Four centuries ago, the people living in Osaka left behind an unlikely record of what they ate. It was not written in a cookbook or preserved in a market ledger, but in the hardened deposits that accumulated on their teeth. Scientists have now analysed ancient dental calculus from eight people buried at the Ofuka-cho site, also known as the Umeda cemetery, in Osaka. By extracting and identifying ancient proteins trapped inside the calculus, researchers reconstructed parts of the diets of ordinary people living in premodern Osaka.
The study identified 38 dietary proteins belonging to 17 taxa, revealing a surprisingly varied menu that included fish, terrestrial mammals and plant products. Among the findings were economically valuable red sea bream, salmonids that had travelled long distances, mammalian meat and proteins from cottonseed, potentially reflecting the use of cottonseed oil. The findings offer a rare glimpse into the food actually reaching ordinary people in Osaka hundreds of years ago.
What did people in premodern Osaka eat?
The research was published in Anthropological Science under the title ‘Dietary reconstruction of individual premodern commoners in Osaka, Japan, through the palaeoproteomic analysis of human dental calculus.’ The authors are Yoko Uchida-Fukuhara, Mariko Iida, Shigenobu Oba, Rikai Sawafuji, Takumi Nishiuchi, Shiori Fujisawa, Tomohito Nagaoka and Takumi Tsutaya. The paper was published online on August 19, 2026. Rather than examining food remains alone, the researchers focused on dental calculus, the mineralised material that forms when plaque accumulates on teeth. This material can preserve proteins from foods consumed by an individual, allowing scientists to investigate diet at a much more specific level than conventional archaeological methods.
The analysis found proteins from 17 different taxa. Fish were particularly prominent, with proteins from nine types of fish identified in the broader research findings. These included red sea bream (Pagrus major), a relatively high-value fish, as well as salmonids. The presence of salmonid proteins is especially significant because these fish were traded over long distances. Their discovery suggests that the people buried at the site could access food transported from distant regions, rather than relying solely on resources available around Osaka.
Ancient teeth reveal a surprisingly diverse food supply
One of the most striking discoveries was evidence for terrestrial mammals. Four of the eight individuals analysed had proteins originating from non-human terrestrial or marine mammals. This is particularly interesting because meat from four-legged terrestrial animals is often associated with dietary restrictions in premodern Japan, influenced partly by Buddhist beliefs and concepts surrounding pollution. However, historical evidence suggests that meat was not completely absent from Japanese diets. Wild animals could be consumed under the practice known as kusurigui, or “medicinal eating”, in which meat was sometimes framed as having therapeutic value.
The new dental-calculus evidence provides something different: a direct biological indication that some people living in premodern Osaka had actually consumed terrestrial mammal meat. Historical records also document the sale of venison in Osaka during the later Edo period. The study therefore adds another layer to the picture of food consumption. What might appear from written customs to have been a restricted or unusual food could nevertheless have reached the tables of some urban residents. The researchers also detected proteins associated with cottonseed. Cotton seeds themselves are not normally eaten because they contain compounds that can be toxic, but cottonseed could be processed to produce edible oil. The finding therefore potentially reflects the use of cottonseed oil as part of food preparation.
Why Osaka gave ordinary people access to so many foods
The diversity revealed in the teeth appears to be closely connected to Osaka's role as a major distribution centre. Premodern Osaka was known as the “Kitchen of the Realm”, a reputation linked to its extensive networks for collecting, transporting and distributing food. The city functioned as a logistical hub through which products from different parts of Japan could move into urban markets. The study's central distinction is between food supply and food accessibility. Finding evidence that a particular food existed somewhere in a region does not necessarily mean that everyone could obtain it.
The proteins preserved in the teeth provide evidence that at least some commoners actually had access to a surprisingly broad selection of foods. This is important because the individuals studied were not members of an elite household. The researchers describe them as commoners, including people who were relatively economically disadvantaged. Yet their dental calculus shows that their diets could include foods with very different geographical and economic origins. In other words, Osaka's sophisticated transport and market networks appear to have brought dietary diversity well beyond the wealthiest sections of society.
How can scientists reconstruct a 400-year-old diet from teeth?
Traditional archaeological techniques can reveal much about past diets, but they have limitations. Animal bones can show which species were present at a settlement, while stable isotope analysis can indicate broad patterns such as the importance of marine foods or terrestrial plants. Dental calculus provides a different kind of evidence. As plaque mineralises into calculus, microscopic biological material can become trapped within it. In this study, researchers used palaeoproteomics, analysing ancient proteins preserved in the calculus. By comparing the protein sequences with reference databases, they could identify food sources at a much more detailed taxonomic level.
The team also combined the dental-calculus analysis with carbon and nitrogen stable-isotope analysis of bone collagen. The isotope results were consistent with previously reported patterns for premodern Japanese commoners, while the protein evidence added much greater detail about individual food items. That combination allowed the researchers to move from a broad question, whether people relied heavily on marine or terrestrial resources, towards a more specific one: which foods were actually reaching individual people? The teeth essentially became tiny archaeological archives.
What the findings reveal about Edo-period food culture
The discovery does more than reconstruct a menu. It provides evidence about how an urban food system worked and who benefited from it. The presence of valuable fish, distant salmonids, terrestrial animal products and plant-derived ingredients suggests that food networks in Osaka were capable of supplying ordinary residents with resources originating from very different places. The researchers argue that this accessibility helped shape Japan's culinary culture and highlights the important role played by commoners in its development.
The study also demonstrates why ancient dental calculus is becoming an increasingly valuable source for archaeologists. A person's teeth can survive long after written memories of their everyday life have disappeared. Hidden inside those teeth may be molecular traces of meals, trade networks and food choices. Four hundred years later, the hardened residue left behind after ordinary meals has provided scientists with an unusually intimate record of life in historic Osaka, one bite at a time.
