“…The types of DF were fiber, 3,8,22–24,26,27,29,30,33,37–40 probiotic, 25,28,31,34–36 and fiber combined with probiotics 32 . The DF supplement doses <20 and ≥20 g were used in 13 studies 22,24,27,28,30–35,37,39,40 and eight studies, 3,8,23,25,26,29,36,38 respectively. Eleven studies did not report the results of adverse outcomes of DF supplement, 23–26,28,30,31,34–36,39 and six studies showed no significant difference in adverse outcomes between the DF group and fiber‐free group 3,22,27,29,33,40 .…”