Tooth Plaque Reveals Prehistoric Ancestors' Diet

Tooth plaque from an ancient fossil uncovered by researchers in Sudan has revealed more about our prehistoric ancestors' diet, as well as shown that these people understood plants long before the development of agriculture.

By extracting chemical compounds and microfossils from dental calculus (calcified dental plaque) from ancient teeth, the researchers were able to provide an entirely new perspective on our ancestors' diets. Their research suggests that purple nut sedge (Cyperus rotundus) - today regarded as a nuisance weed - formed an important part of the prehistoric diet.

The studied dental records were found at Al Khiday, a pre-historic burial site on the White Nile in Central Sudan. Analysis shows that for at least 7,000 years, before agriculture became a major way of life, the people of Al Khiday ate the plant purple nut sedge, possibly understanding both its nutritional and medicinal qualities. The plant is a good source of carbohydrates and indeed does have many medicinal and aromatic uses.

"We also discovered that these people ate several other plants and we found traces of smoke, evidence for cooking, and for chewing plant fibers to prepare raw materials," lead author Karen Hardy, a Catalan Institute for Research and Advanced Studies (ICREA) Research Professor at the Universitat Autònoma de Barcelona, said in a statement. "These small biographical details add to the growing evidence that prehistoric people had a detailed understanding of plants long before the development of agriculture."

Of the five archaeological sites at Al Khiday, one of them was predominantly a burial ground of pre-Mesolithic, Neolithic and Later Meroitic age, providing researchers with more long-term data.

Not only did purple nut sedge make up the bulk of our ancestors' diet both before and after agriculture existed, but it also helped prevent tooth decay, as evidenced by the relatively low number of cavities in the tooth specimens.

Hardy and researchers believe that this study could revolutionize the "perception of ecological knowledge and use of plants among earlier prehistoric and pre-agrarian populations."

Their findings were published in the journal PLOS ONE.