In an attempt to keep their weight down, many people skip whole grains completely. This is perfectly fine if you eat enough fruits and vegetables to provide an adequate fiber intake. Unfortunately if you don’t get the fiber you need you may be increasing your risk of colorectal cancer (CRC), the third most common form of cancer in the U.S.

In a study of 1575 patients with stage I to III colorectal cancer, higher intake of fiber, especially from cereals, was associated with a lower risk of colorectal cancer–specific and overall mortality. Patients who increased their fiber intake after diagnosis from levels before diagnosis showed better survival; higher intake of whole grains was also associated with favorable survival. The study was conducted from December 23, 2016, to August 23, 2017.

Fiber helps to minimize exposure to intestinal carcinogens by diluting fecal content and decreasing transit time and also has systemic benefits on insulin sensitivity and metabolic regulation, which have been linked to CRC prognosis. Moreover, fiber can be fermented by the gut bacteria into short-chain fatty acids, such as butyrate, acetate, and propionate, that possess a diversity of tumor-suppressive effects.

Reference:
https://jamanetwork.com/journals/jamaoncology/fullarticle/2661061