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NCCIH Clinical Digest

for health professionals

Irritable Bowel Syndrome and Complementary Health Approaches: What the Science Says

August 2022

Clinical Guidelines, Scientific Literature, Info for Patients: 
Irritable Bowel Syndrome and Complementary Health Approaches

Two women at a dining table with food

Probiotics

There is some evidence that suggests some probiotics may improve symptoms of IBS; however, benefits have not been conclusively demonstrated, and not all probiotics have the same effects. Clinical guidelines issued in 2021 by the American College of Gastroenterology recommend against the use of probiotics for the treatment of global IBS symptoms. (The recommendation is conditional, with “very low level of evidence.”)

What Does the Research Show?

  • Clinical guidelines issued in 2021 by the American College of Gastroenterology recommends against the use of probiotics for the treatment of global IBS symptoms. (The recommendation is conditional, with “very low level of evidence.”) Authors of the guidelines noted that there are challenges in interpreting the existing literature because of small studies, the multiple types and strains of probiotics, the inconsistent benefits on individual symptoms, and the lack of rigorous trials based on U.S. Food and Drug Administration (FDA) endpoints.
  • A  2022 systematic review and meta-analysis of 10 randomized controlled trials involving 757 patients with constipation-predominant IBS (IBS-C) found that compared to placebo, probiotics significantly improved stool consistency and increased the number of fecal Bifidobacteria and Lactobacillus; however, no significant differences were found in abdominal pain scores, bloating scores, or quality-of-life scores. It is important to note that only three studies included in the review were rated as having low risk of bias.
  • A  2021 systematic review and meta-analysis of 9 randomized controlled trials involving 651 pediatric patients found that probiotics significantly reduced the abdominal pain score, increased the rate of abdominal pain treatment success and abdominal pain relief, and reduced the frequency of abdominal pain. However, there was no significant correlation between abdominal pain and the amount of probiotics ingested. The authors suggest that determining the most suitable probiotics may be relatively more important.
  • A  2019 systematic review of 11 studies evaluating the effects of probiotics on IBS symptoms found mixed results. Seven of the studies included in the review reported that probiotics significantly improved IBS symptoms compared with placebo, whereas the other four studies did not report any significant improvement in IBS symptoms after taking probiotics. It is important to note that three studies included in the review involved a monostrain supplement, while the remaining eight studies used a multistrain probiotic. Overall, the reviewers noted that the multistrain probiotic supplements given over 8 weeks or more appeared to produce more distinct beneficial effects.  
  • 2018 systematic review and meta-analysis of 53 studies involving a total of 5,545 participants found that probiotics may have beneficial effects on global IBS symptoms and abdominal pain, but it was not possible to draw definitive conclusions about their effectiveness or to identify which species, strains, or combinations of probiotics are mostly likely to produce benefits.
  • 2019 randomized, double-blind, placebo-controlled, multicenter trial involving 109 patients with celiac disease on a strict gluten-free diet found that a 6-week probiotic treatment used in the study was beneficial in improving the severity of IBS-type symptoms and is associated with a modification of gut microbiota, characterized by an increase of Bifidobacterium.

Safety

  • In healthy people, probiotics usually have only minor side effects, if any. However, in people with underlying health problems (for example, weakened immune systems), serious complications, such as infections, have occasionally been reported.
  • Most research about safety of probiotics comes from studies of Lactobacillus and Bifidobacterium; less is known about other probiotic strains.

Gut-Directed Hypnotherapy

Some studies have suggested benefit of gut-directed hypnotherapy for IBS symptoms, including gastrointestinal symptoms, anxiety, depression, disability, and health-related quality of life. Significant relief from pain-related functional gastrointestinal pain disorders in children has been reported after hypnotherapy compared with standard care or waitlist approaches. Clinical guidelines issued in 2021 by the American College of Gastroenterology recommend that gut-directed psychotherapies, such as gut-directed hypnotherapy, be used to treat global IBS symptoms. (The recommendation is conditional, with “very low quality of evidence.”)

What Does the Research Show?

  • Clinical guidelines issued in 2021 by the American College of Gastroenterology recommend that gut-directed psychotherapies, such as gut-directed hypnotherapy, be used to treat global IBS symptoms. (The recommendation is conditional, with “very low quality of evidence.”)
  • A  2020 systematic review and network meta-analysis of 41 randomized controlled trials involving a total of 4,072 participants found that gut-directed hypnotherapy was more efficacious than either education and/or support or routine care in adults with IBS. However, other psychological therapies were analyzed as well, and none was superior to another; cognitive behavioral therapy and gut-directed hypnotherapy had the largest evidence base and were the most efficacious over the long term.
  • A  2022 systematic review and meta-analysis of 33 randomized controlled trials involving a total of 2,657 children with functional abdominal pain disorders found that hypnotherapy may be considered as a treatment for these disorders in childhood.
  • A 2015 review of seven randomized trials of gut-directed hypnotherapy for IBS found that six of those trials reported a significant reduction in overall gastrointestinal symptoms compared to supportive therapy only. The reviewers concluded that gut-directed hypnotherapy has durable efficacy in patients with IBS, but there is not enough evidence to determine whether hypnotherapy belongs as a primary or adjunctive therapy option for patients with IBS.

Safety

  • Gut-directed hypnosis is generally considered safe and tolerable among children and adults when led by licensed hypnotherapists with special training in this technique.

Peppermint Oil

There is some evidence that enteric-coated peppermint oil capsules may be modestly efficacious, in the short term, in reducing several common symptoms of IBS, in particular abdominal pain, bloating, and gas. Long-term efficacy has not been established. Clinical guidelines issued in 2021 by the American College of Gastroenterology recommend the use of peppermint to provide relief of global IBS symptoms. (The recommendation is conditional, with “low quality of evidence.”)

What Does the Research Show?

  • Clinical guidelines issued in 2021 by the American College of Gastroenterology recommend the use of peppermint to provide relief of global IBS symptoms. (The recommendation is conditional, with “low quality of evidence.”)
  • 2020 randomized, double-blind trial of 190 patients in the Netherlands found that small-intestinal-release nor ileocolonic-release peppermint oil, administered over 8 weeks, did not produce statistically significant reductions in abdominal pain response or overall symptom relief, when using U.S. FDA/European Medicines Agency recommended endpoints. However, the small-intestinal-release peppermint oil did produce significant reductions in abdominal pain, discomfort, and IBS severity. 
  • 2020 systematic review and network meta-analysis of 51 randomized controlled trials involving 4,644 patients evaluated soluble fiber, antispasmodic drugs, peppermint oil, and gut-brain neuromodulators for IBS. The reviewers found peppermint oil was ranked first for efficacy with regard to improvement in global IBS symptoms, on the basis of data from six trials. However, the reviewers also noted that only 13 trials included in the review were at low risk of bias, and therefore, there is likely to be considerable uncertainty around these findings.
  • 2014 systematic review and meta-analysis of 9 studies involving a total of 726 participants found peppermint oil to be superior to placebo for global improvement of IBS symptoms and improvement in abdominal pain.

Safety

  • Non-enteric coated forms of peppermint oil may cause or worsen heartburn symptoms, but otherwise appears to be generally safe over the short term.

Herbal Remedies

There is evidence to suggest some herbal remedies improve IBS symptoms. However, much of the data available is based on studies with inadequate methodology and small sample populations.

What Does the Research Show?

  • 2017 double-blind, randomized, placebo-controlled trial involving 99 participants found that those who received an herbal remedy (IQP-CL-101) containing a mixture of curcuminoids and essential oils from different Curcuma species, besides fish oil, peppermint oil, caraway oil, and vitamins B1, B9, and D3, had a significant reduction in IBS symptoms compared to placebo.
  • A  2019 randomized trial of 240 women with IBS-D found that crofelemer, an active compound from the latex of the plant Croton lechleri, had no significant effect compared with placebo on the number of days without pain and discomfort. However, in an analysis conducted after the trial ended, crofelemer did improve abdominal pain compared with placebo based on the FDA abdominal pain monthly responder endpoint, which suggests that crofelemer may have a role in the management of pain in IBS-D.
  • 2006 Cochrane review of 75 randomized controlled trials involving a total of 7,957 participants with IBS concluded that while some herbal remedies may improve IBS symptoms, positive findings from less rigorous trials should be interpreted with caution due to inadequate methodology, small sample sizes, and lack of confirming data.

Safety

  • Herbal supplements may contain dozens of compounds and all of its ingredients may not be known.
  • Some herbs can interact with medications. For example, St. John’s wort is a potent inducer of both cytochrome P-450 enzymes and intestinal P-glycoprotein. Clinically significant interactions have been documented with St. John’s wort and cyclosporine, the antiretroviral agent indinavir, oral contraceptives, coumadin, digoxin, and benzodiazepines, among others.
  • Some herbs can cause serious side effects. For example, comfrey and kava can cause liver toxicity.

Acupuncture

In sham-controlled, randomized trials, acupuncture was found to be no better than placebo for IBS symptom severity or health-related quality of life. In other studies, acupuncture appeared to provide greater benefits than two antispasmodic drugs, although the studies could not rule out that these benefits may have been due to patient preferences or expectations of improvement.

What Does the Research Show?

  • A 2019 meta-analysis of 41 studies involving a total of 3,440 participants showed that acupuncture was no more effective than sham acupuncture for symptoms of IBS, but there was some evidence that acupuncture could be helpful when used in addition to other forms of treatment.
  • 2014 meta-analysis of six randomized, placebo-controlled trials found some benefit of acupuncture for IBS symptoms; however, only one of the six studies showed a positive effect. The authors concluded that data are insufficient to establish long-term results or to recommend acupuncture as first-line treatment.
  • 2012 Cochrane review of 17 randomized controlled trials involving a total of 1,806 participants found no evidence of an improvement with acupuncture compared to a sham acupuncture control for symptom severity or quality of life. The review also included four Chinese comparative effectiveness trials and found acupuncture to provide greater benefits than two antispasmodic drugs (pinaverium bromide and trimebutine maleate), which have been known to provide modest benefits for IBS symptoms. However, it is unclear if the benefits of acupuncture in these studies were due to patient preferences or expectation of improvement.

Safety

  • Relatively few complications from using acupuncture have been reported. Still, complications have resulted from use of non-sterile needles and improper delivery of treatments.
  • When not delivered properly, acupuncture can cause serious adverse effects, including infections, bleeding, pneumothorax and injury to the central nervous system.

References

NCCIH Clinical Digest is a service of the National Center for Complementary and Integrative Health, NIH, DHHS. NCCIH Clinical Digest, a monthly e-newsletter, offers evidence-based information on complementary health approaches, including scientific literature searches, summaries of NCCIH-funded research, fact sheets for patients, and more.

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