July 18, 2012 at 8:33 PM ET
Tooth scrapings from tens of thousands of years ago suggest that Neanderthals chewed on medicinal plants to soothe their upsets.
That's the conclusion drawn by an international team of researchers who conducted a chemical analysis on dental calculus from five sets of Neanderthal remains that were excavated inside El Sidron Cave in northern Spain. The calcified crud contained microscopic bits of plant material as well as chemicals associated with wood smoke.
The analysis indicated that the Neanderthals ate cooked plant food that was high in starch, and perhaps also nuts, grasses and green vegetables. One case was particularly intriguing: The scrapings from an individual known as Adult 4 contained chemicals known as azulenes and coumarins. Those are the sorts of chemicals that are found in yarrow and chamomile, two types of herbal remedies.
Yarrow is an astringent that's long been used to cleanse wounds when used externally, or counter internal bleeding when ingested. Chamomile may be best-known today as a soothing tea, but that's because it has a settling effect on colds, headaches, intestinal distress and menstrual cramping. Both plants have anti-inflammatory properties.
The researchers say this is the first molecular-scale evidence supporting the idea that Neanderthals ingested medicinal plants. Their findings — which are based on a high-tech method of analysis known as pyrolysis-gas chromatography-mass spectrometry, plus the study of plant microfossils — were published online today in the journal Naturwissenschaften.
Neanderthals had a varied diet
"The varied use of plants we identified suggests that the Neanderthal occupants of El Sidron had a sophisticated knowledge of their natural surroundings, which included the ability to select and use certain plants for their nutritional value and for self-medication. While meat was clearly important, our research points to an even more complex diet than has previously been supposed," the study's lead author, Karen Hardy, said in a news release from the University of York.
Hardy is a research professor at the Universitat Autonoma de Barcelona's Catalan Institute of Research and Advanced Studies as well as an honorary research associate at the University of York.
One of Hardy's colleagues, Stephen Buckley of the University of York's BioArCh research facility, said the team was surprised to find evidence that this particular Neanderthal was chewing on plants that had no nutritional value. "We know that Neanderthals would find these plants bitter, so it is likely these plants must have been selected for reasons other than taste," Buckley said in the news release.
But in retrospect, Hardy now thinks it's not as surprising as it seems. She pointed out that chimpanzees and other animals chew on non-nutritional plants that have medicinal effects. Why shouldn't it have been the same for Neanderthals?
"We have identified these plants ... we feel the most likely use is for self-medication," Hardy told me in an email. "In fact, I would find it harder to argue that they did not use medicinal plants than that they did, particularly as this fits so well with the extensive evidence for self-medication among higher primates and many other animals. So we have a behavioral context for this use."
Where's the beef?
Previous research has suggested that Neanderthals ate a meat-heavy diet, but Hardy and her colleagues found no evidence of meat consumption in the tooth crud they analyzed. That doesn't necessarily mean these particular Neanderthals were vegetarians. The lack of evidence could be due to the way chemicals in the crud were preserved, or it could suggest that Neanderthals shifted their diet due to seasonal changes or migratory habits.
The findings released today hint at even closer kinship between modern humans and our Neanderthal cousins, who first settled in Europe at least 300,000 years ago but went extinct about 24,000 years ago. The Neanderthals whose teeth were examined for the study were part of a community of at least 13 individuals who lived in the El Sidron Cave somewhere between 47,300 and 50,600 years ago.
"El Sidron has allowed us to banish many of the preconceptions we had of Neanderthals," said Antonio Rosas of the Museum of Natural History in Madrid-CSIC. "Thanks to previous studies, we know that they looked after the sick, buried their dead and decorated their bodies. Now another dimension has been added, relating to their diet and self-medication."
More about ancient humans and their relatives:
In addition to Hardy, Buckley and Rosas, the authors of "Neanderthal Medics? Evidence for Food, Cooking and Medicinal Plants Entrapped in Dental Calculus" include Matthew J. Collins, Almudena Estalrrich, Don Brothwell, Les Copeland, Antonio Garcia-Tabernero, Samuel Garcia-Vargas, Marco de la Rasilla, Carles Lalueza-Fox, Rosa Huguet, Markus Bastir, David Santamaria, Marco Madella, Julie Wilson and Angel Fernandez Cortes.
Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the dwarf planet and the search for new worlds.