Chew like a caveman for good teeth

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Our jaws these days are too small to accommodate our teeth because instead of chewing on sticks of dried meat, we eat a diet of soft, processed foods. Picture: Denzil Maregele

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London - Feeling guilty about that latest filling? It may not be all your fault - the food you’re eating is just too mushy. You should have chewed on a bit of dried meat like our ancient ancestors.

This was the suggestion that emerged from a recent conference, Evolution Of Human Teeth And Jaws: Implications For Dentistry And Orthodontics, in North Carolina in the US.

Experts - including evolutionary biologists, food scientists and dental researchers - noted that our diet is so different from our ancestors’ that dental health problems such as cavities, overbite and crooked or crowded teeth are inevitable.

The conclusions were based on studies of ancient teeth, explains Simon Hillson, professor of bioarchaeology at University College London, who was there. “Teeth are tough and survive particularly well - providing us with a wealth of anthropological data.”

“Not only are there exceptionally well-preserved examples of fossilised human ancestors available, we’ve been able to examine the teeth of people such as the Aboriginals and Kalahari bushmen who ate a hunter-gatherer diet like our pre-agricultural ancestors as recently as the 1950s.”

The shift from hunter-gatherers to farmers, which started 13,000 years ago, is central to our modern dental problems. As it spread throughout the world our food became softer, so we didn’t need to chew as much.

This has a direct effect on the development of our jaws, which are now smaller - too small to accommodate all our teeth.

“Our diets once consisted of everything in raw form - such as seeds, nuts, vegetables, meat and fruit,” explains Professor Jimmy Steele, head of the School of Dental Sciences at Newcastle University. “Now it consists of foods that are often highly processed, pre-packaged, soft and full of sugar.”

Our food is so soft in relation to what it was that our teeth are actually redundant, says Dr Nigel Carter of the British Dental Health Foundation. “Shocking though it might sound, I’d say that apart from the necessity of teeth for appearance and speech, we probably no longer need them.”

The arrival of sugar in Britain, at the start of the 19th century, also had a notable effect, adds Dr Carter: “From that point, the state of our teeth plummeted.”

Here, we reveal how common dental problems are linked to our caveman past - and what you can do about them...

OVERBITE

THIS is where the teeth and jaw do not fit together in a normal way. Malocclusion, as it is also known, is a common problem - a third of 12-year-olds in the UK suffer from some sort of malocclusion, and it’s why so many children today need orthodontic work.

In ancient humans, however, problems such as overbite were rare. A study of 94 skeletons from Amarna, Egypt, the ancient capital of Pharaoh Akhenaton (who reigned from 1353BC to 1333BC) showed their teeth were well-aligned.

“This occurred because the Egyptians had a relatively coarse diet - lots of gritty foods and fibre,” says Professor Steele. “Chewing and the length of time required to eat these foods may have helped with the development of the jaws in childhood, ensuring little overbite.”

Chewing may stimulate growth of the alveolar bone - the thickened ridge of bone our teeth sit in - making it bigger.

OVERCROWDED TEETH

There should be 32 teeth in the human mouth, including four wisdom teeth. However, the average number is only 25.7, according to the Department of Health.

Often teeth are taken out because of lack of space. Wisdom teeth, which appear between the ages of 18 and 25, are frequently removed for this reason. So why is the modern jaw so small?

“Partly it’s because the effort required for our ancestors to rip apart meat and chew on coarse grain led to big, strong mandibular bones [lower jaws] that could accommodate all the teeth,” says Dr Carter.

Some experts believe changing habits in breastfeeding may also contribute. In one study comparing 370 skulls of prehistoric North American Indians with skulls from the 1920s to the 1940s, the prehistoric skulls had broad palates (the roof of the mouth) and properly aligned teeth. Modern skulls had malocclusions, missing teeth and other structural problems. It’s thought baby bottles and dummies were to blame.

Breastfeeding helps because the sucking action draws the nipple and surrounding area into the mouth while extending the tongue over the lower gum. This improves the shape of the hard palate, helping to produce properly aligned teeth.

Evidence suggests early humans breastfed until about three or four years of age.

Today, just 18 percent of women still breastfeed at nine months, according to the 2005 Infant Feeding Survey.

GUM DISEASE

Swollen, sore or infected gums are a major problem, with half the adult population affected to some degree. Yet again the problem was hardly seen in prehistoric Man. In a study of 23 individuals from Taiwan dating from 1800BC to 500BC, there were virtually no cavities or gum disease. Gum disease occurs when plaque, formed by bacteria, builds up leading to inflammation.

“A lack of coarse grains, tough meat and stringy vegetables are again the reason why gum disease is more prevalent nowadays,” says Dr Carter. “These foods act as a natural toothbrush, so with less in our diet, plaque builds quickly.”

Saliva (which contains calcium and phosphate) remineralises the teeth and restores the acid balance in the mouth.

CAVITIES

In our ancestors’ time, dental cavities were a problem of old age. Indeed, in fossils of ancient humans “you can count the cases of dental cavities on one hand,” says Professor Hillson.

But tooth decay is now one of the most widespread health problems in the UK - with 55 percent of adults having one or more decayed teeth. Many under-15s already have some decay in their adult teeth.

The increase is being put down to the emergence of farming.

Cultivating crops means people started to consume more grains and carbohydrates, rather than nuts, meat and vegetables.

“Food high in carbohydrates leads to the bacteria in your mouth producing acid, which dissolves the tooth,” explains Philip Marsh, professor of oral microbiology at Leeds Dental Institute.

But the greatest change occurred when we started eating pure sugar.

“Prior to the 18th century sugar was a luxury, but post-1800s - when Britain took control of the West Indies and started to import considerably more sugar than previously - it became more widely available,” says Dr Carter.

“As a result, so did terrible teeth full of cavities.”

WHAT TO DO

“Some US experts believe orthodontic work, to correct these problems, could be started earlier,” says Professor Steele - as early as four years old.

Eating tougher meat and coarse grain to build bigger jaws has also been suggested. But that would take centuries to have an effect.

“It’s better to eat a wide variety of foods and cut down on sugar,” says Dr Carter. “And if you crave fizzy drinks, drinking them ice-cold can help. Acids produced by bacteria in the mouth in reaction to cold drinks damage teeth less. And use a straw to ensure teeth have less contact with the sugar.” - Daily Mail

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