Trapped dental 'calculus' holds clues to ancient human diets and health

Many ancient human teeth, including specimens tens of thousands of years old, still hold onto tiny pieces of food -- and even bacteria. Anthropologists are studying the tartar attached to ancient human teeth to learn more about the plants people ate and the pathogens they carried long ago.

Tartar, also known as dental calculus, is a hard substance that toothpaste ads promise to obliterate and dentists scrape away. It builds up on human teeth after dental plaque solidifies. A dentist might scrape away 30 milligrams of a patient's calculus each visit. Sets of teeth from hundreds or thousands of years ago might have up to 20 times that much, a mass roughly equal to a small paperclip.

Scientists are only beginning to explore the variety of materials caught in calculus, which preserves organic materials that are often fleetingly preserved in other settings. This allows scientists to address questions that are very difficult to answer using established archaeological methods.

"There are so many time periods in human history where we have theories about what they ate but we really have no idea," said Amanda Henry, a physical anthropologist at the Max Planck Institute for Evolutionary Anthropology, in Leipzig, Germany.

Seeds and grains often degrade slowly and animal bones typically last even longer. But finding direct evidence of vegetable consumption is more difficult. Vegetables such as cabbage and carrots were important foods in medieval Europe, but evidence to confirm their consumption is hard to come by. Reconstructing the full diet for people living in earlier periods is even more difficult.

"We know very little about the vegetable and salad portion of the diet," said Christina Warinner, an archaeological geneticist at University of Zurich's Centre for Evolutionary Medicine, in Switzerland. "[Studying calculus] could potentially be an entirely new way of approaching that."
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Inside Science News Service via phys.org/news