4,000-year-old evidence of psychoactive betel nut chewing found in Southeast Asia - study
The first direct biochemical evidence of the consumption of the psychoactive betel nut, dating back 4,000 years in Southeast Asia, has been uncovered in a study published in the peer-reviewed journal Frontiers in Environmental Archaeology.
The research sheds light on the long history of betel nut chewing, a practice that has been widespread across South Asia and the Pacific Islands for centuries.
Betel nut, the seed of the areca palm fruit, is often chewed inside a betel leaf with lime. The practice has been known for its psychoactive effects, including heightened alertness and euphoria.
However, due to its association with oral cancers, betel nut chewing has declined in many regions, partly due to government efforts to reduce its use. In Thailand, for example, the government launched a campaign in the 1940s to reduce the practice, and India has also promoted initiatives to discourage its consumption.
The research team, led by Piyawit Moonkham, an anthropological archaeologist at Chiang Mai University in Thailand, analyzed 36 samples of dental calculus from six individuals buried at the Nong Ratchawat site in Thailand.
The researchers identified two compounds, arecoline and arecaidine, which are commonly associated with betel nut residue. To validate their method, they created a sample that mimicked betel nut chewing by combining dried betel nut fruit, pink limestone paste, betel leaves, and saliva.
These compounds were detected in three of the 36 dental calculus samples, all linked to a female burial from 4,000 years ago.
The findings provide significant new evidence, but the study's authors cautioned that it is not yet clear whether other individuals at the site also consumed betel nut.
Shannon Tushingham, an anthropologist at the California Academy of Sciences and co-author of the study, notes that the burial site lacked traditional markers of betel nut use, such as stained teeth or betel nutshells, which are commonly found in other archaeological sites.
Miriam Stark, an archaeologist at the University of Hawaii at Manoa, expressed caution about claiming this as the earliest evidence of betel nut use in Southeast Asia. Stark highlighted that the Nong Ratchawat site has not been as thoroughly documented as other regional sites, and additional radiocarbon dating is needed to confirm the site’s age.
Biochemical evidence and further research
Cristina Castillo, an archaeobotanist at University College London, raised concerns about the limitations of the study’s findings. Castillo pointed out that the betel nut belongs to the genus Areca, which includes 51 species.She questioned whether the compounds identified in the study, arecoline and arecaidine, are exclusive to betel nuts or if other species from the same genus could share these compounds.
Castillo also noted that the study does not explain how the betel nut plant may have reached Thailand 4,000 years ago, as the plant is believed to be native to Malaysia or the Philippines.
Roger Forshaw, a biological anthropologist at the University of Manchester, highlighted the potential of dental calculus as a tool for uncovering evidence of ancient practices, suggesting it could help answer longstanding historical questions.
However, Castillo emphasized the importance of combining biochemical evidence with other physical evidence, such as plant remnants, to build a more comprehensive understanding of historical practices.
This new research provides valuable insights into the ancient practice of betel nut chewing, offering the first biochemical evidence of its consumption in Southeast Asia over 4,000 years ago.
While the study represents a significant step in archaeological research, experts agree that more investigation is needed to fully understand the history and spread of betel nut consumption, the Smithsonian Magazine noted.
