Long-term personalized low FODMAP diet improves symptoms and maintains luminal Bifidobacteria abundance in irritable bowel syndrome.

BACKGROUND: Short-term trials demonstrate the low FODMAP diet improves symptoms of irritable bowel syndrome (IBS) but impacts nutrient intake and the gastrointestinal microbiota. The aim of this study was to investigate clinical symptoms, nutrient intake, and microbiota of patients with IBS 12 months after starting a low FODMAP diet. METHODS: Participants enrolled in a previous short-term clinical trial and who had been through structured FODMAP restriction, reintroduction, and personalization were invited to participate in a follow-up study at one time point at 12 months. Gastrointestinal symptoms, stool output, dietary intake, and quality of life were recorded. Stool samples were collected and analyzed for microbiota (qPCR) and short-chain fatty acids (SCFA). Data were compared with baseline (prior to any intervention in the original clinical trial) using non-parametric statistics. KEY RESULTS: Eighteen participants were included in the study. Adequate relief of symptoms occurred in 5/18 (28%) at baseline and increased to 12/18 (67%) following long-term personalized low FODMAP diet (p = 0.039). There was a reduction in IBS-SSS total score between baseline (median 227, IQR 99) and long term (154, 89; p < 0.001). Bifidobacteria abundance was not different between baseline (median 9.29 log10 rRNA genes/g, IQR 1.45) and long term (9.20 log10 rRNA genes/g, 1.41; p = 0.766, q = 0.906); however, there were lower concentrations of total SCFA, acetate, propionate, and butyrate. CONCLUSIONS: In this long-term analysis, two thirds of patients reported adequate relief of symptoms after 12 months of personalized low FODMAP diet that did not result in differences from baseline in Bifidobacteria. FODMAP reintroduction and personalization may normalize some of the effects of short-term FODMAP restriction.

Gut microbiota associations with diet in irritable bowel syndrome and the effect of low FODMAP diet and probiotics.

BACKGROUND AND AIMS: Diet is both a modulator of the gastrointestinal microbiota and an important therapy in irritable bowel syndrome (IBS). We aimed to comprehensively (i) identify diet-microbiota associations in adults with IBS consuming habitual diet; (ii) assess the impact of two nutritional interventions on the microbiota; and (iii) determine whether baseline microbiota can predict clinical response to diet or probiotic intervention. METHODS: Data were analyzed from 95 individuals with IBS participating in a previously published 4-week 2x2 factorial design randomized controlled trial investigating the impact of the low FODMAP diet (LFD) and co-administration of a probiotic. Diet was assessed at four hierarchical levels and partial 16S rRNA gene sequencing was used to profile the microbiota. RESULTS: There were numerous diet-microbiota associations especially at the nutrient level, including a negative association between protein and Bifidobacterium abundance (rs = -0.358, p < 0.001). After correction for multiple testing, the significance for this association (q = 0.237) and all others was lost. Low FODMAP diet led to changes in abundance of major saccharolytic genera compared with sham diet, including higher Bacteroides (LFD 34.1% (15.7%) vs sham 23.3% (15.2%), q = 0.01) and lower Bifidobacterium (0.9% (1.0%) vs 2.1%, (2.5%) q = 0.029). Compared with placebo, probiotic supplementation led to higher Lactobacillus (probiotic 0.08% (0.1%) vs placebo 0.03% (0.2%), q < 0.001), and Streptococcus abundance (2.0% (2.2%) vs 0.6% (1.2%), q = 0.001). The probiotic treatment buffered the impact of the low FODMAP diet on Bifidobacterium. Baseline microbiota did not predict clinical response to either intervention. CONCLUSIONS: Although diet modifies the gut microbiota, bivariate correlation analysis may only provide a limited explanation of the complex diet interactions with individual gut bacteria in IBS. Some diet interventions modify the microbiota in IBS. TRIAL REGISTRY: ISRCTN (http://www.isrctn.com) Registered under ISRCTN registry identifier no.ISRCTN02275221.

Nutrient Intake, Diet Quality, and Diet Diversity in Irritable Bowel Syndrome and the Impact of the Low FODMAP Diet.

BACKGROUND: Individuals with irritable bowel syndrome (IBS) may modify their diet, which may pose nutritional risk. Further, some dietary approaches, such as a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs), are restrictive and may contribute to nutritional inadequacy. OBJECTIVE: Our aim was to evaluate habitual nutrient intake, diet quality, and diversity in IBS and the effect of a 4-week low FODMAP diet on these parameters compared with controls. DESIGN: Data from two randomized controlled trials were included for this secondary analysis. Participants were randomized to low FODMAP diet (n=63) or control diet (sham diet n=48, habitual diet n=19). PARTICIPANTS/SETTING: Participants included 130 individuals with IBS referred to a tertiary center in London, UK between January 2010 to June 2011 and January 2013 to November 2014. INTERVENTION: Participants in one trial were randomized to receive either low FODMAP dietary counseling or sham control dietary counseling. In the other, they were randomized to receive low FODMAP dietary counseling or to continue habitual diet. All advice was provided by a specialist dietitian. MAIN OUTCOME MEASURES: Habitual (usual) dietary intake at baseline (n=130) and after a 4-week intervention period was measured using 7-day food records. STATISTICAL ANALYSES PERFORMED: Analysis of covariance and χ2 tests evaluated differences across groups at 4 weeks. RESULTS: When examining habitual intake of individuals with IBS, fiber intake was low, with only 6 (5%) achieving the target (30 g/day). In those receiving low FODMAP advice, there was no difference in intake of most nutrients compared with controls. However, there was lower intake of starch (109 g/day) vs habitual control diet (128 g/day; P=0.030), and higher intake of vitamin B-12 (6.1 µg/day) vs habitual (3.9 µg/day) and sham control diets (4.7 µg/day; P<0.01). Overall scores for diet quality were lower after low FODMAP advice vs habitual control diet (P<0.01). CONCLUSION: This study demonstrates many individuals with IBS fail to meet dietary reference values for multiple nutrients. A 4-week low FODMAP diet, when delivered by a specialist dietitian, does not impact on intake of most nutrients or diet diversity but decreases diet quality compared with control diets.