600 million people chew betel nuts today

The brownish-green seeds from palm trees are the world's fourth most commonly used mind-affecting substance, after tobacco, alcohol and caffeine. Users report benefits like energy boosts and fresh breath.

Health risks from long-term use

Betel nut chewing can damage teeth, increase heart disease risk, and lead to oral cancer due to chemicals within the nut. Despite these dangers, millions remain addicted.

Ancient teeth show mysterious grooves

Archaeologists in Sulawesi, Indonesia found human remains from 25,000 years ago with strange grooves in the teeth they couldn't explain. A second set of teeth from 8,000 years ago showed similar patterns.

“There were really strange grooves in the teeth that we couldn't explain.”

Ruling out other explanations

Researchers eliminated possibilities like using teeth as tools or processing plant fibers. The grooves were too deep and patterned to match any known food or activity from that era.

Tobacco pipe smokers had similar marks

Researchers remembered that European and American laborers who smoked clay pipes developed distinctive notches in their teeth from holding the pipe stem. This suggested a cultural habit, not food wear.

Testing betel nut extraction

Researchers soaked whole betel nuts in artificial saliva and found it successfully extracted arecoline, an active chemical. Brain receptors turned on when exposed to the saliva, showing a physiological effect.

“We've shown that if you just suck on the nut, there's a physiological reaction that can be released into your bloodstream and then into your brain.”

Chemical traces found in ancient teeth

Dental tissue samples from the ancient remains contained arecoline, a chemical found only in betel nuts. This provided direct evidence that these people had actually consumed betel nuts.

The numbing effect was likely the draw

The lead researcher tasted betel nuts himself and found they cause extreme numbness and pain relief. He theorizes ancient hunter-gatherers sought this effect, potentially creating an addiction cycle.

“It has this extremely bitter and astringent taste that makes your whole mouth go numb.”

Addiction cycle wore teeth to the nerve

Researchers believe ancient betel nut suckers eventually wore their teeth down to the nerve, which was painful. This pain drove more nut-sucking to relieve it, creating a self-perpetuating addiction.

“They were essentially caught in this cycle and they were basically addicted to this natural plant drug.”

Experts call evidence compelling but limited

Outside researchers say the tooth wear and chemical evidence together make a strong case. However, some note the study relies on only two skeletons and would benefit from more direct archaeological evidence.

“There's evidence for the betel nut causing excessive tooth wear. When you add the chemical evidence, that's pretty much a smoking gun.”

Finding actual nuts would strengthen case

Researchers say preserved betel nuts or seeds found in cultural contexts like hearths or burial sites would provide more direct proof. Tropical climates make ancient remains hard to preserve.

“More direct evidence would be the actual finding of the nuts, of the seeds, ideally in some form of cultural context.”

Motives may have been cultural, not just medical

Some experts caution against assuming ancient people used betel nuts only for pain relief. Social and cultural reasons may have driven the practice, just as people today engage in tooth-damaging habits for social purposes.

“We have to be very, very careful not to associate our particular assumptions of pain or patterns.”

Drug use has deep roots in humanity

Researchers note that the instinct to experiment with mind-altering substances is part of human nature. Evidence of drug use by humans dates back thousands of years across multiple continents.