Low dietary fiber intake as a major risk factor for colorectal cancer: evidence from integrated multidatabase analyses

This study investigated the causal relationship between low dietary fiber intake and colorectal cancer (CRC) risk, and quantified the global disease burden attributable to low-fiber diets using Web of Science, GWAS Open, and the Global Burden of Disease (GBD) databases. Bibliometric analysis of Web of Science publications on 'low-fiber diet' and 'colorectal cancer' revealed that clinical research in this field is heavily informed by molecular and genetic evidence, with emerging hotspots focused on immune-metabolic mechanisms. Bidirectional Mendelian randomization analysis demonstrated that higher dietary fiber intake confers a protective effect against CRC, with risk declining progressively as fiber intake increases (inverse-variance weighted odds ratio = 0.249, 95% confidence interval: 0.083-0.744, P < 0.05). Pleiotropy and outlier assessments further corroborated this protective association, whereas reverse Mendelian randomization showed no evidence of causality in the opposite direction. Analyses based on the GBD database revealed substantial variation in CRC burden attributable to low-fiber diets across age, sex, and geographic subgroups. Collectively, these findings indicate that insufficient dietary fiber is a major modifiable risk factor for CRC, and that the global health burden associated with low-fiber diets remains considerable.