Dietary fiber, especially whole grains, may reduce the risk of colorectal cancer

Pour yourself a nice big bowl of whole-grain cereal. A study finds that diets high in fiber, particularly from cereal and whole grains, may reduce the risk of colon cancer.

The study, released online today in the British Medical Journal, is a meta-analysis of 25 studies that examined the relationship between dietary fiber and colorectal cancer, the third most common type of cancer diagnosed among men and women in the U.S., according to the American Cancer Society.

Previous studies have shown that dietary fiber may decrease colorectal cancer risk, but the authors of this study said it’s not apparent whether certain types of fiber are key. After analyzing these papers they found that for every 10 grams of dietary fiber and cereal fiber there was a 10% reduced risk of colorectal cancer. Three servings of whole grains daily, or 90 grams (about three ounces), was associated with a 20% reduced risk. Eating more fiber took the risk down even more.

No link was seen between eating more fruits and vegetables and colorectal cancer risk, although in a previous meta-analysis an association was noted. This suggests that some other factors could influence cancer risk.

Why whole grains? They may help flush carcinogens out of the body quickly, reducing the time they spend in the colon. Whole grains also contain beneficial antioxidants, vitamins and minerals, and eating more of them may also help weight control and lessen the risk of type 2 diabetes, also risk factors for colorectal cancer.