A daily portion of dark chocolate could reduce the risk of oral cancer by almost a quarter.
Scientists discovered that the treat stops the formation of deadly oral tumors thanks to cancer-fighting chemicals found in the cocoa used to make it.
Peppers had a similar effect, but one study found that eating other vegetables, fruits or vitamins provided no benefit, despite their reputation as cancer fighters.
In England alone, more than 10,000 people are diagnosed with oral cancer every year and around 3,600 people die from it every year.
Rates have risen by almost 40 percent in a decade – and by 140 percent in the past two decades – and the disease now kills more people in Britain than road accidents.
It is thought that 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 oral 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 nearly 10,000 volunteers – about a third of whom had been diagnosed with oral cancer.
Scientists have found that eating dark chocolate stops the formation of deadly mouth tumors 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 cancer-fighting effects
They wanted to see if there were links between types of food and the risk of developing 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 of ten different food and drink categories, only dark chocolate and peppers showed signs of protecting against oral tumors, reducing the risk by 22 percent and 26 percent respectively.
Unlike heavily processed milk chocolate, dark chocolate is rich in natural plant compounds that have cancer-fighting effects.
But the study didn’t measure how much chocolate volunteers ate, only that it was a regular part of their diet.
The authors said: ‘We found that dark chocolate and paprika had an inhibitory effect on the development of oral cancer.’
A separate study published in the British Medical Journal suggested that dark chocolate can reduce the risk of developing type 2 diabetes by almost a fifth.
Researchers from Harvard University found that the food was associated with a lower risk of the disease, while those who ate milk chocolate were more likely to gain weight.