A daily portion of dark chocolate could cut the risk of mouth cancer by almost a quarter.
Scientists found the treat stops the formation of deadly oral tumours thanks to cancer-fighting chemicals found in the cocoa used to make it.
Sweet peppers had a similar effect but a study showed no benefit from eating other vegetables, fruits or vitamins – despite their anti-cancer reputations.
More than 10,000 people a year in England alone are diagnosed with mouth cancer and around 3,600 a year lose their lives to it.
Rates have risen by almost 40 per cent in a decade – and 140 per cent in the past 20 years – and the disease now kills more people in the UK than road accidents.
It’s thought increased alcohol consumption – a major trigger – could be one factor but tobacco is also a serious risk for the disease.
Hollywood legend Michael Douglas was diagnosed with stage 4 mouth cancer in 2010.
He underwent radiotherapy and chemotherapy and is now free of the disease.
Researchers from Youjiang Medical University in Guangxi, China, studied the eating habits of almost 10,000 volunteers – around a third of whom had been diagnosed with mouth cancer.
Scientists found eating dark chocolate stops the formation of deadly oral tumours thanks to cancer-fighting chemicals found in the cocoa used to make it
Unlike heavily-processed milk chocolate, dark chocolate is rich in natural plant compounds that have anti-cancer effects
They wanted to see if there were links between types of food and the chances of getting the disease.
Researchers looked at everything from tea, coffee and chocolate to cooked vegetables, fresh fruit and oily fish.
The results, published in the journal Frontiers In Nutrition, showed that out of ten different food and drink categories only dark chocolate and sweet peppers displayed signs of protecting against mouth tumours, reducing the risk by 22 per cent and 26 per cent respectively.
Unlike heavily-processed milk chocolate, dark chocolate is rich in natural plant compounds that have anti-cancer effects.
But the study did not measure how much chocolate volunteers ate, only that it was a regular part of their diet.
The authors said: ‘We found dark chocolate and sweet pepper had an inhibitory effect on the development of mouth cancer.’
A separate study, published in the British Medical Journal, suggested dark chocolate can cut the risk of developing type 2 diabetes by nearly a fifth.
Researchers from Harvard University found the food was associated with a lower risk of the disease while those who ate milk chocolate were more likely to gain weight.
