Because a relationship exists between diet and the chemical composition of the consumer's tissue, paleoanthropologists have focussed attention on the chemical analysis of human skeletal remains. Through study of trace elements such as strontium and the isotopic ratios of carbon and nitrogen, it is often possible to gain insight into foods consumed during an individual's lifetime. In most archaeological excavations food remains especially plant foods - are absent because of poor preservation, and, therefore, skeletal analysis provides the only means to reconstruct subsistence. While, in practice, these techniques seems to work well, the exact mechanisms by which elements are incorporated into tissue such as bone are poorly understood, and without such knowledge, it is difficult to place a high degree of reliance on the results of such studies. Dr. Stanley Ambrose and his colleagues will continue their work to elucidate these mechanisms. They will conduct an integrated program of research comprising a series of experiments. These include controlled diet experiments using small mammals fed naturally labeled carbohydrates and proteins in different combinations under different simulated environmental conditions. This will define the relationship between the stable isotopic composition of diet, biochemical fractions of diet, and consumer tissues. It will also provide insight into the effects of protein nutrition on collagen and apatite turnover rate. The team will also analyze the isotopic composition of hair of six human populations in natural environments whose diets have been accurately quantified in longitudinal nutrition study. These will provide a practical situation in which to evaluate the results of the laboratory experiments. Bones samples from prehistoric population will also be examined. This research is important because it will increase our basic understanding of the nutritional process. It will yield analytic approaches of use in a wide variety of archaeological situation.
