Post-weaning diet in archaeological human populations: A meta-analysis of carbon and nitrogen stable isotope ratios of child skeletons

ObjectivesChildhood is a unique stage in human life history, in which subadults have completed their weaning process but are still dependent on older individuals for survival. Although the importance of food provisioning during childhood has been intensively discussed, childhood diet in the past has rarely been studied in a systematic manner. MethodsIn this study, a meta-analysis of carbon and nitrogen stable isotope ratios of post-weaning children (PWC) in Holocene human populations around the world is presented. The isotope ratios of PWC were standardized with those of adult females and males in the same population, and they were analyzed in terms of the difference in subsistence. ResultsResults of this study indicate that diets of PWC and adults were generally similar (most differences were within the range of 1 parts per thousand), which is consistent with the universal feature of food provisioning to PWC in humans. In huntergatherer populations, there is no significant difference between PWC and adult isotope ratios. In non-huntergatherer populations, however, PWC probably consumed significantly larger proportions of foods from lower trophic levels than did the adults, and such foods would be terrestrial C-3 plants. ConclusionsPotential factors relating to the dietary differences among PWC and adults are presented from a perspective of balance between food provisioning and self-acquisition by PWC. Significant isotopic differences between PWC and adults in non-huntergatherer populations revealed in this study have implications for declined health during the subsistence transition in Holocene, isotopic studies using human tooth enamel, and N-15 dip of subadults after weaning.