A groundbreaking study has revealed the first direct biochemical evidence of betel nut chewing from 4,000-year-old dental plaque, revealing its use in ancient Thai communities.
Published in the journal Frontiers in Environmental Archaeology, this finding marks the earliest evidence of betel nut use in Southeast Asia, predating previous records by at least 1,000 years.
Betel nut is a traditional stimulant, often mixed with slaked lime and wrapped in betel leaves into “chews.” It is widely used in many regions and by hundreds of millions of people worldwide as a means of boosting energy and relaxing.
Previously, archaeologists have inferred the history of betel nut use based on stained teeth or plant fragments, but this study is the first to identify biochemical traces of betel nut in unstained teeth.
Led by archaeologist Piyawit Moonkham of Chiang Mai University in Thailand, the team collected 36 teeth from six individuals from the Neolithic cemetery of Nong Ratchawat in central Thailand and analyzed trace amounts of dental plaque using liquid chromatography-mass spectrometry (LC-MS).
This method can precisely identify compounds and perform molecular detection based on mass-to-charge ratios, all while being virtually non-destructive to the sample.
In a tooth sample from a woman approximately 25 years old, designated “Burial 11,” researchers detected key alkaloids, including arecoline, confirming that she chewed betel nut.
Moonkham noted that this “invisible evidence” suggests that archaeology’s understanding of prehistoric cultures may be far from complete.
The study also employed a control experiment that simulated a modern “chew block,” mixing betel nut, lime, betel leaves, and, in some samples, tobacco and catechu bark, and grinding them together with saliva. These control samples helped establish a chemical signature “standard” for future research.
While LC-MS is widely used in pharmaceutical, food, and environmental testing, it remains cutting-edge in archaeology.
Dr. Melandri Vlok, a bioarchaeologist at Charles Sturt University in Australia, said this study not only demonstrates the potential of science and technology in archaeology but also represents “genuine innovation.”
Vlok emphasized that this research, led by Thai researchers, demonstrates the region’s rise in international archaeological science: “What’s most exciting is that this groundbreaking work comes from Thai scholars.”
The research team comprises experts from eight institutions across three continents, with chemical analysis conducted at Washington State University in the United States, where Moonkham is currently pursuing a doctorate.
In the future, this method may be widely applied to the study of ancient diets and cultures in other parts of the world. Dr. Vlok predicts, “It opens a new window into the lives of prehistoric people.”