Zinc as a Paleodietary Indicator: An Issue of Theoretical Validity in Bone-Chemistry Analysis

The use of the concentrations of zinc in archaeological bone as an indicator of past diets and/or health conditions has become widely accepted in bone-chemistry analysis, despite the fact that the theoretical validity for such an application has not been established. In this paper I present a series of critical variables—such as elemental metabolism, bone physiology, the relationship between dietary intakes of an element and its concentration in bone, trophic-level separation in the foodweb, and diagenetic variability—that must be addressed in the process of theoretical validation. I also discuss how studies that support the use of zinc as paleodietary indicator have generally focused on only one or perhaps two of these criteria. Until a sound model based on physiological principles is developed, the use of zinc as a paleodietary indicator remains unproven.