Prof Key and co-authors Dr Kathryn Bradbury and Dr Neil Murphy studied the diets of nearly half a million British men and women, aged 40 to 69 when the research began, over more than five years – during which time 2,609 of them developed bowel cancer.
Existing evidence points to an increased bowel cancer risk for every 50g of processed meat a person eats per day, but this research found that risk increases at just 25g per day, showing a similar rise in risk at smaller intervals. This is one of the largest single studies in the field and one of few to measure meat quantities and associated risks so precisely.
Dr Julie Sharp, Cancer Research UK’s head of health information, said: “The government guidelines on red and processed meat are general health advice and this study is a reminder that the more you can cut down beyond this, the more you can lower your chances of developing bowel cancer.
“This doesn't necessarily mean cutting out red and processed meat entirely, but you may want to think about simple ways to reduce how much you have and how often. Although breaking habits we’ve had for a long time can be hard, it’s never too late to make healthy changes to our diet. You could try doing meat free Mondays, looking for recipes using fresh chicken and fish, or swapping meat for pulses like beans and lentils in your usual meals.”