Different Sources of Fiber Intake and Risk of 17 Specific Cancers and All Cancers Combined: Prospective Study of 364,856 Participants in UK Biobank

Abstract

Abstract Inverse associations between dietary fiber (DF) and colorectal cancer risk are well-established. However, evidence is limited in relation to other cancer sites. This study, of 364,856 participants from UK Biobank, aimed to evaluate the associations between total and source-specific partial DF and risk of 17 specific cancers and all cancers combined. Partial DF was derived from baseline touch-screen questionnaire data on cereal, bread, fruit and vegetable intake. The outcomes were incident cancer at 17 sites and all cancers combined. Cox proportional hazard models were applied. Over a median 8.8-year follow-up period, 30,725 people were diagnosed with cancer. After adjusting for sociodemographic and lifestyle factors, those in the highest quintile of DF compared to the lowest quintile (<9.6 vs ≥19.1 g/day) had 10% lower risk of cancer overall, with the greatest risk reductions observed for cervical (HR: 0.33, 0.14; 0.82), esophageal (HR: 0.66, 0.52; 0.84), lung (HR: 0.67, 0.59; 0.76), bladder (HR: 0.72, 0.56; 0.91) and kidney (HR: 0.75, 0.61; 0.92) cancers. Associations between DF and lung cancer were observed only in current and ex-smokers. Higher dietary fiber intake, in particular cereal fiber and fruit and vegetable fiber, was associated with a lower risk of overall and multiple site-specific cancers.