Low dietary fiber diet does not reduce risk for adhesive small bowel obstruction development: self-controlled study

Adhesive small bowel obstruction (ASBO) is a major postoperative complication with no established methods of prevention. ASBO is a form of mechanical obstruction caused by intra-abdominal adhesions that lead to kinking or twisting of the small intestine. Although low-fiber diets are occasionally recommended for post-abdominal surgery patients, their efficacy in preventing ASBO remains unclear. This study aimed to investigate whether a low-fiber diet reduces the risk of ASBO. A self-controlled case-crossover study was conducted on patients with ASBO admitted to an acute care hospital in Japan between April 2017 and March 2022. Conditional logistic regression modeling was used to compare fiber intake between 24 h before ASBO onset (case period) and 5–8 weeks earlier (control periods). The mean age of the 40 enrolled patients (160 control period cases) was 82 years and 19 were women. Median dietary fiber intake during the case period was 12.3 g/day (interquartile range [IQR] 10.0–16.5 g/day), compared to 12.9 g/day (IQR 9.5–16.5 g/day) during control periods (p = 0.78). Among the patients, 25% were on a low-fiber diet (< 10 g/day) during both case and control periods. Multivariable conditional logistic regression adjusting for potential time-dependent confounders likewise found no association between dietary fiber intake and ASBO development (odds ratio 1.00, 95% confidence interval 0.90–1.11). Potential high-fiber ingredients intake showed no significant differences between case and control periods. This study found no evidence to support low-fiber diets for preventing ASBO in post-abdominal surgery patients. Restricting dietary fiber content may not be needed to prevent ASBO especially in older patients following abdominal surgery.