Fruit is a good source of fibre

"We placed the 400,000 people on the study into five sets according to their consumption of fibre.

"Of the 400,000, 470 have developed colorectal cancer since joining the study. The group eating the most fibre reduced their risk of colorectal cancer by as much as 40%."

People taking part in the study recorded their consumption of foods - either by keeping diaries, as in the UK, or answering questionnaires on their eating habits.

Their consumption of fibre - from fruit and vegetables, cereals and wholegrain foods - was then recorded in grammes.

No distinction was made between different types of food or fibre.

Those who were at lowest risk of cancer consumed half as much again as the average.

Wide-ranging nature

Professor Nick Day, who also heads the Epic team at the CRC lab in Cambridge, said the European study is likely to avoid the mistakes of some earlier research because of its wide-ranging nature.

These findings put fibre firmly back on the menu as an important part of a healthy diet

Professor Gordon McVie

He said: "There have been reports recently that appear to suggest fruit and vegetable consumption isn't important in reducing the risk of colorectal cancer.

"But they have been based on much narrower studies. For example, a study looking at the diet of nurses in the US found there was no benefit in eating fibre.

"But this is an homogenous group with very similar habits.

"The people recruited for Epic have much greater variations in their eating habits. This wide-ranging study is likely to give us a much truer picture of the links between diet and cancer."

Professor Gordon McVie, CRC director general, said: "These findings are extremely important because of the sheer scope of the Epic study.

"They put fibre firmly back on the menu as an important part of a healthy diet, and vindicate our defence of fibre, when others were saying its benefits were at best limited, and at worst, inconclusive.

"We should all now aim to include wholegrain bread and cereals as well as the recommended five portions of fruit and vegetables in our daily diet."

Meats

Other preliminary results presented to the conference show an increased risk of colon cancer with total consumption of preserved meats, such as ham, bacon and salami, and a significant reduction of the same risk with fish consumption.

Eating red meat seems currently to be weakly associated with the risk of developing colorectal cancer, but there are further analyses to be carried out.

Follow-up is in progress and these first results need to be interpreted with caution.

The study findings were presented to a conference on nutrition and cancer organised by the International Agency for Research on Cancer.