Using Teeth to Interpret Social Status and Childhood Health in Historic Japan

Our bones are pretty amazing- they keep a record of what has happened to us throughout our lifetime. Bones show the trauma and disease we faced, how well we healed from these events, what muscles we used and activities we did repeatedly, the type of diet we had, whether we migrated to new locations, and even just basic information about our biological identities- sex, age and ancestral background. But it isn’t just the bone- teeth keep great records of our lives, whether it be in the isotopes contained within the enamel, the amount of wear and tear they face from our diet, and their overall health. We can even use teeth to help us make interpretations about lifestyle and social status. We’ve discussed this a little before– your teeth, even today, can be an indicator of your status. Better teeth are often associated with higher status since these individuals have access to dentists and orthodontists.

Woodcut of a street scene during the Edo period of Japan from the city of Edo, shows the common people, by Hiroshinge via Wikimedia.

Today, we’re looking at a new study by Nakayama (2016) that compares coffins to dental health in the historic Edo period of Japan in order to see whether there is a relationship between wealth, status and one’s health during childhood. During the Edo period (1603–1867), Japanese society was ruled by the absolute order of a feudal system. Within this system, the Tokugawa Shogun family ranked highest and had the power to impose social status. Followed by the Shogun, were the warriors, and at the lowest rank was the farmers, townspeople, and merchants. Since social status was dictated rather than achieved or spontaneously developed, it meant that your status would be inherited and there was virtually no way to change it. This status not only dictated one’s lifestyle, it also determined burial location and type. Because the social status of an individual was so clearly marked in death, by comparing the location of the burial and coffin with the human remains allows us to learn more about how status effected the health of individuals. 

Nakayama (2016) examines burials from the Sugenji-Shokenji site in Tokyo, Japan. Excavations of the site revealed 1464 burials that belonged to middle and low class warriors, as well as townspeople. Burials can be divided into status groups based on their containers: ceramic jar coffins for middle-class warriors, wooden square coffins for low-class warriors and townspeople, and wooden circular coffins for the lowest class of townspeople. In order to examine their health, Nakayama (2016) specifically looks at the presence of linear enamel hypoplasia (LEH). LEH manifests as furrows or indentations of decreased enamel on teeth due to interruption during development. They are attributed to times of high metabolic stress, such as periods of malnutrition, but can also be due to trauma or chronic illness (Roberts and Manchester 2005:75). It is useful in determining whether individuals were stressed during their childhood, and at what age this stress started and stopped.

Example of LEH, via National Museum of Health

Based on the analysis of teeth, Nakayama (2016) found an overall high prevalence of LEH. 91% of all individuals had some evidence of LEH on at least one tooth. Individuals buried in ceramic jar coffins (middle class warriors), were less likely than the lower class warriors and townspeople to have LEH, indicating that this higher status afforded them slightly better health. This difference in childhood stress is further supported by historical documents. According to a survey completed in the mid-19th century, 68% of Edo was occupied by warriors and only 16% was occupied by townspeople. This means that for every square kilometer of space in Edo, there was 16,816 warriors, and 67,317 townspeople. The average person would have been living in very cramped conditions, that were likely dirty and had a lack of access to basic necessities. We also know from documents that the lower classes didn’t have access to a wide range of food and consisted on very small simple diets. Nakayama (2016) concludes that the differences in LEH were due to differences in social status that determined living conditions and health.

This isn’t just an issue of the past- health continues to be affected by one’s social status. The amount of money a family has and the locations they live in can dictate what types of food they have access to, how healthy those foods are, whether they have a clean safe environment to raise their children, and whether there are programs available to help them. Studies like these demonstrate that there have been historic connections between health and status, and that we need to be aware of how this continues to impact modern peoples.

Works Cited

Nakayama, N. (2015). The Relationship Between Linear Enamel Hypoplasia and Social Status in 18th to 19th Century Edo, Japan International Journal of Osteoarchaeology DOI: 10.1002/oa.2515