Nestled in a limestone cave in County Limerick, Ireland, archaeologists uncovered two remarkably preserved Bronze Age molars dating from around 2280–2140 BCE. A meticulous look at the microscopic passengers lodged in those teeth has shed fresh light on how our ancestors’ diet shaped their dental health—and why they enjoyed far fewer cavities than we do today.
a rare ancient dna analysis of a cavity-causing bacterium
When researchers extracted and sequenced DNA remnants from the molars, they were astonished to find abundant traces of Streptococcus mutans, the chief culprit behind tooth decay. In modern mouths, this bacterium’s acid production erodes enamel, yet the Bronze Age individual showed no sign of actual cavities in life. “Had he lived longer, there’s little doubt he would have developed dental caries,” admits Lara Cassidy, associate professor of genetics at Trinity College Dublin. Published in the journal Molecular Biology and Evolution on 27 March 2024, the study marks one of the oldest full-genome analyses of S. mutans—and it speaks volumes about changing human diets over millennia.
Why the 12-5-30 Incline Walking Method Is the Ultimate Fat-Burning Workout, According to Fitness Experts
The ultimate trick to banish mold from your bathroom grout in just 7 minutes—no vinegar or baking soda needed
I can’t help but recall my own dentist visits growing up, marveling at the X-rays of tiny cavities I’d accumulated despite religious brushing. In contrast, our Bronze Age forebear was armed with none of today’s oral hygiene tools, yet fared far better—until the sugar revolution arrived.
more sugar, more s. mutans, more cavities
Comparing that ancient strain of S. mutans with its modern counterpart revealed a pivotal shift in the bacterium’s evolutionary tree. After the medieval era, population expansions of S. mutans correlate with the surge in refined sugar consumption, creating a more hospitable environment for these acid-loving microbes. “We see a major increase in virulence traits in post-medieval samples,” explains Cassidy, pointing to the bacterium’s enhanced capacity to cling to tooth surfaces and generate cavity-causing acid.
This dovetails with historical records: cavity rates remained low until the 19th century, when industrial sugar refining made sweet treats widely available. Louise Humphrey, research lead at the Human Evolution Research Centre, Natural History Museum, London, emphasises that “the spike in dental decay coincides unmistakably with the advent of large-scale sugar production” (quoted in CNN).
a troubling loss of biodiversity
The study didn’t stop at S. mutans. Scientists also identified two distinct strains of Tannerella forsythia, a gum-disease bacterium, in the same Bronze Age teeth—yet today we typically find just one. This suggests that prehistoric mouths hosted a richer microbiome, with friendly species holding harmful ones in check. Over time, dietary shifts have tipped the balance in favour of sugar-loving pathogens, eroding microbial biodiversity in our oral ecosystems.
Back in 2013, researchers publishing in Nature Genetics analysed enamel from 34 prehistoric skeletons and noted a similar trend: as cereals and other starchy crops entered the human menu some 10,000 years ago, certain bacteria gained the upper hand. Now, with sugar pervading our diets, harmful strains have surged while beneficial ones have dwindled.
what this means for our dental future
Understanding how diet has driven the evolution of tooth-friendly and tooth-troubling bacteria offers practical insights. “By recognising that our microbiome co-evolves with our eating habits, we can begin to craft dietary strategies that support a healthier balance of oral microbes,” Cassidy concludes. In my own kitchen, I’ve started swapping refined sweets for whole fruits and savouring naturally crunchy snacks that promote saliva flow—nature’s own defence against decay.
We may never live as cavity-free as our Bronze Age predecessors, but by acknowledging the deep connection between what we eat and who we host in our mouths, we stand a better chance of keeping our smiles bright for generations to come.
Similar Posts
- 325 million years frozen: giant sharks emerge almost intact from secret US caves
- 325 million years preserved: two giant sharks reveal stunning prehistoric secrets underground
- Archaeologists Warn of Hidden Traps in China’s First Emperor Tomb
- Archaeology Breakthrough: 3,000-Year-Old Sculptor’s Workshop Unearthed with Pristine Statues!
- Mighty Beetle Halts Highway Construction: How a Tiny Insect Challenged Engineers!
Hi, I’m Brandon from the Decatur Metro team. I guide you through the trends and events reshaping our region.
