Red meats and processed meats like bacon, salami and sausage are strongly associated with bowel cancer, according to the most authoritative study ever on the issue.
The report by the World Cancer Research Fund/American Institute for Cancer Research’s Continuous Update Project examined an extra 10 studies to the 14 already reviewed as part of a literature review released in 2007.
The review panel concluded there was a strong link between red meat consumption and bowel cancer, advising that people eat no more than 500g of cooked red meat per week – around five or six medium serves of roast beef, lamb or pork. Eating an extra 100g per day of red meat increases bowel cancer risk by 17%, the panel found.
Processed meats like ham, smoked meats, hot dogs and other popular deli choices should be avoided altogether, they found. Eating an extra 100g per day of processed meat increases bowel cancer risk by 36%, boosting the average person’s risk of bowel cancer from five in 100 to seven in 100.
Being overweight and carrying excess abdominal fat also increases the risk of bowel cancer, while boosting fibre and garlic intake and exercise can reduce the risk, they found.
Ian Olver, CEO of the Australian Cancer Council and a clinical professor at the University of Sydney, said all the evidence pointed to the same conclusion.
“When everything lines up in the same direction, you can be more definitive in your advice. They have strengthened the reason for their recommendations that we should cut down our intake of red meat as part of a balanced diet,” he said, adding that barbecuing meat was particularly bad because it increases the amount of carcinogens ingested compared to slow-cooked meat.
The fattiness of deli meats and marbled meats appear to be the prime reason for the increase in bowel cancer risk, he said.
“But as for cutting it out altogether, it is difficult to take that step completely,” he said. “People tend to react adversely to people wanting to ban things. People should have to strike that balance for themselves.”