Intake of dietary fiber, especially from cereal foods, is associated with lower incidence of colon cancer in the HELGA cohort

Abstract

The role of dietary fiber on the risk of colon and rectal cancer has been investigated in numerous studies, but findings have been inconsistent. The purpose of this study was to examine associations between intake of dietary fiber and risk of incident colon (including distal and proximal colon) and rectal cancer in the prospective Scandinavian HELGA cohort and to determine if fiber source (vegetables, fruits, potatoes, cereals) impacted the association. We included 1,168 incident cases (691 colon, 477 rectal cancer), diagnosed during a median of 11.3 years, among 108,081 cohort members. Sex-specific incidence rate ratios (IRRs) of colon and rectal cancer were related to intake of total or specific fiber source using Cox proportional hazards models. For men, an inverse association was observed between intake of total fiber and the risk of colon cancer per an incremental increase of 10 g day 21, IRR (95% CI): 0.74 (0.64-0.86). Intake of cereal fiber per 2 g day 21 was associated with an IRR of 0.94 (0.91-0.98), which was also seen for intake of cereal fiber from foods with high fiber content (!5 g per 100 g product), where the IRR per 2 g day 21 was 0.94 (0.90-0.98). In women, intake of cereal fiber per 2 g day 21 was also associated with lower risk of colon cancer, 0.97 (0.93-1.00). No clear associations were seen for rectal cancer. Our data indicate a protective role of total and cereal fiber intake, particularly from cereal foods with high fiber content, in the prevention of colon cancer.

How can the Nordic experience be used for nutrition in the future?

“…Some of the studies included in HELGA suggest that dietary fiber and whole grain intake are associated with lower risk of colorectal cancer. (32)(33)(34) Furthermore, associations were found between adherence to a healthy Nordic diet and lower mortality rate. (35,36) Association between intakes of whole grain and risk of type 2 diabetes is now under investigation and the results are expected in 2015.…”

Cancer incidence attributable to insufficient fibre consumption in Alberta in 2012

“…Furthermore, the use of Alberta's Tomorrow Project data to estimate fibre consumption levels meant that the longer latency periods suggested by large cohort studies between fibre consumption and colorectal cancer incidence could not be explored. [10][11][12] For this reason, if a longer latency period represented a more biologically relevant window for exposure, and fibre consumption levels in Alberta in the more distant past were higher or lower than those captured among cohort members, estimates of population attributable risk could have been either over-or underestimated.…”

“…Follow-up times from assessment of fibre consumption at baseline to case ascertainment in published cohort studies ranged from 6 to 20 years. [10][11][12] Because detailed information on fibre consumption in Alberta by both sex and age group was only available from the Alberta's Tomorrow Project data, this data source was selected and the mean latency period set at 8 years for data collected between 2000 and 2009. …”

“…Furthermore, the use of Alberta's Tomorrow Project data to estimate fibre consumption levels meant that the longer latency periods suggested by large cohort studies between fibre consumption and colorectal cancer incidence could not be explored. [10][11][12] For this reason, if a longer latency period represented a more biologically relevant window for exposure, and fibre consumption levels in Alberta in the more distant past were higher or lower than those captured among cohort members, estimates of population attributable risk could have been either over-or underestimated.A strength of this analysis was the use of Monte Carlo methods that incorporated variation associated with estimates of RR and exposure prevalence to produce 95% CIs to quantify the precision of population attributable risk estimates. However, these CIs are relatively wide and indicate that although we estimate an excess 114 cases of colorectal cancer in Alberta due to insufficient fibre consumption, the true number could be as low as 11 or as high as 146.…”

The use of laser Doppler blood flow to assess the effect of acute administration of vitamin D on micro vascular endothelial function in people with diabetes

“…Coenzyme Q10 and vitamins A, C, and E reduce free radicals in the blood [11,12]. In the past 40 years an important vitamin that has been investigated is vitamin D [13].…”