Taforalt (Maroc): Ancient hunter-gatherers had rotten teeth
In need of some fillings (Image: Isabelle De Groote)
Ancient hunter-gatherers may have sustained themselves by eating lots of nuts and other starchy foods, but they paid a high price: rotten teeth.
Scientists have long thought that tooth decay only became common in humans about 10,000 years ago, when we began farming – and eating starchy crops that fed sugar-loving bacteria on our teeth. But Isabelle De Groote of the Natural History Museum in London, UK, and her colleagues have found widespread tooth decay in hunter-gatherers that lived several thousand years before the origin of agriculture.
Her team analysed the remains of 52 adults who lived between 15,000 and 13,700 years ago, and who were buried together in a cave in Taforalt, Morocco. They found evidence of decay in more than half of the surviving teeth, a prevalence of dental disease comparable to that of modern, industrial societies with diets high in refined sugars. Only three skeletons at the site showed no signs of cavities.
"This is the first time we've seen such bad oral health in a pre-agricultural population," says De Groote. Tooth decay has been found in a handful of other scavenging societies, but scientists have not found evidence of such a high incidence of dental disease in a group of this size.
Call the dentist
Until now, archaeologists have found that the oldest populations with lots of cavities were ones that ate domesticated wheat and barley. Such crops, especially when finely ground into porridges and breads, are much stickier and higher in sugar than wild fruits and grains. That makes them an ideal food source for cavity-causing bacteria, which produce acids that corrode tooth enamel as they digest carbohydrates.
"But if this society lived too early to have relied on a domesticated crop, what could they have been eating that caused such high rates of tooth decay?" asks De Groote.
The cave contained clues: the remains of pine nuts and sweet North African acorns. There were also remnants of grindstones that could have processed nuts into flat breads and sticky porridges.
That could be the explanation. "A heavy reliance on certain plant foods well before people started to rely on cultivated plants could, in certain circumstances, lead to significant [tooth decay] levels," says Marijke van der Veen of the University of Leicester, UK.
The finding suggests that the transition from a nomadic hunter-gatherer lifestyle to a sedentary farming one may not have been as clear-cut as thought, says De Groote.
Journal reference: PNAS, DOI: 10.1073/pnas.1318176111