feeding behavior at Đurđevac-Sošice, medieval Croatia: Exploring life course through incremental analysis of dentin

Abstract

This study uses incremental sectioning of dentin to understand patterns of diet and metabolic stress in human remains from the Saint George Catholic Church at the medieval Đurđevac-Sošice site in Croatia. Mesiobuccal thin sections were produced from the permanent first molars of 12 individuals and collagen was extracted using 1 mm biopsy punches. Carbon and nitrogen stable isotope ratios (δ¹⁵N and δ¹³C) were analyzed using mass spectrometry. Age at weaning completion was estimated using curvilinear models of δ¹⁵N and δ¹³C relative to age. Opposing δ¹⁵N and δ¹³C patterning was explored to identify evidence for metabolic stress. Weaning completion was estimated at 2.9 years, with animal source protein gradually increasing following the weaning process. Weaning foods were diverse and include a combination of C3/C4 plant foods or animal source foods that were foddered on C3/C4 plants. Interindividual variation in maternal nursing and weaning practices was observed, with one individual lacking evidence for nitrogen enrichment and one individual continuing the weaning process until approximately 5.0 years. Opposing δ¹⁵N and δ¹³C were identified in two individuals, one between 6.6 and 10.0 years, and another between 5.0 and 7.0 years of age. These findings are consistent with age at weaning completion observed across medieval Eastern Europe and further emphasizes diversity in maternal nursing and weaning practices. Opposing δ¹⁵N and δ¹³C is associated with metabolic stress during childhood and is consistent with bioarchaeological research that reports widespread evidence for growth disruption during infancy and childhood in this region. Overall, this work emphasizes the value of incremental isotopic sections in understanding the early life environment.