A report released Monday by an international team of researchers says there’s convincing evidence that eating too much red meat and processed meat raises colorectal cancer risk and that consuming plenty of fiber in the form of plant-based foods reduces that risk.
The World Cancer Research Fund and American Institute for Cancer Research together produce the Continuous Update Project, which gathers research about various forms of cancer, updating its database every few years. For this report, scientists at Imperial College London conducted a review of published studies and ended up adding 263 new papers about colorectal cancer to the 749 that had been analyzed for the last report, issued in 2007. After that, an expert panel analyzed all the collected evidence regarding the relationships between diet, weight and physical activity and colorectal cancer.
The report notes that there is “convincing evidence” that:
• Red meat, processed meat, excess body fat and fat carried around the waist increase risk of colorectal cancer.
• Regular physical activity reduces risk of colorectal cancer.
• Foods containing dietary fiber, such as fruits, vegetables, whole grains and beans, reduce risk of colorectal cancer; garlic probably does, too, though the evidence for this isn’t as strong.
• Alcohol increases colorectal cancer risk in men. For women, it probably increases risk.
Red meats studied in the survey included beef, lamb and pork. Processed meats included foods such as ham, bacon and sausage as well as sandwich meats like pastrami and salami.
The report further finds that calcium-rich milk probably reduces colorectal cancer risk and that dietary supplements containing calcium also probably reduce cancer risk, but that in general it is more beneficial to get such nutrients from foods, not supplements.
According to the U.S. Centers for Disease Control and Prevention, among cancers affecting both men and women colorectal cancer is the second leading cause of cancer death in the United States, as it is in Maine. Nationwide, 142,672 people were diagnosed with the disease in 2007, and 53,219 people died from it. Men are at higher risk than women, and risk in both men and women increases with age.