JUANA SUMMERS, HOST:
Betel nuts are commonly chewed in the Asian Pacific region for their stimulant effects. As NPR's Pien Huang reports, new evidence points to the ancient origins for this common drug. That evidence comes in the form of very old teeth.
PIEN HUANG, BYLINE: The teeth in question date back to a hunter-gatherer who lived during the Ice Age, and they're marked with deep grooves.
ADAM BRUMM: We showed images of these grooves to all of the world's leading experts in ancient dental wear. None of them could explain how these grooves could have formed.
HUANG: That's Adam Brumm with Griffith University in Australia. He excavated those teeth, which come from the remains of a person who lived in Sulawesi, an island in modern-day Indonesia, some 16- to 25,000 years ago. At another nearby site, they found a second human who lived maybe 8,000 years ago with similar tooth marks. Brumm says the rounded, hollowed pits likely took decades to form.
BRUMM: The grooves were so deep that they'd actually exposed the pulp cavity or the nerve center of several teeth.
HUANG: Hunter-gatherers from that time often used their teeth as tools to hold, break and stretch things. But those uses didn't account for the depth of these grooves.
BRUMM: We ruled out any type of food that they might have been eating. We ruled out the possibility that they were processing plant fibers or something to make string in their mouth.
HUANG: Then he remembered an example from a different time and place.
BRUMM: A type of dental wear recorded during the colonial period in Europe and America and Australia.
HUANG: From laborers who regularly smoked tobacco from clay pipes.
BRUMM: These people would have the clay pipe sticking out of their mouth Popeye-style, and then over time, maybe, like, a lifetime of this habit, they've got, like, a perfectly round notch worn into their teeth that you can just slot the clay pipe stem straight into.
HUANG: That led him to think that the teeth grooves he found might come from a similar habit. In Asia and the Pacific region today, betel nuts are seeds from palm trees that are commonly chewed with other chemicals for a powerful stimulant effect. Brumm and his colleagues think they found an early stage of the practice.
BRUMM: And we think it might have started with hunter-gatherers just sucking on the nuts, almost as though they were Gobstoppers.
HUANG: Since this isn't something people do today, Brumm and his colleagues needed to test their theory that merely sucking the betel nut could cause a drug effect.
BRUMM: And we soaked whole betel nuts, like complete betel nuts, in artificial saliva and then introduced the resultant extracts into frog egg cells engineered to produce human brain receptors.
HUANG: And they saw that the brain receptors turned on when they touched the saliva. Then they asked whether these ancient people actually did it. They tested dental tissues from the bodies of the 200 gathers and found traces of the betel nut chemical. The research is published in the journal Science Advances. Peter Ungar is an anthropologist who studies teeth. He wasn't involved in the paper, but he says it makes a compelling case.
PETER UNGAR: There's evidence for the betel nut causing excessive tooth wear. When you add the chemical evidence, that's pretty much a smoking gun.
HUANG: Others, like archaeologist Jose Capriles at Penn State University, are a little less convinced.
JOSE CAPRILES: In terms of the evidence itself, I wish there was more. I must admit there are two skeletons that they report.
HUANG: Though Capriles does say well-preserved remains are especially hard to find in tropical places where heat and humidity breaks them down.
CAPRILES: More direct evidence would be the actual finding of the nuts of the seeds, ideally in some form of cultural context.
HUANG: Finding them in a hearth, house floor or burial site - he does agree that ancient peoples probably did use some kind of psychoactive drugs. It seems like part of human nature. Pien Huang, NPR News. Transcript provided by NPR, Copyright NPR.
NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.
