Title

Improving Stable Isotopic Interpretations Made From Human Hair Through Reduction of Growth Cycle Error

Authors

Authors

L. J. Williams; C. D. White;F. J. Longstaffe

Comments

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Abbreviated Journal Title

Am. J. Phys. Anthropol.

Keywords

hair; paleodiet; stable isotopes; carbon; nitrogen; ANDROGENETIC ALOPECIA; NITROGEN-BALANCE; S-34 ANALYSIS; FOLLICLE; DELTA-N-15; PREGNANCY; CARBON; BONE; DIET; C-13; Anthropology; Evolutionary Biology

Abstract

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, similar to 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 145:125-136, 2011. (C)2011 Wiley-Liss, Inc.

Journal Title

American Journal of Physical Anthropology

Volume

145

Issue/Number

1

Publication Date

1-1-2011

Document Type

Article

Language

English

First Page

125

Last Page

136

WOS Identifier

WOS:000289355600012

ISSN

0002-9483

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