A recent study that appeared in the journal Nature Genetics has found that humans have lost diversity in their oral bacteria over the past 7,500 years which scientists attribute to chronic oral diseases in modern humans. This study was done by researchers from the University of Adelaide’s Australian Centre for Ancient DNA, the University of Aberdeen Department of Archaeology in Scotland, and the Welcome Trust Sanger Institute of Cambridge, England.

Less Diverse Oral Bacteria

By analyzing the DNA in calcified bacteria from teeth of humans from ancient periods up through modern day, the researchers have “shed light on the health consequences of the evolving diet and behavior from the Stone Age to modern day.” Their findings show that oral bacteria became less diverse when the human diet changed with the move from hunter-gatherers to farmers and again during the Industrial Revolution when food became manufactured. According to study leader Professor Alan Cooper, director of the Australian Centre for Ancient DNA, “this is the first record of how our evolution over the last 7500 years has impacted the bacteria we carry with us, and the important health consequences.” He attributes the decreasing diversity in oral bacteria to “chronic oral and other disease in post-industrial lifestyles.”

Why It’s a  Problem

The study sample included DNA extracted from calcified dental plaque from 34 different prehistoric, northern European skeletons and compared the changes in oral bacteria between hunter-gathers, farmers from the Bronze Age through Medieval times, and people living during and after the Industrial Revolution. Professor Cooper claims that this decrease in bacteria coincided with “the introduction of processed sugar and flour in the Industrial Revolution” and that it is “allowing domination by caries-causing strains. The modern mouth basically exists in a permanent disease state.” Professor Keith Dobney of the University of Aberdeen who worked on this project with Professor Cooper believes that this study can help scientists better understand diseases by observing genetic history, “making the archaeological record extremely relevant and important to modern-day medics and geneticists.” The scope of this study is currently being expanded both geographically and chronologically and will soon include data from other species such as Neanderthals to get a more complete picture of this change.

With our mouths predisposed to cavities due to the lack of bacteria varieties, it is even more important to visit your dentist twice a year for a check up and cleaning.

“Sequencing ancient calcified dental plaque shows changes in oral microbiota with dietary shifts of the Neolithic and Industrial revolutions”
Christina J Adler, Keith Dobney, Laura S Weyrich, John Kaidonis, Alan W Walker, Wolfgang Haak, Corey J A Bradshaw, Grant Townsend, Arkadiusz Sołtysiak, Kurt W Alt, Julian Parkhill & Alan Cooper
Nature Genetics, (2013) doi:10.1038/ng.2536. Published online, Feb 17th, 2013.
Nordqvist, Christian. “Modern Diet Is Rotting Our Teeth.” Medical News Today. MediLexicon, Intl., 19 Feb. 2013. Web.
22 Mar. 2013. http://www.medicalnewstoday.com/articles/256516.php