Dietary fiber intake is inversely correlated with incident stroke risk and stroke-related all-cause mortality, according to findings published in Stroke.

Using data from the National Health and Nutrition Examination Survey, researchers examined the associations and causal relationships between dietary fiber intake and stroke in adults. Logistic regression models, Kaplan-Meier analysis, Cox regression models, and Mendelian randomization were employed for statistical analysis.

A total of 39,010 participants were included in the study, of whom mean (SE) age was 47.10 (0.21) years, 50.24% were men, and 46.87% were Non-Hispanic White. Mean (SE) dietary fiber intake was 16.64 (0.12) g/day. Dietary fiber intake was categorized into tertiles:

  • T1, ≤10.9 g/day
  • T2, 10.9-18.3 g/day
  • T3, ≥18.3 g/day

Overall, 3.73% (n=1455) of participants reported a physician-confirmed diagnosis of stroke. A lower prevalence was observed among those with low vs high dietary fiber intake (T1, 4.74%; T2, 3.55%; T3, 2.87%). Of the participants with stroke, 1453 (mean [SE] age, 63.52 [0.62] years) were included in a survival analysis. This cohort was more likely to be older, women, have a higher education level, earn a middle income, and consume tobacco and alcohol. Mean (SE) dietary fiber intake was 14.33 (0.31) g/day.

Collectively, our findings demonstrate an inverse association between dietary fiber intake and stroke, highlighting its importance in stroke prevention and management.

Dietary fiber intake as a continuous variable was negatively associated with stroke (odds ratio [OR], 0.98; 95% CI, 0.97-0.99; P <.0001). As a categorical variable, dietary fiber intake demonstrated a protective effect against stroke across statistical models. Multivariate analysis confirmed a stable, linear inverse association between dietary fiber intake and stroke risk.

Further, greater dietary fiber intake was significantly associated with reduced all-cause mortality among those with stroke. After adjusting for patient characteristics, those in T2 and T3 had a 23% and 32% reduction in risk for all-cause mortality, respectively, compared with T1 (P =.04 for both). Additional analysis showed a statistically significant difference in rates of all-cause mortality between the high and low fiber-intake groups, with higher fiber intake linked to improved survival (P =.02325).

Subgroup analysis showed a consistent inverse relationship between dietary fiber intake and stroke incidence across demographics, lifestyle habits, and disease conditions (P >.05 for most); significant interactions were documented between fiber intake and both smoking status and education level (P =.04 for both).

Moreover, Mendelian Randomization demonstrated a significant association between increased dietary fiber intake and decreased risk for small vessel stroke (OR, 0.8326; 95% CI, 0.7051-0.9833).

Study limitations include a genome-wide analysis using primarily European population data, and a lack of differentiation between fiber sources.

“Collectively, our findings demonstrate an inverse association between dietary fiber intake and stroke, highlighting its importance in stroke prevention and management,” the authors wrote.