Researchers affiliated with the NIH-AARP Diet and Health Study have reported that individuals who consume a diet that is rich in vegetables, fruits, whole grains, and healthy oils, contains sufficient dietary calcium and vitamin D, and is low in solid fats, added sugar, and red meats have a significantly reduced risk of developing colorectal cancer. These results were recently published in the July 1, 2008 issue of the American Journal of Epidemiology.

Most studies have shown that an increased intake of red and processed meats is associated with an increased incidence of colorectal cancer. Increased dietary fiber has been more controversial with both positive and negative studies reported. Fat intake does not seem to be an adverse risk factor, but obesity is clearly a risk factor. There has been very little convincing data that vitamin supplementation affects colorectal cancer, and there is the suspicion that natural foods are more preventive than artificial vitamins. A recent Nurses’ Health Study (NHS) has shown that women who were in the highest quartile of fruit and vegetable consumption had a significant reduction in the risk of developing colorectal adenomas. However, a pooled analysis of 14 cohort studies has shown that a higher intake of fruits and vegetables does not appear to reduce the risk of colon cancer (see first item of related news).

Researchers affiliated with the National Cancer Institute recently conducted a clinical study to further evaluate the potential associations between diet and rates of colorectal cancer among individuals involved in the NIH-AARP Diet and Health Study. The study included approximately 500,000 individuals who completed questionnaires regarding their dietary habits.

Overall, individuals, and men in particular, who ate more fruits, vegetables, healthy fats, and whole grains while minimizing consumption of red meat, added sugars, and oils had a significantly reduced risk of developing colorectal cancer. The risk reduction for colorectal cancer was 28% when comparing the highest intake of fruits, vegetables, health fats and whole grains with the lowest consumption of such items.

The researchers concluded that “dietary patterns that are consistent with given dietary guidelines are associated with reduced risk” of colorectal cancer. These results provide further data indicating that diets focused on consumption of fruits, vegetables, and whole grains may reduce disease.

Comments: Although studies are not consistent in regard to fruits and vegetables, it would appear that a “healthy diet” may decrease the risk of colorectal cancer.

Related News:

No Clear Link between Fruit and Vegetable Intake and Colon Cancer Risk (10/5/2007)

Red and Processed Meat Consumption Increases Risk of Colorectal Cancer (6/17/2005)

Red Meat Consumption Increases Risk of Colorectal Cancer (1/21/2005)

Selenium Levels Associate with Risk of Recurrent Polyps (1/5/2005)

Low-Fat Diet Does Not Reduce Colorectal Cancer Risk (2/21/2006)

Antioxidant Vitamins May Not Prevent GI Cancers (10/8/2004)

High Dietary Intake of Calcium and Milk Associated with Lower Risk of Colorectal Cancer (7/15/2004)

Calcium and Vitamin D Supplementation May Not Prevent Colorectal Cancer (3/6/2006)

Beer and Alcohol Spirits Increase Risk of Colorectal Neoplasia (9/19/2005)

Reference: Reedy J, Mitrou P, Krebs-Smith S, et al. Index-based dietary patterns and risk of colorectal cancer. American Journal of Epidemiology. 2008; 168:38-48.