Dietary fiber

Suggested

8 studies · 1 recommendation

Last updated: February 25, 2026

Suggested8 studies

Higher dietary fiber intake linked to 15-30% lower colorectal cancer risk

Eight studies spanning cohort, case-control, systematic review, and umbrella review designs—covering over 135 million person-years and hundreds of thousands of participants—consistently demonstrate fiber's protective role against colorectal cancer. An umbrella review of 185 prospective studies found a 15-30% reduction in colorectal cancer incidence among the highest fiber consumers, with optimal benefit at 25-29 g/day and potential gains at higher intakes. A large cohort study (137,217 participants) linked a fiber-rich prudent diet to a 57% lower risk of F. nucleatum-positive colorectal cancer (HR 0.43, 95% CI 0.25-0.72). Case-control data from over 9,200 cases confirmed fiber's independent protective effect, while a Danish case-cohort study showed a 27% risk reduction per 10 g/day increase (IRR 0.73, 95% CI 0.60-0.88). Fiber promotes butyrate production, supporting colonic epithelial integrity and counteracting carcinogenic bacterial metabolites. Targeting at least 25-29 g of daily fiber through vegetables, fruits, whole grains, and legumes offers meaningful colorectal cancer risk reduction.

Evidence

Latin American and the Caribbean Code Against Cancer 1st edition : Weight, physical activity, diet, breastfeeding, and cancer

Authors: Aburto, T.C., Barnoya, J., Barquera, S., Canelo-Aybar, C., Cavalcante, T.M., Corvalán, C., Espina, C., Feliu, A., Hallal, P.C., Reynales-Shigematsu, L.M., Rivera, J.A., Romieu, I., Santero, Marilina, Stern, M.C., Universitat Autònoma de Barcelona

Published: January 1, 2023

The consensus statement establishes fiber as protective against colorectal cancer based on comprehensive evidence review. The recommendation to eat plenty of vegetables, fruits, whole grains, and legumes collectively addresses fiber intake. These fiber-rich foods form the foundation of the cancer-preventive dietary pattern endorsed by the Latin American and Caribbean Code Against Cancer for the general public.

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The burden of colon cancer attributable to modifiable factors—The Norwegian Women and Cancer Study

Authors: Borch, Kristin Benjaminsen, Laaksonen, Maarit A., Licaj, Idlir, Lukic, Marko, Rylander, Charlotta, Weiderpass, Elisabete

Published: August 22, 2022

Among 35,525 women in the NOWAC cohort study, low intake of dietary fiber was identified as a modifiable risk factor contributing to colon cancer incidence, though its individual population attributable fraction was described as small compared to smoking (18.7%, 95% CI 4.7%-30.6%) and alcohol (14.5%). Fiber intake was one of seven modifiable lifestyle factors assessed using a parametric piecewise constant hazards model with competing risk of death, which jointly explained 46.0% (95% CI 23.0%-62.4%) of colon cancer cases in this Norwegian female population.

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Carbohydrate quality and human health:a series of systematic reviews and meta-analyses

Authors: Cummings, John, Mann, Jim, Mete, Evelyn, Reynolds, Andrew, Te Morenga, Lisa, Winter, Nicola

Published: February 2, 2019

Pooled analysis of 185 prospective studies with nearly 135 million person-years showed a 15-30% decrease in colorectal cancer incidence when comparing highest versus lowest dietary fibre consumers. Dose-response analysis indicated greatest risk reduction at 25-29g/day, with curves suggesting higher intakes could confer even greater benefit against colorectal cancer specifically. The striking dose-response evidence indicated the relationship could be causal. Evidence certainty was graded as moderate for dietary fibre using the GRADE approach. Estimates from random-effects models were robust through sensitivity analyses and meta-regression.

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Dietary Patterns and Risk of Colorectal Cancer Subtypes Classified by Fusobacterium nucleatum in Tumor Tissue

Authors: Bullman, Susan, Cao, Yin, Chan, Andrew T., Drew, David A., Fuchs, Charles S., Fung, Teresa T., Garrett, Wendy S., Giovannucci, Edward L., Hamada, Tsuyoshi, Huttenhower, Curtis, Kostic, Aleksandar D., Kosumi, Keisuke, Masugi, Yohei, Mehta, Raaj S., Meyerhardt, Jeffrey A., Mima, Kosuke, Nishihara, Reiko, Nowak, Jonathan A., Ogino, Shuji, Qian, Zhi Rong, Song, Mingyang, Willett, Walter C., Wu, Kana, Zhang, Xuehong

Published: July 1, 2018

Among 137,217 participants followed for 26–32 years with 1,019 documented colorectal cancer cases, dietary component analyses revealed significant differential associations between colorectal cancer subgroups based on dietary fiber intake (Pheterogeneity = .02). Fiber was a key component of the prudent dietary pattern that achieved a 57% risk reduction (HR 0.43, 95% CI 0.25–0.72) for F. nucleatum-positive colorectal cancer when comparing the highest to lowest quartile of prudent diet adherence.

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Interactions between meat intake and genetic variation in relation to colorectal cancer

Authors: Andersen, Vibeke, Vogel, Ulla

Published: December 10, 2014

In the context of this systematic review examining meat-gene interactions and CRC risk across 239 initially identified records from PubMed and Embase, high dietary fiber intake is cited as a recognized protective factor against colorectal cancer based on the World Cancer Research Fund 2014 evaluation of observational and experimental evidence. The biological rationale includes fiber's role in promoting butyrate production — the primary energy source for colonocytes — which is suppressed by hydrogen sulphide generated from meat protein fermentation by colonic bacteria such as Bilophila Wadsworthia. Meat-derived organic sulphur compounds fuel sulphate-reducing bacteria, increasing colonic H2S that impairs butyrate oxidation and induces intestinal hyperproliferation. Dietary fiber may counteract these mechanisms by supporting healthy microbial fermentation and maintaining colonic epithelial integrity.

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Genome-Wide Diet-Gene Interaction Analyses for Risk of Colorectal Cancer

Authors: A Tenesa, AD Skol, AH Nguyen, AL Price, AM Nomura, Andrew T. Chan, Anja Rudolph, AY Liu, B Mukherjee, B Woolf, Barbara Fortini, Bette J. Caan, Brent W. Zanke, Brian E. Henderson, BW Zanke, C Kooperberg, Carolyn M. Hutter, CC Dahm, CE Murcray, Christopher I. Amos, Christopher S. Carlson, CJ Hoggart, CL Pearce, CM Hutter, Conghui Qu, Cornelia M. Ulrich, Daniela Seminara, David Duggan, DD Alexander, DD Alexander, Deanna L. Stelling, E Giovannucci, Edward L. Giovannucci, Emily White, F Dudbridge, FJ van Duijnhoven, Fredrick R. Schumacher, GA Colditz, GP Christophi, Graham Casey, Greg S. Warnick, H Brenner, Hermann Brenner, I Fortier, I Ionita-Laza, I Pe'er, I Tomlinson, IP Tomlinson, J Chou, J Lin, Jane C. Figueiredo, JC Figueiredo, Jenny Chang-Claude, Jian Gong, John A. Baron, John D. Potter, John L. Hopper, JY Dai, JY Dai, K Roeder, Kana Wu, Keith R. Curtis, KR Rosenbloom, L Hsu, Laurence N. Kolonel, Li Hsu, Loic Le Marchand, M Cotterchio, M Hedlund, M Hoffmeister, Mark A. Jenkins, Mark Thornquist, Martha L. Slattery, Mathieu Lemire, Michael Hoffmeister, Michelle Cotterchio, ML Slattery, N Risch, NJ Ollberding, P Broderick, PA Newcomb, PC Prorok, Peter T. Campbell, Polly A. Newcomb, QJ Wu, R Siegel, R Zheng, RB Gupta, Richard B. Hayes, Robert E. Schoen, Robert W. Haile, RS Houlston, S Jiao, S Kury, Shuo Jiao, SN Bennett, Sonja I. Berndt, Stephanie A. Rosse, Stephen J. Chanock, Stephen N. Thibodeau, Steven Gallinger, T Hosoya, Tabitha A. Harrison, U Peters, Ulrike Peters, W. James Gauderman, WG Christen, WH Jia, WJ Gauderman, WW Piegorsch, Y Park, Yi Lin

Published: January 1, 2014

In a case-control study of 9,287 colorectal cancer cases and 9,117 controls from ten studies, per quartile increment in fiber intake was associated with statistically significant lower risk of colorectal cancer. The genome-wide interaction analysis tested dietary factors against approximately 2.7 million genetic variants, confirming fiber's protective association in the overall pooled analysis across multiple study populations.

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Interaction between interleukin-10 (IL-10) polymorphisms and dietary fibre in relation to risk of colorectal cancer in a Danish case-cohort study

Authors: Andersen, Vibeke, Egeberg, Rikke, Tjonneland, Anne, Vogel, Ulla Birgitte

Published: January 1, 2012

In a Danish case-cohort study nested within a prospective cohort of 57,053 persons (378 CRC cases, 775 subcohort members), IL10 rs3024505 homozygous wildtype carriers had a 27% reduced risk of colorectal cancer per 10 g fiber per day (IRR 0.73, 95% CI: 0.60-0.88). Significant interaction was observed between IL10 C-592A and fiber intake (P for interaction = 0.02). Among those consuming less than 17.0 g fiber per day, carriers of the C-592A variant allele had statistically significantly higher CRC risk compared to wildtype homozygotes. No significant risk difference was observed between wildtype carriers eating less than 17.0 g/day and variant allele carriers consuming 17.0 g/day or more, suggesting higher fiber intake offsets the genetic risk increase.

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A case-control study on environmental and familial risk factors for colorectal cancer in Hong Kong: dietary determinants of colorectal cancer risk

Authors: Ho, JWC, Lam, TH, Yuen, ST

Published: January 1, 2006

In this case-control study of 822 cases and 926 controls, increasing tertiles of daily crude fibre intake were associated with progressively reduced colorectal cancer risk on univariate analysis, with significant protection for both colon and rectal cancer subsites. On multivariate analysis adjusting for demographic, familial, environmental, and nutritional confounders, crude fibre emerged as an independent protective nutrient specifically against colon cancer, alongside copper. It is a key component of the protective effect observed for fruit and vegetable consumption.

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