Association between dietary fiber and lower risk of all-cause mortality: a meta-analysis of cohort studies

Although in vitro and in vivo experiments have suggested that dietary fiber might have beneficial effects on health, results on the association between fiber intake and all-cause mortality in epidemiologic studies have been inconsistent. Therefore, we conducted a meta-analysis of prospective cohort studies to quantitatively assess this association. Pertinent studies were identified by searching articles in PubMed and Web of Knowledge through May 2014 and reviewing the reference lists of the retrieved articles. Study-specific risk estimates were combined using random-effects models. Seventeen prospective studies (1997-2014) that had a total of 67,260 deaths and 982,411 cohort members were included. When comparing persons with dietary fiber intakes in the top tertile with persons whose intakes were in the bottom tertile, we found a statistically significant inverse association between fiber intake and all-cause mortality, with an overall relative risk of 0.84 (95% confidence interval: 0.80, 0.87; I(2) = 41.2%). There was a 10% reduction in risk for per each 10-g/day increase in fiber intake (relative risk = 0.90; 95% confidence interval: 0.86, 0.94; I(2) = 77.2%). The combined estimate was robust across subgroup and sensitivity analyses. No publication bias was detected. A higher dietary fiber intake was associated with a reduced risk of death. These findings suggest that fiber intake may offer a potential public health benefit in reducing all-cause mortality.