Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder that affects nearly twice as many women (14–24%) as men (5–19%) and is most often found in people younger than 45 years of age.1 Studies estimate that IBS affects 3% to 20% of the adult population, with most studies ranging from 10% to 15%.1 Only 5% to 7% of the adult population has been diagnosed with IBS, and yet it is one of the most frequent reasons for work or school absenteeism, second to the common cold.2,3 Up to 40% of visits to gastroenterologists are for evaluation of a functional GI disorder, and IBS is the most common reason for consultation with a gastroenterologist.4,5
IBS symptoms include bloating, abdominal pain, constipation, diarrhea, or a mixture of constipation and diarrhea. It is common for the symptoms to wax and wane and for patients to switch from one type of bowel habit to the other over time.5 IBS patients are also more likely to suffer from other functional gastrointestinal disorders such as dyspepsia and gastroesophageal reflux disease (GERD).6
Among women, IBS is most prevalent during the menstruation years, with symptoms being the most severe during the postovulatory and premenstrual phases.4 According to studies, over 50% of women seeing a gynecologist for lower abdominal pain also have IBS symptoms, and are more likely to be diagnosed with endometriosis, and 3 times more likely to receive a hysterectomy.4 The physicians at the SIBO Center for Digestive Health at the National College of Natural Medicine find a significant correlation between endometriosis-induced abdominal adhesions and small intestine bacterial overgrowth (SIBO). SIBO is the most common cause of IBS.
Often deemed a diagnosis of exclusion, IBS is officially diagnosed by the Rome criteria, revised in 2006 to Rome III (Table 1).11,12 Rome III defines IBS as abdominal pain or discomfort along with changes in bowel habits at least 6 months prior, and at least 3 times a month for the last 3 months without other disease or injury. However, a recent survey of international IBS experts revealed that the majority diagnose IBS based on their own clinical experience, without the Rome criteria.6 They believe that the current criteria do not reflect the IBS seen in their clinical practices. Notably, even those involved in creating the Rome criteria thought that the criteria did not reflect their practices. In their report, they called for a new set of criteria to be established. Specifically they identified four issues: lack of multinational validation, failure to include bloating in the criteria, a relative overemphasis on abdominal pain, and lack of a definition for pain. In particular, they wish to see a definition that includes both abdominal pain and bloating. Since bloating was believed to be a primary IBS symptom, both from published reports and based on the experience of the panel, we suggest that a reasonable approach to IBS diagnosis is to use the previous Rome II criteria, which includes bloating, along with the other symptoms (Table 2).13
Table 1: Rome III Diagnostic Criteria for IBS (Rome III)
Recurrent abdominal pain or discomfort** at least 3 days/month in the last 3 months associated with two or more of the following:
1. improvement with defecation
2. onset associated with a change in frequency of stool
3. onset associated with a change in form (appearance) of stool
* Criterion fulfilled for the last 3 months with symptom onset at least 6 months prior to diagnosis.
** "Discomfort" means an uncomfortable sensation not described as pain.
Table 2: Rome II Diagnostic Criteria for IBS
At least 12 weeks, which need not be consecutive, in the preceding 12 months of abdominal discomfort or pain that has two out of three features:
1. relieved with defecation; and/or
2. onset associated with a change in frequency of stool; and/or
3. onset associated with a change in form (appearance) of stool.
Symptoms that cumulatively support the diagnosis of irritable bowel syndrome are defined as "abnormal" for research purposes and include abnormal stool frequency (greater than 3 bowel movements per day and less than 3 bowel movements per week), abnormal stool form (lumpy/hard or loose/watery), and abnormal stool passage (straining, urgency, or feeling of incomplete evacuation). The passage of mucus, and bloating or a feeling of abdominal distension, also supports the diagnosis.
Screening blood tests for other etiologies may be useful. Additional diagnostic tests may be needed in cases with fevers, rectal bleeding, unexplained weight loss, anemia, and/or a family history of colon cancer, inflammatory bowel disease, or celiac disease. These tests may include stool and blood testing, a lower GI series, upper endoscopy, flexible sigmoidoscopy, or colonoscopy.2 Differential diagnosis of IBS includes SIBO, carbohydrate/fructose malabsorption, lactose intolerance, yeast overgrowth or hypersensitivity, parasitic infection, large intestine bacterial overgrowth or infection, abdominophrenic dyssynergia, celiac disease, IBD: Crohn's/ulcerative colitis, VIPoma, Zollinger-Ellison syndrome, cancer (pancreatic, stomach, small intestine), H. pylori infection, hypochlorhydria, and pancreatic insufficiency.
Changes in hormone status associated with pregnancy or menopause may also influence symptoms. During pregnancy, gastrointestinal symptoms may increase and intestinal transit decrease due to high estrogen and progesterone levels.13 Reports of abdominal bloating after menopause were primarily among women who are not receiving hormone replacement therapy. The National Survey of the Effects of Changes in Female Sex Hormones on Irritable Bowel Symptoms came to the following conclusions14:
- Pregnancy appears to temporarily improve IBS symptoms for many women.
- Oral estrogen and progesterone do not seem to have any effect on IBS symptom levels.
- Irregular menstruation has no association with IBS symptom severity.
- Hysterectomy or tubal ligation appears to have little effect on IBS severity.
- Endometriosis increases bloating symptoms but not other symptoms in IBS.
These findings seem to suggest a hormonal influence, yet no mechanism was mentioned by the authors, which raises an interesting new focus for research.
A suggestive physiologic mechanism is progesterone levels that peak 8 to 9 days after ovulation. The variation in progesterone levels leads to increased intestinal secretions and prostaglandin production that causes contraction of colonic smooth muscle.7 The predominant prostaglandin the endometrium produces during the premenstrual phase is PGF2µ. The release of PGF2µ leads to smooth muscle contraction, ischemia, and sensitization of nerve endings. Endometrial prostaglandin levels are three times higher in the luteal phase than in the follicular phase.8
An important risk factor for women with IBS is a history of physical or sexual abuse. Somatization may occur in patients with a history of abuse, leading to an expression of psychological stress through physical symptoms. An abuse history is suggested when the patient reports an average of three additional medical symptoms, with the most common symptoms being pelvic pain, headache, genitourinary complaints, and shortness of breath. These women also report a greater pain reference scale, and spend twice the number of days in bed due to illness. They also have a greater disability in all areas of functioning, more physiological distress, and more lifetime surgeries.4
The SIBO Center for Digestive Health has seen a steady increase in people who continue to search for an answer to their IBS etiology. Many have gone through extensive diagnostic workup yet have not been given effective treatment. The most often prescribed recommendations for IBS begin with increasing fiber and water or the use of laxatives.16 Depending on the presentation, opioid receptor agonists such as loperamide, antispasmodics such as hyoscine, cimetropium, pinaverium, and antidepressants such as low-dose tricyclic antidepressants and selective serotonin reuptake inhibitors may be prescribed. Rifaximin can reduce abdominal bloating by treating SIBO.16 More people have begun to seek out practitioners such as those at the SIBO Center for a diagnosis of SIBO (2013 ICD-9 008.8/569.89, 2014 ICD-10 CM K63.89: other specified disease of the intestine) as the potential etiology for their IBS.
The most common IBS assessments used by the physicians at the SIBO Center for Digestive Health include stool screening and SIBO assessment via lactulose breath testing.15 In some cases fructose, sucrose, lactose, and carbohydrate malabsorption may also be tested. One may also want to consider gluten intolerance, gluten cross-reactive foods, and autoimmunity.15 We find resolution of SIBO important in the successful treatment of IBS. We also address functional syndromes such as ileocecal value syndrome and hiatal hernia syndrome, as well as functional gastrointestinal tract support via selective botanicals, digestive enzymes, and probiotics. Research has found that it is also important to address sleeping habits and patterns in the IBS patient and to offer biofeedback/mindfulness or breath training as part of treatment.16 Many of our patients report further improvement with the addition of emotional freedom technique (EFT), or "tapping," and food hygiene education to improve digestive psychophysiology. Studies also support the use of hypnotherapy, regular exercise, and cognitive behavioral therapy with a focus on the person's thoughts and actions.16,17
The physicians at the SIBO Center for Digestive Health extend an invitation to all those interested in further information on IBS and SIBO to review the recording of the 2014 1st annual SIBO Symposium: "Current Perspectives and Management of IBS." It is available through the National College of Natural Medicine's Continuing Education Department (ce.ncnm.edu).
SIBO Center for Digestive Health at National College of Natural Medicine:
Allison Siebecker, ND, MSOM, LAc; Steven Sandberg-Lewis, ND, DHANP; Lisa Shaver, ND, MSOM, LAc; and Melanie Keller ND
1. Grundmann O, Yoon SL. Irritable bowel syndrome: epidemiology, diagnosis, and treatment: an update for health-care practitioners. J Gastroenterol Hepatol. 2010;25:691–699.
2. Understanding irritable bowel syndrome [online article]. American College of Gastroenterology. www.patients.gi.org/gi-health-and-disease/understanding-irritable-bowel-syndrome. Accessed August 15, 2013.
3. Porter CK. The incidence and gastrointestinal infectious risk of functional gastrointestinal disorders in a healthy US adult population. Am J Gastroenterol. 2011 Jan;106(1):130–138.
4. UNC Center for Functional GI & Motility Disorders. Women and irritable bowel syndrome (IBS) [online document]. UNC School of Medicine. http://www.med.unc.edu/ibs/files/educational-gi-handouts/IBS%20in%20Women.pdf.
5. Cremonini F, Talley NJ. Irritable bowel syndrome: epidemiology, natural history, health care seeking and emerging risk factors. Gastroenterol Clin North Am. 2005 Jun;34(2):189–204. Review.
6. Pimentel M, Talley NJ, Quigley EM, Hani A, Sharara A, Mahachai V. Report from the multinational irritable bowel syndrome initiative 2012. Gastroenterology. 2013 Jun;144(7):e1-5. doi:10.1053/j.gastro.2013.04.049.
7. Kane S. Gender issues in the management of inflammatory bowel disease and irritable bowel syndrome. Int J Fertil Womens Med. 2002;47(3):136–142.
8. Coco AS. Primary dysmenorrhea. Am Fam Physician. 1999;60(2):489–496.
9. Crowell MD, Dubin NH, Robinson JC, et al. Functional bowel disorders in women with dysmenorrhea. Am J Gastroenterol. 1994;89(11):1973–1977.
10. Thevarajah S, Polaneczky M, Scherl EJ, Frissora CL. Hormonal influences on the gastrointestinal tract and irritable bowel syndrome. Pract Gastroenterol. May 2005:62–75.
11. Drossman DA, Dumitrascu DL. Rome III: New standard for functional gastrointestinal disorders. J Gastrointestin Liver Dis. 2006 Sep;15(3):237–441. Review.
12. Rome III Diagnostic Criteria for Functional Gastrointestinal Disorders. C1 Irritable Bowel Disease [online document]. Rome Foundation. http://www.romecriteria.org/assets/pdf/19_RomeIII_apA_885-898.pdf.: p. 889. Accessed December 7, 2013.
13. Comparison Table of Rome II & Rome III Adult Diagnostic Criteria C1 Irritable Bowel Syndrome [online document]. Rome Foundation. http://www.romecriteria.org/assets/pdf/20_RomeIII_apB_899-916.pdf.: p. 907. Accessed December 7, 2013.
13. Wald A, Van Thiel DH, Hoechstetter L, et al. Gastrointestinal transit: the effect of the menstrual cycle. Gastroenterology. 1981;80(6):1497–1500.
14. Lewis MJV, Houghton LA, Whorwell PJ. Abdominal distension in females with irritable bowel syndrome (IBS): the effect of the menopause and hormone replacement therapy. Gut. 2001;48(3 Suppl 1):A-43. Abstract #168.
15. Sandberg-Lewis S. Irritable bowel syndrome demystified. Functional Gastroenterology Webinar Series. FMTown.com.
16. Irritable bowel syndrome [Web page]. National Digestive Diseases Information Clearinghouse (NDDIC). http://digestive.niddk.nih.gov/ddiseases/pubs/ibs.
17. Moser G, Trägner S, Gajowniczek EE, et al. Long-term success of GUT-directed group hypnosis for patients with refractory irritable bowel syndrome: a randomized controlled trial. Am J Gastroenterol. 2013 Apr;108(4):602–609. doi:10.1038/ajg.2013.19. Epub 2013 Feb 19.
Melanie Keller, ND, is in private practice, Natural Functional Medicine LLC in Portland, Oregon, and is one of the private practice physicians at the SIBO Center for Digestive Health at the National College of Natural Medicine (NCNM). During her training at NCNM she had an extensive internship with Dr. Steven Sandberg-Lewis, followed by postgraduate training with Dr. Allison Siebecker. Her areas of focus include SIBO, IBS, functional gastroenterology, and musculoskeletal medicine. Dr. Keller utilizes functional testing, nutrition, energetic psychology techniques, and visceral and structural manipulation to address the whole person.
Steven Sandberg-Lewis ND, DHANP, has been a practicing naturopathic physician for 35 years, previously on Orcas Island in Washington State and now exclusively at the NCNM Clinic. Dr. Sandberg-Lewis receives referrals of patients with digestive diseases who desire naturopathic treatment options; often these are conditions that have defied diagnosis by other physicians. He understands the diseases of the gastrointestinal tract, but also can assess function and often find successful treatments to regain normal function of the digestive system.
Allison Siebecker, ND, MSOM, LAc, has worked in the nutritional field since 1988 and is a 2005 graduate of NCNM where she earned her doctorate in naturopathic medicine and her masters in Oriental medicine. Dr. Siebecker is the medical director of the SIBO Center for Digestive Health at NCNM Clinic in Portland, Oregon, where she specializes in the treatment of SIBO. She is instructor of advanced gastroenterology at NCNM, teaches continuing education classes for physicians, is the author of the educational website siboinfo.com, and is writing a book synthesizing the SIBO data into one source. In 2005 and 2013, she received the Best in Naturopathy award from the Townsend Letter for her articles "Traditional Bone Broth in Modern Health and Disease"(2005) and "Small Intestine Bacterial Overgrowth: Often Overlooked Cause of IBS" (2013).