"Instead of looking at insulin we measured glycated haemoglobin “ a marker of blood glucose levels over the past few months “ which is likely to be a good indicator of metabolic processes that influence insulin levels," she says.

"Understanding these metabolic changes, and the lifestyle factors responsible, may help us to prevent and treat cancer."

Prof Robert Souhami, Director of Clinical and External Affairs, says: "Colorectal cancer is one of most common cancers and is the second most common cause of cancer death. This puts it at the top of the research agenda and any information that helps formulate prevention strategies is welcome."

*(1) Cancer Epidemiology and Biomarkers: Vol 13; No. 6*(2) glycated haemoglobin*(3)The EPIC study began in 1992 and is looking prospectively at the diets of 400,000 men and women aged 45 “ 74 years in nine European countries. Extensive social, medical and lifestyle information is being collected as well as biological samples.

There are around 35,600 cases of bowel cancer diagnosed each year in the UK. More than 80 per cent of cases are in people over 60. In Britain male incidence rates have increased by an average of 1 per cent each year over the last 20 years. But in women rates have changed little. Around two-thirds of cases of colorectal cancer may be preventable by changes in diet. Bowel cancer incidence is generally lower in populations with high fibre, low fat diets rather than "westernised" diets.