Very old plaque preserved on the teeth of the long dead reveals their favorite foods.
Researchers trying to figure out what our ancestors ate have discovered that ancient Britons, like us, loved their carbs.
Plaque preserved on the teeth of people dead for centuries can be used to reveal what their favorite foods were, an international team of researchers found. This dental calculus shows a diet heavy on carbohydrates, including oats, peas and cabbage, from the eighth century right up to modern times.
And people from the year 700 through modern times all appear to have depended heavily on milk for their protein.
Archeologist Jessica Hendy of Germany's Max Planck Institute for the Science of Human History and colleagues are trying to find the best ways to use ancient teeth to figure out what ancient people ate.
Researchers struck it lucky when the frozen, mummified body of a 5,000-year-old man, later named Ötzi, was found in the Alps in 1991. His stomach contents were well preserved by the dry cold — revealing a last meal of goat meat, venison and wheat.
But often, all that is left of people long dead are bones and teeth. Hendy's team is looking at ways to optimize the study of dental plaque, which, they wrote, "entombs and preserves" molecules of food.
"Traces of foodstuffs can be sourced directly from the human mouth, uniquely revealing precise evidence of particular foods consumed," they wrote in their report, published Tuesday in the Proceedings of the Royal Society B.
They used a high-tech approach called proteomics, which analyzes specific proteins in a sample, to re-examine the data collected from 38 samples dating back to England's Iron Age and the Roman occupation of the island. They used a new protein extraction method to analyze samples from the teeth of people who died in the 18th and 19th centuries, as well as people living now or who recently died.
"A total of 100 archaeological samples of dental calculus were analyzed," they wrote.
One challenge is to separate human proteins from food proteins. The only meat sample they could distinguish was a single incidence of venison. It's not clear whether that is because meat was rarely eaten, or because it's too difficult to use current methods to tell animal proteins from the human proteins that would naturally be found in the mouth of a human being.
Hendy's team found proteins they could identify as coming from oats, peas and plants from the cabbage family in the ancient samples. In modern samples, potatoes, soybeans and peanuts were common.
"Interestingly, we observe that milk proteins are consistently detected throughout all time periods within this study and are detected in 20 percent of individuals overall in ancient and modern individuals," Hendy's team wrote.
Northern Europeans commonly carry a genetic mutation that allows them to drink and tolerate milk well into adulthood. Scientists believe that the ability to drink milk gave people a survival advantage.
Understanding what people ate and how diets have changed help paint a clearer picture of long-gone cultures. People can analyze the residue left in ceramic cookware and offerings at gravesites. They can also analyze hair and bones to find chemical signatures of certain classes of food.
But analyzing the hardened plaque on teeth gives a unique picture of what actually went into people's mouths, Hendy's team noted.