Scientists extract genetic secrets from 4,000-year-old teeth to illuminate the impact of changing human diets over the centuries

• Remarkably preserved microbiomes were recovered from 4,000-year-old teeth found in an Irish limestone cave.
• Genetic analyses revealed major changes in oral microbial communities from the Bronze Age to today, including strains of bacteria associated with gum disease and tooth decay.
• The presence of Streptococcus mutans, a major contributor to tooth decay, was exceptionally rare in ancient oral microbiomes, likely due to acid production and lack of favorable habitats.
• Evidence suggests that the introduction of sugary foods in the industrial era significantly impacted oral microbiome diversity and disease prevalence.
• The study supports the "disappearing microbiome" hypothesis, indicating a loss of oral microbial diversity over time and raising concerns about its implications for human health.