The Role of Fiber in the Treatment of Irritable Bowel Syndrome

Abstract

Irritable bowel syndrome is a common clinical condition that often presents a therapeutic challenge. There is no standard therapy and a multilevel approach is recommended. A high-fiber diet is often one of these components. Many investigators have studied the effectiveness of either fiber supplementation or bulking agents in patients with irritable bowel syndrome. The purpose of this review is to summarize the current literature on the use of fiber in irritable bowel syndrome and to provide some specific recommendations. Systematic reviews of these trials have generally not found fiber to be significantly more effective than placebo at relieving global irritable bowel syndrome symptoms. There may be differences between results obtained with soluble and insoluble fiber. Adverse effects of fiber use may include abdominal discomfort and bloating. Although dietary fiber or bulking agents do not appear to be useful as sole treatment of irritable bowel syndrome, they may have a limited role in empiric therapy depending upon the patient's symptom complex, especially if constipation is the most significant symptom. The basic principles for using fiber therapy are to start with a low dose and increase slowly, to give an adequate trial and to evaluate the results early and periodically.

Probiotic Fermented Milk Containing Dietary Fiber Has Additive Effects in IBS with Constipation Compared to Plain Probiotic Fer-mented Milk

“…It seems to be due to main mechanism of action of fiber, which accelerates oro-anal transit and decrease the intra-colon pressures. 18 Although for urgency there was a little difference between subtypes, in the constipation predominant subtype only fermented milk group showed significant improvement differently from other subtypes. Kim et al 6 reported that VSL#3 had no effect in urgency in which didn't analyze as subtypes.…”

“…Although dietary fiber does not appear to be useful as the sole treatment for IBS, fiber appears to play a role in the management of some patients with IBS, especially if constipation is the dominant concern. [16][17][18] The two types of fiber, soluble and insoluble, have different effects on global IBS related symptoms. Insoluble fiber in probably no better than placebo.…”

“…However, there may be a limited role for the careful use of dietary fiber or bulking agents, in the management of some patients with IBS, especially in those with the constipation dominant form. 18 Therefore, in this study, we evaluated the effects of Streptococcus thermophilus, Lactobacillus acidophilus and Bifidobacterium infantis in patients with IBS, and evaluated whether supplementary dietary fiber had an additive effect in patients with constipation-predominant IBS.…”

Updates on treatment of irritable bowel syndrome

“…The proposed mechanism for fiber is a decrease in intra-colonic pressures and an acceleration of oroanal transit [135,136] though results from studies on transit times are conflicting [137,138] . There have been a number of trials evaluating the effectiveness of fiber, but many have methodological limitations including small sample sizes, short follow-up periods, selection bias, and lack of welldefined endpoints [123,139] . In a recent systematic review of 17 randomized controlled trials examining the role of fiber in the treatment of IBS, Bijkerk et al found only a minimal improvement in overall relief of IBS global symptoms (RR 1.33; 95% CI, 1.19-1.50), and found no evidence that fiber reduces abdominal pain [140] .…”

Constipation Is Relieved More by Rye Bread Than Wheat Bread or Laxatives without Increased Adverse Gastrointestinal Effects ,

“…Daily intake of 25 g of fiber is considered effective (3). Soluble fiber produces viscous solutions and is fermented, in the proximal colon, by bacteria to a greater extent than insoluble fiber (5). SCFA and gas produced during fermentation reduce colonic transit time.…”