Hydrogen and oxygen isotope ratios in human hair are related to geography

Proc Natl Acad Sci U S A. 2008 Feb 26;105(8):2788-93. doi: 10.1073/pnas.0712228105. Epub 2008 Feb 25.

Abstract

We develop and test a model to predict the geographic region-of-origin of humans based on the stable isotope composition of their scalp hair. This model incorporates exchangeable and nonexchangeable hydrogen and oxygen atoms in amino acids to predict the delta(2)H and delta(18)O values of scalp hair (primarily keratin). We evaluated model predictions with stable isotope analyses of human hair from 65 cities across the United States. The model, which predicts hair isotopic composition as a function of drinking water, bulk diet, and dietary protein isotope ratios, explains >85% of the observed variation and reproduces the observed slopes relating the isotopic composition of hair samples to that of local drinking water. Based on the geographical distributions of the isotope ratios of tap waters and the assumption of a "continental supermarket" dietary input, we constructed maps of the expected average H and O isotope ratios in human hair across the contiguous 48 states. Applications of this model and these observations are extensive and include detection of dietary information, reconstruction of historic movements of individuals, and provision of region-of-origin information for unidentified human remains.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acids / chemistry
  • Dietary Proteins / analysis
  • Geography
  • Hair / chemistry*
  • Humans
  • Hydrogen / analysis*
  • Models, Biological*
  • Oxygen Isotopes / analysis*
  • United States
  • Water Supply / analysis

Substances

  • Amino Acids
  • Dietary Proteins
  • Oxygen Isotopes
  • Hydrogen