Effects of the bread containing resistant starch from wheat (Triticum aestivum) on the improvement in bowel movements: a randomized, double-blind, placebo-controlled, crossover study.

This study aimed to evaluate the gut-regulating effects of wheat-derived resistant starch. A randomized, double-blind, placebo-controlled crossover study was conducted with 46 healthy Japanese adults. They were divided into 2 groups, consuming 3.26 g/day of wheat-derived resistant starch and a control food for 4 weeks each, separated by a 4-week washout period. There were no significant differences observed in the primary endpoint of defecation frequency. However, subgroup analysis showed significant improvements in bowel movements for participants who felt a strong sensation of incomplete evacuation. No gut-regulating effects were noted in other subgroups and secondary endpoints. The intake of 3.26 g/day of resistant starch was safe with no overall efficacy observed. Increased stool frequency was observed in participants with less frequent bowel movements and a strong feeling of incomplete evacuation, but no effects were confirmed in other subgroup analyses. No significant changes were observed at secondary endpoints (UMIN ID: UMIN000052543).