As farming became pervasive, so did the supply of refined sugars, starchy foods and cavities. It turns out that medieval folks would die to have the smile of their supposedly, less-evolved ancestors.

Stone age smiles

Sugar and processed foods are what cause tooth decay, not a lack of maintenance, according to research examining how our prehistoric ancestors managed to maintain healthy teeth without toothbrushes, floss and dentists.

Our modern teeth require a lot of maintenance and even if we do it with monastic discipline, there is no guarantee that our teeth will be free from complications. If we stopped brushing, flossing, rinsing and going for check-ups we would lose many, if not all, of our teeth. We would expect our prehistoric adult ancestors to be almost toothless, tormented by perpetual tooth decay and infections; but archaeological remains show that most prehistoric humans had their teeth in good shape.

Adults who lived during the stone age were missing, on average, 2.2 teeth, according to an anthropological study by J. Lawrence Angel. Early farmers were missing 3.5 teeth. For the ancient Romans, this figure rose to 6.6, which explains how the ancient Roman poet Martial found inspiration for one of his lines:

‘If I recall, Aelia, you used to have four teeth. One cough expelled two of them, and a second cough expelled the other two. Now you can cough all you want: a third cough won’t harm you.’

Did our prehistoric ancestors take better care of their teeth than their descendants? Or was something else at play?

 

Tiny flight recorders

An individual’s age at death is written on their teeth – in essence, they serve as the flight recorder of human remains. Dental development follows a strict sequence from infancy to young adulthood. Biological sex can be established with 70% accuracy by looking at the canines, which are proportionally bigger than the other teeth in adult males compared to females. Today, we can even establish the identity of a body by using their dental records. Not bad for our only, clearly visible skeletal units.

Even food preferences can be discerned by looking at a skeleton’s teeth, as different food leaves different types of microscopic marks. For example, meat leaves long vertical marks on the lateral surfaces, while plant-based foods leave horizontal and shorter vertical marks. Tartar deposits contain trapped food remains, from plant fragments to bone particles. Because tartar builds up over time, it is even possible to obtain a food history of an individual by comparing the contents of the different layers.

How did we ruin our teeth?

Tooth cavities do not arise spontaneously; they only appear when certain elements come together. First, we need bacteria — always present in our mouths. Second, we need fermentable sugars for the bacteria to eat. Lastly, we need acids, which the bacteria produce as they feed on the sugars. The acids demineralize the enamel (the outer protective layer of our teeth), but this is not a problem initially; teeth can regenerate the lost protection. But if the acid level increases, the enamel may demineralize faster than its regenerative capacity. Once the protective layer cracks, the bacteria penetrate the tooth, and we are now on a one-way journey towards infection, pain, and tooth loss.

The good dental health of our prehistoric ancestors was linked to their diet. A nutrition low in sugary and starchy food removes one of the fundamental conditions of tooth cavities formation. Before farming became ubiquitous, our ancestors ate low-processed food such as fruits, vegetables, nuts, roots, seeds, and meat. A diet like this makes tooth decay a less likely scenario. The scientific analysis of human teeth reveals that tooth decay rates surged as societies abandoned their foraging practices and moved towards farming.

Farming came down on our teeth like a wrecking ball. Consuming excessive amounts of starchy and sugary food was only one chapter in this tragedy. Crop processing leaves residues in the food, small rocky particles derived from all the pounding and grounding. These abrasive fragments erode the enamel. Other foods that undergo a pestle and mortar treatment, such as herbs, seeds, and spices, also increase the presence of abrasive particles.

The right balance

Does this mean that all farming societies suffered from poor dental health? Research suggests that when a farming community replaces some of its starchy and sugary food with less processed food, there is potential for a healthy smile.

For example, some pre-modern lakeshore communities in the Alpine region of Switzerland had access to a good supply of fish. Here, at least some individuals could secure enough fish supply to reduce their intake of starchy food. The key was to reach a balance where the consumption of wholesome, protein-rich food pushed starchy food levels down below damaging limits. And we know that some of these individuals did consume a considerable number of fish because this type of food leaves a clear molecular marker in the human remains that can be measured, but this would deserve an article on its own to explain.

The consumption of starchy foods and refined sugars has been an ongoing issue since the rise of farming. If we did not have toothbrushes, mouthwashes, and all the modern dental care paraphernalia that we use, our smiles would be ugly like the ancient Romans.

We know that a diet full of processed food can be harmful in the long run, increasing the likelihood of diabetes and heart disease, among other complications. A change towards less industrialized and better-quality food could stave these off.

And such change would even be noticeable in our smiles.

Suggested reading:

• Forshaw, R. 2009. The Practice of Dentistry in Ancient Egypt. British Dental Journal 206, 481-486.
• Waldron, T. 2009. Paleopathology. New York: Cambridge University Press

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