Commentary: Revisiting Physiological and Theoretical Dimensions of Stable Isotope Variation in Human Tissues

Typically used to reconstruct diets and migration histories, isotope ratios in human tissues also reflect physiological states associated with health and stress. The publication in 2013 of a paper in the American Journal of Human Biology reviewing such cases has been widely cited. This article revisits this topic and reviews key research exploring the use of isotope ratios as a means for evaluating physiological processes. The review permits a critical evaluation of how scholarly works have engaged with the potential to add physiological factors to well-trodden models of how isotope ratios become fixed in the body by considering recent theoretical trends in the social sciences and conducting a meta-analysis of a select body of literature published in the period of 2013-2024 to see how exactly research has engaged with the topic. This approach reveals that while stable isotope data do have exciting future applications to understanding physiology, stress, and disease states, this potential is still underdeveloped, with published research more often using physiology as a "disclaimer" for unexplained isotope variation than deliberately testing and advancing the potential.