Betel nut, also known as areca nut, is one of the most popular plant-based drugs in Asia and the South Pacific, to the point that it is estimated that almost 10% of the world's population regularly chews this psychoactive substance. This seed comes from the areca palm (Areca catechu) and is valued for its stimulating properties, as it produces a mild euphoric sensation and increased alertness.
Not only is it an extremely popular drug. As revealed in a study published on Wednesday in the journal Science Advances, betel nut was one of the first psychoactive substances consumed by humans of which there is evidence. An international team led by archaeologists from Griffith University in Australia has found in Indonesia what they claim to be the oldest known evidence of human drug consumption.
New analysis of the skeletons of two gatherers found in two sites on the island of Sulawesi suggests that our ancestors already had the habit of chewing whole betel nuts thousands of years earlier than previously thought. One of the skeletons dates back between 25,000 and 16,000 years, leading scientists to argue that this is the oldest known evidence of human consumption of mind-altering substances. The remains of this individual were found in Leang Bulu Bettue cave. The second skeleton, discovered at the Leang Cappalombo 1 site, 33 kilometers away from Leang Bulu Bettue, belonged to an individual who lived between 7,600 and 6,300 years ago.
Until now, it was believed that the consumption of psychoactive drugs emerged during the Neolithic period, after the advent of agriculture, starting with the production of fermented alcoholic beverages such as barley beer, around 13,000 years ago in Israel. Evidence of opium use in Europe dates back to around 5700 BC, and cannabis seeds to around 8000 BC. Regarding betel nut, it was estimated to have been used around 3,500 years ago.
The use of betel nut is currently part of the cultures of many Asian countries, although the main way of consuming it varies by region. It can be taken dry, fresh, or mixed with slaked lime (calcium hydroxide obtained by grinding burnt shells), spices such as cardamom, cinnamon, anise, or cloves, and sometimes with tobacco. The mixture is wrapped in a betel leaf to form a bolus called quid. "Slaked lime is an essential ingredient because it triggers a chemical reaction that releases the psychoactive compounds of the nut into the bloodstream more rapidly," explains Adam Brumm, a professor at the Australian Research Centre for Human Evolution at Griffith University and leader of the study.
Betel nut is consumed mainly by working-age men, as it helps them stay awake for many hours: "Although little known in Western societies, it is the fourth most consumed psychoactive substance in the world, after alcohol, caffeine, and nicotine," Brumm points out.
However, the World Health Organization (WHO) has linked its consumption to a higher risk of several types of cancer. Additionally, it can cause jaw alterations and tooth loss. Therefore, countries like Taiwan, India, and Thailand have launched campaigns to curb its consumption by informing about the risks involved.
Areca seeds are rarely preserved in archaeological sites, but the scientists behind this study combined archaeological findings (the skeletons of these two individuals) with chemical analysis to find evidence of the consumption of this substance. Both hunter-gatherers show a very unusual pattern of dental wear - deep and rounded grooves in the teeth - which scientists attribute to a previously unknown drug consumption behavior: regularly sucking whole betel nuts.
Previous studies suggested that the main neuroactive alkaloid in betel nut, arecoline, was released when chewing the processed nut within that prepared quid with slaked lime. However, experiments conducted by this team demonstrated that simply sucking intact betel nuts releases sufficient amounts of arecoline to produce a physiological effect and alter brain function. Likewise, biochemical analyses detected the presence of arecoline in the dental tissues of these ancient gatherers.
"Our findings allow us to infer the prehistoric roots of one of the most widespread addictive stimulants in the world. It now seems likely that betel consumption as we know it evolved from a much simpler and older practice: sucking the intact nut," suggests Brumm.
Although the effect produced by sucking betel nuts was likely milder than that obtained through modern chewing of the quid, scientists believe that this habit could have caused severe periodontal disease in our ancestors. The ancient gatherers on this island generally had poor dental health, and arecoline is a natural analgesic. Therefore, researchers believe that one of the reasons for sucking betel nuts was to alleviate the discomfort caused by toothaches.
"However, over time, sucking these hard and abrasive seeds wore down the gatherers' teeth so much that, in some cases, the internal pulp chamber was completely exposed. This would have been extremely painful, made feeding difficult, and significantly increased the frequency of chronic dental infections," Brumm states. A habit that may have started as a remedy for toothaches ended up causing much more serious dental health problems due to continued consumption.