Improving stable isotopic interpretations made from human hair through reduction of growth cycle error
Article first published online: 10 FEB 2011
Copyright © 2011 Wiley-Liss, Inc.
American Journal of Physical Anthropology
Volume 145, Issue 1, pages 125–136, May 2011
How to Cite
Williams, L.J., White, C.D. and Longstaffe, F.J. (2011), Improving stable isotopic interpretations made from human hair through reduction of growth cycle error. Am. J. Phys. Anthropol., 145: 125–136. doi: 10.1002/ajpa.21479
- Issue published online: 11 APR 2011
- Article first published online: 10 FEB 2011
- Manuscript Accepted: 30 NOV 2010
- Manuscript Received: 24 JUL 2010
- Canada Research Chairs Program (CDW)
- Natural Sciences and Engineering Research Council (FJL)
- Canada Foundation for Innovation
- stable isotopes;
A recent trend in stable isotopic analysis involves the reconstruction of short-term variations in diet using hair segments. However, bulk hair samples typically contain a growth cycle error, which may conceal or confound the most recently incorporated isotopic information. It is assumed that, at any given time, ∼85–90% of scalp hairs are actively growing, while the remaining 10–15% have transitioned into a resting or inactive phase, which lasts up to 4 months before hairs are shed. This study uses growth phase to determine the effects of age, sex, and health status on carbon and nitrogen isotopic ratios of hair analyzed in sequential segments. For this study, we selected archaeological hair samples from 10 individuals from Dakhleh Oasis, Egypt. Isotopic analyses of actively growing hair segments were compared to those for mixed growth phase segments from each individual. These data demonstrate the presence of growth cycle error and show that an understanding of structural–functional relationships is essential for interpreting normal versus pathological changes in hair follicle and fiber production. In situations where diet change and mobility produce variations in an individual's isotopic composition, elimination of positional–temporal error in sequential segment hair analyses can facilitate greater understanding of intraindividual metabolic reactions and changes in hair growth cycles. Phase identification may aid in determining the presence of pathological conditions in individuals, especially in those lacking skeletal indications, and provide a more precise estimation of seasonal dietary patterns, access to changing food resources, and metabolic equilibration to a new locality. Am J Phys Anthropol, 2011. © 2011 Wiley-Liss, Inc.