BACKGROUND: Gallstone disease is a widespread condition affecting the gastrointestinal tract, and poor diet is believed to be one of the reasons for its occurrence. Previous studies of dietary fiber intake and gallstones have limitations. The study's goal is to investigate the relationship between dietary fiber intake and gallstone prevalence in US adults. MATERIALS AND METHODS: Data from NHANES 2017 to March 2020 is used for the study. The association between fiber intake and gallstone prevalence was analyzed using multivariate logistic regression. To confirm the results' robustness, we performed sensitivity analyses also. RESULTS: Among the 6,051 U.S. adults aged over 20 with complete information, the prevalence of gallstones was 10.8 % (651/6051). After adjusting for relevant covariates, an increase in fiber intake of 5 g/day was associated with an 11 % decrease in the prevalence of gallstones (fully adjusted OR = 0.89, 95 % CI: 0.83-0.95). Participants were divided into high (>
25 g/d) and low (≤25 g/d) fiber intake groups. Still significant negative association between dietary fiber intake and gallstones (fully adjusted OR = 0.66, 95 % CI: 0.49-0.91). Further dividing dietary fiber intake level into quintiles sustained this negative relationship, particularly showing the lowest gallstone occurrence in the highest dietary fiber group (OR = 0.63, 95 % CI: 0.44-0.91). While the stratified analyses indicated variability in the relationship between dietary fiber intake and the prevalence of gallstones, no interactive effects were identified in this association according to the interaction analysis. CONCLUSIONS: This study confirms that dietary fiber intake is negatively associated with the prevalence of gallstones. Sufficient dietary fiber intake might protect from gallstones. In order to formulate dietary recommendations, it is important to carry out prospective studies to validate the observed associations.