Dietary fibre to reduce colon cancer risk in Alaska Native people: the Alaska FIRST randomised clinical trial protocol

Dietary fibre to reduce colon cancer risk in Alaska Native people: the Alaska FIRST randomised clinical trial protocol

IntroductionDiet, shown to impact colorectal cancer (CRC) risk, is a modifiable environmental factor. Fibre foods fermented by gut microbiota produce metabolites that not only provide food for the colonic epithelium but also exert regulatory effects on colonic mucosal inflammation and proliferation....

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Bibliographic Details
Published in:BMJ open Vol. 11; no. 8; p. e047162
Main Authors: Koller, Kathryn R, Wilson, Annette, Normolle, Daniel P, Nicholson, Jeremy K, Li, Jia V, Kinross, James, Lee, Flora R, Flanagan, Christie A, Merculieff, Zoe T, Iyer, Priya, Lammers, Daniela L, Thomas, Timothy K, O'Keefe, Stephen J D
Format: Journal Article
Language:English
Published: England BMJ Publishing Group LTD 27-08-2021
BMJ Publishing Group
Series:Protocol
Subjects:
Age
Alaska
Alaska Natives
Bile
Biomarkers
Body mass index
Clinical trials
Colonic Neoplasms - prevention & control
Colonoscopy
Colorectal cancer
COVID-19
Data collection
Diet
Dietary Fiber
Disease
Gastroenterology and Hepatology
Humans
Metabolism
Metabolites
Microbiota
Randomized Controlled Trials as Topic
Alaska
United States > US
bacteriology
gastroenterology
nutrition & dietetics
public health
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Summary:IntroductionDiet, shown to impact colorectal cancer (CRC) risk, is a modifiable environmental factor. Fibre foods fermented by gut microbiota produce metabolites that not only provide food for the colonic epithelium but also exert regulatory effects on colonic mucosal inflammation and proliferation. We describe methods used in a double-blinded, randomised, controlled trial with Alaska Native (AN) people to determine if dietary fibre supplementation can substantially reduce CRC risk among people with the highest reported CRC incidence worldwide.Methods and analysesEligible patients undergoing routine screening colonoscopy consent to baseline assessments and specimen/data collection (blood, urine, stool, saliva, breath and colon mucosal biopsies) at the time of colonoscopy. Following an 8-week stabilisation period to re-establish normal gut microbiota post colonoscopy, study personnel randomise participants to either a high fibre supplement (resistant starch, n=30) or placebo (digestible starch, n=30) condition, repeating stool sample collection. During the 28-day supplement trial, each participant consumes their usual diet plus their supplement under direct observation. On day 29, participants undergo a flexible sigmoidoscopy to obtain mucosal biopsy samples to measure the effect of the supplement on inflammatory and proliferative biomarkers of cancer risk, with follow-up assessments and data/specimen collection similar to baseline. Secondary outcome measures include the impact of a high fibre supplement on the oral and colonic microbiome and biofluid metabolome.Ethics and disseminationApprovals were obtained from the Alaska Area and University of Pittsburgh Institutional Review Boards and Alaska Native Tribal Health Consortium and Southcentral Foundation research review bodies. A data safety monitoring board, material transfer agreements and weekly study team meetings provide regular oversight throughout the study. Study findings will first be shared with AN tribal leaders, health administrators, providers and community members. Peer-reviewed journal articles and conference presentations will be forthcoming once approved by tribal review bodies.Trial registration numberNCT03028831.
ISSN:2044-6055
2044-6055
DOI:10.1136/bmjopen-2020-047162