Flash Those Pearly Whites!

Behind their hairy jutting jaws, our Stone Age forebears had remarkably healthy teeth. It’s not that their choppers were stronger than ours. They weren’t. Cavemen and women just didn’t have many cavities.

It is remarkable how healthy most fossil teeth are.  Some paleontologists devote  their entire careers to studying the structure and functioning of ancient teeth. It helps that tooth enamel is the hardest, longest lasting substance in our bodies, leaving durable evidence of the change that human dentition has undergone as we evolved.

These fossils reveal that Stone Age teeth had a rough time of it, undergoing wear and tear as tools for cutting and grinding and chewing many hours a day. Of course, cavemen didn’t have toothbrushes, fluoridated water or dental floss. Nor did they endure school programs and television commercials admonishing them to brush twice a day and after meals.

So how did they avoid cavities, even though their tooth enamel had the same composition as ours?

The answer is diet. We know that the bacteria that rot teeth feed on sugars in our mouths. Unlike proteins and fats, which are large molecules that require the harsh conditions of our stomachs to break down, carbohydrates can be quite small and sticky. An enzyme in our saliva called amylase starts to break down starch into sugar as soon as we begin chewing. This is why carbs give us such a quick burst of energy.

Streptococcus mutans, the main bacterial culprit in tooth decay, lives in the crevices of our teeth and gums and turns sucrose, which we know as table sugar, into lactic acid which can quickly erode dental enamel. This leaves holes, or cavities, the better for more bacteria to live in.

We know from genetic studies that S. mutans has kept its current form for several million years.  And since the structure of tooth enamel hasn’t changed over that time span either, the difference must be diet.

Back when fibrous roots and bitter fruits comprised nearly all the carbohydrates in a person’s diet, bacteria in the mouth had little opportunity to produce lactic acid.  The bacteria starved and the teeth remained healthy. In contrast, our modern diet – chock full of simple carbs, starchy grains and sugary sodas – offers a veritable paradise for decay causing bacteria. It’s no surprise that dental cavities are the most widespread chronic disease of childhood in the world today, five times as common as asthma.

It’s something to chew on—another disease that the dietary changes of our advanced culture have foisted upon our ancient bodies.

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