How the dawn of farming ruined our TEETH

Before the introduction of agricultural processes, hunter-gatherers had what has been dubbed as ‘perfect harmony’ between the shape of their jaws and the size and alignment of their teeth.

But as farming became more widespread, and food became easier to chew, jaws shrunk and in turn triggered the beginnings of a condition known as malocclusion and dental crowding.

Researchers from the University College Dublin (UCD) analysed the lower jaws and teeth dimensions of 292 skeletons from the Levant, Anatolia and Europe, dating back between 6,000 and 28,000 years ago.

This included hunter-gatherers, semi-sedentary hunter-gatherers, transitional farmers, and farmers.

Skeletons were studied from different regions in order to rule out specific geographic anomalies.

In the case of hunter-gatherers, the scientists from UCD, led by Professor Ron Pinhasi, Israel Antiquity Authority, and the State University of New York, Buffalo, found a correlation between inter-individual jawbones and dental distances, suggesting an almost ‘perfect’ state of equilibrium between the two.

While in the case of semi-sedentary hunter-gatherers and farming groups, they found no such correlation.

This suggests the 'harmony' between the teeth and the jawbone was disrupted during the shift towards agriculture.

The researchers believe farming practices led to changes in diet that directly impacted the shape and structure of the jawbones.

For example, the diet of a hunter-gatherer was based on ‘hard’ foods such as wild uncooked vegetables and meat.

By comparison, the staple diet of the sedentary farmer is based on ‘soft’ cooked or processed foods like cereals and legumes.

Eating soft cooked foods requires less, chewing which in turn lessened the size of the jaws.

However, instead of the farmers’ jaws and teeth simply being smaller versions of their ancestors’, the jaws reduced in size while the teeth kept the same dimensions.

Without adequate space for the teeth in the mouths of farmers, this led to malocclusion – the misalignment of teeth - and dental crowding.

Today, malocclusion and dental crowding affects around one in five people in modern-world populations.

‘Our analysis shows that the lower jaws of the world's earliest farmers in the Levant are not simply smaller versions of those of the predecessor hunter-gatherers, but that the lower jaw underwent a complex series of shape changes commensurate with the transition to agriculture,’ said Professor Pinhasi. 

‘Our findings show that the hunter gatherer populations have an almost ‘perfect harmony’ between their lower jaws and teeth,’ he explained. 

‘But this harmony begins to fade when you examine the lower jaws and teeth of the earliest farmers’.

The findings are published in the journal Plos One.

Last year, separate research, covering a period of more than 7,000 years of human evolution, revealed modern-day skeletons are lighter and more fragile than those belonging to our hunter-gatherer ancestors.

In fact, the bones of our early ancestors were comparable in strength to modern orangutans, but once farming spread, these bones became 20 per cent weaker. 

(dailymail.co.uk)