insights

Read Time 4 Minutes

While irritable bowel syndrome (IBS) is not life threatening for most patients, it has enormous influence on quality of life and mental health, with symptoms like severe fatigue, abdominal pain, gastrointestinal (GI) distress and urgency, and mood disorders.^1-3 A recent meta-analysis found that patients with different subtypes of IBS (i.e., IBS with constipation, with diarrhea, or with mixed symptoms) had higher levels of depression and anxiety compared to healthy controls.⁴

Just how prevalent is IBS? Globally, the estimated prevalence rates are 9.2% and 3.8% based on ROME III and IV diagnostic criteria, respectively.⁵ IBS with mixed bowel habits and IBS with diarrhea have been the most commonly reported subtypes.⁵ In the United States, estimated prevalence is between 7% and 16%, with annual direct costs believed to be more than one billion dollars.⁶ IBS is prevalent across ages (from 15 to 65 years), especially among adults (18 years and above), with the first presentation of patients to a healthcare professional usually in the adult (30 to 50 years) age group.²

From a functional medicine perspective, a variety of treatments, including lifestyle modifications, may improve the quality of life and clinical outcomes for these patients. The functional medicine model for health care involves understanding the underlying factors that contribute to dysfunction and applying treatments that address those causes. In other words, functional medicine is concerned less with the disease itself and more about the dynamic processes that resulted in the person’s dysfunction. While IBS can seem like an intractable problem to many patients, modifiable lifestyle factors, from diet to stress management, may help to improve symptoms.^6,7

In the video below, IFM educator Tom Sult, MD, describes his functional medicine approach to IBS, which focuses on diet and lifestyle.

Diet & IBS

The last 20 years has seen an increasing amount of research on the role of modifiable lifestyle factors in improving symptoms for patients with IBS. Principal among this research is the growing recognition of food intolerances and cognitive/emotional factors as important triggers for symptoms in these patients.^8,9 Using the IFM Elimination Diet may help patients identify food triggers. And both observational and intervention studies have indicated reduced IBS symptoms and improved quality of life after introduction of a low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (low-FODMAP) diet in patients with IBS.¹⁰ In January 2021, the American College of Gastroenterology released clinical guidelines for the management of IBS and recommended (among other treatments) a limited trial of a low-FODMAP diet in patients with IBS to improve global symptoms.¹

The use of probiotics in the diet to help improve IBS symptoms has also been studied, and while the exact mechanisms of probiotics related to IBS are not fully understood, some research suggests that probiotics may improve IBS symptoms through manipulation of the gut microbiota.^11,12 A 2022 meta-analysis of randomized controlled trials that compared probiotic and drug interventions for IBS treatment found that while additional large-scale trials are warranted, both probiotic and drug interventions improved IBS symptoms (RR=0.60; CI 0.51-0.92 versus RR=0.87; CI 0.81 – 0.92, respectively).¹²

Interest in the role of gluten intolerance (and the possible benefit of a gluten-free diet) in IBS continues; however, only a limited number of studies with a small number of participants have evaluated the effectiveness of a gluten-free diet.¹³ Research studies indicate that IBS shares some similar gastrointestinal symptoms and gut microbiota profiles as celiac disease,¹⁴ and older studies have suggested an increased prevalence of celiac disease among patients with IBS symptomology compared to healthy controls.^15,16

Exercise & Other Lifestyle Modifications

Studies suggest that increasing levels of physical activities and reducing sedentary behavior may reduce IBS risk and may help improve IBS symptoms.^17,18 A 2019 study of 683 patients with IBS from 14 randomized controlled trials suggested that exercise interventions like yoga, walking/aerobic activity, tai ji, mountaineering, and Baduanjin quigong activity had significant benefits for patients with IBS.¹⁹ A 2020 observational study investigated the relationship between GI symptoms and physical activity among patients with IBS and found that among 101 university students with IBS, increased walking activity (measured by wearing a pedometer for one week) was associated with reduced severity of GI symptoms compared to less activity.²⁰

New research suggests that cognitive behavioral therapy (CBT) may also be an effective treatment for sustained GI symptom improvement compared with education alone.²¹ CBT has been found to be the most effective behavioral therapy in this brain-to-gut domain, with techniques that enhance the patient’s ability to downregulate pain pathways and reduce avoidance/isolation associated with symptoms.⁸ Acknowledging that levels of evidence vary, other common psychosocial-mind-body therapies for reducing IBS symptoms include diaphragmatic breathing, heart-rate variability biofeedback (through digital applications), progressive muscle relaxation, and mindfulness-based stress reduction.^22,23

Gut dysfunction compromises a patient’s health and diminishes vitality, but lifestyle modifications are showing promise in the treatment of chronic gastrointestinal diseases like IBS. Functional medicine takes a whole systems approach to evaluating and treating not only local gastrointestinal disease but the many systemic diseases that are linked to GI dysfunction. Learn more about IBS and the functional medicine model at IFM’s Applying Functional Medicine in Clinical Practice (AFMCP) course.

IBS development: primary causes and triggers

The Gut-Brain Axis and Systems Biology

SIBO: Comorbidities, SIFO, and Diagnosis

References

1. Lacy BE, Pimentel M, Brenner DM, et al. ACG clinical guideline: management of irritable bowel syndrome. Am J Gastroenterol. 2021;116(1):17-44. doi:14309/ajg.0000000000001036
2. Shorey S, Demutska A, Chan V, Siah KTH. Adults living with irritable bowel syndrome (IBS): a qualitative systematic review. J Psychom Res. 2021;140:110289. doi:1016/j.jpsychores.2020.110289
3. Ohlsson B. Extraintestinal manifestations in irritable bowel syndrome: a systematic review. Therap Adv Gastroenterol. 2022;15:17562848221114558. doi:1177/17562848221114558
4. Hu Z, Li M, Yao L, et al. The level and prevalence of depression and anxiety among patients with different subtypes of irritable bowel syndrome: a network meta-analysis. BMC Gastroenterol. 2021;21(1):23. doi:1186/s12876-020-01593-5
5. Oka P, Parr H, Barberio B, Black CJ, Savarino EV, Ford AC. Global prevalence of irritable bowel syndrome according to Rome III or IV criteria: a systematic review and meta-analysis [published correction appears in Lancet Gastroenterol Hepatol. 2020;5(12):e8]. Lancet Gastroenterol Hepatol. 2020;5(10):908-917. doi:1016/S2468-1253(20)30217-X
6. Camilleri M. Diagnosis and treatment of irritable bowel syndrome: a review [published correction appears in JAMA. 2021;325(15):1568]. JAMA. 2021;325(9):865-877. doi:1001/jama.2020.22532
7. D’Silva A, Marshall DA, Vallance JK, et al. Meditation and yoga for irritable bowel syndrome: a randomized clinical trial. Am J Gastroenterol. 2023;118(2):329-337. doi:14309/ajg.0000000000002052
8. Chey WD, Keefer L, Whelan K, Gibson PR. Behavioral and diet therapies in integrated care for patients with irritable bowel syndrome. Gastroenterology. 2020;160(1):47-62. doi:1053/j.gastro.2020.06.099
9. Jansson-Knodell CL, White M, Lockett C, Xu H, Shin A. Associations of food intolerance with irritable bowel syndrome, psychological symptoms, and quality of life. Clin Gastroenterol Hepatol. 2022;20(9):2121-2131.e3. doi:1016/j.cgh.2021.12.021
10.  van Lanen AS, de Bree A, Greyling A. Efficacy of a low-FODMAP diet in adult irritable bowel syndrome: a systematic review and meta-analysis [published correction appears in Eur J Nutr. 2021;60(6):3523]. Eur J Nutr. 2021;60(6):3505-3522. doi:1007/s00394-020-02473-0
11.  Dale HF, Rasmussen SH, Asiller ÖÖ, Lied GA. Probiotics in irritable bowel syndrome: an up-to-date systematic review. Nutrients. 2019;11(9):E2048. doi:3390/nu11092048
12.  van der Geest AM, Schukking I, Brummer RJM, van de Burgwal LHM, Larsen OFA. Comparing probiotic and drug interventions in irritable bowel syndrome: a meta-analysis of randomised controlled trials. Benef Microbes. 2022;13(3):183-194. doi:3920/BM2021.0123
13.  Dionne J, Ford AC, Yuan Y, et al. A systematic review and meta-analysis evaluating the efficacy of a gluten-free diet and a low FODMAPs diet in treating symptoms of irritable bowel syndrome. Am J Gastroenterol. 2018;113(9):1290-1300. doi:1038/s41395-018-0195-4
14.  Transeth EL, Dale HF, Lied GA. Comparison of gut microbiota profile in celiac disease, non-celiac gluten sensitivity and irritable bowel syndrome: a systematic review. Turk J Gastroenterol. 2020;31(11):735-745. doi:5152/tjg.2020.19551
15.  Irvine AJ, Chey WD, Ford AC. Screening for celiac disease in irritable bowel syndrome: an updated systematic review and meta-analysis. Am J Gastroenterol. 2017;112(1):65-76. doi:1038/ajg.2016.466
16.  Domzal-Magrowska D, Kowalski MK, Szczesniak P, Bulska M, Orszulak-Michalak D, Malecka-Panas E. The prevalence of celiac disease in patients with irritable bowel syndrome and its subtypes. Prz Gastroenterol. 2016;11(4):276-281. doi:5114/pg.2016.57941
17.  Gao X, Tian S, Huang N, Sun G, Huang T. Associations of daily sedentary behavior, physical activity, and sleep with irritable bowel syndrome: a prospective analysis of 362,193 participants. J Sport Health Sci. Published online February 18, 2023. doi:1016/j.jshs.2023.02.002
18.  Nunan D, Cai T, Gardener AD, et al. Physical activity for treatment of irritable bowel syndrome. Cochrane Database Syst Rev. 2022;6(6):CD011497. doi:1002/14651858.CD011497.pub2
19.  Zhou C, Zhao E, Li Y, Jia Y, Li F. Exercise therapy of patients with irritable bowel syndrome: a systematic review of randomized controlled trials. Neurogastroenterol Motil. 2019;31(2):e13461. doi:1111/nmo.13461
20.  Hamaguchi T, Tayama J, Suzuki M, et al. The effects of locomotor activity on gastrointestinal symptoms of irritable bowel syndrome among younger people: an observational study [published correction appears in PLoS One. 2020;15(12):e0244465]. PLoS One. 2020;15(5):e0234089. doi:1371/journal.pone.0234089
21.  Black CJ, Thakur ER, Houghton LA, Quigley EMM, Moayyedi P, Ford AC. Efficacy of psychological therapies for irritable bowel syndrome: systematic review and network meta-analysis. Gut. 2020;69(8):1441-1451. doi:1136/gutjnl-2020-321191
22.  Liu J, Lv C, Wang W, et al. Slow, deep breathing intervention improved symptoms and altered rectal sensitivity in patients with constipation-predominant irritable bowel syndrome. Front Neurosci. 2022;16:1034547. doi:3389/fnins.2022.1034547
23.  Shah K, Ramos-Garcia M, Bhavsar J, Lehrer P. Mind-body treatments of irritable bowel syndrome symptoms: an updated meta-analysis. Behav Res Ther. 2020;128:103462. doi:10.1016/j.brat.2019.103462