The most comprehensive and authoritative report on colon cancer risk ever published concludes that red and processed meat increases risk of the disease and high-fiber foods offer protection.
Dr. Anne McTiernan of the Public Health Sciences Division served on the nine-member expert panel that reviewed the evidence on colon cancer risk factors.
“This report shows that colon cancer is one of the most preventable cancers,” said Dr. Elisa Bandera, who served on the World Cancer Research Fund/American Institute for Cancer Research’s Continuous Update Project (CUP) expert panel that authored the report. “AICR has estimated that about 45 percent of colon cancer cases could be prevented if we all ate more fiber-rich plant foods and less meat, drank less alcohol, moved more and stayed lean. That’s over 64,000 cases in the U.S. every year.”
The report, released May 23, examined the links between colon cancer risk and diet, physical activity and weight, and updated the organization’s 2007 expert report. WCRF/AICR-funded scientists at Imperial College London systemically reviewed the evidence in 263 new papers on colon cancer, adding to the 749 analyzed for the last report.
Meat link remains convincing
For red and processed meat, findings from 24 studies led the panel to conclude that there is convincing evidence that both red and processed meat increase colon cancer risk.
AICR recommends that people limit consumption to 18 ounces (cooked weight) of red meat a week—roughly the equivalent of five or six small portions of beef, lamb or pork—and avoid processed meat. The report showed that ounce for ounce, consuming processed meat increases risk twice as much as consuming red meat.
Fiber’s protective role upgraded
The expert panel also concluded that the evidence showing that foods containing dietary fiber reduce colon cancer risk has become stronger since the publication of the 2007 report. They considered the evidence of 15 studies sufficient to strengthen the conclusion that foods containing fiber are protective from “probable” to “convincing.”
This reaffirms AICR’s recommendation for people to eat a plant-based diet, including foods containing fiber, such as whole grains, fruits, vegetables and beans.
Evidence on activity, body weight, alcohol still convincing
The experts concluded that studies published since 2007 add to the evidence that maintaining a healthy weight and being physically active are both convincingly linked to lowering colon cancer risk. The panel also affirmed that carrying excess fat— especially around the waist—is a convincing cause of colon cancer. There is also convincing evidence that alcohol consumption increases colon cancer risk in men and it also probably increases risk in women.
AICR fosters research on the relationship of nutrition, physical activity and weight management to cancer risk, interprets the scientific literature and educates the public about the results. It has contributed more than $96 million for research conducted at U.S. universities, hospitals and research centers.
[Adapted from an AICR news release]