Complementary and Alternative Medicine and Mind–Body Therapies for Treatment of Irritable Bowel Syndrome in Women

Abstract

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder, characterized by chronic or recurrent abdominal pain with constipation, diarrhea and/or an alternation of the two, and often bloating. Complementary and alternative medicine (CAM) consists of a group of medical treatments that are not commonly considered to be a part of traditional medicine. CAM is commonly used for difficult-to-treat chronic medical conditions. Many patients choose CAM because there are only a limited number of treatments available for IBS or because they would like to have a ‘natural therapy’. Mind-body therapies for IBS have proven efficacy, but have not been well accepted by patients or practitioners for treatment. This article reviews the use of CAM and mind-body therapies in IBS, with a focus on probiotics, acupuncture, herbal medicines and psychological therapies.

Keywords

acupuncture Chinese herbs complementary and alternative medicine irritable bowel syndrome Padma Lax peppermint oil probiotics psychological therapy STW 5 Tong Xie Yao Fang

Irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common problem accounting for numerous outpatient visits to physicians, large expenditures of healthcare dollars and monetary costs due to loss of productivity. In the USA in 2004, IBS accounted for approximately 1.6 million office-based visits with the primary diagnosis and 3.05 million visits of all-diagnosis physician visits [1]. Notably, women had four-times more visits than men. Additionally, medication expenditures for IBS were over US$294 million and the overall cost for IBS in 2004 in the USA was estimated to be US$950 million in direct costs and US$57.5 million in indirect costs [1].

The knowledge and understanding of IBS has undergone rapid expansion within the past decade owing to scientific advancement and breakthroughs in basic science research [2 –5]. IBS is a functional gastrointestinal (GI) disorder, characterized by chronic or recurrent abdominal pain over a period of 3 months associated with alterations in bowel habits and often bloating, in the absence of structural, inflammatory or biochemical abnormalities [6 –8]. It is associated with a change in intestinal and colonic motility, altered visceral and somatic sensation, changes in the gut–brain interaction, low-grade inflammation and often changes in psychological function, such as depression [3,9]. IBS is one of the most common disorders affecting the GI tract and manifests as a heterogeneous association of symptoms. This differing symptomatology suggests that IBS may have several possible etiologies. IBS can be further divided based on the predominant bowel habit: constipation (IBS-C), diarrhea (IBS-D) or mixed (i.e., alternating pattern of diarrhea and constipation). In North America, IBS affects between 10 and 20% of the population and has been found to be more predominant in women, with a female to male ratio of approximately 2:1. However, the female predominance reported in the west has not been reported in some of the Asian countries. IBS accounts for 10–15% of primary care visits and 25–50% of gastroenterology referral visits [7,10,11].

Conventional therapies for IBS are targeted at symptom reduction and improvement in quality of life (QOL) [6 –8]. Treatment for women and men is the same, except with serotonin receptor agonist/antagonists. Both tegasarod, now withdrawn from the US market due to cardiovascular complications, and alosetron were approved only for use in women with IBS [12,13]. Antidiarrheals, such as loperamide, or 5-hydroxytryptamine type 3 receptor antagonists, such as alosetron, are used in IBS-D, whereas laxatives, stool softeners and prokinetics are used in IBS-C. Fiber remains an important therapy for IBS-C. Fiber stimulates motility of the GI tract and helps alter the consistency of the stool. Two new recently approved prokinetic medications are lubipros-tone and linaclotide. Lubiprostone acts on chloride channels to increase water secretion into the intestines. Linaclotide, a guanylate cyclase agonist, stimulates intestinal fluid secretion and transit. Antispasmodics are helpful in both forms of IBS; they help reduce contractions in the GI tract and are often used in combination with the above treatments. Lastly, selective serotonin reuptake inhibitors and tricyclic antidepressants are more commonly used to treat visceral pain and global symptoms in IBS patients [12,14 –16].

Complementary & alternative medicine & IBS

Despite the recent advances in the treatment of IBS, including lifestyle modifications, dietary changes, fiber supplementation and pharmacotherapy, many individuals, predominantly women, continue to struggle with this disease. Therefore, many patients have turned to complementary and alternative medicine (CAM) in the hope of finding more efficacious treatments.

CAM is a group of diverse medical and healthcare systems, practices and products that are not generally considered part of traditional medical treatment [101]. In 2007 in the USA, approximately 38% of adults (~four in ten) were using some form of CAM, with the majority of users being women (42.8% women and 33.5% men), and they spent US$33.9 billion on visits to CAM practitioners and purchases of CAM products, classes and materials. A population-based study from Australia demonstrated that approximately 21% of IBS patients sought care from a CAM provider [17], while a study from the UK found that approximately 50% of IBS patients attending an outpatient GI clinic had used CAM [18]. In the USA, 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 US$200 per person. In this study, CAM use was highest in women, those with higher education and those with anxiety [19,101].

This article will review current evidence supporting the use of CAM in women who have IBS, with a focus on probiotics, acupuncture and herbal medicines. It will also discuss mind–body interventions, such as cognitive–behavioral therapy (CBT; mindfulness training) and hypnosis, which are not commonly used by practitioners treating patients with IBS. A review of special diets for IBS can be found elsewhere [20]. The available data on CAM use in women compared with men with IBS are limited since there are very few high-quality studies and these have not focused on the effect of different forms of CAM on IBS in women.

Probiotics

In 2001, the Food and Agriculture Organization of the United Nations/WHO defined probiotics as “live microorganisms, which confer a health benefit when administered in adequate amounts” [21]. Probiotics have been used in a variety of GI disorders including IBS, Clostridium difficile colitis and inflammatory bowel disease [22,23]. Eli Metchnikoff, a Nobel Prize recipient, recognized the importance of probiotics in 1907 [24]. Also around this time, Henry Tissier, a French pediatrician, observed that children with diarrhea had a low number of bacteria in their stools, characterized by a peculiar, Y-shaped morphology. These ‘bifid’ bacteria were abundant in healthy children. He suggested that these bacteria could be administered to patients with diarrhea to help restore their gut flora [25].

Why should probiotics be helpful? There are 395–500 different bacterial species in the intestinal tract and ten-times more microbes than human cells in our bodies [26,27]. Progressing down the intestinal tract from the esophagus into the colon, the number of bacteria increases. The stomach and small bowel (the duodenum and jejunum) normally contain few bacteria (< 10<sp>⁴ colony-forming unit [CFU]/ml) with 10⁹ CFU/ml in the terminal ileum and 10¹² CFU/ml in the colon [28]. Probiotics can be beneficial for one's health as a result of several mechanisms. Possible mechanisms of action include competitive interactions with pathogens and the production of chemical products, which are directly toxic to pathogenic bacteria or viruses. Probiotics also reinforce the mucosal barrier, inhibit the movement of bacteria across the gut wall, and influence the motility and sensation of the gut due to the production of neurotransmitters. These mechanisms in particular may be useful in the treatment of IBS. They also produce numerous cytokines, neuroactive peptides, fatty acids, gas and other substances [22,29,30]. Further supporting the role of bacteria in IBS and the suggestion that probiotics may play a role in treatment is the occurrence of IBS after infection (postinfectious IBS) in 3–36% of individuals [31 –33], the presence of small intestinal bacterial overgrowth in some individuals with IBS and reports of the successful treatment of IBS with antibiotics [33,34]. Finally, studies have shown an alteration in the colonic and fecal bacteria of individuals with IBS with some studies showing a decrease (or increase) in Lactobacillus and a decrease in Bifidobacterium [35 –38]. Thus, probiotics have a beneficial effect on the GI tract through multiple mechanisms.

There are several organisms, that have been shown to be helpful in treating the symptoms of IBS, although many of these studies had a small sample size. These bacteria include Lactobacillus rhamnosus GG, Lactobacillus plantarum, Lactobacillus acidophilus, the probiotic cocktail VSL#3, Bifidobacterium animalis and Bifidobacterium infantis 35624 [22,39]. Other probiotics have been studied that have been shown to have some benefit in the treatment of IBS (Table 1). Since the benefits of these other probiotics have not been supported by rigorous studies, further investigation is necessary to prove their true usefulness in therapy. A number of meta-analyses have assessed the efficacy of probiotics in IBS. These meta-analyses have varied in their conclusions, in part because of inadequate sample sizes, poor study designs and the use of different probiotic strains in the studies [22,39 –42]. Moayyedi et al. reviewed 19 studies performed in 1650 patients with IBS. It was concluded that probiotics were better than placebo (relative risk of IBS not improving: 0.71; 95% CI: 0.57–0.88) [40]. In another meta-analysis, Clarke et al. reviewed 42 randomized control trials (RCTs), all of which studied the effect of lactic acid bacteria probiotics on IBS symptoms. In total, 34 of these trials reported benefit in at least one of the end points studied [41]. Brenner et al. evaluated 16 RCTs [42]. Eleven of the studies had too small a sample size, were inadequately blinded, were of too short duration and/or lacked an intention-to-treat analysis. They concluded that only two of the studies – those using the probiotic B. infantis 35624 – demonstrated significant improvements in the symptoms of IBS. One of these studies, performed by Whorwell et al., evaluated the efficacy of B. infantis 35624 in women [43]. In this multicenter study, 362 women were chosen from 20 primary care centers in the UK who met Rome II criteria for IBS (abdominal discomfort or pain relieved with defecation, and/or onset associated with a change in frequency of stool and/or onset associated with a change in appearance of stool). In addition to determining the efficacy, the second goal of the study was to determine the optimal dosage of the probiotics. Patients received B. infantis 1 × 10⁶, 1 × 10⁸ or 1 × 10¹⁰ CFU/day, or placebo for 4 weeks [43]. IBS symptoms were monitored daily and scored on a 6-point Likert scale, with the primary outcome being abdominal pain or discomfort. The study demonstrated that B. infantis 35624, at a dose of 1 × 10⁸ CFU, was significantly superior to placebo and all other Bifidobacterium doses. B. infantis significantly reduced abdominal pain (the primary outcome) and other IBS symptoms including bloating, bowel dysfunction, incomplete evacuation, straining and the passage of gas compared with placebo. Secondary measures were also significantly improved compared with placebo. The dose of 1 × 10⁸ CFU/day provided the greatest benefit, while the two other doses were not significantly different from placebo [43]. There are many other probiotics currently being studied and in current use for the treatment of IBS symptoms. Convincing data demonstrating the benefit of less-studied probiotics are awaited from further trials before widespread use of these probiotics can be recommended (Table 1).

Table 1.

Probiotics shown to be efficacious in irritable bowel syndrome.

Probiotic (bacterial strain)	Targeted symptom relief	Sample size (patients, n)	Length of study (weeks)	Other comments	Ref.
Bifidobacterium animalis	Reduced discomfort and bloating in constipation-predominant IBS	274	3 or 6	Appropriate sample size Men and women	[77]
Bifidobacterium infantis 35624	Reduced abdominal pain and other IBS symptoms	362	4	Large sample size Women	[43]
Bifidobacterium bifidum MIMBb75	Alleviated global IBS, improved IBS symptoms and QOL	122	4	Appropriate sample size Men and women	[78]
Escherichia coli Nissle	Helped in patients with altered enteric microflora, e.g., after gastroenterocolitis or use of antibiotics	120	12	Long treatment duration Men and women	[79]
Lactobacillus plantarum 299v	Improved abdominal pain and bloating	214	4	Short treatment duration Men and women	[80]
Saccharomyces boulardii	Improved QOL, but not significantly in individual symptoms	67	4	Short treatment duration Small sample size Men and women	[81]
Lactobacillus acidophilus NCFM	Improved bloating	60	4	Small sample size Men and women	[82]
Bifidobacterium lactis Bi-07	Improved bloating	60	4	Small sample size Men and women	[82]
Lactobacillus acidophilus	Reduced abdominal pain	40	4	Small sample size Men and women	[83]
Lactobacillus rhamnosus GG	Reduced frequency and severity of abdominal pain in children	50	6	Small sample size Men and women	[84]
VSL#3	Reduced flatulence and retarded colonic transit	48	4 or 8	Small sample size Men and women	[85]

IBS: Irritable bowel syndrome; QOL: Quality of life.

Acupuncture

Acupuncture, an ancient traditional Chinese medical practice, has become more widely used in western society, particularly in the USA, since the 1970s. It is based on a life force ('qi') that runs through the body in channels called meridians. Disruptions in qi are believed to result in disease processes, which can then be corrected at specific anatomical locations ('acupoints') with acupuncture [44]. Treatment of IBS with acupuncture has been reported in 17 RCTs. Five of these RCTs have compared true acupuncture with sham acupuncture [45]. Review of these RCTs demonstrate that sham acupuncture is as effective as acupuncture on IBS symptom severity or IBS-related QOL [46]. Since the numbers of participants in the studies were small, an alternative explanation is that the numbers in the trials were too small to detect a difference in benefit.

In 2012, a Cochrane review was published to assess the safety and efficacy of acupuncture in IBS [47]. This review included 17 RCTs with a total of 1806 patients. The RCTs included trials comparing acupuncture to sham acupuncture, to pharmacological medications, to Bifidobacterium, to psychotherapy, to no therapy, to acupuncture with psychotherapy versus psychotherapy alone, and to acupuncture with another traditional Chinese medication to the Chinese medication alone. Acupuncture was better than pharmacological therapy (84 vs 63%) and no specific therapy (63 vs 34%), but the possible bias in the trials was thought to be high. Acupuncture with Chinese herbs versus Chinese herbs alone showed an effect (93 vs 79%), but the sample sizes were small and therefore not statistically significant. Acupuncture was no better than Bifidobacterium (76 vs 71%) or psychotherapy (84 vs 80%) for IBS. The studies of acupuncture versus sham acupuncture were of good quality. Acupuncture was compared with sham acupuncture in five of the RCTs. In sham acupuncture, the patient believes that he or she is receiving true acupuncture. However, the needles do not penetrate the skin or the needles are inserted at wrong points or nonpoints, which deliberately violate traditional acupuncture theories of point locations or indications and are, therefore, predicted to be incapable of achieving the outcomes intended by true acupuncture [46,48]. The end points of these studies included effects of acupuncture on IBS symptom severity and QOL. There was no evidence of improvement with acupuncture compared with sham acupuncture for symptom severity (standardized mean difference [SMD]: −0.11; 95% CI:-0.35–0.13; four RCTs; 281 patients) or QOL (SMD: −0.03; 95% CI: −0.27–0.22; three RCTs; 253 patients). Adequate pain relief was achieved in 55% (acupuncture) versus 49% (sham acupuncture) in the three studies that report it. One of the side effects reported in nine of the trials was fainting, although the data are not very useful given small sample sizes. This review was followed by a systematic review and meta-analysis by Manheimer et al. using 17 RCTs with a total of 1806 patients [46]. There was no evidence of improvement with acupuncture, relative to sham acupuncture in regard to symptom severity (SMD: –0.11; 95% CI: −0.35–0.13; four RCTs) and QOL (SMD: −0.03; 95% CI: −0.27–0.22; three RCTs).

One of the studies cited in both the Cochrane review [47] and the meta-analyses by Manheimer et al. [46] that was carried out at our institution by Lembo et al. [45] tested the effect of acupuncture and sham acupuncture compared with no treatment in the relief of IBS symptoms. In this study, the needles did not penetrate the skin of the recipients of sham acupuncture. There was a run-in phase in which all patients, except those in the no treatment arm, received sham acupuncture. A total of 230 adult IBS patients were then randomly assigned to 3 weeks of true or sham acupuncture (six treatments) or continued no treatment. In addition, patients receiving true or sham acupuncture were also randomly assigned to either an ‘augmented’ or ‘limited’ patient–practitioner interaction. The primary end point of the study was the Global Improvement Scale, which assessed changes in the the participant's IBS symptoms. Secondary end points included IBS adequate relief, IBS symptom severity and IBS QOL. There was no significant difference in either primary or secondary outcomes between the acupuncture and sham acupuncture groups. However, this study did demonstrate that acupuncture and sham acupuncture were both significantly better than no treatment. Another important finding was that it showed that more contact of the patient with the practitioner had a marked beneficial effect on a Global Improvement Scale and relief of symptoms [45,49].

Other RCTs that did not use a placebo arm reported that acupuncture was more effective than medication (relative risk of symptom improvement: 1.28; 95% CI: 1.12–1.45; five RCTs) and no treatment (relative risk: 2.11; 95% CI: 1.18–3.79; two RCTs). There were no differences in outcomes between acupuncture and Bifidobacterium treatment or between acupuncture and psychotherapy [46]. It was proposed that expectations of outcome may play a role in the positive acupuncture and sham acupuncture effects compared with placebo or medication [50]. Whether or not there is a benefit of acupuncture for IBS will have to await further studies.

Herbal medicines

When traditional medications fail to treat a condition, people often turn to herbal medications for therapy. Herbal medicines are based on the use of plants and plant extracts as remedies to treat a variety of symptoms and diseases. The herbs may be used alone, in a mixture of multiple herbs, as a combination of Chinese proprietary medicines, or as one of the three types in combination with western medication to try to achieve efficacy. Many prescription drugs in western medicine are derived from plants and plant extracts. Purity of the herbs free from contamination and the amount of active ingredient of the herb in each preparation may not be standardized. In a recent Cochrane review of herbal medicines for treatment of IBS (not including peppermint oil) there were 75 randomized trials of 71 different herbal medicines [51]. The authors felt that out of the trials, there were three high-quality, double-blind, placebo-controlled trials. These were a standard Chinese herbal formula and individualized Chinese herbal medicines, herbal preparations of STW 5 and STW 5-II, and a Tibetan herbal formulation (Padma® Lax, Padma AG, Schwerzenbach, Switzerland) [51 –54]. These herbs will be discussed below along with the well-studied Tong Xie Yao Fang (TXYF) and peppermint oil. Additional herbs have had variable benefit in IBS, but the studies were of low quality and, therefore, difficult to interpret.

Chinese herbs

Chinese herbal therapies are based on well-established recipes and can be formulated as either tablets or capsules [52]. There are Chinese diagnostic patterns (i.e., inspection, listening, smelling, inquiry and palpation), which dictate the mixture of herbs that are prescribed for certain symptoms. The active ingredients of these Chinese herbal medicines are not entirely elucidated and the herbal combinations often vary. The clinical effectiveness of these herbs has been shown to be associated with antagonistic effects of acetylcholine and histamine on intestinal smooth muscle. A Cochrane review published in 2011 demonstrated that Chinese herbs had a significant improvement of IBS global symptoms [51]. The herbal formulation showed a potential beneficial effect on decreasing the bowel symptom scale scores at the end of 16 weeks of treatment. However, this effect was not statistically significant at 14-weeks follow-up.

Padma Lax

Padma Lax is a complex Tibetan herbal formula composed of aloe dry extract, calumba root, cascara, chebulic myrobalan fruit, condurango, elecampane, frangula bark, gentian root, ginger, heavy kaolin, long pepper, nux vomica, rhubarb, sodium hydrogen carbonate and sodium sulphate. In reviews of the literature there appears to be variations in the ingredients of Padma Lax [14,51]. A double-blind randomized pilot study was conducted in Israel in patients with IBS-C [54]. Patients were treated with either Padma Lax or placebo for 3 months. Those receiving Padma Lax demonstrated significant improvement compared with placebo in constipation, the severity of abdominal pain and its effect on daily activities, incomplete evacuation, abdominal distension and flatus/flatulence. Side effects included loose stools in a small number of patients, but they responded well to lowering the dosage. This study suggests that Padma Lax is a potential treatment for IBS-C, but further studies are needed.

Tong Xie Yao Fang

TXYF is an herbal medicine composed of four Chinese herbal medicines: Rhizoma atractylodis macrocephalae, Radix paeoniae alba, Pericarpium citri reticulatae and Radix saposhnikoviae. Additional herbs may also be added to the mixture. A meta-analysis on TXYF in IBS reviewed 12 clinical studies. The quality of the studies was low due to heterogeneity in the formulas, treatment duration and outcome measurements. Despite these drawbacks, the pooled analysis demonstrated that TXYF was better than conventional medicines [55]. More recently, a study was conducted in China with 120 IBS-D patients who were treated with TXFY (n = 80) or Miyarisan, a probiotic consisting of butyric acid bacteria (n = 40), for 4 weeks [56]. The efficacy was compared between the two groups based on symptoms before treatment and 2 and 4 weeks after treatment. There was no significant difference between the two groups with regard to IBS symptoms, although activated mast cells that can be present (and may be important) in IBS were reduced in number to a greater degree in the TXYF group compared with the Miyarisan group.

STW 5

STW 5 is composed of bitter candytuft, chamomile flowers, peppermint leaves, caraway fruit, licorice root, lemon balm leaves, celandine herbs, angelica root and milk thistle fruit. STW 5-II is similar to STW 5, except it does not include angelica root and milk thistle fruit. A double-blind, placebo-controlled, multicenter trial from Germany evaluated the safety and cost–effectiveness of STW 5 and STW 5-II [53]. A total of 208 outpatients with IBS were randomly assigned to STW 5, STW 5-II, bitter candytuft monoextract or placebo three-times daily for 4 weeks. At the end of 4 weeks, STW 5 and STW 5-II were more effective than placebo. After 2 weeks of treatment, the IBS symptom scores were significantly better for STW 5 and STW 5-II compared with placebo (p = 0.0085 and p = 0.0006 vs placebo, respectively). After 4 weeks, the differences between STW 5/STW 5-II and placebo became more apparent (p = 0.001 and p = 0.0003 vs placebo, respectively). While there were significant differences in the primary end points of changes in total abdominal pain and IBS symptom scores before and after treatment with STW 5 and STW 5-II compared with placebo, this did not occur with bitter candytuft monoextract alone. The tested herbal preparations were well tolerated with a few adverse events. One patient reported a headache and the second patient reported constipation. A more recent study by von Arnim et al. published in 2007 evaluated the role of STW 5 in patients with functional dyspepsia [57]. A total of 315 patients, two-thirds of whom were women, were included in this multicenter, placebo-controlled, double-blind study. After a washout period, individuals were randomized to either placebo or STW 5 for a study period of 8 weeks. The primary end point was a change in the GI symptom score (GIS) before and after treatment. The GIS is comprised of ten dyspeptic symptoms. Secondary end points included overall efficacy and tolerability of STW 5 over the treatment period. Both the STW 5 group and the placebo group showed continuous improvement during the treatment period. There was a statistically significant improvement in the GIS in patients on STW 5 (p < 0.04). Efficacy of STW 5 was also found to be significantly greater than placebo with a p-value of approximately 0.02. At the end of 8 weeks, the number of responders (78.3 vs 72.2%) and symptom-free patients (62.4 vs 53.0%) was higher for STW 5 compared with placebo. These studies suggest that both STW 5 and STW 5-II may be effective for the treatment of patients with IBS and functional dyspepsia, although further trials are needed. Their mechanisms of action remain to be elucidated.

Peppermint oil

Peppermint oil, a cross between watermint and spearmint, is the major component of several over-the-counter compounds used to treat symptoms of IBS [58]. Peppermint oil has calcium-channel blocking activity thought to be due to menthol. This results in the reduction of smooth muscle contractions. In the intestine, blocking the flow of calcium into smooth muscle reduces muscle contractions [58]. A meta-analysis published in 1998 included eight trials that used peppermint oil in IBS [58]. Of these studies, five double-blind, placebo-controlled trials were included for further analysis. The meta-analysis demonstrated a significant (p < 0.001) global improvement of IBS-symptoms in patients treated with peppermint oil compared with placebo. The placebo response in these trials ranged from 13 to 52%. A randomized, double-blind, placebo-controlled study was also conducted in Taiwan. This study randomized 110 patients with IBS symptoms to an enteric-coated peppermint oil formulation (Colpermin®, Tillotts Pharma, Ziefen, Switzerland) containing 0.2 ml of peppermint oil or placebo three-to-four-times daily for 1 month [59]. Patients receiving the peppermint oil formulation had less abdominal distention, stool frequency and flatulence compared with patients receiving placebo. A few patients reported adverse effects with peppermint oil including heartburn and a transient skin rash. These studies demonstrate that peppermint oil is effective in patients with IBS, but secondary outcome measures did not show any positive effects on QOL, anxiety, depression or stress level. In a double-blind study published in 2007 by Cappello et al., 57 IBS patients were treated with peppermint oil for 4 weeks, and by the end of the study, 75% of peppermint oil-treated patients showed a greater than 50% reduction in IBS symptoms compared with 38% in the placebo group [60]. The difference persisted in the peppermint oil-treated group compared with placebo (54 vs 11%) 4 weeks after the end of therapy. However, not all studies show a benefit. In a 2013 report from Bangladesh, peppermint oil therapy resulted in only short-term relief of abdominal pain in patients with IBS-D [61]. Enteric-coated peppermint oil is readily available and is often reasonably priced, therefore making it appealing as a treatment for IBS. Other possible side effects of peppermint oil include perianal burning, bradycardia and muscle tremor [62]. At higher doses, peppermint oil can reduce the lower esophageal sphincter pressure, which is probably the cause of heartburn in patients using this medication.

Mind-body therapy

Mind-body interventions have been shown to be successful in the treatment of IBS. Traditionally, IBS patients have turned to pharmacotherapies, such as antispasmodics, antidepressants and bulking agents, for the treatment of their symptoms. However, owing to the limitations in the effectiveness of these medicines, more patients are now turning to psychological treatments. This is a result of the development of the biopsychosocial model of IBS. The basis of this model is that psychosocial factors are closely related to gut physiology, symptom manifestations and illness behavior. Dysregulation of these factors can result in illness. The brain receives a continuous stream of information regarding the activity of the GI tract. Many patients with IBS often show hypervigilence and hypersensitivity to visceral sensations, and an increased autonomic arousal to visceral events, thus supporting the need for psychological intervention [63 –65].

In order to build a good patient-physician relationship and optimize therapy, it is important for physicians to recognize these psychosocial issues in their IBS patients [66]. Psychological therapies modulate the input from the brain's emotional motor system, greatly influencing the brain–gut relationship.

There are a wide range of these therapies to treat IBS including CBT, interpersonal psychotherapy (IPP), hypnotherapy and relaxation techniques. CBT is a combination of cognitive and behavioral treatment modalities. CBT is based on the principle that the way that patients feel depends partly on the way that they think. Studies have demonstrated that people can train themselves to react differently to symptoms by using relaxation techniques and staying positive. CBT includes techniques such as systemic desensitization, problem solving therapy, social skills training, imagery and home/work exercises [12,15,67,68]. The therapist and patient usually work as a team to set treatment goals, evaluate the effectiveness of techniques and determine when to stop treatment. Hypnotherapy is another method that induces relaxation while the patient is awake, and allows helpful suggestions, such as those aimed at controlling health problems, to be directed into the subconscious mind. A specific therapy, designed to be short term and to focus on the events in a person's life that are felt to be most important in the cause and maintenance of that person's disease, is psycho-dynamic interpersonal psychotherapy. Relaxation therapy, which includes biofeedback, yoga and meditation, helps patients by reducing levels of stress and anxiety [68].

There have been several studies evaluating the efficacy of the above modalities in IBS. In 2009, a Cochrane review was performed to evaluate the efficacy of psychological therapies in IBS [69]. The authors concluded that both CBT and IPP were effective after a course of treatment was completed. Two of the studies included in the analysis with a total of 254 patients compared IPP with usual care. While these studies suggested immediate relief of symptoms by IPP, it is unclear how long the treatment effect lasts. The studies of relaxation and stress relief reported symptom improvement, including abdominal pain, but may depend on the suitability of the patient to the therapy [70]. Boyce et al. showed symptom improvement over time, but there was no difference in the type of therapy in patients (80% women) treated with ‘usual therapy’, CBT or relaxation techniques [71]. In another study (70% women) comparing four sessions with relaxation training versus standard medical care, IBS severity was significantly reduced immediately after and at 6 and 12 months after the completion of therapy [72].

Hypnotherapy, individually or in groups, has been used successfully in the treatment of IBS. In 2007, a Cochrane review was published to evaluate the efficacy of hypnotherapy as a treatment for IBS. There was a total of 147 patients in four studies meeting the inclusion criteria of the meta-analysis [73]. One study compared hypnotherapy with an alternative therapy (psychotherapy and placebo pill); two studies compared hypnotherapy with waiting list controls; and the final study compared hypnotherapy with usual medical management. Hypnotherapy was found to be superior to the waiting list control or usual medical management for the treatment of IBS symptoms. There has been some suggestion that women respond better than men to hypnotherapy [12]. However, the results of these studies should be interpreted cautiously due to poor methodological quality and small size [12,15,73].

To evaluate the efficacy of gut-directed group hypnosis in patients with refractory IBS, Moser et al. randomized 90 patients with IBS to supportive talks with medical treatment (SMT) or to SMT with gut-directed hypnotherapy (GHT) [74]. After treatment, 28 (60.8%) out of 46 GHT patients and 18 (40.9%) out of 44 SMT patients improved (absolute difference: 20.0%; 95% CI: 0–40.2%; p = 0.046) in several dimensions of daily life, such as fatigue, impact on daily activities, sleep disturbance, emotional distress and eating habits, which was the primary end point. There was also improvement in the secondary end point of QOL, which was assessed on eight dimensions: limitations in physical functioning; role limitation because of physical health problems; bodily pain; general health perception; vitality; social functioning; role limitations because of emotional limitations; and mental health. In 25 (86%) out of 29 patients with GHT compared with 11 (32%) out of 34 controls at 12-months follow-up (p < 0.001) there was no effect on the results by factors, such as gender, age, duration of disease and IBS subtype. With regard to QOL, almost all patients with GHT had a significantly greater improvement in their QOL in compared with individuals who received SMT [74].

A recent study by Lowén et al. of refractory IBS patients treated with hypnotherapy and an education intervention demonstrated a significant reduction in IBS severity scoring system and a Visceral Sensitivity Index [75]. Pre- and post-therapy measurement of blood oxygen level-dependent signals in the brain, measured by functional MRI during expectation and delivery of high- and low-intensity rectal distension showed changes in the hypnotherapy group almost exclusively. Furthermore, after therapy, the brain response in the hypnotherapy group was similar to that observed in healthy controls. Similar changes were not seen in the education-treated group, although this group did have similar symptom reduction.

Future of IBS

The future of IBS depends on a better understanding of its pathophysiology, the ability to better characterize the subgroups of patients and the ability to make treatment more personalized. Regarding CAM therapy, we are most likely to see the development of new probiotics and probiotic products that may be used for the general group of individuals with IBS, or may be individualized for people with a specific IBS subtype. Treatment could differ for IBS-C, IBS-D or mixed IBS, or could differ based on gender, ethnicity or other characteristics. The normal enteric bacterial microbiota influences various intestinal functions, whereas disturbances in this microbiota can result in disease processes. This microbiota may differ in subgroups of individuals with IBS. In the future, probiotics will be developed to supplement strains of bacteria that are decreased in number or are absent in individuals with IBS, or to restore an immunological or physiological imbalance, thereby positively impacting the IBS symptoms. Another potential therapy for IBS are prebiotics. Prebiotics are defined as nondigestible, fermentable foods that stimulate the growth of a limited number of species of bacteria in the colon. In contrast to probiotics, which introduce exogenous bacteria into the colon, prebiotics stimulate the growth of endogenously growing bacteria, particularly Lactobacilli and Bifidobacteria. Investigations on the effectiveness of prebiotics in IBS have been limited. While no definitive conclusions can be drawn, the use of prebiotics with or without probiotics is a growing area of interest in the treatment of IBS [22,76]. Unless further studies demonstrate benefit, acupuncture is less likely to play a role in therapy, given that sham acupuncture appears to work just as well as acupuncture. Peppermint oil may become more widely used as it is cheap and effective for some symptoms, and new herbal medicines are likely to be developed for therapy. Use of STW 5 and STW 5-II should become more widespread. Further research is needed on its mechanism of action and likely modification of the formula may result in an increased therapeutic benefit. Further studies showing efficacy of psychological therapies and mind–body techniques will help firmly root these therapies in the treatment armamentaria for IBS. However, as long as individuals want a ‘pill’ or herbal treatment for a quick fix of their symptoms, and the cost of psychological therapies are expensive and not covered by health insurance (in the USA), psychological therapies are unlikely to play a major role in the treatment of IBS. Group mind–body therapies might be cost effective and acceptable to the IBS patients.

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Executive summary

Probiotics

Probiotics are live microorganisms that confer a health benefit when administered in adequate amounts.

In large, well-designed trials, Bifidobacterium infantis 35624 has been shown to be efficacious in women with irritable bowel syndrome (IBS).

Many other probiotics have been shown to benefit women with IBS but, to date, most of the studies are not as well designed and/or often include small numbers of participents.

Acupuncture

Acupuncture may be an alternative treatment for IBS symptoms.

To date, sham acupuncture appears to be as efficacious as true acupuncture and both are better than no treatment.

Acupuncture has been shown to be more effective than pharmacological therapy, and when combined with Chinese herbs, more efficacious than Chinese herbs alone.

Acupuncture is no better than treatment with Bifidobacterium or psychological therapy.

Herbal medicines

Herbal medicines, such as Chinese herbal medicine combinations, STW 5 and STW 5-II, Padma Lax, Tong Xie Yao Fang and peppermint oil, have been shown to be possible effective treatments for IBS.

The data for each of the herbal medicines are limited due to the small number of studies available.

The ingredients in many of these medicines are not entirely clear since there is usually a mixture of herbs and their purity is not often guaranteed.

Mind-body therapy

Mind–body therapies for the treatment of IBS include cognitive–behavioral therapy, interpersonal psychotherapy, hypotherapy and relaxation techniques.

Cognitive–behavioral therapy, interpersonal psychotherapy, relaxation techniques and hypnotherapy have all been shown to provide some benefit in IBS symptoms, but some of these studies should be interpreted cautiously due to small sample size and some heterogeneity of results.

Future perspective

Future treatment of IBS depends on a better understanding of its pathophysiology and characterization of subgroups of patients in order to personalize treatment.

Development of supplement strains of bacteria that are decreased in number, or absent in individuals with IBS, or that may restore immunological or physiological imbalance are likely to be readily available and used for directed therapy.

Prebiotics may prove to be useful in the future for treating IBS either as an adjunct to probiotic therapy or as an individual therapy.

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