Are Rats Related to Tooth Decay?

From Karl Gruber at Scientific American:

You could be forgiven for thinking that tooth decay is an inevitable fact of life; even ancient Egyptians practiced dentistry. But the study of human teeth suggests that before our ancestors started cultivating plants for food, cavities were uncommon. Tooth decay, it seems, spread once we changed to an agricultural lifestyle.

New evidence from Omar Eduardo Cornejo Ordaz, a postdoctoral research fellow at the Stanford School of Medicine, and his colleagues back up this hypothesis. They analyzed the genomes of several strains of the prevalent caries-causing bacterium,Streptococcus mutans, to determine when new genes evolved in this species and its close relatives. The team’s statistical analyses suggest the bacteria’s population started expanding exponentially about 10,000 years ago, which coincides quite nicely with the birth of agriculture.

Smiling LipsThe article mentions Peter Brown, an Australian paleoanthropologist, who favors sugar and other refined carbohydrates as a cause of dental decay.  No need to invoke rats.  Australian aborigines and Japanese samurai in the Edo period saw deterioration of dental health after introduction of sugars and other refined carbs.

Maybe it’s true: No carbs, no cavities.


h/t Amy Kubal

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