In this study, we analysed the metagenomic content stone age chewed masic particles and its relation to oral health.
Oral health in historical populations has mostly been studied using morphological traits in teeth and jaw bone. However, DNA sequences from teeth, dental plaque, and chewed pitch provide hitherto inaccessible information on oral health via the composition of microorganism sequences. Here we present the metagenomic analysis of three chewed pitch pieces from Huseby Klev in Sweden that were dated to around 9890-9540 before present. The microbial profile exposes a Mesolithic oral microbiome which comprise ancient bacterial genomes that include oral and systemic pathogens. We compared the data with healthy and dysbiotic microbiome datasets and we identified a high abundance of periodontitis specific microbes, along with bacteria that cause infective endocarditis. In addition, trained machine learning models predicted a dysbiotic microbiome with 70-80% probability. Moreover, we identified DNA sequences from eukaryotic species as red fox, trout and apple. Our results indicate poor oral health during the Scandinavian Mesolithic, and we show that pitch pieces have the potential to provide information on important aspects of lifestyle in prehistoric populations: material use, diet and oral health.