Isotopic insights into the early Medieval (600–1100 CE) diet in the Luistari cemetery at Eura, Finland

Abstract

In this article, we present the results of an isotopic study of diet for the early medieval (Merovingian, Viking, Early Christian) humans buried in the unique Luistari cemetery at Eura (ca. 600–1400 CE), southwestern Finland, the largest cemetery of the region. Isotope analysis was conducted on 37 humans for dentine and bone collagen (δ13C, δ15N, and δ34S), and five of them were also studied using compound-specific nitrogen isotope analysis. Dental enamel and/or bone carbonate δ13C values were studied from altogether 65 humans, five cattle, and five sheep/goats. The bone and dentine collagen and carbonate data show that throughout the centuries, freshwater fish was a stable part of the diet for the population. Our results do not show systematic dietary differences between estimated males and females, but differences can be large on the individual level. We also discovered a possible temporal change in the enamel carbonate ẟ13C values that could be related to the increasing role of carbohydrates (e.g., crops) in the diet. Luistari burials are well comparable to contemporary Swedish Viking trading communities like Birka in their higher protein intake. But contrary to the wider Viking network, they do not show the same marine signal.

North and South: Exploring isotopic analysis of bone carbonates and collagen to understand post‐medieval diets in London and northern England

“…The utilization of both 𝛿 13 C coll and 𝛿 13 C carb in isotopic studies, therefore, provides a more holistic estimate of several dietary inputs. In Europe, some studies have made use of both components (Dotsika et al, 2022 ; Etu‐Sihvola et al, 2022 ; Grupe et al, 2009 ; Gugora et al, 2022 ; Olsen et al, 2016 ; Reitsema et al, 2010 ; Toyne et al, 2022 ; Yoder, 2012 ; Zechini et al, 2021 ). Although 𝛿 13 C coll data from these studies suggested that dietary protein was primarily derived from C 3 resources, the differences in the 𝛿 13 C carb values among the individuals at certain sites indicated that some individuals may have consumed more C 4 or marine foods than others (Dotsika et al, 2022 ; Reitsema et al, 2010 ; Yoder, 2012 ), demonstrating the utility of analyzing 𝛿 13 C carb alongside 𝛿 13 C coll values.…”