Dietary fiber intake and total and cause-specific mortality: the Japan Public Health Center-based prospective study

Background: An inverse association has been shown between dietary fiber intake and several noncommunicable diseases. However, evidence of this effect remains unclear in the Asian population. Objective: We examined the association between dietary fiber intake and all-cause and cause-specific mortality, as well as the association between fiber intake from dietary sources and all-cause mortality. Methods: We conducted a large-scale population-based cohort study (Japan Public Health Center-based prospective study). A validated questionnaire with 138 food items was completed by 92,924 participants (42.754 men and 50.170 women) aged 45-74 y. Dietary fiber intake was calculated and divided into quintiles. HR and 95% CI of total and cause-specific mortality were reported. Results: During the mean follow-up of 16.8 y, 19,400 deaths were identified. In multivariable adjusted models, total, soluble, and insoluble fiber intakes were inversely associated with all-cause mortality. The HRs of total mortality in the highest quintile of total fiber intake compared with the lowest quintile were 0.77 (95% CI: 0.72, 0.82; P-tr(end) <0.0001) in men and 0.82 (95% CI: 0.76, 0.89; P-tr(end) <0.0001) in women. Increased quintiles of dietary fiber intake were significantly associated with decreased mortality due to total cardiovascular disease (CVD), respiratory disease, and injury in both men and women, whereas dietary fiber intake was inversely associated with cancer mortality in men but not women. Fiber from fruits, beans, and vegetables, but not from cereals, was inversely associated with total mortality. Conclusion: In this large-scale prospective study with a long follow-up period, dietary fiber was inversely associated with all-cause mortality. Since intakes of dietary fiber, mainly from fruits, vegetables, and beans were associated with lower all-cause mortality, these food sources may be good options for people aiming to consume more fiber.