In Sweden, prehistoric “chewing gum” reveals its mysteries

DNA present on “chewing gum” chewed by adolescents in the Stone Age and found at a 9,700-year-old archaeological site in Sweden sheds light on oral diseases of the time, according to a Swedish study. The study by a team of paleontologists from Stockholm University, published in the journal Scientific Reports, also provides information on the diet of these prehistoric hunter-gatherer populations.

“The chewing gum from which the samples were taken was probably chewed by adolescents, girls and boys. There was a specific age when they did this,” explains Anders Götherström, co-author of the study during an interview with AFP on Tuesday.

These pieces of birch bark soaked in saliva and bearing tooth marks were found thirty years ago alongside bones at the site of Huseby Klev, north of what is now the city of Gothenburg. It is one of the oldest archaeological sites with human bones in Scandinavia. “It is believed that these chewing gums were used like glue, to put things together. It is also possible that they chewed them for pleasure or because they believed they had medicinal properties,” adds the researcher.

In 2019, a first study of the pieces of putty made it possible to establish the genetic profile of the individuals. Now traces of non-human DNA are being revealed. “What we found was a large number of bacteria indicating a severe case of periodontitis, it's a serious infection of the gums,” says Anders. Götherström. “In one of the cases, we know that it was a young woman, she probably started to lose her teeth after using this chewing gum. This infection must have hurt a lot,” he adds.

The research results also shed light on the diet of this Scandinavian community. A diversified diet of hazelnuts, deer and trout. Traces of apple, duck and fox DNA were also detected in the analyses. “When we analyze a human bone, we extract human DNA. But what is particularly interesting with these chewing gums is to have the trace of what was ingested before, and the bacteria of the person who wears them, there is no other way to obtain these results. , enthuses Anders Götherström.

“We see the imprint made in chewing gum by the teeth of adolescents thousands of years ago,” he concludes. For us archaeologists there is also a philosophical dimension, it is the connection between man, DNA and the artifact.