When did humans develop tooth decay?

19 April 2016

Question

Speaking about primeval men: I have heard that the caries disease is to be found only among 1 of 100 hunters and gatherers, whereas every 2nd farmer  50 of 100) is subjected to caries. Wasn't the food that the farmers grew nutritious enough? I wonder whether today our teeth are more healthy than our hunting and gathering ancestor's were?

Answer

Kat Arney put this question to Cambridge archaeologist Margarita Gleba...

Margarita - Right, I think I know where this question comes from. There was a study, just a couple of years ago by Dr Alan Cooper and his team of the Australian Centre for Ancient DNA, and they were looking at genetic material trapped in dental plaque (known as calculus) from skulls spanning from hunter gatherers, so we're talking Paleolithic period before about 10,000 BC, farmers from the Neolithic so this is from 10,000 to about 5 to 4,000 BC, and all the way through to modern humans. This material contained microbial DNA which allowed them to build a picture of how and why the microbes that we contain in our mouths have changed. The two main species for bacteria that are known to contribute to tooth decay, or carriol disease, appear in humans only with the advent of Neolithic, so with the appearance of farming. It seems a straightforward relationship but, actually, it's not as easy as that because we have evidence from contemporary societies that consumed a fair amount of sugars in their diet but do not have tooth decay like the Neolithic farmers did and unlike the Paleolithic hunter gatherers who supposedly had very good teeth because they were consuming lots of meat and very little sugar.

Kat - So, in theory, they would have had better looking teeth and the idea of our ancestors with these horrible, hairy faces and horrible, teeth isn't actually true? They probably had.

Chris - Not just you Kat.

Kat - Well I know - you know my ancestors. But they actually probably had quite nice teeth.

Margarita - Well, supposedly they had better teeth and, at least, the skulls that are preserved from those periods seem to indicate that they were in pretty good shape. Much better, in fact, than even our own teeth. We have terrible teeth compared to hunter gatherers, actually. But to go back, actually to the question - what caused the tooth decay in the early farmers. It is not the sugars but, actually, the starches, and starches are recognised today but a lot of dentists as also the main cause of tooth decay.

Chris - Because what - starch gets metabolised into sugar - doesn't it?

Margarita - The starch yes, exactly, but it sticks to your teeth, and it's not just any kind of starch; it's the grain starches that do and if you think that the transition to farming and consuming grains, that would have been the major switch in human evolution. Kat - I eat eggs, and my teeth are as great as they are...

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