Evidence of Pellagra on 19th Century Human Crania From Northern Italy by Combining Stable Isotope and Paleopathological Analyses

Pellagra is a disease caused by a nutritional deficiency, with fatal outcome due to multiple-organ failure, that affected European rural areas until the early decades of the 20th century, especially Veneto region (Italy). At the skeletal level, previous studies pointed out that pathological signs left by the disease are generic and typical of many forms of avitaminosis, not useful to recognize the deaths by pellagra in archaeological contests. Here, a detailed paleopathological study was conducted on skulls of individuals dating to the late 19th-early 20th century, for which the health state and causes of death have been well-documented at the time. Individuals severely affected by pellagra and non-pellagrous individuals were investigated; differential analysis was conducted considering pathologies that leaves on skeletal tissue similar anomalies, such as tuberculosis meningitis, scurvy, and meningioma. By integrating the skeletal alterations reported in literature and the intracranial alterations found in this study, we provide recommendations on a framework that could be used to demonstrate diagnostic validity in cases of severe vitamin B3 deficiency. Peculiar lesions that have been found contrasted with lesions linked to other pathologies and those indicated in the literature, and they could prove fundamental to ensure the identification of pellagra. Finally, pathological evidence observed in pellagrous skulls was compared with diet reconstruction, carried out on stable C and N isotope analysis, highlighting a poor-to-moderate protein consumption and possible fasting or nutritional stress, together with a large input from C4 plants, as maize. We think that this work can contribute to the understanding of adaptations and variability among past communities by more confidently identifying severe niacin deficiency. The framework allows for greater consistency in diagnostic certainty, facilitating greater comparability in research.