Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a gastrointestinal disorder characterized by irregular bowel habits and abdominal pain. ^[1] Four subtypes of IBS have been identified: constipation-predominant IBS (IBS-C), diarrhea-predominant IBS (IBS-D), mixed IBS (IBS-M), and un-subtyped IBS. One subtype is not completely independent of the others, for example, patients with IBS-C will most likely experience IBS-D as well at some point in their lives. ^[2] IBS is a chronic condition that affects an estimated 3-25% of the population; it is two or three times more common in females. Although prevalent in all age groups, IBS symptoms seem to decline with advancing age. ^[3] Approximately 30% of patients report symptom resolution within one year, however, 70% of IBS sufferers will re-experience symptoms within five years. ^[4]

Causes

There are numerous risk factors for IBS. IBS can occur as a result of hypochlorhydria. Hypochlorhydria occurs when there is insufficient stomach acid production. Stomach acid is important for the breakdown of food and acts as a defence mechanism against the entry of pathogenic organisms. ^[5] Pathogenic organisms can cause gastrointestinal infections which alter the GI flora and function, and thus may be responsible for post-infectious IBS. ^[1] Intestinal dysbiosis can also cause symptoms of IBS. Dysbiosis is an alteration of the normal intestinal microflora resulting from acute GI infections, antibiotic use, poor dietary choices, as well as food allergies and sensitivities. ^[5] Alteration of the normal flora produces small intestinal bowel overgrowth (SIBO), where pathogenic bacteria begin to outnumber beneficial bacterial cultures. Patients suffering from IBS have a tendency to lower fecal concentrations of beneficial bacteria Bifidobacteria and Lactobacilli, and higher concentrations of pathogenic Enterobacteriaceae. The small intestine typically has low levels of colonic-type bacteria, but issues such as dysmotility and lack of stomach acid may exacerbate SIBO. ^[1] Meanwhile, low-grade inflammation may also contribute to symptoms of IBS: inflammation is theorised to cause local disruptions to neuromuscular function. ^[1] It has been postulated that the release of certain inflammatory mediators may affect nearby enteric nerves, causing alteration in gut function and sensory perception. ^[6] Altered GI tract motility, visceral hypersensitivity, and neurotransmitter imbalances are also potential contributors to the symptoms of IBS. ^[5] Psychological issues are also associated with IBS: stress, traumatic events, anxiety, and/or depression often precede the initial onset of IBS and exacerbate its symptoms. ^[1] A sympathetic tone prevails in all IBS patients, as well as an elevated stress index. ^[7] IBS may also have a genetic predisposition, where there is an alteration in the central nervous system’s response to stimuli. ^[1] As mentioned above, several dietary factors contribute to dysbiosis: a high sulfate diet, a diet high in animal protein, and a high simple sugar/refined carbohydrate diet. A diet high in sulfate leads to more sulfate-reducing bacteria in the colon, where sulfite and sulfate are reduced to sulfide. Sulfide can form toxic hydrogen sulfide which causes common symptoms of IBS such as abdominal gas and bloating. In addition, protein can escape digestion in the upper GI tract, thereby reaching the colon in its original form. The protein can then be fermented by colon microflora into toxic compounds: protein alters the function of several enzymes, including beta-glucuronidase, which in turn results in an increased production of toxic substances in the bowel. Lastly, simple sugars and refined carbohydrates slow bowel transit time resulting in increased fermentation in the colon, as well as a compromised mucosal defense. ^[5] Neurotransmitter imbalances may also affect IBS. IBS patients have decreased serotonin synthesis and use, which may contribute to abdominal pain. Eighty percent of serotonin is found in the GI tract. ^[2] The low levels of serotonin alter motor and secretory function resulting in constipation or diarrhea. ^[1] In adequate amounts, serotonin stimulates receptors which are responsible for peristalsis and GI tract secretions. Serotonin also acts to promote communication along the gut-brain axis. The diarrhea and urgency commonly experienced by IBS-D patients may be due to an exaggerated serotonin response leading to increased peristalsis and secretions. ^[2]

Diagnosis

A diagnosis of IBS can be made clinically and based on the exclusion of “red flag” symptoms. Red flag symptoms include blood in the stool, unintentional weight loss, fever, and night sweats. ^[8] There exists no identifiable organic cause for IBS, and no reliable diagnostic marker has been identified. ^[2] In addition, there is no cure for IBS; treatments are used to reduce symptom onset and severity. ^[4] IBS patients show no identifiable inflammation on colonic biopsies. However, some patients show increased inflammatory markers suggesting that low-grade inflammation is possible. ^[1] IBS presents with symptoms of recurrent abdominal discomfort/pain, altered bowel function, as well as bloating and gas. ^[4] Two or more of the following criteria must be present for at least three days per month during the preceding three months ^[3]: i) improvement of GI disturbances with defecation, ii) onset associated with a change in frequency of stool, or iii) onset associated with a change in appearance of stool. Individuals with IBS may also suffer from systemic symptoms such as tension headaches, fibromyalgia syndrome, chest pain, chronic fatigue syndrome, or chronic pelvic pain. ^[5] Laboratory tests are often requisitioned to rule-in an underlying cause for the IBS. The Gastro-Test is ordered for those suspected of having hypochlorhydria. Urinary indican measurements will help determine whether small intestine bacterial overgrowth is of concern. Meanwhile, urinary lactulose and mannitol levels are measured to determine if intestinal hyper-permeability is a possibility. Food sensitivities and allergies also need to be tested for: IgG and IgE antibodies, respectively, can help determine if an issue is present. ^[5]

Natural Treatments

Dietary Modifications

1. Low-Sulfate Diet: In order to improve dysbiosis, and symptoms of IBS, a low-sulfate diet should be followed for at least 6 to 12 months. This allows time for the bowel to normalize and for toxins to be eliminated. Common sources of sulfates include: preservatives, shellfish, baked goods, white bread, alcoholic beverages, and foods rich in sulfur-containing amino acids (milk, cheese, eggs, meat, and cruciferous vegetables). ^[5]
2. Elimination Diet: This type of diet can be extremely beneficial for those suffering from IBS. Patients are instructed to abstain from common allergens for a set period of time, and to continue to abstain from allergic or intolerant foods once these particular foods are identified. ^[3]
3. Low-FODMAP Diet: A diet low in fermentable oligo-, di-, and monosaccharides and polyols (sugar alcohols) has shown improvements in symptoms of IBS. These FODMAPS generally have high osmotic activity and are fermented by colonic bacteria rather quickly: causing symptoms of distention, bloating, and gas. Luminal distention caused by unabsorbed and fermented FODMAPS could be the basis for many IBS symptoms. ^[2]
4. Fiber is essential for the health and proper function of the GI tract. Fiber can significantly improve GI transit time and reduce overall risk of cancer and disease. Although fiber helps with IBS symptoms, it appears to exacerbate abdominal pain. Soluble fiber improves IBS symptoms and constipation, whereas insoluble fiber has been shown to have no effect on IBS symptoms. Soluble fiber appears to be most therapeutic for the treatment of IBS-C in particular. Sources of soluble fiber include: ground flaxseeds, psyllium husks, slippery elm powder, oat bran, and pectin. ^[1]
5. Fluid intake (2100-2600ml per day) is also important for proper bowel function. Stool frequency and weight have been reported to be significantly decreased in individuals not drinking enough water. ^[1]

Lifestyle Changes

Exercise is effective in treating constipation in those with IBS. Daily moderate exercise is capable of significantly accelerating GI transit time, which results in softer and more frequent stools. ^[5] It is also effective for stress reduction, which may also be a cause of IBS symptoms. ^[3]

Stress management can also help reduce the occurrence and severity of IBS. Techniques include guided imagery, deep breathing exercises, meditation, tai chi, and yoga (to name a few).

Supplements

Probiotics (100 million to 6 billion CFU per day and gradually increased over time): Beneficial bacteria provide relief of IBS symptoms: suppressing growth and binding of pathogenic bacteria, improving barrier function of epithelium, and altering immune activity in the host. ^[6] Probiotics have also been used in many GI disorders. Appropriate strains of probiotics help to normalize the disrupted intestinal and colonic microflora, as well as reduce toxic by-products of fermentation. ^[5] Probiotic use is associated with improvements in global IBS symptoms and reductions in abdominal pain compared to placebo. ^[4] Probiotic organisms (Bifidobacteria and Lactobacilli) are found in supplements and in fermented foods (mainly yogurt, sauerkraut, and kefir). Commercially available probiotic strains that have shown efficacy in the treatment of IBS include Lactobacilli fermentum and Lactobacilli plantarum. ^[1]

Synbiotics (5 x 10^9 CFU Bifidobacterium longum and 2.5g fructo-oligosaccharides) are an effective way to deliver both probiotics and prebiotics to the colon, as a combination. This method is known to improve survival of probiotics through the upper GI tract so that colonization in distal areas can be successful. Synbiotics also have a stimulating effect on the growth and activities of probiotic strains delivered and those that are already present within the bowel. Patients with IBS-C report a decrease in abdominal pain as well as increased stool frequency when taking synbiotics. ^[1]

Botanicals

1. Abdominal pain is often treated with the use of carminatives and antispasmodics. Peppermint (Mentha piperita), ginger (Zingiber officinale), coriander seed (Coriandrum sativum), and orange peel (Citrus reticulata) appear to be effective. ^[1]
2. Psychological distress can be minimized with the use of anxiolytics, adaptogens, and nervines, which offer support for the nervous system. Passiflora incarnate and Valeriana officinalis are common anxiolytics used to treat anxiety. Meanwhile, there are two major subtypes of adaptogens: stimulating and relaxing. Stimulating adaptogens include Rhodiola rosea, Panax ginseng, and Eleutherococcus senticosus; there herbs are superior choices for patients who present with fatigue as part of their symptom picture. On the other hand, relaxing adaptogens are prescribed if anxiety or other forms of overstimulation are present; some of these herbs include Withania somnifera, Schisandra chinensis, and Ganoderma lucidum. ^[1]
3. Inflammation, if present, is usually very mild and can be managed using herbs like Curcuma longa, Glycyrrhiza glabra, and Matricaria recutita. ^[1]

Conclusion

IBS is a chronic condition that results from a variety of contributing factors. While the exact cause of IBS is ambiguous, treatments are geared toward symptom management and improving quality of life. Diagnosis is made clinically and is subject to the presence of at least two of three criteria: i) improvement of GI symptoms with defecation, ii) onset associated with change in frequency of stool, or iii) onset associated with change in appearance of stool. There is currently no cure for IBS. Changes in lifestyle and dietary habits may provide relief of symptoms. Please consult with a health professional prior to taking any supplements or medications: side effects and interactions among supplements and/or drugs have the potential to be harmful.