Study Reveals Medieval Diets Through Ancient Proteins and Isotopes

Research published in the journal Scientific Reports has uncovered significant insights into the diets of medieval Europeans by analyzing ancient proteins and stable isotopes found in human remains. The study highlights the critical roles of legumes and freshwater fish, revealing a more nuanced understanding of daily meals during this period.

The team of researchers utilized both stable isotope analysis and proteomics to reconstruct dietary habits from two burial sites: the Baar cemetery in Zug, Switzerland, and the Dalheim monastic cemetery in North Rhine-Westphalia, Germany. These sites date back to the 7th century CE and the 9th to 12th centuries CE, respectively. The combination of these analytical methods allowed for a more comprehensive view of what individuals consumed, moving beyond traditional assumptions based solely on isotopic data.

Stable isotope analysis measures the ratios of bio-elements such as carbon, nitrogen, and sulfur in bones and teeth, offering a glimpse into the types of food consumed. For instance, the stable carbon isotope value (δ13C) helps differentiate between the consumption of C3 and C4 plants, while stable nitrogen isotope values (δ15N) indicate the source and quantity of animal proteins in the diet. Despite these advantages, isotope analysis has limitations, particularly in identifying specific food types like legumes or fish.

In contrast, proteomics, which analyzes proteins extracted from dental calculus, provides a more detailed picture of dietary components. Dental calculus, which forms on teeth over a person’s lifetime, serves as a unique archive of dietary information, trapping food fragments and proteins. Researchers collected samples from both burial sites, enabling a thorough examination of ancient diets.

The study analyzed samples from 11 individuals’ bones and eight individuals’ teeth from Dalheim, along with 52 dental calculus samples. After rigorous quality screening, 37 samples were deemed suitable for proteomic analysis. The findings revealed that medieval diets were more diverse than previously understood, with legumes like green peas (Pisum sativum) emerging as a crucial source of nutrition, providing essential amino acids that were often lacking in other plant-based foods.

Researchers noted that the collagen yields from bone and dentin samples indicated excellent preservation conditions, allowing for reliable isotopic measurements. The average bone collagen δ13C, δ15N, and δ34S values were recorded at -20‰, 10‰, and 9.4‰, respectively. Meanwhile, dental calculus samples exhibited significantly different δ13C values, highlighting the complexity of dietary reconstructions based on isotopic data alone.

Among the dietary proteins identified, 14 were from plant sources, predominantly from the Fabaceae family. Noteworthy findings included the identification of proteins specific to green peas, a significant dietary component for medieval populations, particularly among lower socioeconomic groups. The study also confirmed the presence of freshwater fish proteins, specifically from the European perch (Perca fluviatilis), which were likely consumed during Christian fasting periods when terrestrial meats were prohibited.

The researchers concluded that while stable isotope analysis provides an overview of dietary patterns, the integration of proteomic data allows for species-level identification, enhancing the understanding of medieval diets. This interdisciplinary approach sheds light on the dietary practices of the Dalheim population, which appeared to rely heavily on plant intake and limited animal proteins.

In summary, the study emphasizes the importance of both stable isotopes and proteomics in reconstructing historical diets. By revealing the consumption of legumes and freshwater fish, the research aligns with historical records of medieval diets and underscores the need for further exploration into ancient dietary practices. Moving forward, researchers recommend enhanced decontamination protocols and standardized preservation assessments to improve the reliability of ancient proteomic analyses.

This groundbreaking research sets the stage for a deeper understanding of the lifeways of medieval populations, paving the way for future interdisciplinary studies that can provide a more detailed picture of human history.