Palaeodiet at Eton College Rowing Course, Buckinghamshire: isotopic changes in human diet in the Neolithic, Bronze Age, Iron Age and Roman periods throughout the British Isles

Through isotopic investigations of directly dated human remains recovered from the Eton College Rowing Course, we examine changes in diet from the Neolithic to the Roman period. The human isotope signatures point to a diet based on C-3 terrestrial resources. A significant correlation is visible between human delta C-13 values and time, but no such trend is observed in delta N-15. The animal isotope data from Eton are unevenly distributed, making it difficult to determine if the human values mirror the animal values. To assess whether the results from Eton are typical, we compare our results to isotope data from other British sites dating from the Neolithic to the Roman period. Across this time period, we see a strong correlation between the mean delta N-15 of the humans and that of the main domesticated herbivores, with an offset of similar to 4.5% between the two. Thus, the changes in the human isotope values are likely linked to changes in the isotopic signatures of the herbivores rather than changes in the protein composition of human diets. By contrast, no clear temporal relationship is observed between the mean delta C-13 of the humans and that of the main domesticated herbivores, with an offset of similar to 1.4% between the two. There is, however, a weak correlation observed between the mean delta C-13 of the humans and that of the cattle, which may account for some of the variation in human delta C-13 values between sites. The absence of a strong correlation between mean human and animal delta C-13 suggests that the primary factor influencing human delta C-13 values between sites is dietary composition. The lack of co-variation between delta C-13 and delta N-15 is likely to reflect the different representation of dietary macronutrients. Given that the nitrogen results suggest that the animal protein consumption patterns are similar across sites, the human delta C-13 variation between sites is likely to reflect the plant portion of the diet.