When I was a young and innocent BSc student, I was assigned a study about an Egyptian mummy. I was incredibly proud of my Egyptian boy, whose name was Ptahmose. He was around 35 years old and had his brain removed through his nose, as expected of every good mummy from the Greco-Roman period.
One doubt, however, remained stuck in my young scientist mind for years. Namely, Ptahmose’s skull had signs of scurvy, a metabolic disease related to low intake of vitamin C, often connected to diets poor in vegetables and citrus fruit. Why on earth was a wealthy Egyptian guy, with access to as many greens and fruits as he wanted, lacking in vitamin C? As no information about his diet was available, this question remained locked in a small drawer in my brain for the remainder of my studies. I had the scurvy in my study, but not the orange (or, in his case, the lack of it).
Everyday science in pyjamas
Five years and an MSc in biological anthropology later, I got involved with health, food, and bones once again, but this time in Estonia. I know the first thought that comes to mind when you think of a “biological anthropologist” is flawless Dr Temperance Brennan dressed as Wonder Woman in an episode of the famous TV show “Bones”, with her hot and loyal partner Seeley Booth. Technically, that was forensic anthropology, but this does not prevent me from receiving the evergreen comment: “Hey, you are like Bones!”
I am really sorry to destroy this myth by telling you that biological anthropology is definitely less sexy and glossy, involving hours, days, and sleepless nights in pyjamas, learning how to side a metatarsal or how some vertebrae may develop discal herniation – particularly when your specialization is ancient bone pathology. However, archaeological human remains can tell you rather unexpected tales, sometimes beyond expectations.
Archaeological human remains can tell you rather unexpected tales, sometimes beyond expectations. Image credit: Andres Tennus / UT
Double-checking historians and chroniclers
My research brought me to a PhD project on medieval and early modern Estonian populations. This period was marked by complex political, economic, and socio-cultural changes, which dug under the surface, burned deep into Estonian culture and consciousness, and transmuted this area in the country we know today.
All of these major facts have been thoroughly described in historical records, and numerous written sources report the direct effects of cultural development and wars on the nutritional status of European populations. One could easily guess what these effects were: epidemics, famines, and malnutrition, tormenting locals and foreigners as never before.
However, the examination of similar apocalyptic scenarios may lead to a simple question: are we really sure about what historians and chroniclers have written? Was that epidemic really plague, and did that famine really affect that many people? In addition, there is a whole section of the rural population that is likely to have never been considered in historical chronicles. What was going on over there? This is where my research came to life.
A mummy at the University of Tartu Art Museum. Image credit: Andres Tennus / UT
What can the skeleton tell us?
Along with historical sources, another primary source of information concerning ancient pathologies and their relation to everyday diet comes from people themselves. Or, more precisely, from what they were.
Within archaeological sciences, the multidisciplinary combination of paleopathology – i.e., the study of disease patterns in past populations – and bone chemistry has the potential to offer unique insights into health and dietary issues.
Physiological stress is a central issue in the study of past populations, and paleopathology has been extensively used to address nutritional stress issues. Nutritional deficiencies (anaemia, scurvy, rickets, etc.), metabolic alterations related to diet (e.g., gout), as well as dental and infectious diseases do leave visible signs on the skeleton, and are therefore widely used in the reconstruction of population profiles and dietary habits of ancient human groups.
However, the discipline of paleopathology has important limitations. Firstly, bone tissue is basically lazy. The response to stress and disease is incredibly monotonous, resulting mainly in bone production or destruction. This can be challenging, as different conditions may result in very similar patterns. In addition, only a subset of diseases affecting humans also affect the skeleton. For instance, in the case of acute disease resulting in rapid death, the body does not have enough time to produce stress markers for the causative agent. Those who die from acute diseases associated with famine or epidemics (let’s say typhus, dysentery, or plague) will apparently show a healthy skeleton. And what about when historical sources about the diet are not there (i.e., Ptahmose’s mysterious scurvy)?
“We are what we eat”. Food greatly affects not only the human body structure, but also the individual’s consciousness and identity. Image credit: Meal Makeover Moms / Flickr CC BY-ND 2.0
We are what we eat
In light of these limitations, I selected bone chemistry as the perfect companion science, as it has the potential to provide detailed and quantitative insights into the study of pathology and its relation to diet. Already in 1862, Ludwig Feuerbach wrote the famous words: “We are what we eat – der Mensch ist was er isst”. Food greatly affects not only human body structure, but also the individual’s consciousness and identity. Moreover, it is possible to recognize and understand a man from what he eats, and from how he eats it. Indeed, this is the principle on which stable isotope analysis in archaeological sciences is based.
Stable isotope analyses of collagen and bone mineral are generally used to reconstruct the protein components of an individual’s diet. Stable carbon analysis is used to infer the type of plants ingested (barley, millet, or maize?), or if the diet mainly consisted of marine or terrestrial foods.
Nitrogen stable isotopes reflect the position of an animal in the food chain, as nitrogen values differ in relation to whether an animal is consuming plants or the meat of other animals. Nitrogen isotope values are also employed to understand if the fish consumed came from a marine or freshwater habitat (tuna or trout?). In light of this study, it becomes clear how dietary reconstruction via stable isotope analysis is a precious tool in the interpretation of the pathological data in ancient human remains.
And finally, let’s return to the apparent flamboyancy of our opening phrase, and to my first anthropological love and dilemma, Ptahmose. In the case of my old scurvy-afflicted mummy, isotopes would finally tell me the truth. The orange and the scurvy, then.
Alessandra Morrone is a PhD student in archaeology; her field of study is paleopathology.
