Dietary patterns and social structures in medieval Sigtuna, Sweden, as reflected in stable isotope values in human skeletal remains

Stable isotopes (δ¹³C, δ¹⁵N) have been studied in human burials from the medieval town Sigtuna in Sweden. Dietary patterns of 80 adult individuals were analyzed on three cemeteries representing the phases of establishment, prosperity and decline of the town. All analyzed individuals were radiocarbon dated. One of the cemeteries, Church 1, represents a population of higher social status than those at the other two cemeteries.The δ¹³C values are homogenous and showed that the protein intake was mainly of terrestrial origin in the whole population. δ¹⁵N values varies more and they may indicate a higher input of vegetables in the diet at one of the cemeteries, the Nunnan block.Already in the initial phases of Sigtuna a social hierarchy had been established which is reflected in dietary patterns. Apparently more animal protein was consumed among the high status population of the town. Furthermore, differences in dietary patterns between the sexes were noted. In all phases the females show more clustered values indicating a more homogeneous diet than that of the males.     

Stable carbon and nitrogen isotope variations in tooth dentine serial sections from Wharram Percy

Here we report δ¹³C and δ¹⁵N measurements of serial sections of human deciduous and permanent tooth dentine from archaeological samples taken from the medieval village site of Wharram Percy, Yorkshire, UK. We found a pattern of enrichment, for both δ¹³C and δ¹⁵N, where the tooth crown was greater than the cervical part of the root, which in turn was greater than the apical portion of the root and the associated rib collagen values. This pattern reflects a decrease in the consumption of isotopically enriched breast milk and the introduction of less enriched weaning foods in the diet. The (mean±SD) difference between the deciduous second molar crowns and corresponding rib samples from the same individuals after 2 years of age was 1.2±0.4‰ for δ¹³C and 3.2±0.8‰ for δ¹⁵N. The δ¹⁵N values are as predicted, but as there were no C₄plants at Wharram Percy, this 1.2‰ enrichment in δ¹³C represents clear evidence of a carbon trophic level effect in collagen from breastfeeding infants. Carbon and nitrogen results also show that the infant diet among those who died in infancy did not differ from those who survived into childhood. This study demonstrates the promise of using dentine serial sections to study the temporal relationships of breastfeeding, weaning, and dietary patterns of single individuals.     

Taxonomic, anatomical, and spatio-temporal variations in the stable carbon and nitrogen isotopic compositions of plants from an African savanna

Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope ratios are commonly used to reconstruct palaeodiets and palaeoenvironments. The method is based on our knowledge of isotopic patterns in plants, which are subject to taxonomic and environmental variability. While previous researchers have addressed isotopic variability amongst plants, no studies have looked extensively at a broad suite of taxa over multiple temporal scales from within the savanna biome so as to provide baseline data for palaeodietary and palaeoenvironmental studies. Here we document variations in the isotopic compositions of plants collected over two years from the Kruger National Park, South Africa, with respect to species and anatomical differences, and the influences of geological substrate and spatio-temporal shifts in climate. Results show that environmentally-induced carbon isotopic variations in plants within this region are generally smaller than 2‰, which is lower than what has been previously reported for plants compared across multiple habitat-types. These data suggest that δ¹³C differences of 2‰ or more (or 1‰ if the diet is predominantly C₄) between animals from a given area reliably indicate real dietary differences. Plant δ¹⁵N values vary greatly between different microhabitats (by up to 4‰), responding to a range of environmental influences that may, in turn, significantly influence variation in animal δ¹⁵N values.     

Mummies, maize, and manure: multi-tissue stable isotope analysis of late prehistoric human remains from the Ayacucho Valley, Perú

This paper reports the δ¹³C and δ¹⁵N values of bone collagen, muscle and skin from several late prehistoric–early colonial (AD 1490–1640) mummies from Perú's Ayacucho Valley. The mean of the δ¹³C and δ¹⁵N values of bone collagen are −11.5 ± 1.4 and 11.1 ± 0.7‰, respectively. The mean of the δ¹³C values for Vinchos skin is −11.8 ± 1.2‰ and the mean of δ¹⁵N values is 13.2 ± 0.5‰. The samples of muscle tissue have a δ¹³C mean of −11.9 ± 0.9‰ and a δ¹⁵N mean of 12.7 ± 0.3‰. The data from bone collagen indicate maize was the basis of the region's subsistence economy. A significant correlation between δ¹³C and δ¹⁵N values of bone collagen (R² = 0.75) is consistent with the preferential fertilization of maize with composted manure. Both skin and muscle samples are consistently enriched in δ¹⁵N relative to paired samples of bone (2.1 ± 0.5 and 1.6 ± 0.7‰, respectively), possibly as a result of short term physiological stress or differential decomposition.     

Investigating foetal and perinatal mortality in prehistoric skeletal samples: a case study from a 3000-year-old Pacific Island cemetery site

The Teouma skeletal sample from Vanuatu represents one of the few truly colonising populations in the Pacific Islands. Therefore, investigating the factors that may have affected foetal/infant mortality in this population is potentially important for understanding the success of settlement in this region of the world. We investigate whether stable isotope analyses of carbon and nitrogen in conjunction with skeletal ageing techniques, can aid in identifying whether the subadults from Teouma died before or after birth in an attempt to understand the potential threats to foetal and infant survival. Multiple skeletal ageing methods using diaphyseal lengths were used to age the young subadults (n = 7). Using regression-based skeletal ageing methods, four of the individuals were aged at around full-term gestation (37–42 weeks gestation), while the remaining three individuals died preterm. The isotope analyses did not assist in identifying the individuals that survived post-birth because none of the subadults displayed the 2–3‰ trophic increase in δ¹⁵N values expected for a breastfed infant, probably as a result of their young age. However, all of the foetal/perinatal individuals exhibited higher δ¹⁵N values in their bone collagen compared with the adult females of the sample, with two of the individuals demonstrating unusually high δ¹⁵N values. The δ¹³C values of the foetuses/perinates did not exhibit the same variation. We explore a number of possible explanations for this elevation of perinatal/foetal δ¹⁵N values and tentatively suggest that this is a result of in utero stress as a consequence of chronic maternal ill-health. The osteological and palaeodemographic evidence supports the assertion that females, foetuses and perinates were susceptible to environmental stress within this colonising population, resulting in early death of the perinatal individuals in addition to early terminations of pregnancy or premature birth possibly caused by infectious and/or metabolic diseases.     

The Seaweed FlyThoracochaeta zosterae(Hal.) (Diptera: Sphaerocidae) in Inland Archaeological Contexts: δC and δN Solves the Puzzle

The presence of the flyThoracochaeta zosteraein cesspits had led to the unlikely interpretation that seaweed had been present in Mediaeval cesspitis. Archaeological and modern pupae fromT. zosteraewere sampled along with their probable larval diets (extracted plant material from cesspit and seaweed, respectively). The spacing between pupae and food for δ¹³C and δ¹⁵N was similar for both modern and archaeological samples. Modern pupae had isotopic ratios typical for marine invertebrates for δ¹³C. Archaeological puparia had isotopic values typical for terrestrial grazers (i.e., non-marine), indicating that there was no marine inclusion in the cesspits.     

Coast–inland mobility and diet in the Danish Mesolithic and Neolithic: evidence from stable isotope values of humans and dogs

Here we present the stable isotope ratios of carbon and nitrogen measured in bone collagen extracted from humans, dogs, herbivores and fish from Mesolithic and Neolithic coastal and inland sites in Denmark. Bones of freshwater fish from several Early Mesolithic lake-side sites have δ¹³C values surprisingly similar to those seen in marine fish. We propose a model, based on δ¹³C and δ¹⁵N, for the correction for both marine and hard water reservoir effect in radiocarbon dates. A strong reliance on aquatic protein is demonstrated for the Mesolithic inhabitants of the region from the middle of the Early Mesolithic onwards. A significant part of the protein in the diets of the dogs and humans from the Middle and Late Mesolithic was of marine origin, even at inland sites. This observation points to a high degree of (seasonal) coast-inland mobility. The isotopic evidence indicates that during the Neolithic small quantities of aquatic foods were still common sources of dietary protein.     

Stable isotope analysis of human and animal remains from the Late Upper Palaeolithic site of Balma Guilanyà, southeastern Pre-Pyrenees,Spain

Stable isotope analysis of carbon (¹³C/¹²C) and nitrogen (¹⁵N/¹⁴N) was performed on collagen extracted from three human and five herbivore bone and tooth samples from the Late Upper Palaeolithic site of Balma Guilanyà (Catalonian Pre-Pyrenees, Spain). Contextual and palaeoecological data as well as radiocarbon dates indicate that the studied occupation phase took placed during the Bolling/Allerod interstadial (GI-1a event). The human remains were co-mingled without any anatomical association, corresponding to a minimum number of three individuals, and it was not possible to determine if the three analyzed samples are from one or more individuals. The mean isotope values obtained from the human remains are δ¹³C = −19.8‰ and δ¹⁵N = 6.7‰, while those of the large herbivores (red deer and wild goat) were −19.8‰ and 1.7‰ for δ¹³C and δ¹⁵N respectively. This indicates that the main source of protein in the diet of the Balma Guilanyà human(s) came from terrestrial herbivores. There is no zooarchaeological or isotopic evidence for the consumption of freshwater or marine resources at the site, which lies 80 km from the present Mediterranean coast. The low δ¹⁵N values observed in both human and animal samples correspond to a trend reported by other researchers working in northwestern Europe: a significant δ¹⁵N reduction in collagen from bones datable within 20,000–10,000 BP, followed by a rise to present values in the Early Holocene. This phenomenon, generally attributed to climatic and/or pedological processes, had not been previously observed in the Mediterranean region and, until now, was thought to be restricted to northern Europe.     

New light on early caprine herding strategies from isotope analysis: a case study from Neolithic Anatolia

The measurement of stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopes of caprine bone collagen from the Neolithic sites of Çatalhöyük and Aşıklı Höyük in south-central Anatolia have allowed examination of exploitation and herding practices of sheep and goats. The isotope values from protodomestic caprines at Aşıklı Höyük suggests that these animals were consuming very similar foods to each other and were all confined to the same or similar environments with no access to C₄ plants. At Çatalhöyük, the results show how the caprine management strategy develops from the strategy seen at Aşıklı Höyük into a more varied practice at an early stage as the site grows with an increasing dietary contribution obtained from C₄ plants. No change in diet is isotopically discernible at Aşıklı Höyük. Interestingly, no distinction could be made between the diets of sheep and goats at either site. Therefore, such studies are a useful method of examining the development of early herding or management strategies of caprines in the Near East.     

Variations in the C/C ratios of modern wheat grain, and implications for interpreting data from Bronze Age Assiros Toumba, Greece

Variations in the ¹³C/¹²C ratios of wheat grain at different spatial and temporal scales are examined by analysis of modern samples, including harvests of einkorn and durum wheat from Greece, and serve as a guide to interpreting data for Bronze Age grains from Assiros Toumba. The normal distribution and low variability of δ¹³C values of einkorn from 24 containers in the Assiros storerooms are consistent with pooling of local harvests, but less likely to represent the harvest of several years or include grain imported from further afield. Correlation between emmer and spelt δ¹³C values provides strong support for other evidence that these were grown together as a maslin crop. ¹³C discrimination (Δ) for the Bronze Age samples is estimated to be 2.5‰ larger than at present, and would be consistent with an intensive, horticultural regime of cereal cultivation, possibly involving some watering.     

Non-linear relationship between bulk δC and percent maize in carbonized cooking residues and the potential of false-negatives in detecting maize

Bulk δ¹³C values on charred cooking residues adhering to pottery sherd interior surfaces have been used as a source of information on the histories of maize in various locations in the western hemisphere. This approach is based on an assumption of a linear relationship between the percent maize in the resource mix cooked in a pot and δ¹³C. Previous experiments suggest that this relationship is non-linear, and maize may not be identified from bulk δ¹³C values even when it contributed substantially to the resource mix. A second round of experiments, presented here, indicates that the mobilization of carbon from maize and C₃ resources over time is the critical variable in residue formation and the resulting bulk δ¹³C value. This is influenced by the form of maize being cooked.     

A Late Holocene vertebrate food web from southern Haida Gwaii (Queen Charlotte Islands, British Columbia)

This study presents isotopic data (δ¹³C and δ¹⁵N from bone collagen) for 104 samples representing 29 vertebrate taxa from late pre-contact through to contact era (ca. 2000 – 100 BP) Haida Gwaii (British Columbia, Canada) from a wide variety of mostly marine organisms. The results demonstrate the considerable isotopic variability that characterizes potential prey items in coastal contexts and underscores the need for baseline faunal data to interpret human subsistence practices. Based on these data, a detailed marine food web was constructed, which provides insight into local ecological conditions. We present a simple method for quantifying the trophic level of ancient fauna using δ¹⁵N of bone collagen. Finally, we discuss the implications of this study for the reconstruction of human diet.     

Early Neolithic diet and animal husbandry: stable isotope evidence from three Linearbandkeramik (LBK) sites in Central Germany

The first appearance of the Neolithic Linearbandkeramik (LBK) in Central Germany occurred during the 6th millennium BC. However, though LBK sites are abundant in the German loess areas, there are only a few studies that reconstruct the diet of these first farmers using biochemical methods. Here we present the largest study undertaken to date on LBK material using stable isotope analysis of carbon and nitrogen to reconstruct human diet and animal husbandry strategies. We analyzed the bone collagen of 97 human individuals and 45 associated animals from the sites of Derenburg, Halberstadt and Karsdorf in the Middle Elbe–Saale region of Central Germany. Mean adult human values are ?19.9 ± 0.4‰ for δ¹³C and 8.7 ± 0.8‰ for δ¹⁵N. The δ¹³C values are typical for terrestrial, temperate European regions, whereas the δ¹⁵N values fall within an expected range for farming societies with a mixed diet consisting of products from domestic animals and plants. The consumption of unfermented dairy products is unlikely as there is direct palaeogenetic evidence of lactose intolerance available for one of the sites. There are no clear indications for dietary differences in sex. Young children under three years of age are enriched in δ¹⁵N due to breastfeeding indicating that weaning likely occurred around the age of three years. The fauna exhibit mean δ¹³C values of ?20.9 ± 0.8‰ and mean δ¹⁵N values of 7.0 ± 0.9‰ respectively. Variation in the δ¹³C and δ¹⁵N in the domestic animals is probably caused by different livestock managements.     

Diet in the Iron Age cemetery population at Wetwang Slack,East Yorkshire,UK: carbon and nitrogen stable isotope evidence

This paper reports δ¹³C and δ¹⁵N values for human and animal bone collagen from the middle Iron Age site at Wetwang Slack, East Yorkshire, UK. The data indicate a human diet which was high in animal protein, with no evidence for any significant marine food input. No differences were found between high-status vehicle (or ‘chariot’) burials and the rest of the population and no other status differentiations are visible according to burial rite, age or sex groupings, although the data obtained for the older males display an unusual trend. No dietary variation is seen between two site phases and no evidence for an early immigrant group is present. The range of isotope values for the adult human group as a whole is small, indicating that the diet is likely to have been consistent over time and across the population, although two individuals stand out as unusual amongst the 62 analysed.     

An experimental study of nitrogen flux in llamas: is N preferentially excreted?

Nitrogen isotope analysis is now commonly used to investigate the diets, and to a lesser extent, the environments of ancient populations. These studies assume that mammals are predictably enriched in ¹⁵N over their food, and concomitantly, that ¹⁵N becomes increasingly concentrated as one moves up the food chain. The literature commonly states that this ¹⁵N-enrichment of mammalian tissues is due to preferential excretion of light nitrogen (¹⁴N), but there are few data to support this assertion. To address the gap, we conducted two nitrogen flux trials in which four llamas (Lama glama) were fed high- and low-protein diets. The ratios of fecal nitrogen loss to urinary nitrogen loss were 0.30 and 0.88 on the high- and low-protein diets respectively. Feces were enriched in ¹⁵N by approximately +3‰ on both diets, whereas urinary nitrogen was depleted in ¹⁵N (−2.1‰) on the low-protein diet, but not significantly different from intake δ¹⁵N on the high-protein diet. Most importantly, there was no statistically significant difference between dietary and total excreta δ¹⁵N on either diet. Given these data and theoretical considerations, we argue that the nitrogen influx and efflux of adult mammals at steady state should be isotopically commensurate. However, during growth, diet change, thermal or nutritional stress, animals may not be at steady state and fractionation between intake and excreta δ¹⁵N may occur.     

Prehistoric Fijian diet and subsistence: integration of faunal, ethnographic, and stable isotopic evidence from the Lau Island Group

We explore subsistence practices and dietary change on islands in the central Lau Group of Fiji with zooarchaeological methods and stable isotopic analysis of human and animal skeletal material interpreted through an ethnoarchaeological lens. Our dataset combines detailed identifications of fauna, especially fishes, with stable isotopic (δ¹³C, δ¹⁵N) values of human and animal bone collagen and apatite carbonate spanning approximately three thousand years of human occupation on three study islands. Additionally, over fifty inshore and offshore contemporary fishing expeditions were observed on all study islands over a six-year period. We integrate these separate lines of evidence to form robust interpretations of Lauan subsistence patterns over a broad temporal scale. We add to the existing literature on stable isotopic analysis of archaeological bone from Remote Oceania and compare all of these groups through time. Our results indicate that Lauans differentially relied on nearshore reef resources rather than pelagic fishes, and terrestrial endemic species may have served as a portion of the diet during the early prehistoric period. Root crops (e.g., taro, yam) provided the majority of calories to the diet; however, sea grapes likely contributed to the early diet. Our isotopic results differ from previous studies of Fijian diet and that of Remote Oceania at a time of probable marine ecosystem shifts (AD 1300) illustrating diet breadth and variability in subsistence strategies potentially due to climatically influenced resource depletion.     

Reconstructing Diet of the Early Qin (ca. 700–400 BC) at Xishan,Gansu Province,China

Here we report the bone collagen carbon and nitrogen isotopic results of humans (n = 33) and animals (n = 58) to reconstruct the dietary practices of an early Qin population dating to the Zhou Dynasty (Late Western–Early Eastern period ca. 700–400 BC ) at the Xishan site in Gansu Province, China. The humans have a very large range of δ¹³C (−23.3‰ to −7.1‰) and δ¹⁵N (4.3‰ to 10.9‰) values which reflects extraordinarily diverse diets and included individuals with predominately C₃ as well as those with exclusive C₄ diets. This wide span of isotopic results produced a subtle linear trend (R² = 0.62) in the human data, which paralleled the animals across the C₃ and C₄ environmental gradient. However, the majority of the individuals had a predominately C₄ diet based on millet with δ¹⁵N results only slightly elevated above the animals, except for the pigs and cattle. This is evidence that many of the animals were likely used for their secondary products, labour or as sacrificial offerings and that pork and beef were the main sources of animal protein for the population. High status individuals had elevated δ¹⁵N values (10.2 ± 0.6‰) compared to medium (8.9 ± 0.3‰) and lower status (8.8 ± 0.8‰) individuals, possibly related to increased animal protein in the diet. Differences related to gender were also found with females having elevated δ¹³C (−11.2 ± 1.9‰) and δ¹⁵N (9.4 ± 0.8‰) values compared to the males (δ¹³C = −14.1 ± 4.2‰; δ¹⁵N = 7.9 ± 1.9‰), but these results necessitate caution given the large number of individuals that could not be sexed. The results of this study support the view that the early Qin people were a more sedentary society focused on millet agriculture and animal husbandry, and that they were influenced by the pre‐existing populations of the central Gansu region. Copyright © 2015 John Wiley & Sons, Ltd.     

Stable isotopic analysis of human bones from Jiahu site,Henan, China: implications for the transition to agriculture

We have investigated change in subsistence during the transition to agriculture in the site of Jiahu, Henan Province, China, using stable isotopic analysis of collagen and apatite in human bones. Millet agriculture is well documented at drier high latitudes of the Yellow River Valley, while rice agriculture predominated at wetter lower latitudes of the Yangtze Valley region. The early Neolithic site of Jiahu lies near the boundary between the drier north and wetter south. Archaeobotanical evidence shows that rice was a significant component of diet at Jiahu, but its δ¹³C value is similar to that of other foods, and therefore cannot be conclusively identified by carbon isotope analysis. Foxtail and broomcorn millets are the only C₄ crops known for the Chinese Neolithic. Because of their high δ¹³C values, their consumption can be evaluated by stable carbon isotope analysis of human bone. Collagen reflects mainly the δ¹³C value of dietary protein, and apatite accurately records that of the whole diet. Isotopic analysis of 15 well-preserved samples from three periods shows that collagen δ¹³C values were very low for almost all individuals, suggesting C₃-based foods dominated their diets. However, apatite carbonate δ¹³C values and δ¹³C spacing between collagen and apatite (Δ¹³C_ap-co) indicate that millet may have been a minor component of the diet in this region. Individuals, who consumed the smallest amounts of animal protein, as indicated by low δ¹⁵N, generally had the highest apatite δ¹³C values. Archaeobotanical evidence for millet at Jiahu is needed to support this interpretation.     

Chemical analyses of organic residues in archaeological pottery from Arbon Bleiche 3, Switzerland – evidence for dairying in the late Neolithic

Fatty acids distribution and stable isotope ratios (bulk δ¹³C, δ¹⁵N and δ¹³C of individual fatty acids) of organic residues from 30 potsherds have been used to get further insights into the diet at the Late Neolithic (3384–3370 BC) site of Arbon Bleiche 3, Switzerland. The results are compared with modern equivalents of animal and vegetable fats, which may have been consumed in a mixed ecology community having agrarian, breeding, shepherd, gathering, hunting, and fishing activities. The used combined chemical and isotopic approach provides valuable information to complement archaeological indirect evidence about the dietary trends obtained from the analysis of faunal and plant remains. The small variations of the δ¹³C and δ¹⁵N values within the range expected for degraded animal and plant tissues, is consistent with the archaeological evidence of animals, whose subsistence was mainly based on C₃ plants. The overall fatty acid composition and the stable carbon isotopic compositions of palmitic, stearic and oleic acids of the organic residues indicate that the studied Arbon Bleiche 3 sherds contain fat residues of plant and animal origin, most likely ruminant (bovine and ovine). In several vessels the presence of milk residues provides direct evidence for dairying during the late Neolithic in central Europe.     

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 C₃ terrestrial resources. A significant correlation is visible between human ??¹³C values and time, but no such trend is observed in ??¹⁵N. 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 ??¹⁵N of the humans and that of the main domesticated herbivores, with an offset of ??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 ??¹³C of the humans and that of the main domesticated herbivores, with an offset of ??1.4?? between the two. There is, however, a weak correlation observed between the mean ??¹³C of the humans and that of the cattle, which may account for some of the variation in human ??¹³C values between sites. The absence of a strong correlation between mean human and animal ??¹³C suggests that the primary factor influencing human ??¹³C values between sites is dietary composition. The lack of co-variation between ??¹³C and ??¹⁵N 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 ??¹³C variation between sites is likely to reflect the plant portion of the diet.