Scientists find cocoa can cut tooth decay

Chocolate may be rehabilitated from its place as an enemy of children's teeth - and future versions may even make teeth healthier.

The reason? Cocoa beans contain antibacterial agents which offset the sugar content and reduce the chance of decay, Japanese researchers report in New Scientist magazine.

The problem is that the useful chemicals in the cocoa beans are predominantly in the husk, which is normally thrown away. But Takashi Ooshima and colleagues at Osaka University found that husk extracts could be used in mouthwash or toothpaste to fight tooth decay.

Teeth begin to rot when the common bacteria Streptococcus mutans secrete a sticky molecule called glucan, which helps them anchor themselves to teeth, and so form a layer of plaque. In that plaque, the bacteria convert sucrose molecules into acid which attacks the enamel.

The Japanese team added an extract from the husk to a culture of the bacteria and found that it blocked production of glucan. They then added the extract to the drinking water of laboratory rats and found that it halved the rate of tooth decay. After three months, rats infected with the bacteria and fed a high sugar diet had 14 cavities on average. But those given the cocoa extracts had no more than six.

Dr Ooshima said: "It may be possible to use cocoa extract in a mouthwash, or supplement it to toothpaste."

It could also be added to chocolate confectionery to make it better for teeth.

David Beighton, from the Guy's, King's and St Thomas's Dental Institute in London, thought the agents in the cocoa extract were also found in other plants, such as the chewing sticks used in Africa.

"They certainly do have effects," he said. But, he said, good oral hygiene was a much better route to healthy teeth than eating chocolate.

The British Dental Association said: "Our advice remains the same: if people want to eat sugary sweets, they should limit them to meal times."

- INDEPENDENT