Program on Ancient Technologies and Archaeological Materials at the University of Illinois at Urbana-Champaign

Chemical and isotopic analyses of collagen and carbonate preserved in ancient bone make it possible for archaeologists to reconstruct some human diets. Tiny samples of mummy bone were taken to the stable isotope laboratory in the department of Anthropology at the University of Illinois.

C₄ plants such as maize and sorghum use different enzymes to fix atmospheric carbon than do C₃ plants (wheat, rice, fruits and nuts). Carbon preserved in the mineral phase of bone (carbonate) reflects consumption of the different plant groups in the form of distinct ratios of the two carbon isotopes, ¹³C and ¹²C. The difference between carbon isotope ratios of carbonate and the organic phase of bone (collagen) provide an estimate of the degree of carnivorousness (consumption of animal meat, milk, and blood).

The mummy's "collagen" turned out to be "noncollagenous." It was badly degraded and possibly contaminated by embalming fluids. Nevertheless, the carbon ratios are close to those expected for a typical Egyptian diet of bread and onions (C₃ foods) with little animal fat and protein.

Proefke, M. L., et al. (1992). Probing the Mysteries of Ancient Egypt: Chemical Analysis of a Roman Period Egyptian Mummy. Analytical Chemistry 64(2):105A-111A.

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