People who eat more than 160 grams of red or processed meat a day are 35 percent more likely to develop bowel cancer than those who eat less than 20 grams a day, according to one of the biggest nutrition investigations ever carried out.

The European Prospective Investigation into Cancer and Nutrition (EPIC) followed 478,040 men and women aged 35 to 70 from 10 European countries.

All subjects were free of cancer at enrollment between 1992 and 1998, but after an average follow-up of almost 5 years 1,329 Colorectal cancer had been reported.

The subsequent analysis, published in the Journal of the National Cancer Institute, confirms the long-held suspicion that high intakes of red meat are associated with increased bowel cancer risk.

After factoring in age, sex, height, weight, energy intake, physical activity, Smoking, dietary fibre, folate, and alcohol consumption, the investigators found that bowel cancer was associated with intake of red and processed meat but not chicken.

Risk of Colorectal cancer dropped with increasing intake of fish. Eating more than 80 grams a day of fish was associated with a 31 percent reduction in risk compared with eating less than 10 grams a day.

Subjects with high red meat and low fish intake were at 63 percent higher risk of bowel cancer compared with subjects with low red meat and high fish intake. In addition, the risk of developing the disease was increased for those people who ate a low fibre diet.

Sheila Bingham, study investigator at the UK’s Medical Research Council nutrition unit, said: “People have suspected for some time that high levels of red and processed meat increase risk of bowel cancer, but this is one of the largest studies worldwide and the first from Europe of this type to show a strong relationship.”

She added in a statement: “The overall picture is very consistent for red and processed meat and fibre across all the European populations studied.”

Study coordinator, Elio Riboli, of the World Health Organisation International Agency for Research into Cancer, said: “Other risk factors for bowel cancer include obesity and lack of physical activity. Smoking and excess alcohol may also play a role. These factors were all taken into account in the analysis.”

Professor Tim Key, Deputy Director of Cancer Research UK’s epidemiology unit, said: “We estimate that more than two thirds of colorectal cancer cases - 25,000 cases in the UK - could be avoided by changes in lifestyle in Western countries.”

SOURCE: Journal of the National Cancer Institute, June 15, 2005.