This article is part of our May 2020 special issue. Download the full issue here.
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. Gastroenterology. 2020;158(1):176-188.e7.
To investigate the effects of low-FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diet on persistent gut symptoms, the intestinal microbiome, and circulating markers of inflammation in patients with quiescent inflammatory bowel disease (IBD)
Multicenter, randomized, parallel, single-blinded, placebo-controlled, 4-week trial
Fifty-two patients (27 patients in the low-FODMAP–diet group and 25 patients in the control diet group) aged ≥18 years, with quiescent Crohn’s disease (CD) and ulcerative colitis (UC), from 2 large gastroenterology clinics in London, United Kingdom (UK). Patients were limited to those with ongoing gut symptoms meeting Rome III criteria for irritable bowel syndrome with diarrhea predominant (IBS-D), IBS with mixed bowel habits (IBS-M), or unsubtyped IBS (IBS-U), functional bloating or diarrhea, abdominal pain, bloating, and/or diarrhea on 2 or more days during the baseline screening week with inadequate relief, and who were naïve to a low-FODMAP diet. Quiescent IBD was determined by physician global assessment, absence of IBD flare in the prior 6 months, fecal calprotectin <250 µg/g, and C-reactive protein (CRP) <10 mg/L.
Study Parameters Assessed
1. Gut symptoms
- IBS symptom severity scale (IBS-SSS)
- Bristol stool form scale (BSFS)
- Gastrointestinal symptom rating scale (GSRS)
2. Health-related quality of life (HR-QoL)
- UK-specific IBD questionnaire
3. Disease activity
- Harvey-Bradshaw Index for CD
- Partial Mayo Score for UC
4. Patient-perceived IBD control
- IBD control questionnaire
5. Stool parameters, including
- Inflammatory markers
- Fecal calprotectin
- Fecal microbiome composition
- Short-chain fatty acids
6. T-cell phenotypes in blood
- Flow cytometry
Primary Outcome Measures
Primary outcome: Change in IBS-SSS.
Secondary outcomes: Other measures of gut symptoms (total IBS-SSS score, proportion of patients achieving a 50-point IBS-SSS reduction, global symptom questionnaire; and GI symptom rating scale), disease-specific HR-QoL, stool frequency and consistency, clinical disease activity, inflammatory markers, dietary intake, microbiome composition and function, short-chain fatty acid concentrations, and peripheral T-cell phenotype.
The low-FODMAP diet group had greater relief in gut symptoms, higher HR-QoL scores, and lower abundance of gut microbes that regulate immune response. There were no differences in microbiome diversity and markers of inflammation between the 2 groups.
The low-FODMAP diet has been found to benefit people with IBS. There is evidence that it can also help reduce persistent gastrointestinal symptoms in quiescent IBD, such as Crohn’s disease and ulcerative colitis.1,2 IBD is characterized by periods of remission and relapse. Current treatments are aimed at decreasing inflammation during the relapse and extending time in remission. However, many patients with quiescent IBD continue to have gastrointestinal symptoms. It is unclear why but could possibly be due to concurrent presence of IBS, low-grade inflammatory process, or the psychological impact of IBD.3
The takeaway from this study is that a low FODMAP diet can be used for patients with quiescent IBD for persistent IBS-like gastrointestinal symptoms such as gas, bloating, flatulence, and frequent stools.
The low-FODMAP diet limits foods high in certain types of sugars that are poorly absorbed by the digestive tract. These sugars are abbreviated as FODMAP, which stands for fermentable oligosaccharides (fructans and galacto-oligosaccharides), disaccharides (lactose), monosaccharides (fructose), and polyols (sorbitol and mannitol). Due to limited absorption, foods high in FODMAPs will move more slowly through the digestive tract and draw more water inside the lumen of the small intestine. Once FODMAPs pass down to the large intestine, they are fermented by colonic bacteria, a process that generates gas in the bowel. This increased amount of fluid and gas in the gut can lead to bloating, pain, and diarrhea in susceptible individuals. Eating fewer FODMAP carbohydrates can help decrease these symptoms.4
The low-FODMAP diet limits fermentation in the colon; however, microbiome diversity did not significantly change between the low-FODMAP and control groups in this study. Patients in the low-FODMAP group had less Bifidobacterium adolescentis, Bifidobacterium longum, and Faecalibacterium prausnitzii species, believed to regulate immune response, but this finding did not affect the inflammatory markers.
The takeaway from this study is that a low-FODMAP diet can be used for patients with quiescent IBD for persistent IBS-like gastrointestinal symptoms such as gas, bloating, flatulence, and frequent stools. A low-FODMAP diet can improve the quality of life, but it does not seem to have a significant effect on inflammation for patients in remission. Larger and longer-term studies are needed. Once symptomatic relief is obtained, long-term plans should be in place to address further nutritional needs of the patients.
Other considerations for management of functional gastrointestinal symptoms in IBD should include careful rule out of underlying conditions and monitoring of inflammation. Repeated fecal calprotectin measurement for monitoring inflammation is useful.5 A partial list of underlying conditions to consider includes small intestinal bacterial overgrowth (SIBO),6 increased intestinal permeability,7 prior surgical care and resulting adhesions, and the effect of underlying psychological conditions, such as anxiety.
Additional recommendations for management of IBD should include exercise, as there is evidence that exercise decreases the risk of future relapses.8 Counseling, cognitive behavioral therapy (CBT), mindfulness therapies, and hypnosis have been helpful for patients to manage their condition.9 Acupuncture and moxibustion therapy demonstrated good outcomes for IBD compared to oral sulfasalazine.10 Aloe vera gel and curcumin have been studied for IBD as well.11