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Modern diet to blame for dental problems
Our need for braces on our teeth could be down to our ancestors' switch from a hunter-gathering lifestyle to farming, a study suggests.
Modern diet to blame for dental problems
Nick Collins
By Nick Collins, Science Correspondent
8:00PM GMT 21 Nov 2011
Our soft food diet may be causing our jaws to grow too short and small relative to the size of our teeth, meaning our mouths are too crowded.
Comparisons of skulls from 11 different human populations spread across the globe show that those with hunter-gatherer lifestyles grew longer and narrower jaws.
Those with a more modern lifestyle who did not have to chew so much would have put less pressure on the jaw, explaining why theirs were shorter and wider, researchers said.
Although almost all the world's communities now have agricultural rather than hunter-gatherer ways of life, the changes could be seen in skulls from Inuit populations from Greenland and Alaska within the last 200 years.
In Britain it is likely to have occurred much earlier, with the development of farming coming about 5,000 years ago.
Dr Noreen von Cramon-Taubadel of Kent University, who led the research, published in the Proceedings of the National Academy of Sciences journal, said the global nature of the study showed that while features such as skull size are genetic, the variation in jaw size was down to eating habits.
She said: "The jaw is very plastic so depending on your individual behaviour it changes shape during childhood growth and development.
"There have been suggestions that changing children's chewing behaviour could have a dramatic effect on the shape of their lower jaw."
Separate animal studies have shown that a change from hard to soft food reduces lower jaw size by about ten per cent.
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