SMOKERS may increase their chances of contracting colon cancer by eating fruit and vegetables, according to a new Europe-wide scientific study says.

A high intake of fruit and vegetables appeared to reduce the risk among non-smokers but seemed to have the reverse effect on smokers, findings by the Dutch National Institute for Public Health and the Environment (RIVM) showed on Wednesday.

"People who eat 600 grams or more vegetables and fruit a day appear to have a 20 to 25 per cent lower chance of developing colon cancer than people who eat 220 grams or less," said the statement.

"For smokers, the consumption of vegetables and fruit appears, on the contrary, to increase the chances of colon cancer. Protection against colon cancer through the consumption of vegetables and fruit therefore appears to depend on smoking habits."

RIVM official Hans Verhagen told AFP this did not mean that smokers should stop eating their greens.

"On the contrary, the conclusion is to: 'Please stop smoking'", he said.

The research project questioned some 500,000 people in 10 European countries about their eating and smoking habits and studied them for 8.5 years.

The authors of the final article published in the American Journal for Clinical Nutrition, said the findings meant that substances within fruit and vegetables may even increase the carcinogenic potential of tobacco smoke.

"What is new about this study is that we have for the first time examined the effects of fruit and vegetable consumption while making a distinction between smokers and non-smokers," said Verhagen.

Colon cancer is the second-most common form of the disease in the Netherlands, after breast cancer, with 11,000 new cases diagnosed every year.