A University of Oxford study discovered that participants who ate four servings of red meat a week were 42 percent more likely to develop colorectal cancer than those who had one serving or none at all. Participants who ate red meat at least twice a week were 18 percent more likely to develop colorectal cancer than vegetarians.
The study, which will be presented Tuesday at a conference for the National Cancer Research Institute, tracked the meat-eating habits of more than 500,000 British men and women aged 40 to 69. (Researchers didn’t quantify the amount of each serving — they only tracked how often people ate meat.)
Surprisingly, the research did not find a link between eating processed meats and an increased risk of colorectal cancer, though the World Health Organization (WHO) identified processed meats as a “known human carcinogen” last week, citing one of the top reasons as its link to colorectal cancer. The WHO experts concluded that each 50-gram portion of processed meat (less than 2 ounces) eaten daily increases the risk of colorectal cancer by 18 percent.
According to the American Cancer Society, colorectal cancer is the third most common cancer diagnosed in men and women in the U.S. More than 93,000 Americans will be diagnosed with colon cancer in 2015 and nearly 40,000 will be diagnosed with rectal cancer, the organization says.
Lead study author Kathryn Bradbury, PhD, a nutritional epidemiologist at the University of Oxford, tells Yahoo Health that there may be a few compounds in red meat that explain the link with bowel cancer.
“Cooking meat produces heterocyclic aromatic amines (HAA), which are suspected carcinogens,” she says. “Red meat also contains haem iron and, when eaten, this leads to the formation of N-nitroso-compounds (NOC), which again are suspected to be carcinogenic.”
The message is simple, Bradbury says: If you’re big on eating red meat, it’s a good idea to cut back.