On 2013 Oct 11, Hilda Bastian commented:

This review could not take into account lifestyle factors that often accompany healthier diets and lower risk of cancer, such as not smoking. Studies like those analyzed here probably aren't enough to establish that a nutrient can prevent disease: Moorthy D, 2013. In the case of fiber and colorectal cancer, a systematic review of randomized trials (Asano T, 2002) did not find a reduction of colorectal cancer either from fiber supplements or dietary intake as in, for example, the large National Cancer Institute trial: Schatzkin A, 2000. This trial evidence is not discussed in this review by Aune and colleagues. Anyone interested in this subject would be better off starting with the systematic review of trials and trials on fiber and resistant starch published since then: Ishikawa H, 2005, Burn J, 2011. Further discussion here.

On 2013 Oct 11, Hilda Bastian commented:

This review could not take into account lifestyle factors that often accompany healthier diets and lower risk of cancer, such as not smoking. Studies like those analyzed here probably aren't enough to establish that a nutrient can prevent disease: Moorthy D, 2013. In the case of fiber and colorectal cancer, a systematic review of randomized trials (Asano T, 2002) did not find a reduction of colorectal cancer either from fiber supplements or dietary intake as in, for example, the large National Cancer Institute trial: Schatzkin A, 2000. This trial evidence is not discussed in this review by Aune and colleagues. Anyone interested in this subject would be better off starting with the systematic review of trials and trials on fiber and resistant starch published since then: Ishikawa H, 2005, Burn J, 2011. Further discussion here.