The Encyclopedia of Natural Medicine, 3rd Ed.

Irritable Bowel Syndrome

images

Characterized by some combination of:

• Abdominal pain or distension

• Altered bowel function, constipation, or diarrhea

• Hypersecretion of colonic mucus

• Dyspeptic symptoms (flatulence, nausea, anorexia)

• Varying degrees of anxiety or depression

Irritable bowel syndrome (IBS) is the most common gastrointestinal disorder and represents 30 to 50% of all referrals to gastroenterologists. Determining the true frequency is virtually impossible, as many sufferers never seek medical attention. It has, however, been estimated that approximately 15% of the population complains of IBS, with women predominating two to one (it is likely that an equal number of men have IBS but that they do not report symptoms as often). IBS has been attributed to physiological, psychological, and dietary factors.

Causes

IBS is a functional disorder of digestion that is the result of an interplay of digestive secretions, bacterial flora, and dietary factors. The diagnosis of IBS is often made by exclusion, as a result of ruling out other conditions that can mimic IBS (see the list opposite). We recommend that you consult a physician if you have symptoms suggestive of IBS. The physician will decide just how extensive the diagnostic process will be. A detailed medical history and physical examination are critical in diagnosing IBS. Abdominal distension, relief of pain with bowel movements, and the onset of loose or more frequent bowel movements with pain seem to correlate best with the diagnosis of IBS.

images

CONDITIONS THAT MIMIC IRRITABLE BOWEL SYNDROME

• Cancer

• Diarrhea caused by infections such as amebiasis or giardiasis

• Disturbed bacterial microflora as a result of antibiotic or antacid usage

• Diverticular disease

• Inflammatory bowel disease

• Intestinal candidiasis

• Lactose intolerance

• Laxative abuse

• Malabsorption diseases, such as pancreatic insufficiency and celiac disease

• Mechanical causes, such as fecal impaction

• Metabolic disorders, such as adrenal insufficiency, diabetes, or hyperthyroidism

• Response to dietary factors that interfere with digestion, such as excessive consumption of tea, coffee, carbonated beverages, and simple sugars

images

Therapeutic Considerations

Once other conditions have been ruled out, there appear to be several treatments to consider in the successful resolution of IBS:

• Increasing dietary fiber

• Eliminating allergic/intolerant foods

• Eliminating refined sugars

• Reducing dietary FODMAPs (fermentable oligo-, di-, and monosaccharides and polyols)

• Taking probiotics

• Taking enteric-coated peppermint oil

• Controlling psychological components, especially stress

Unfortunately, instead of addressing underlying factors, the medical treatment of IBS focuses on drugs that primarily suppress symptoms.1,2 As a general measure, we recommend that you read the chapter “Digestion and Elimination.” In our experience, improving digestion sometimes resolves the symptoms of IBS.

Dietary Fiber

The treatment of irritable bowel syndrome through an increase in dietary fiber has a long history of success. Patients with constipation are much more likely to show response to dietary fiber than those with diarrhea. One problem that has not been addressed in studies on the therapeutic use of dietary fiber is the role of food allergy. The type of fiber often used in both research and clinical practice is wheat bran.3Wheat and other grains are among the foods most commonly implicated in malabsorptive and allergic conditions, and food allergy is a significant etiological factor in IBS, so the use of wheat bran is usually contraindicated.

Increasing dietary fiber from fruit and vegetable sources rather than grain sources may offer more benefit to some individuals, although in one uncontrolled clinical study there was no significant difference in improvement when a diet including 30 g fruit and vegetable fiber and 10 g cereal fiber was compared with a diet consisting of the opposite ratio.4 Although the two diets resulted in similar significant improvement in abdominal pain, bowel habits, and state of well-being, the presence of large quantities of potentially allergic cereal fiber in both diets probably would have obscured any differences.

Psyllium seed husks are a popular bulk-forming laxative (they are, for example, the primary ingredient in commercial products such as Metamucil) and can be very helpful in improving IBS symptoms.5Another type of soluble fiber that may be useful and that is without the allergenic component of a wheat-based fiber is partially hydrolyzed guar gum (PHGG). The guar plant, Cyamopsis tetragonoloba, has been grown in India and Pakistan since ancient times. PHGG is a natural, soluble dietary fiber derived from the guar plant and has been shown to decrease the frequency of IBS symptoms such as abdominal spasms, flatulence, and abdominal tension.6 The researchers concluded that PHGG works well in cases of altered intestinal motility and is easy to use because of its nongelling properties, unlike unhydrolyzed gum, which is much higher in viscosity and more difficult to incorporate into the diet.

Put simply, for most cases of irritable bowel syndrome, nonwheat sources of fiber—fiber-rich vegetables and fruits, or bulk-forming soluble fiber, such as psyllium or guar gum—may be the best choice to help reduce symptoms associated with IBS.

Food Allergies

The importance of food allergies in IBS has been recognized since the early 1900s.7,8 Later studies have further documented the association between food allergy and IBS.912 According to double-blind challenge methods, approximately two-thirds of patients with IBS have at least one food intolerance, and some have multiple intolerances.9 Foods rich in carbohydrates, as well as fatty food, coffee, alcohol, and hot spices, are most frequently reported to cause symptoms.1,2 The most common allergens are dairy products (40 to 44%) and grains (40 to 60%).11 Many patients have noted marked clinical improvement with the use of elimination diets.913

In one of the most recent studies, 20 patients with IBS who had had no success with standard medical therapy were evaluated for food allergies by means of IgG blood tests and treated with an elimination diet followed by an allergy rotation diet and probiotic supplementation. The results were impressive: 100% of the study subjects reported improvement in symptoms. There was a trend toward an increase in beneficial flora after treatment but no change in the number and type of abnormal flora.

For more information on elimination and allergy rotation diets, see the chapter “Food Allergy.”

Sugar

Meals high in refined sugar can contribute to IBS as well as to small intestinal bacterial overgrowth by decreasing intestinal motility.14 When blood glucose levels rise too rapidly, gastrointestinal tract peristalsis slows down. Because glucose is absorbed primarily in the first parts of the small intestine (the duodenum and jejunum), the message affects this portion of the gastrointestinal tract most strongly. Basically, the duodenum and jejunum become paralyzed by high sugar intake. A diet high in refined sugar may be the most important reason that IBS is such a common condition in the United States.

Dietary FODMAPs (Fermentable Oligo-, Di-, and Monosaccharides and Polyols)

There is a group of short-chain carbohydrates that are poorly absorbed in the small intestine and thus are likely to be fermented by intestinal bacteria, producing large amount of gases (such as hydrogen and carbon dioxide) that cause abdominal bloating. These carbohydrates include fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs for short). Recent work has identified these short-chain carbohydrates as important triggers of functional gut symptoms.

One particular type of FODMAP is the oligosaccharides called fructans, which are chains of fructose with one glucose molecule on the end. Fructans-rich foods include wheat and foods made from wheat flour (bread, pasta, pastries, cookies, etc.); onions; and artichokes. Fructans with more than 10 molecules of fructose in a chain are known as inulins, and those with fewer than 10 fructose molecules are referred to as fructooligosaccharides (FOS) or oligofructoses. These compounds are now commonly added to many foods and dietary supplements as a source of prebiotic fiber to promote the growth of “friendly” gut bacteria.

Similar to fructans are galactans (such as stachyose and raffinose), which are composed of chains of fructose with one galactose molecule on the end. Galactans-rich foods include legumes (soy, chickpeas, lentils, and other dried beans), cabbage, and brussels sprouts.

The major disaccharide that is an issue in IBS is lactose (milk sugar). Lactose is in dairy products, but it may be also found in chocolate and other sweets, beer, prepared soups and sauces, and so on. Lactose is poorly absorbed in individuals with lactose intolerance, an overgrowth of bacteria in the small intestine, Crohn’s disease, and celiac disease.

Even fructose (fruit sugar), a monosaccharide, can be an issue for some people. Fructose-rich foods include honey, dried fruits (prunes, figs, dates, or raisins), apples, pears, sweet cherries, peaches, agave syrup, watermelon, and papaya. Fructose is often added to commercial foods and drinks as high-fructose corn syrup.

Polyols, also known as sugar alcohols (often used as artificial sweeteners in commercially produced foods and drinks), include mannitol, sorbitol, erythritol, arabitol, glycol, glycerol, lactitol, and ribitol. These may also be a problem, especially if consumed in large quantities.

Open studies have suggested that three out of four patients with IBS will see a decrease in symptoms when they restrict intake of FODMAPs.15 A randomized placebo-controlled rechallenge trial confirmed that the benefit was likely to be due to reduction of FODMAP intake.16

Nutritional Supplements

Probiotics are dietary supplements containing beneficial live microorganisms. Among the most commonly utilized and studied are Lactobacillus (several species), Bifidobacterium (several species), and Saccharomyces boulardii.Randomized, controlled clinical trials using probiotics to treat IBS symptoms have shown some benefits, but probiotics are not likely to resolve all symptoms.17 In two studies, Bifidobacterium infantis produced improvement in all IBS symptoms except stool frequency and consistency.18,19 Other studies have also shown positive results with Lactobacillus rhamnosus GG and Lactobacillus plantaris alone and in combination with other probiotic species.2022One study used a probiotic mixture containing Lactobacillus rhamnosus GG, L. rhamnosus, Bifidobacterium breve, and Propionibacterium freudenreichii in IBS patients for a period of six months. There was improvement in total symptom scores (reflecting abdominal pain, distension, flatulence, and bowel rumbling) in the treatment group compared with the placebo group.21 Other studies using combinations of species have also shown benefit.1925

While probiotics appear to be a key component in a comprehensive approach to treating IBS, they should be used in combination with diet therapy. In general, we prefer probiotic formulations that include multiple species rather than a single one, as these are more similar to what is found in nature.

Botanical Medicines

Peppermint oil (and presumably other similar volatile oils) inhibits gastrointestinal smooth muscle action in both laboratory animal preparations and humans. Clinically, peppermint oil has been used to reduce colonic spasm during endoscopy,26 and an enteric-coated peppermint oil (ECPO) capsule has been used in the treatment of IBS.27 Enteric coating is believed to be necessary because menthol (the major constituent of peppermint oil) and other plant monoterpenes in peppermint oil are rapidly absorbed.28 This rapid absorption tends to limit its effects to the upper intestine, resulting in relaxation of the cardioesophageal sphincter and common side effects, such as esophageal reflux and heartburn, after administration. A transient hot burning sensation in the rectum during defecation, due to unabsorbed menthol, has been noted in some patients taking ECPO.

A detailed analysis of five studies supported the efficacy of peppermint oil, with most of the studies using ECPO at a dosage of 0.2 ml twice per day between meals.28,29 One well-designed study involved 110 patients with symptoms of IBS.30 The patients took one capsule of either ECPO (0.2 ml) or a placebo three to four times per day, 15 to 30 minutes before meals, for one month. The results (listed below) are quite impressive, especially given the safety of ECPO. Only two cases of side effects were reported; one patient experienced heartburn (because of chewing the capsule), and one patient had a transient rash.

ECPO is thought to work by improving the rhythmic contractions of the intestinal tract and relieving intestinal spasm. An additional benefit of these volatile oils is their efficacy against Candida albicans.31This is because an overgrowth of C. albicans may be an underlying factor in IBS, especially in patients who do not respond to dietary advice and those who consume large amounts of sugar. Administration of the antifungal drug nystatin (600,000 IU per day for 10 days) to patients whose IBS did not respond to an elimination diet produced dramatic clinical improvement.10

ECPO is especially helpful for children with IBS as long as they can swallow the capsules. In one randomized, double-blind, controlled trial of 42 children with moderate levels of pain from IBS, peppermint oil was considered a safe and effective treatment.32

Psychological Factors

Mental and emotional problems—anxiety, fatigue, hostile feelings, depression, and sleep disturbances—are reported by almost all patients with IBS. Severity and frequency of symptoms tend to correlate with these psychological factors. Anxiety is associated with a high degree of food-related symptoms in IBS.1 Especially significant is sleep quality; poor sleep quality results in a rise in symptom severity.33 See the chapter “Insomnia” for recommendations to improve sleep quality if it is relevant.

Several theories link psychological factors to the symptoms of IBS. The “learning model” holds that when exposed to stressful situations, some children learn to develop gastrointestinal symptoms to cope with the stress. Another theory holds that IBS is a manifestation of depression, chronic anxiety, or both.

Percentage of Patients Showing Improvements with ECPO or Placebo on Major Symptoms of IBS

PARAMETER

% SHOWING IMPROVEMENT WITH ECPO

% SHOWING IMPROVEMENT WITH PLACEBO

Abdominal pain

79

43

Abdominal distension

83

29

Stool frequency

83

33

Stomach rumbling

73

31

Flatulence

79

22

Stress is certainly an important factor to consider. Greater intestinal motility during exposure to stressful situations has been shown to occur in both normal subjects and people suffering from IBS.34 This finding apparently accounts for the increase in abdominal pain and irregular bowel function seen in both patients with IBS and normal subjects during periods of emotional stress.

Psychotherapy, in the form of relaxation therapy, biofeedback, hypnosis, counseling, or stress management training, has been shown to reduce symptom frequency and severity of IBS.3538

image

QUICK REVIEW

• Irritable bowel syndrome is a functional disorder of the large intestine.

• Because IBS is caused by many interrelated factors, the best approach is to address each of the major ones.

• Rather than addressing underlying factors, conventional medical treatment of IBS focuses primarily on drugs that suppress symptoms.

• Increasing consumption of fiber can be a successful treatment for irritable bowel syndrome.

• The majority of patients with IBS have at least one food intolerance, and some have multiple intolerances.

• Meals high in refined sugar can contribute to irritable bowel syndrome.

• Open studies have suggested that three out of four patients with IBS respond well to restriction of FODMAP intake.

• Probiotics appear to be a key component in the comprehensive approach to treating IBS but should be used in combination with diet therapy.

• Enteric-coated peppermint oil is quite beneficial in relieving the symptoms of irritable bowel syndrome.

image

TREATMENT SUMMARY

Because IBS represents a health condition caused by many interrelated factors, the best approach is to address each of the following major factors:

• Increasing dietary fiber

• Eliminating foods to which there is an allergy or intolerance

• Eliminating refined sugars

• Reducing dietary FODMAPs

• Taking probiotics

• Taking enteric-coated peppermint oil

• Controlling psychological components, especially stress

Diet

The guidelines given in the chapter “A Health-Promoting Diet” are appropriate for improving IBS. Particularly important is increasing dietary fiber intake. It is also important to identify and eliminate food allergies. It may also help to eliminate or reduce FODMAPs.

Nutritional Supplements

• Follow the general recommendations in the chapter “Supplementary Measures.”

• Probiotic supplement (multistrain, including species of lactobacillus and bifidobacteria): 5 billion to 20 billion live organisms per day

Botanical Medicines

• Enteric-coated peppermint oil: 0.2 to 0.4 ml twice per day between meals



If you find an error or have any questions, please email us at admin@doctorlib.info. Thank you!