Researchers affiliated with the Nurses’s Health Study (NHS) have reported that women who were in the highest quartile of fruit and vegetable consumption had a significant reduction in the risk of developing colorectal adenomas.

Diet is clearly an important factor in the development of colorectal cancer. This is apparent from the divergent incidence in different cultures where the main variable is diet. However, the exact food products associated with a decreased or increased incidence of colorectal cancer is controversial.

Most studies have shown that 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 preventative than artificial vitamins. The current study would tend to substantiate this.

These researchers looked at the association between fruit and vegetable intake and the prevalence and incidence of adenomas of the distal colon. They used data from over 34, 000 women in the NHS who had undergone colonoscopy or sigmoidoscopy between 1980 and 1998 and correlated these findings with dietary histories. They found that frequent consumption of fruit was associated with a 40% reduction in the incidence of polyps (5 or more servings a day). They also found that vegetable consumption was associated with a 38% reduction in the incidence of polyps (5 or more servings of per day). They also reported that eating 4 or more servings of legumes per week was associated with a 33% reduction in the incidence of polyps.