Bronze Age innovations and impact on human diet: A multi-isotopic and multi-proxy study of western Switzerland

Abstract

The archaeological Bronze Age record in Europe reveals unprecedented changes in subsistence strategies due to innovative farming techniques and new crop cultivation. Increasing cultural exchanges affected the economic system. The inhabitants of Switzerland played a pivotal role in this European context through relationships with the Mediterranean, the High and Middle Danube regions and the Alps thanks to the area’s central position. This research aims to reconstruct, for the first time in Switzerland, human socio-economic systems through the study of human diet, herding and farming practices and their changes throughout the Bronze Age (2200–800 BCE) by means of biochemical markers. The study includes 41 human, 22 terrestrial and aquatic animal specimens and 30 charred seeds and chaff samples from sites in western Switzerland. Stable isotope analyses were performed on cereal and legume seeds (δ13C, δ15N), animal bone collagen (δ13Ccoll, δ15N, δ34S), human bone and tooth dentine collagen (δ13Ccoll, δ15N,) and human tooth enamel (δ13Cenamel). The isotopic data suggest a) an intensification of soil fertilization and no hydric stress throughout the Bronze Age, b) a human diet mainly composed of terrestrial resources despite the proximity of Lake Geneva and the Rhone river, c) a diet based on C3 plants during the Early and Middle Bronze Age as opposed to the significant consumption of 13C-enriched resources (probably millet) by individuals from the Final Bronze Age, d) no important changes in dietary patterns throughout an individual’s lifespan but a more varied diet in childhood compared to adulthood, e) no differences in diet according to biological criteria (age, sex) or funerary behavior (burial architecture, grave goods).

Isotopic reconstruction of the subsistence strategy for a Central Italian Bronze Age community (Pastena cave, 2nd millennium BCE)

“…Four resources (cereals, broad beans, fauna, freshwater fish) have been identified as putative food groups in the model. We used the data from local resources for the first three categories, while freshwater fish values are based on published values (Varalli et al 2021). The carbon and nitrogen offset/weight ratios are based on Hedges, Reynard (2007), Fernandes et al (2015) and Styring et al (2017); and the estimation of source values and the amount of energy and proteins in each food groups were calculated following Fernandes et al (2015).…”

“…The carbon and nitrogen stable isotope analysis on bio-archaeological remains has been steadily considered able to identify the dietary habits, and in turn, the economy and social behavior of past communities (e.g., Shoeninger, DeNiro 1984; Katzenberg 2008; Fontanals-coll et al 2015; Goude et al 2016; De Angelis et al 2019; De Angelis et al 2020; Varalli et al 2021; Romboni et al 2022). Briefly, the collagen from bones could be extracted and its carbon and nitrogen composition would relate to the individual dietary landscape.…”

“…The analysis of the plant remains has often supported the archeological identification of horticultural practices, which were critical for developing farming strategies. Specifically, fertilization and irrigation practices, recognizable with changes in carbon and nitrogen stable isotopes ratios, are two of the most significant technological improvements for boosting soil exploitation, supporting both sedentary lifestyles and the market economy (Wallace et al 2015; Styring et al 2016; Gron et al 2017, 2020; Knipper et al 2020; Mnich et al 2020; Varalli et al 2021).…”

Dining in Tuva: Social correlates of diet and mobility in Southern Siberia during the 2nd–4th centuries CE

“…Separate models were calculated first without priors, and then assuming as prior a higher dietary contribution of herbivores and C 4 plants compared with respectively fish and C 3 plants. The FRUITS models include our isotopic data for humans and herbivores, and published values for freshwater fish, C 3 and C 4 plants (Fernandes et al, 2015; Murphy et al, 2013; Svyatko et al, 2007; Varalli et al, 2021). We realize that published data cannot substitute a full isotopic set from the context under study.…”

Strontium isotopes and concentrations in cremated bones suggest an increased salt consumption in Gallo-Roman diet

“…Sufficient evidence shows that in western Europe the Iron Age diet was fairly homogeneous, rich in animal protein in the form of meat and dairy and almost exclusively terrestrial e.g. : 9 – 11 . Although, for Belgium, clear archaeozoological and archaeobotanical evidence on Iron Age food economies is scarce, data from neighbouring areas indicates that the population relied mainly on varying proportions of cattle, sheep, and pig as main suppliers of animal protein, and cereal and, to a lesser extent, pulses as a staple food 10 , 12 , 13 .…”