4,000-year-old teeth record the earliest traces of people chewing psychoactive betel nuts

In Southeast Asia, chewing of Bétel has been practiced since Antiquity. Plants contain compounds that improve vigilance, energy, euphoria and consumer relaxation. Although the practice becomes less common in modern times, it has been deeply rooted in social and cultural traditions for thousands of years. The bétel jaws generally cause dark and reddish brown teeth to blacks.

However, teeth without coloring may not mean that people did not chew the Bétel nuts. Now, using a new method, an international team of researchers examined the old dental plaque of the Bronze Age in Thailand and has found proof of chewing of Bétel.

“We have identified the derivatives of plants in dental calculation from a 4,000 -year -old funeral at Nong Ratchawat, Thailand,” said the first author of the Borders in environmental archeology Study Dr. Piyawit Moonkham, anthropological archaeologist at Chiang Mai University in Thailand. “This is the first direct biomolecular proof of the use of Bétel in Southeast Asia.”

“We demonstrate that dental calculation can preserve chemical signatures from the use of psychoactive plants for millennia, even when conventional archaeological evidence is completely absent,” added Dr Shannon Tashingham, the principal author, who is the associate of anthropology at California Academy of Sciences.

“In essence, we have developed a way to make behavior and revolutionary practices invisible that has been lost for 4,000 years.”

Hidden in the plate

In Nong Ratchawat, an archaeological site in the center of Thailand which dates back to the Bronze Age, 156 human burials have been discovered since 2003. For this study, the team collected 36 dental calculation samples of six individuals.

Back in the laboratory, they deleted tiny quantities of samples plate and the chemical residues found there underwent an analysis. The team also used Bétel liquid samples they produced to ensure that psychoactive compounds could be reliably detected by their analysis and to understand complex biochemical interactions between the ingredients.

“We used a dried betel nut, a pink limestone paste, beel puppet leaves and sometimes a bark of Senegalia Catechu and tobacco. We locate the ingredients of human saliva to reproduce authentic chewing,” said Moonkham.

“Supply materials and Bétel” to chew “experimentally to create authentic counterpart samples were both a fun and interesting process.”

The results have shown that three of the archaeological samples – all from a molar from the same individual, burial 11 – have limited traces of arecoline and acaidine. These organic compounds, found in Bétel nuts but also in plants such as coffee, tea and tobacco, have pronounced physiological effects on humans. This suggests that Bétel was chewed in 4,000 years in Thailand.

Proof “archaeologically invisible”

“The presence of Bétel compounds in dental calculation suggests repeated consumption, as these residues are incorporated into mineralized plaque deposits over time by regular exposure,” said Tushingham.

Consequently, the lack of teeth coloring questions. This could be the result of different consumption methods, said the team. This could also be due to post-consumption teeth cleaning or post-dead processes affecting the preservation of stains over 4,000 years.

Although the traces of chewing of Bétel were found in samples of a single individual, there is currently no evidence that burial 11 has received a special treatment or was of high social status or a single ritual meaning compared to the other burials of Nongchawat. However, the presence of stone pearls as serious goods could provide clues to the lived identity or experience of the individual.

The study of more people in Nong Ratchawat and other local sites to learn when and to who such serious products have been given could provide precious evidence, the team said.

The methods that researchers have applied can be used to examine the remaining burials at Nonghawat and other sites, they said.

“The analysis of dental calculation can reveal behaviors that leave no traditional archaeological trace, potentially revolutionizing our understanding of the old ways of life and the relationships of the human plant,” said Tashingham. “This could open new windows in the deep history of human cultural practices.”

“Understanding the cultural context of the traditional use of plants is a broader theme that we want to amplify – psychoactive, medicinal and ceremonial plants are often rejected as drugs, but they represent millennia of cultural knowledge, spiritual practice and community identity”, concludes Moonkham.

“Archaeological evidence can shed light on contemporary discussions by honoring the deep cultural heritage behind these practices.”