1. Home
  2. Irritable Bowel Syndrome
Irritable Bowel Syndrome

Irritable Bowel Syndrome

  • June 2, 2022

Dietary changes, fiber, probiotics, and herbal medicine for the common complaint are reviewed by John D. McGuire and Philip A. Towers.

Irritable bowel syndrome (IBS) is a common, debilitating, multifactorial, functional gastrointestinal disorder for which a definitive etiology has not been established and there is no consistently successful treatment. The disease is very widespread in developed countries, with 8-22% of the population suffering from IBS symptoms1. IBS therefore represents a significant economic burden for both the community and the individual.

IBS is characterized by a combination of symptoms and signs, such as abdominal pain, constipation (IBS-C), diarrhea (IBS-D) – or alternating between the two (IBS-A) – a noted change in both frequency and stool consistency, rectal Mucus due to hypersecretion of colonic mucus, dyspeptic symptoms including anorexia, flatulence, gastroesophageal reflux (GOR) and nausea, and an emotional component of which anxiety and/or depression are often noted. Abdominal pain is often relieved after a bowel movement.

Although there may be some genetic predisposition to IBS, no biological marker exists and diagnosis is now usually based on symptoms meeting Rome II criteria. Originally, IBS was diagnosed based on the Rome I criteria. This previous criterion specified that there should be at least 3 months of abdominal pain, either continuous or recurrent, that is relieved by defecation and/or associated with a change in the frequency or consistency of bowel movements. Conversely, the Rome II criteria differ from the Rome I criteria in that the abdominal pain must be either continuous or recurrent for a period of 12 weeks or >. Both the Rome I and Rome II criteria are consistent in their description of what constitutes concomitant symptoms, ie, relief of abdominal pain after defecation and/or associated changes in both frequency and consistency of defecation , but the Rome II criterion is more explicit that at least 2 of these concomitant symptoms are to be observed in addition to abdominal pain. Although the Rome I criteria were also quite detailed in specifying that a person had to have 2 or more associated symptoms of IBS, e.g. B. an altered stool frequency of more than 3 per day or 25% of the time, the more recent Rome II criteria have helped simplify the diagnosis of IBS. Where patients are pathophysiology

IBS can develop from a number of different mechanisms. Several have been suggested, including abnormal colonic fermentation or gallbladder motility; altered microbial flora; anxiety depression; bacterial gastroenteritis; an exaggerated sensory component of the gastrocolonial response; food allergy, intolerance, or sensitivity; gastroesophageal reflux; impaired transit time or tolerance to bowel gas loads; increased intestinal sensitivity; mild mucosal inflammation; dysmotility; neuronal degeneration of the myenteric plexus; Oxytocin-elevated thresholds for visceral perception; rectal hypersensitivity; and visceral hypersensitivity.

Regardless of the mechanism by which IBS develops, symptoms are typically related to altered gut motility resulting in abnormal gas and bowel movements.

conventional treatment

Conventional drug therapy includes the prescription of antispasmodics/anticholinergics (used to treat gastrointestinal spasms), antidiarrheals, laxatives, serotonin receptor agonists (for IBS-C), serotonin receptor antagonists (for IBS-D), and SSRIs for related anxiety, depression, compulsive behavior and panic disorder. These drugs typically have wide-ranging side effects; However, their effects and side effects are beyond the scope of this review. There does not appear to be any general agreement in the administration of IBS. In terms of a conventional approach and patient education, when advice is given most are only advised to increase their fiber intake (e.g. wheat bran) or supplement with, for example, ispaghula or psyllium husk. However, some practitioners recognize the importance of stress management and counseling.


Most nutritional studies related to irritable bowel syndrome have been observational, and only a small proportion are randomized controlled trials. Nonetheless, they are useful for suggesting treatment options.

Gas, Diet and IBS

The daily gas production in the human gastrointestinal tract (GIT) is 500-1500 ml, and the volume found at any given time is 200 ml. Five main gases are responsible for causing flatulence, namely carbon dioxide, hydrogen, hydrogen sulfide, methane and Oxygen. Oxygen in the gastrointestinal tract is the result of swallowed air while eating and drinking (aerophagia) or may be due to hyperventilation in anxiety. Larger amounts would be expected in people who eat too quickly, chew gum, or smoke, since not everything is absorbed or excreted after burping.

The human colon is home to at least 400 different species of bacteria, and examples include carbohydrate-fermenting bacteria, methane-producing bacteria (methanogens), and pectinolytic bacteria. These bacteria are responsible for the production of carbon dioxide (the main gaseous product), hydrogen, hydrogen sulfide and methane. Flatus is the by-product of fermentable substrates (carbohydrates and proteins). Examples of these fermentable substrates include: beans, cabbage, Brussels sprouts, broccoli, and whole grains (which contain raffinose; and fruits, onions, and wheat (which contain fructose). These nonabsorbable carbohydrates, along with ingested sugars such as fructose, are found in fruit Foods such as potatoes, corn, wheat, and dietary fiber such as that found in oat bran, beans, and peas are all capable of producing flatulence by being metabolized by the colonic flora, followed by bacterial fermentation.

A number of different treatment options are reported in the literature for irritable bowel syndrome; However, dietary changes are not considered a priority in many cases. Sulfur-containing foods, such as beans, broccoli, Brussels sprouts, cabbage, cauliflower, garlic, and onions, have been identified as extremely gas-inducing.3 Evidence to exclude sulfur-containing foods is limited, and many cases argue against elimination diets being useless, limited in use, or not proven to be effective. 4,5 Nonetheless, other studies recognize that some foods may play a role in gas formation in IBS patients.3,6-12

The sulphur-containing amino acids cysteine, cystine, methionine and taurine are the main sources of dietary sulphur. Other sources are from glucosinolates found in Brassica vegetables (broccoli, Brussels sprouts, cabbage, cauliflower, and beets).13 In garlic and onions, the organic sulfur compounds are found in the form of diallyl thiosulfinates (allicin). Other dietary sources of sulfur come from meat or food additives used as preservatives (eg, sulfur dioxide and sodium metabisulfite). Magee et al.13 found a significant dose-dependent increase in fecal sulfide concentrations associated with meat intake.

Some oligosaccharides, such as raffinose and stacchiose, appear to be the key gas sources from bean digestion, as these compounds cannot be broken down by enzymes in the gut lining.3,14 These complex carbohydrates can be expected to contribute to gas and bloating after fermentation in IBS patients. Again, these patients might show greater sensitivity to just because of their reduced ability to handle gases as a result of altered motility. Information in the literature on the gas-forming ability of sulfur-containing foods and oligosaccharides is limited, and filling this knowledge gap can be an important step in the management of IBS.

Thanks to John Mcguire

Leave Your Comment