One of the hinge points in human history was the invention of agriculture. It led to large communities, monumental architecture and complex societies. It also led to tooth decay.
When hunter-gatherers started adding grains and starches to their diet, it brought about the "age of cavities." At least that's what a lot of people thought. But it turns out that even before agriculture, what hunter-gatherers ate could rot their teeth.
The evidence comes from a cave in Morocco — the Cave of the Pigeons, it's called — where ancient people lived and died between 12,000 and 15,000 years ago. These were hunters and gatherers; they didn't grow stuff. And what was astonishing to scientists who've studied the cave people was the condition of their teeth.
"Basically, nearly everybody in the population had caries," or tooth decay, says Louise Humphrey, a paleo-anthropologist with the Natural History Museum in London.
Humphrey says 94 percent of the more than 50 people from the cave she studied had serious tooth decay. "I was quite surprised by that," says Humphrey. "I haven't seen that extent of caries in other ancient populations."
Certainly, life was brutal and short for Stone Age folks, what with saber tooth cats, parasites, and not an aspirin to be found anywhere. But at least the paleo diet — meat, tubers, berries, maybe some primitive vegetables and very few carbs-- was supposed to be good for the teeth. Carbohydrates can turn sugary in your mouth, then bacteria turn that into enamel-eating acid.
But apparently, these ancient people had a thing for acorns.
"Acorns," says Humphrey, "are high in carbohydrates. They also have quite a sticky texture. So they would have adhered easily to the teeth."
Yes, these people did eat meat. And snails, apparently, whose shells littered the cave. But they also ate a lot acorns, judging by the debris they left behind.
Without toothbrushes ... without dental floss ... that diet rotted their teeth.
Eventually, the tooth crowns wore away, says Humphrey: "They were eating on the polished roots of their teeth. I think they would have been in pain."
Humphrey says this is the earliest case of widespread dental caries ever seen, by thousands of years. It contradicts the idea that agriculture ushered in tooth decay, and that the so-called "paleo diet" is inherently healthy, she says.
When it came to cuisine, she says, paleolithic people were simply opportunistic. Some elements of the ancient diet were good; others were not.
"There's not one kind of paleo diet," Humphrey says. "I think wherever people lived, they had to make best of the wild food resources available to them."
In this case, Humphrey believes, ground acorn patties. She hasn't tried them herself, but she plans to.
"I would like to," she says. "I imagine that they would be something like sweet chestnuts."
Kind of like the Twinkies of the paleolithic.
The research appears in the Proceedings of the National Academy of Sciences.