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Vegan and vegetarian foods among prehistoric people that led to no tooth decay

An international team of researchers has found new evidence that our prehistoric ancestors had a detailed understanding of plants long before the development of agriculture. Researchers suggest that in prehistoric times eating the plant known as purple nut sedge (Cyperus rotundus) prevented the people at that time from developing tooth decay and plaque buildup, according to the study, "Dental Calculus Reveals Unique Insights into Food Items, Cooking and Plant Processing in Prehistoric Central Sudan," published online July 16, 2014 in the journal PLOS One. It's as if prehistoric people, at least in the tropics, lived on wild weeds and other greens, beans, roots, and fruits, most of the time, assuming the beans were found in the wild long before the age of agriculture.

Purple nut sedge chewing may have prevented tooth decay and plaque among prehistoric peoples.
Photo by Buddhika Weerasinghe/Getty Images

The plant has the ability to inhibit Streptococcus mutans, a bacterium which contributes to tooth decay, and it may have contributed to the unexpectedly low level of cavities found in the agricultural population. So if you've wondered why so many isolated, indigenous tribes who never brush their teeth have so little tooth decay, it could be because they're not exposed to foods such as sugar, strong acidic foods, certain grains, and white flour conducive to tooth decay. The plants weren't all eaten raw. Researchers found evidence for cooking, and smoke inhalation was identified in all samples.

Tooth plaque provides unique insights into our prehistoric ancestors' diet

Tooth plaque provides unique insights into our prehistoric ancestors' diet, says new research showing that long before the age of agriculture people ate lots of vegetarian foods, knew where to find them, and which foods were edible, tasty, and good for them as far as feeling well or improving health. An international team of researchers has found new evidence that our prehistoric ancestors had a detailed understanding of 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.

Crucially, the research led by the Universitat Autònoma de Barcelona and the University of York, suggests that prehistoric people living in Central Sudan may have understood both the nutritional and medicinal qualities of this and other plants

Scientists carried out the research at Al Khiday, a pre-historic site on the White Nile in Central Sudan. It demonstrates that for at least 7,000 years, beginning before the development of agriculture and continuing after agricultural plants were also available the people of Al Khiday ate the plant purple nut sedge. The plant is a good source of carbohydrates and has many useful medicinal and aromatic qualities.

Lead author Karen Hardy, a Catalan Institute for Research and Advanced Studies (ICREA) Research Professor at the Universitat Autònoma de Barcelona (UAB) and an Honorary Research Associate at the University of York, said, according to the July 16, 2014 news release, Tooth plaque provides unique insights into our prehistoric ancestors' diet, "Purple nut sedge is today considered to be a scourge in tropical and sub-tropical regions and has been called the world's most expensive weed due to the difficulties and high costs of eradication from agricultural areas.

"By extracting material from samples of ancient dental calculus we have found that rather than being a nuisance in the past, its value as a food, and possibly its abundant medicinal qualities were known. More recently, it was also used by the ancient Egyptians as perfume and as medicine.

People ate several different types of plants cooked and raw

"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. These small biographical details add to the growing evidence that prehistoric people had a detailed understanding of plants long before the development of agriculture."

Al Khiday is a complex of five archaeological sites which lie 25km south of Omdurman; one of the sites is predominantly a burial ground of pre-Mesolithic, Neolithic and Later Meroitic age. As a multi-period cemetery, it gave the researchers a useful long-term perspective on the material recovered.

The researchers found ingestion of the purple nut sedge in both pre-agricultural and agricultural periods

Dr Stephen Buckley, a Research Fellow at the University of York's BioArCh research facility, conducted the chemical analyses. He said, according to the news release, "The evidence for purple nut sedge was very clear in samples from all the time periods we looked at. This plant was evidently important to the people of Al Khiday, even after agricultural plants had been introduced."

Dr Donatella Usai, from the Instituto Italiano per l'Africa e l'Oriente in Rome led the excavation and Dr Tina Jakob from Durham University's Department of Archaeology, performed the analysis of the human remains at Al Khiday. Anita Radini, an Archaeobotanist at the University of Leicester Archaeological Service (ULAS) and a PhD candidate at BioArCh, University of York, contributed to the analysis of microfossils found in the dental calculus samples.

People made good use of available wild plant foods, to eat, as raw materials, and as medicine

Dr Usai said, according to the news release, "Al Khiday is a unique site in the Nile valley, where a large population lived for many thousands of years. This study demonstrates that they made good use of the locally available wild plant as food, as raw materials, and possibly even as medicine."

Dr Hardy added, according to the news release, "The development of studies on chemical compounds and microfossils extracted from dental calculus will help to counterbalance the dominant focus on meat and protein that has been a feature of pre-agricultural dietary interpretation, up until now. The new access to plants ingested, which is provided by dental calculus analysis, will increase, if not revolutionize, the perception of ecological knowledge and use of plants among earlier prehistoric and pre-agrarian populations."

The world's most expensive weed spreads rapidly through other bulbs, tubers, and rhizomes

Fieldwork was funded by the Italian Minister of Foreign Affairs, Istituto Italiano per l'Africa e l'Oriente, Centro Studi Sudanesi e Sub-Sahariani, and the Universities of Milano, Padova and Parma. The research was endorsed by the National Corporation for Antiquities and Museums (NCAM) of Sudan.

If you check out the study's abstract, it notes that Cyperus rotundus is particularly interesting as it is present in all periods. C.rotundus or ‘purple nut sedge’ is a C4 plant that is profligate in moist tropical environments. It has been called the ‘world’s most expensive weed’ due to its ability to spread rapidly through its underground storage system of bulbs, rhizomes and tubers, whose proliferation may be caused by an excess of carbohydrates.

You also may wish to check out the book by Holm LG, Plucknett DL, Pancho JV, and Herberger JP (1977) The World's Worst Weeds: Distribution and Biology. Honolulu: University Press of Hawaii.

Researchers also explained in the study that C. rotundus has been highlighted as a potentially key component of the diet of the Late Palaeolithic population of Wadi Kubbaniya in southern Egypt (17,000–15,000 BC) 1000 km north of Al Khiday, where it predominated in the abundant assemblages of charred plant remains. However, despite identification of several plant species in charred human coprolites, C. rotundus was not detected, says the study.

It looked to the researchers as if the people chewed the plant, which cleaned their teeth, and then spit out the fiber and liquid, whether it was raw or cooked. That's possibly the reason why after chewing, researchers didn't find any physical evidence for C. rotundus in the coprolites at Wadi Kubbaniya despite the abundant carbonized remains, the study notes.