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Sniffing danger

CHOCOLATE could one day help prevent tooth cavities, say researchers in
Japan. They have found that parts of the cocoa bean, the main ingredient of
chocolate, thwart mouth bacteria and stop dental decay.

Tooth cavities start when Streptococcus mutans bacteria produce a sticky
molecule called glucan. This helps the bacteria anchor themselves to teeth and
form plaque. These and other bacteria in plaque convert sugars to acids, which
eat away the tooth’s surface and lead to cavities.

Chocolate is not as bad for teeth as many other sweet foods. Scientists
believe that antibacterial agents in cocoa beans offset its high sugar levels.
Now Takashi Ooshima and his colleagues at Osaka University in Japan have found
that cocoa bean husk (CBH)—the outer part of the bean, which usually goes
to waste in chocolate production—is a more potent source of these
agents.

When the group added CBH extract to S. mutans it blocked glucan production.
What’s more, rats given CBH in their drinking water had healthier teeth. After 3
months, rats that were infected with S. mutans and fed with a high-sugar diet
had 14 cavities on average—but those fed CBH had no more than six.

Ooshima thinks the results could lead to new treatments for tooth decay. “It
may be possible to use CBH extract in a mouthwash—or supplement it to
toothpaste.” It could even be put back into chocolate to make it better for
teeth, he says. The group now plans to test CBH on human teeth.

David Beighton at the Guy’s, King’s & St Thomas’ Dental Institute in
London thinks that the active substances in CBH are also found in other
plants—like chewing sticks used in Africa. “They certainly do have
effects,” says Beighton. But good oral hygiene, rather than eating lots of
chocolate, is the way to healthy teeth, he adds.

  • Source: Archives of Oral Biology (vol 45, p 639)