Dietary seasonal variations in the Medieval Nubian population of Kulubnarti as indicated by the stable isotope composition of hair

Objectives The island of Kulubnarti is located in Sudanese Nubia and contains two cemeteries, named R and S, which are dated to AD 550–800. In order to provide more detailed dietary information for this population and examine seasonality of diet, we analyzed the carbon isotope composition of hair samples from both cemeteries. Materials and methods Forty seven separate hair samples from 8 adults, 29 adolescents, 7 infants and 3 individuals with unknown age were analyzed. Long hair samples were cut transversely and divided into 2 cm longitudinal segments, to examine temporal variations in the dietary carbon sources. Results The average carbon isotope value for the whole population was −17.95‰ (SD = 1.8). A significant difference between the two cemeteries was found with variances in the amount of C4 dietary carbon sources consumed. Discussion The results of hair isotope compositions concur with previous soft tissue investigations of Kulubnarti population which suggested that the dietary regimen contains a mix of C3 and C4 plant-based sources. A seasonal variation in diet can be inferred from the sequential hair segments of Kulubnarti individuals. These suggest a dietary transition between dominant C3 plant-based sources in winter to dominant C4 ones in summer with a small contribution of the non-harvested, alternative, crop