Chewing gum may seem like a modern invention, but new research reveals that ancient peoples were chewing tree resins and barks as early as the Mesolithic era over 10,000 years ago. Analysis of these ancient “chewing gums” has provided remarkable insights into stone age diets, health, and lifestyles.
Mesolithic Chewing Gums Show Heavy Reliance on Aquatic Foods
A study published this week in Nature Communications analyzed birch bark tar “chewing gums” dated to around 10,300 years ago, recovered from Huseby-Klev in western Sweden . Using shotgun proteomics, researchers reconstructed the oral microbiomes embedded within the tar, revealing the diets of Mesolithic hunter-gatherers in Scandinavia .
The analyses showed that these groups relied heavily on proteins derived from aquatic foods like fish and seals. Lead author Theis Jensen explained, “It was very surprising to see how much aquatic foods dominated the protein sources in these chewing gums, which suggests that marine resources were more important than previously thought.” 
Specific species identified in the oral microbiomes included European perch, pike, brown trout, eel, seals, and even sea eagles. Red deer and wild boar proteins were also present but to a lesser degree, suggesting supplementation with terrestrial mammal hunting .
Table 1. Relative Abundance of Dietary Proteins in Mesolithic Chewing Gums
|% Total Proteins
|Aquatic (fish, seals, birds)
This research challenges earlier notions that Mesolithic groups in this region subsisted primarily through hunting land mammals and gathering terrestrial plants. Instead, it underscores the critical importance of marine and freshwater food resources for these stone age peoples.
Chewed Birch Tar Reveals Poor Dental Health in Mesolithic Times
In addition to diet, analysis of the ancient chewing gums gave insight into the oral health and lifestyles of Mesolithic hunter-gatherers . The research team was able to reconstruct near-complete genomes of several oral microbes, including bacteria linked to poor dental health.
High abundances of Methanobrevibacter oralis were uncovered, a microbe associated with inflammation and bleeding of the gums today . Jensen noted, “It seems they did not have very good oral health. It was full of bacteria that we would associate with gingivitis.” Inflammation biomarkers were also elevated in the chewing gum samples.
Surprisingly, the oral microbiomes of these ancient foragers mirrored what might be seen in individuals today with moderate-to-severe gingivitis. The tough and fibrous diets of stone age peoples are believed to protect against tooth decay but may have also irritated their gums. This is supported by evidence of antemortem tooth loss and periodontal disease observed archaeologically in some Mesolithic remains.
Birch Bark Chewing Gum Was Likely Used to Quench Thirst
In addition to oral health and dietary clues, researchers hypothesized why stone age hunter-gatherers may have chewed the bitter birch bark resins in the first place.
The team speculated that the chewing gum was used primarily to quench thirst while hunting and foraging, as the resins contain compounds that promote salivation. Jensen explained, “I think one of the reasons could be the thirst quenching qualities. Birch bark contains xylitol – a common sweetener today – which helps to stimulate saliva production.” This would have been useful during long expeditions away from sources of freshwater.
Researchers believe it may also have served as a kind of primitive toothbrush, clearing away food debris since toothpicks and flosses were not available during the Mesolithic . However analysis showed tooth decay rates were still quite high, disputing this idea.
Additionally, the group suggests the birch tar chewing gum may have been used recreationally, as a primitive sweet similar to gum chewing today . Its stickiness may have also made it appealing and habit-forming. Further analysis of additional stone age chewing gums is needed to better understand these early uses in humans.
Implications and Future Directions
This research provides a remarkable snapshot into Mesolithic dietary ecology, health, and behavior using the novel analysis of ancient chewing gums. Lead author Theis Jensen concluded, “Here we find direct evidence sustaining aquatic resource procurement and thus for the dietary practice of Mesolithic hunter-gatherers. ”
The heavy reliance on fish and marine mammals observed conflicts with previous studies and underscores the vital nature of these food sources for hunter-gatherers in Scandinavian environments. This will prompt re-evaluation of current models.
The poor oral health observed also reveals surprising insights into the early emergence of oral diseases in relation to shifts toward tougher, pre-agricultural diets. Birch bark chewing gums represent an advantageous new proxy for reconstructing aspects of Paleolithic lifestyles and behaviors using biomolecular techniques.
Several additional tar “chewing gums” have been recovered from archaeological sites across Scandinavia and Europe dating through the Neolithic, Bronze and Iron ages. Analyzing these in similar ways is expected to unveil dynamic shifts in diets, health, and chewing practices as cultures evolved toward food production and agriculture. It may also clarify why such unusual habits emerged and persisted over thousands of years since the late Paleolithic.
Jensen, T.Z. et al. 2024. Proteomic profiling of an Early Mesolithic mastication product unveils aquatic resource procurement by hunter-gatherers in southern Scandinavia 10 300 years ago. Nature Communications.
Medriva 2023. Unraveling the secrets of the Stone Age: A fascinating study of ancient chewing gum. Retrieved from https://medriva.com/uncategorized/unraveling-the-secrets-of-the-stone-age-a-fascinating-study-of-ancient-chewing-gum/
Phys.org 2024. DNA in Stone Age gum traces the origin and diet of Scandinavian hunter-gatherers. Retrieved from https://phys.org/news/2024-01-dna-stone-age-gum-diet.html
The Hindu 2024. What did people on the west coast of Scandinavia eat 10,000 years ago? Retrieved from https://www.thehindu.com/sci-tech/science/what-did-people-on-the-west-coast-of-scandinavia-eat-10000-years-ago/article67756783.ece
Cosmos Magazine 2023. Stone Age chewing gum reveals poor dental health. Retrieved from https://cosmosmagazine.com/history/archaeology/stone-age-chewing-gum-dental-health/
Jensen et al. 2024. Ibid.
StudyFinds 2023. 10,000-year-old chewing gum found. Retrieved from https://studyfinds.org/10000-year-old-chewing-gum/
Jensen et al. 2024. Ibid.
Archaeology 2024. Mesolithic Birch Pitch. Retrieved from https://www.archaeology.org/news/12066-240119-mesolithic-birch-pitch
Jensen et al. 2024. Ibid.
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