Reconstruction of ancient diet using stable isotope analysis of human soft tissue remains

Abstract

Carbon and nitrogen stable isotope values were measured in tissues of Nubian mummies from two Christian cemeteries (AD 550–800) located on the island of Kulubnarti about 130 Km south of Wadi Halfa in Sudanese Nubia. Protein suitable for isotopic analysis for dietary reconstruction was extracted from soft tissue samples of 90 naturally mummified individuals (47 adults, 42 immature and one of unknown age at death), plus 47 hair samples. Then, the carbon and nitrogen isotopic compositions of the samples were analysed using Continuous Flow-Elemental Analysis-Isotope Ratio Mass Spectrometry (CF-EA-IRMS). The isotopic data indicated that the diet of these Nubian populations included a mix of C3 and C4 plants (predominantly C3) in addition to a relatively small contribution of animal protein from terrestrial sources and no aquatic protein sources. The quality of the diet, as indicated by the protein type, was the same in the two cemeteries. However, a significant difference was found regarding the δ13C values between the two cemeteries VIII which may indicate a diet enriched in 13C (more C4 plants) in the individuals buried in the Kulubnarti R cemetery. Significant differences were found between different soft tissues in the nitrogen isotopic signatures with meninges and periosteum being the most 15N- enriched tissues, followed by skin, while cartilage was the least 15N-enriched tissue. No significant differences were found in the δ13C values between different tissues. No significant isotopic differences between age and sex categories have been found in the collagencontaining tissues. However, hair samples showed a significant depleted nitrogen compositions in the S-cemetery juveniles. Additionally, the hair results showed seasonality in the consumed diet. Key words: Carbon isotopes, nitrogen isotopes, ancient diet, Kulubnarti, Sudanese Nubia, mummified soft tissues.