Colorectal cancer, cancer that affects the large
intestine, is among the most common cancers to affect people worldwide. The
environment plays a role in determining the risk for colorectal cancer. This is
evident from the fact that if people from areas with lesser incidence of
colorectal cancer move into areas where it is more common and adopt their diet
and lifestyle, the incidence of colorectal cancer in this migrant population
becomes similar to that of the new place.
Diet, especially red and processed meat, and
alcohol, have been shown to be associated with colorectal cancer. On the other hand, dietary fiber lowers the
risk of colorectal cancer
. Dietary fiber could protect against colorectal
cancer by increasing bulk of stools and diluting any cancer causing substances
in the digestive tract. It also enhances clearance, thus reducing the contact
time of any cancer causing substances with the digestive tract. Dietary fiber
gets converted into short chain fatty acids, which protect against colorectal
cancer. However, which fibers are likely to provide benefit is not clearly
are not only a good source of dietary fiber, but also contain antioxidants,
vitamins, minerals, phytate, phenolic acids, lignans and phytoestrogens which
may contribute to their anticancer effect. They also contain large amounts of
folate and magnesium, which have known anticancer effects. Their ability to
reduce weight and improve insulin resistance may also play a role in reducing cancer
A group of reviewers analyzed 21 previously
published studies with more than 14,500 cases to establish the role of dietary
fiber and whole grains in preventing the development of cancer. They found that there was a 10% reduction
in risk of developing colorectal cancer for each 10 g/day intake of total
dietary fiber and cereal fiber and about a 20% reduction for each three
servings (90 g/day) of whole grain daily. Further reductions in risk were
observed with higher intake.
The study thus found that dietary fiber, cereal
fiber and whole grains do reduce the risk for developing colorectal cancer.
However, fibers from other sources like fruits,
vegetables and legumes do not appear to show the same beneficial effect.
Thus, a diet
consisting of high fiber and whole grains does appear to reduce the risk of
. Besides, these foods also provide other health benefits. They contribute in preventing heart
disease, diabetes, obesity and improve chances of survival.
Thus, food rich
in fiber and whole grains should definitely be a part of your daily diet.
1. Dietary fibre, whole grains, and risk of colorectal cancer:
systematic review and dose-response meta-analysis of prospective studies; BMJ
2011; 343 doi: 10.1136/bmj.d6617 (Published 10 November 2011).