Despite the multitude of medications available, treating patients with inflammatory bowel disease (IBD) remains challenging. Patients often receive numerous medications throughout their disease course, ranging from corticosteroids and immunomodulators to tumor necrosis factor alpha (TNF-α) and integrin inhibitors. The ultimate goal in treating IBD is to induce and maintain remission, which has multiple subtypes that include clinical, biochemical, and endoscopic remission.
Even if patients attain some form of remission, approximately 50% can still experience functional-type symptoms consistent with irritable bowel syndrome (IBS).1,2 Frequently reported IBS symptoms include bloating, flatulence, abdominal pain, and diarrhea.1,2 Based on the nature of the reported symptoms, it can be challenging to classify a specific symptom as IBS or IBD-related. Evaluating the patient using laboratory and/or stool studies, imaging, and endoscopic procedures can assist in making this determination. If the patient is thought to have more IBS-predominant symptoms based on this evaluation, treatment options may be limited.
Many patients with IBD may understandably become overwhelmed by use of multiple medications. Thus, some will inquire about any potential adjunct “therapies”, such as certain diets. One diet that has become increasingly popular for many patients (not only those with IBD or IBS) is the low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet (LFD).
FODMAPs are not well absorbed in the small bowel and may cause increased fermentation and luminal distension in the colon, leading to subsequent cramping, diarrhea and bloating.1,3 Examples of foods high in FODMAPs include wheat, barley, certain fruits (apples, pears, mangoes) and vegetables (onions, garlic, peas), and dairy (milk, yogurt, ice cream).4 An LFD has been included in the American Gastroenterological Association (AGA) 2019 expert review for managing functional GI symptoms in patients with IBD, as long as special attention is paid to a patient’s nutritional status.3
There is increasing research interest in evaluating an LFD in patients with IBD. However, the amount of large, prospective, blinded studies is relatively limited. Zhan et al conducted a meta-analysis and systematic review of studies evaluating LFD in the treatment of IBD.2 A total of 6 studies, of which 2 were randomized controlled trials, that included 319 patients were analyzed. Overall, patients were significantly more satisfied with their GI symptoms in the LFD group (OR, 26.84; 95% CI, 4.6-156.54; P <.00001). Specifically, an LFD was associated with improvements in multiple GI symptoms including diarrhea (OR, 0.24; 95% CI, 0.11-0.52; P =.0003), abdominal bloating (OR, 0.10; 95% CI, 0.06-0.16; P <.00001), abdominal pain (OR, 0.24; 95% CI, 0.16-0.35; P <.00001), nausea (OR, 0.51; 95% CI, 0.31-0.85; P =.009) and fatigue (OR, 0.40; 95% CI, 0.24-0.66; P =.0003). There was no statistical difference seen with respect to constipation, which may be attributed to the low fiber content included in the LFD.
A group led by Bodini et al conducted a prospective study evaluating the LFD in 55 patients with IBD who were in remission or with mild disease activity (Mayo score <6).1 Patients were evaluated at baseline and after 6 weeks of LFD compared with standard diet (SD) using disease severity indices, fecal calprotectin (FCP), and quality of life assessments. There was a statistically significant decrease in median FCP at 6 weeks in the LFD group (76.6 vs 50.0 mg/kg; P =.004) but not in the SD group (91.0 vs 87.0 mg/kg; P =.175). There was no statistical difference in median C-reactive protein (CRP) value between the two groups at baseline and 6 weeks. The modified Harvey-Bradshaw index (HBi) was the only index to have a statistically significant difference in favor of the LFD. There was no significant difference between the two groups using the IBD-Q quality of life scale. It is important to note that this was a relatively short term study with no endoscopic procedures performed.
Cox et al conducted a 4 week prospective study evaluating LFD in 52 patients with quiescent IBD.5 Significantly more patients in the LFD group reported adequate relief of their GI symptoms compared with the control group (52% vs 16%; P =.007) and had higher health-related quality of life scores. LFD had the greatest impact on flatulence and bloating. There was no statistical difference in IBS severity scores between the groups. Patients in the LFD group also had lower numbers of certain bacteria, including several strains of Bidifobacterium, which play an important role within the immune system. While there were some differences in the gut microbiomes of both groups, the differences were relatively small. Of note, both study groups had high levels of self-reported compliance.
At this point, it appears that most research currently available indicates that short-term utilization of an LFD may help ameliorate some of the mild IBS symptoms associated with quiescent IBD. Long term studies are needed to further evaluate the impact of an LFD on a patient’s gut microbiome and their overall nutritional status. Although compliance is reported as relatively high in many studies, “real-life” adherence rates will need to be closely monitored, as an LFD may not be practical for many patients. If a patient chooses to follow an LFD, they should be closely monitored by their gastroenterologist with strong consideration for the involvement of a skilled dietician.
- Bodini G, Zanella C, Crespi M, et al. A randomized, 6-week trial of a low FODMAP diet in patients with inflammatory bowel disease. Nutr. Published online July 1, 2019. doi: 10.1016/j.nut.2019.06.023
- Zhan Y, Zhan Y, Dai S. Is a low FODMAP diet beneficial for patients with inflammatory bowel disease? a meta-analysis and systematic review. Clin Nutr. 2018;37(1):123-129. doi: 10.1016/j.clnu.2017.05.019
- Colombel JF, Shin A, Gibson PR. AGA clinical practice update on functional gastrointestinal symptoms in patients with inflammatory bowel disease: expert review. Clin Gastroenterol Hepatol. 2019;17(3):380-390. doi: 10.1016/j.cgh.2018.08.001
- Shepherd SJ, Lomer MCE, Gibson PR. Short-chain carbohydrates and functional gastrointestinal disorders. Am J Gastroenterol. 2013;108(5):707-717. doi: 10.1038/ajg.2013.96
- Cox SR, Lindsay JO, Fromentin S, et al. Effects of low FODMAP diet on symptoms, fecal microbiome, and markers of inflammation in patients with quiescent inflammatory bowel disease in a randomized trial. Gastroenterol. 2020;158(1):176-188. doi: 10.1053/j.gastro.2019.09.024