Tracing changes in human diet during the transition from hunting to farming

A large team of researchers affiliated with a host of institutions across Italy have used DNA found in the dental calculus of ancient peoples to help trace changes in human diets during the transition from hunting to agriculture in Italy for thousands of years. In their article published in the journal Nature Communication, the group describes their study of calcified plaque found on the teeth of people living in the Copper, Neolithic, and Paleolithic Ages to learn more about the changes wrought by the shift from food hunting to cultivation.

Previous research has shown that much can be learned about the oral microbiome of ancient people by studying DNA found in material clinging to their teeth. The oral microbiome is the assortment of microbes living in the mouth, and studying the oral microbiome can tell scientists a lot about the diets of people who once used those teeth to chew their food.

In this new work, the researchers removed pieces of dental calculus from the teeth of people who lived in certain regions of Italy at different times to assess changes in their diets over time. In doing so, they were able to identify dietary changes over a period of 30,000 years, a time period that included when people in the region drastically changed their way of life. As people learned to grow food, they not only changed their diet, but also their way of life. They stopped wandering in search of food in small groups and formed large communities centered on agricultural endeavors.

By examining the oral microbiome of these people, the researchers found that it shifted from a microbiome that supported meat consumption to one that relied on plant-based and fermented foods such as those produced by dairy products. .

Specifically, the team sequenced DNA from material found in 76 samples of dental calculus, spanning the years 31,000 BC to 2,200 BC. In doing so, the researchers discovered two major changes in the composition of the oral biome: an early and subtle change when people started eating home-grown foods, and then a more pronounced change that occurred when consuming products farming became common in the Neolithic period.

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