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Irritable Bowel Syndrome (IBS)

Irritable bowel syndrome (IBS) is a common type of digestive disorder, with symptoms such as bloating, stomach cramps, constipation, and diarrhea.

Our evidence-based analysis on irritable bowel syndrome (ibs) features 5 unique references to scientific papers.

Research analysis led by and reviewed by the Examine team.
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Summary of Irritable Bowel Syndrome (IBS)

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder that affects approximately 11% of the global population[1]. It is associated with abdominal pain, bloating, excessive flatulence, and altered bowel habits, severely lowering a person’s quality of life. Functional gastrointestinal disorders like IBS are not caused by structural abnormalities such as ulcers or tumors. Rather, they occur as a result of an abnormally functioning GI tract. This makes it difficult to accurately diagnose a person because no biomarker can indicate whether or not someone is suffering from IBS. Thus, clinicians have to rely on the reports of patients and on a set of criteria that have evolved over time for diagnosis.

Although the cause of IBS is still not well understood, researchers have put forth several hypotheses. Some of these theories include infections of the GI tract[2], psychological stress[3], abnormalities in gut motility[4], and gut-brain axis problems.[5] Unfortunately, no cures currently exist for IBS. It is usually managed through a combination of lifestyle changes (e.g., avoiding triggering foods, staying well hydrated), with prescription drugs being used if warranted.

IBS can be characterized according to its predominant symptoms: diarrhea (IBS-D), constipation (IBS-C), both (IBS-M, where the ‘M’ stands for ‘mixed’), or undetermined (IBS-U) as shown in Figure 1.

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Human Effect Matrix

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The Human Effect Matrix looks at human studies to tell you what supplements affect Irritable Bowel Syndrome (IBS).

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Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Level of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Supplement Magnitude of effect
? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
Notes
grade-a Notable Very High See all 8 studies
In persons with IBS, supplementation of peppermint oil appears to reliably and effectively reduce abdominal pain for as long as it is taken. Benefits are no longer seen two weeks after supplement cessation and abdominal pain is the only symptom notably reduced.
grade-c Strong Very High See all 12 studies
A low-FODMAP diet reduces global IBS symptom severity scores compared to a high-FODMAP diet, traditional Australian diet or placebo diet, but it is not always superior to traditional dietary advice for IBS or the modified National Institute for Health and Care Excellence guidelines (mNICE). The low-FODMAP diet appears to be more effective for IBS-D than IBS-C.
grade-d Minor - See study
One open-label study (lacks blinding for investigators or subjects and no placebo-control) indicated that pynogenol efficacy for IBS symptoms was on par with some of the common pharmacological antispasmodic agents. Although the study design was weak, other studies demonstrating that pycnogenol has a relaxing effect on intestinal smooth muscle tissue lends some increased confidence that it may also be effective as a treatment for IBS.

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Things to Note

Also Known As

IBS

Click here to see all 5 references.