People who eat red and processed meat four or more times a week have a higher risk of developing bowel cancer than those who eat red and processed meat less than twice a week, according to a study jointly funded by Cancer Research UK and published in the International Journal of Epidemiology.

Scientists have shown that people eating around 76g of red and processed meat a day - which is roughly in line with government recommendations - still had a 20% higher chance of developing bowel cancer than those who only ate about 21g a day.

One in 15 men and 1 in 18 women born after 1960 in the UK will be diagnosed with bowel cancer in their lifetime. This study found that risk rose 20% with every 25g of processed meat (roughly equivalent to a rasher of bacon or slice of ham) people ate per day, and 19% with every 50g of red meat (a thick slice of roast beef or the edible bit of a lamb chop).

Cancer Research UK’s expert in diet and cancer, Professor Tim Key, who co-authored the study and is deputy director at the University of Oxford’s cancer epidemiology unit, said: “There’s substantial evidence that red and processed meat are linked to bowel cancer, and the World Health Organisation classifies processed meat as carcinogenic and red meat as probably carcinogenic – but most previous research looked at people in the 1990s or earlier, and diets have changed significantly since then, so our study gives a more up-to-date insight that is relevant to meat consumption today.”

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 the few to measure meat quantities and associated risks so precisely.

Dr Lisa Wilde, Director of Research and External Affairs of Bowel Cancer UK, added: “This interesting study adds to a growing body of evidence highlighting the link between red and processed meat, and bowel cancer. The findings underline the importance of cutting back on these foods as part of maintaining a healthy lifestyle.

“Bowel cancer is the fourth most common cancer in the UK, with almost 42,000 people diagnosed every year. Making simple changes to your lifestyle can help stack the odds against bowel cancer. As well as avoiding processed foods, like bacon, ham and salami and limiting our intake of red meat, increasing our intake of wholegrains and pulses, being of a healthy weight, cutting down on alcohol, taking more exercise, and stopping smoking will make a real difference to our health in general.”