Complementary and Alternative Medicine for the Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disorder, characterized by chronic or recurrent abdominal pain and bloating. Complementary and alternative medicine (CAM) is a diverse group of medical treatments that are not commonly considered to be a part of conventional medicine yet frequently used together with conventional medicine. CAM is widely used, particularly for chronic medical conditions that are difficult to treat. Because only a limited number of treatments are available for IBS, many patients choose CAM. This article reviews current evidence supporting the use of CAM in IBS, with a focus on prebiotics, acupuncture, and herbal medicines.

Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disorder, characterized by bloating and chronic or recurrent abdominal pain associated with alterations in bowel habits. IBS can be categorized based on the predominant bowel habit: constipation, diarrhea, or both (ie, alternating pattern of diarrhea and constipation). IBS affects between 10% and 15% of the North American population. Because only a limited number of treatments are available for IBS, many patients choose complementary and alternative medicines (CAMs).

CAM is a diverse group of medical treatments that are not commonly considered to be a part of conventional medicine yet frequently used together with conventional medicine. CAM is widely used particularly among patients who have chronic medical conditions that are difficult to treat. In 2002, it was estimated that approximately 35% of the population used CAM in the previous year. A population-based study from Australia showed that approximately 21% of patients with IBS sought care from a CAM provider, and a study from the United Kingdom found that approximately 50% of patients with IBS attending an outpatient gastrointestinal clinic had used CAM. In the United States, a prospective 6-month study conducted in a large health maintenance organization setting found CAM use in 35% of patients with functional bowel disorders, including IBS, with an annual cost of $200. In this study, CAM use was highest in women and in those with higher education and anxiety.

This article reviews current evidence supporting the use of CAM in IBS, with a focus on prebiotics, acupuncture, and herbal medicines.

Prebiotics

A prebiotic is considered to be a “non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one of a limited number of potentially health-promoting bacteria in the colon,” most notably lactobacilli and bifidobacteria. Stimulating the growth of probiotics such as Lactobacillus or Bifidobacterium results in an increase in the absorption of vitamin and minerals, improves digestion, and increases protection against harmful bacteria, fungi, and viruses. Other mechanisms by which prebiotics modulate the immune system include increasing the number of lactic acid–producing bacteria, increasing the amount of short-chain fatty acids, and activating carbohydrate receptor immune cells.

Prebiotics are most commonly carbohydrates. Fructo-oligosaccharides such as oligofructose and inulin are the best studied and meet the strict definition of a prebiotic put forth by Roberfroid. Other commonly used prebiotics include galacto-oligosaccharides (GOS), trans-GOS, soya oligosaccharides, xylo-oligosaccharides, pyrodextrins, isomalto-oligosaccharides, and lactulose. Prebiotics can be further classified into short-chain, long-chain, and full-spectrum prebiotics. Short-chain prebiotics, such as oligofructose, ferment more quickly in the colon, whereas long-chain prebiotics, such as inulin, ferment more slowly and therefore work predominantly in the. Full-spectrum prebiotics, such as oligofructose-enriched inulin, target the entire colon. Prebiotics can also be found in a variety of food sources such as bananas, garlic, wheat, rye, and asparagus.

Only a few studies have been conducted on the role of prebiotics in patients with IBS. A clinical trial published in 2009 evaluated the effect of the prebiotic trans-GOS in changing the colonic microbiota and IBS symptoms. A total of 44 patients with Rome II IBS-C (IBS with constipation), IBS-D (IBS with diarrhea), or IBS alternate criteria were enrolled in this 12-week trial. The patients were randomized to receive 3.5 g/d or 7.0 g/d of the prebiotic trans-GOS or 7.0 g/d placebo. IBS symptoms were assessed using the Bristol Stool Form Scale and an IBS-specific questionnaire developed and validated by Drossman and colleagues on a weekly basis over the course of 12 weeks. In this study, the prebiotic trans-GOS significantly increased fecal bifidobacteria counts (3.5 g/d, P <.005; 7.0 g/d, P <.001) compared with placebo. The bacteriologic data suggested that the 7.0-g dose rather than 3.5-g dose had the best effect on increasing fecal bifidobacteria counts. The prebiotic trans-GOS also improved IBS symptoms, particularly at the 3.5-g/d dose, which resulted in significant improvement in stool consistency, flatulence, and bloating. This study suggests that prebiotics may serve as a therapeutic treatment of IBS. There were no adverse events in this study.

Other studies have analyzed the optimal dose of prebiotics. A study examined the dose-response effects of short-chain fructo-oligosaccharides (scFOS). In this study, 40 healthy volunteers following their usual diets were randomized to 2.5, 5.0, 7.5, or 10 g/d of scFOS or placebo. The investigators concluded that 7 days of ingestion of scFOS at a dosage of 10 g/d resulted in an increase in fecal bifidobacteria counts and minimized side effects.

For a discussion on the role of probiotics in the treatment of IBS, see the articles by Mark Pimentel and Eamonn Quigley elsewhere in this issue.

Only gold members can continue reading. Log In or Register to continue