Healthnotes Newswire (January 11, 2001)—Women who suffer from constipation have no higher risk of forming precancerous colon polyps than do other women, according to a recent report from the Harvard-based Nurses’ Health Study (NHS).¹ NHS researchers believe their findings suggest that constipation does not increase the risk of colon cancer.

The NHS tracked 17,400 women for approximately 12 years. None of the women had a history of colon cancer or precancerous polyps. Women reporting that they had only one bowel movement every third day were at no greater risk of forming a polyp than were women who reported having frequent bowel movements. Similarly, the use of laxatives, a marker for constipation, was unrelated to the risk of developing precancerous colon polyps during the course of the study.

Since the nineteenth century some people have viewed constipation as the culprit behind many diseases—particularly diseases of the colon. In the 1970s, scientists came to believe that Africans rarely had colon cancer because high-fiber diets protected them from constipation.^{2 3} Constipation was thought to increase the amount of time cancer-causing substances within the intestines could work their mischief.

While earlier reports supported a link between fiber and colon cancer-protection, recent studies have suggested that avoidance of eating meat—not consumption of fiber—is primarily responsible for the link between certain diets (including African diets) and a reduced risk of colon cancer.^{4 5 6} The new NHS report fits well with the findings of these recent studies. It further suggests that fiber may not be protective, because most of the protection against colon cancer that fiber was believed to confer resulted from its ability to alleviate constipation. A protective role for fiber seems increasingly unlikely given that constipation does not appear to increase the risk of precancerous colon polyps.