I had previously noted research indicating that modern diet has changed the bacterial profile of our guts.
This new paper looks at the oral microbiome at different time periods and how that has affected dental health. Like the previous paper it finds a marked change in the microbiomes between ancient and modern samples specifically tied to dietary changes. Just like in the outside world, it seems that diversity is also the healthier option for our mouths.
Nature Genetics (2013) doi:10.1038/ng.2536
Sequencing ancient calcified dental plaque shows changes in oral microbiota with dietary shifts of the Neolithic and Industrial revolutions
The importance of commensal microbes for human health is increasingly recognized1, 2, 3, 4, 5, yet the impacts of evolutionary changes in human diet and culture on commensal microbiota remain almost unknown. Two of the greatest dietary shifts in human evolution involved the adoption of carbohydrate-rich Neolithic (farming) diets6, 7 (beginning ~10,000 years before the present6, 8) and the more recent advent of industrially processed flour and sugar (in ~1850)9. Here, we show that calcified dental plaque (dental calculus) on ancient teeth preserves a detailed genetic record throughout this period. Data from 34 early European skeletons indicate that the transition from hunter-gatherer to farming shifted the oral microbial community to a disease-associated configuration. The composition of oral microbiota remained unexpectedly constant between Neolithic and medieval times, after which (the now ubiquitous) cariogenic bacteria became dominant, apparently during the Industrial Revolution. Modern oral microbiotic ecosystems are markedly less diverse than historic populations, which might be contributing to chronic oral (and other) disease in postindustrial lifestyles.