Association between dietary fiber intake and stroke among American adults: National Health and Nutrition Examination Survey 1999–2023

Background: Stroke is a significant cause of disability and mortality. Dietary fiber has been shown to mitigate the occurrence of various stroke risk factors. Objectives: Our study aims to evaluate the correlation between dietary fiber intake and stroke among adults in the United States. Methods: We analyzed data from people over 20 years old who took part in the National Health and Nutrition Examination Survey between 1999 and 2023. The main analytical methods utilized in this study were multivariable logistic regression, stratified analysis with interaction, restricted cubic splines, and threshold effect analysis. Results: There were 42,290 participants, among whom 3.9% (1632/42,290) were diagnosed with stroke. Compared with Q1, the adjusted OR values for dietary fiber intake and stroke in Q2, Q3, and Q4 were 0.88 (95% confidence interval [CI]: 0.77–1.01, P = 0.077), 0.72 (95% CI: 0.62–0.85, P < 0.001), and 0.67 (95% CI: 0.55–0.81, P < 0.001), respectively. The association between dietary fiber intake and stroke exhibited an L-shaped curve (nonlinear, P = 0.011). In the threshold analysis, the OR of developing stroke was 0.974 (95% CI: 0.963–0.986, P < 0.001) in participants with fiber intake <26.0 g/day (rounded to the nearest whole number). There was no significant association between dietary fiber intake and stroke when the dietary fiber intake was ≥26.0 g/day. Conclusion: The link between dietary fiber intake and stroke in US adults is L-shaped, with an inflection point of roughly 26.0 g/day. Appropriately increasing dietary fiber consumption may help lower the incidence of stroke.