Exploration of differential responses to FODMAPs and gluten in people with irritable bowel syndrome- a double-blind randomized cross-over challenge study

INTRODUCTION

There is large variation in response to diet in irritable bowel syndrome (IBS) and determinants for differential response are poorly understood.

OBJECTIVES

Our aim was to investigate differential clinical and molecular responses to provocation with fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs) and gluten in individuals with IBS.

METHODS

Data were used from a crossover study with week-long interventions with either FODMAPs, gluten or placebo. The study also included a rapid provocation test. Molecular data consisted of fecal microbiota, short chain fatty acids, and untargeted plasma metabolomics. IBS symptoms were evaluated with the IBS severity scoring system. IBS symptoms were modelled against molecular and baseline questionnaire data, using Random Forest (RF; regression and clustering), Parallel Factor Analysis (PARAFAC), and univariate methods.

RESULTS

Regression and classification RF models were in general of low predictive power (Q2 ≤ 0.22, classification rate < 0.73). Out of 864 clustering models, only 2 had significant associations to clusters (0.69 < CR < 0.73, p < 0.05), but with no associations to baseline clinical measures. Similarly, PARAFAC revealed no clear association between metabolome data and IBS symptoms.

CONCLUSION

Differential IBS responses to FODMAPs or gluten exposures could not be explained from clinical and molecular data despite extensive exploration with different data analytical approaches. The trial is registered at www.

CLINICALTRIALS

gov as NCT03653689 31/08/2018.

IBS randomized study: FODMAPs alter bile acids, phenolic- and tryptophan metabolites, while gluten modifies lipids

Diet is considered a culprit for symptoms in irritable bowel syndrome (IBS), although the mechanistic understanding of underlying causes is lacking. Metabolomics, i.e., the analysis of metabolites in biological samples may offer a diet-responsive fingerprint for IBS. Our aim was to explore alterations in the plasma metabolome after interventions with fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) or gluten versus control in IBS, and to relate such alterations to symptoms. People with IBS (n = 110) were included in a double-blind, randomized, crossover study with 1-wk provocations of FODMAPs, gluten, or placebo. Symptoms were evaluated with the IBS severity scoring system (IBS-SSS). Untargeted metabolomics was performed on plasma samples using LC-qTOF-MS. Discovery of metabolite alterations by treatment was performed using random forest followed by linear mixed modeling. Associations were studied using Spearman correlation. The metabolome was affected by FODMAP [classification rate (CR) 0.88, P < 0.0001], but less by gluten intake CR 0.72, P = 0.01). FODMAP lowered bile acids, whereas phenolic-derived metabolites and 3-indolepropionic acid (IPA) were higher compared with placebo. IPA and some unidentified metabolites correlated weakly to abdominal pain and quality of life. Gluten affected lipid metabolism weakly, but with no interpretable relationship to IBS. FODMAP affected gut microbial-derived metabolites relating to positive health outcomes. IPA and unknown metabolites correlated weakly to IBS severity. Minor symptom worsening by FODMAP intake must be weighed against general positive health aspects of FODMAP. The gluten intervention affected lipid metabolism weakly with no interpretable association to IBS severity. Registration: www.clinicaltrials.gov as NCT03653689.NEW & NOTEWORTHY In irritable bowel syndrome (IBS), fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs) affected microbial-derived metabolites relating to positive health outcomes such as reduced risk of colon cancer, inflammation, and type 2 diabetes, as shown in previous studies. The minor IBS symptom induction by FODMAP intake must be weighed against the positive health aspects of FODMAP consumption. Gluten affected lipids weakly with no association to IBS severity.

Effects of FODMAPs and Gluten on Gut Microbiota and Their Association with the Metabolome in Irritable Bowel Syndrome: A Double-Blind, Randomized, Cross-Over Intervention Study

BACKGROUND

A mechanistic understanding of the effects of dietary treatment in irritable bowel syndrome (IBS) is lacking. Our aim was therefore to investigate how fermentable oligo- di-, monosaccharides, and polyols (FODMAPs) and gluten affected gut microbiota and circulating metabolite profiles, as well as to investigate potential links between gut microbiota, metabolites, and IBS symptoms.

METHODS

We used data from a double-blind, randomized, crossover study with week-long provocations of FODMAPs, gluten, and placebo in participants with IBS. To study the effects of the provocations on fecal microbiota, fecal and plasma short-chain fatty acids, the untargeted plasma metabolome, and IBS symptoms, we used Random Forest, linear mixed model and Spearman correlation analysis.

RESULTS

FODMAPs increased fecal saccharolytic bacteria, plasma phenolic-derived metabolites, 3-indolepropionate, and decreased isobutyrate and bile acids. Gluten decreased fecal isovalerate and altered carnitine derivatives, CoA, and fatty acids in plasma. For FODMAPs, modest correlations were observed between microbiota and phenolic-derived metabolites and 3-indolepropionate, previously associated with improved metabolic health, and reduced inflammation. Correlations between molecular data and IBS symptoms were weak.

CONCLUSIONS

FODMAPs, but not gluten, altered microbiota composition and correlated with phenolic-derived metabolites and 3-indolepropionate, with only weak associations with IBS symptoms. Thus, the minor effect of FODMAPs on IBS symptoms must be weighed against the effect on microbiota and metabolites related to positive health factors.

An inverse association between plasma benzoxazinoid metabolites and PSA after rye intake in men with prostate cancer revealed with a new method

Prostate cancer (PC) is a common cancer among men, and preventive strategies are warranted. Benzoxazinoids (BXs) in rye have shown potential against PC in vitro but human studies are lacking. The aim was to establish a quantitative method for analysis of BXs and investigate their plasma levels after a whole grain/bran rye vs refined wheat intervention, as well as exploring their association with PSA, in men with PC. A quantitative method for analysis of 22 BXs, including novel metabolites identified by mass spectrometry and NMR, was established, and applied to plasma samples from a randomized crossover study where patients with indolent PC (n = 17) consumed 485 g whole grain rye/rye bran or fiber supplemented refined wheat daily for 6 wk. Most BXs were significantly higher in plasma after rye (0.3–19.4 nmol/L in plasma) vs. refined wheat (0.05–2.9 nmol/L) intake. HBOA-glc, 2-HHPAA, HBOA-glcA, 2-HPAA-glcA were inversely correlated to PSA in plasma (p < 0.04). To conclude, BXs in plasma, including metabolites not previously analyzed, were quantified. BX metabolites were significantly higher after rye vs refined wheat consumption. Four BX-related metabolites were inversely associated with PSA, which merits further investigation.

Fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs), but not gluten, elicit modest symptoms of irritable bowel syndrome: a double-blind, placebo-controlled, randomized three-way crossover trial

BACKGROUND

Irritable bowel syndrome (IBS) has been associated with diets rich in fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs), and gluten. Most previous studies have been single-blind and have focused on the elimination of FODMAPs or provocation with single FODMAPs. The effect of gluten is unclear, large trials isolating the effect of gluten from that of FODMAPs are needed.

OBJECTIVES

The aims of this study were to ensure high intakes of a wide range of FODMAPs, gluten, or placebo, and to evaluate the effects on IBS symptoms using the IBS-severity scoring system (IBS-SSS).

METHODS

The study was carried out with a double-blind, placebo-controlled, randomized 3-way crossover design in a clinical facility in Uppsala from September 2018 to June 2019. In all, 110 participants fulfilling the IBS Rome IV criteria, with moderate to severe IBS, were randomly assigned; 103 (90 female, 13 male) completed the trial. Throughout, IBS participants maintained a diet with minimal FODMAP content and no gluten. Participants were block-randomly assigned to 1-wk interventions with FODMAPs (50 g/d), gluten (17.3 g/d), or placebo, separated by 1-wk washout. All participants who completed ≥1 intervention were included in the intention-to-treat analysis.

RESULTS

In participants with IBS (n = 103), FODMAPs caused higher IBS-SSS scores (mean 240 [95% CI: 222, 257]) than placebo (198 [180, 215]; P = 0.00056) or gluten (208 [190, 226]; P = 0.013); no differences were found between the placebo and gluten groups (P = 1.0). There were large interindividual differences in IBS-SSS scores associated with treatment. No adverse events were reported.

CONCLUSION

In participants with IBS, FODMAPs had a modest effect on typical IBS symptoms, whereas gluten had no effect. The large interindividual differences in responses to the interventions warrant further detailed studies to identify possible underlying causes and enable individual prediction of responses. This trial was registered at www.clinicaltrials.gov as NCT03653689.

FODMAPs, but Not Gluten, Affect Symptoms and the Fecal Environment in Subjects With Irritable Bowel Syndrome. A Double Blinded-Randomized Three-Way Crossover Study

Objectives

Irritable bowel syndrome (IBS) symptoms have been associated with fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) as well as gluten. We aimed to evaluate the effects of provocations with diets rich in such components on IBS symptoms. We further aimed to study effects of FODMAPs and gluten on microbiota and if the microbiota composition was related to the severity of IBS symptoms.

Methods

A double-blind, placebo-controlled, randomised three-way crossover design (n = 110) was conducted. From run-in and throughout the study, IBS subjects maintained a diet with

minimal FODMAP content and no gluten. Participants were block-randomised to one-week interventions with FODMAPs (50 g/day), gluten (17.3 g/day) or placebo, separated by one week of wash-out. Fecal samples were collected after each study week and analyzed for gut microbiota composition by sequencing of 16S rRNA gene amplicons. IBS symptoms were monitored by the IBS severity scoring system (IBS-SSS).

Results

In subjects with moderate to severe IBS (n = 103), FODMAPs caused higher total IBS-SSS (mean [SE] = 240 [9]) than placebo (208 [9]; p = 0.00056) or gluten (198 [9]; p = 0.013), but with no difference between gluten and placebo (p = 1.0). Relative abundance of Anaerostipes, Bifidobacterium and Faecalibacterium were higher after FODMAP compared to placebo. We found no difference in gut microbiota composition between gluten and placebo and no significant correlations between genera and severity of IBS-SSS.

Conclusions

In subjects with IBS, FODMAPs had an adverse but modest effect on typical IBS symptoms, whereas gluten had no effect. The microbiota composition was affected by the FODMAP but not the gluten intervention, in comparison to placebo. None of these differences were correlated to the severity of symptoms reflected in IBS-SSS, suggesting no apparent link between gut microbiota composition and IBS symptoms following intervention.

Funding Sources

Formas and the Swedish Research Council.

Benzoxaxinoids Are Inversely Associated With Prostate-Specific Antigen Levels- a Whole Grain Rye vs Refined Wheat Randomized Cross-Over Trial in Men With Prostate Cancer

Objectives

Prostate cancer is a common cancer diagnosis among men, but the role of diet and food components remains controversial. Benzoxazinoids (BXs) is a potent group of bioactive compounds found in rye foods that seem to have the potential to inhibit prostate cancer growth in vitro but studies in humans are lacking. We therefore aimed to investigate the concentrations of different BXs and their metabolites after whole grain rye consumption in comparison to refined wheat and to correlate these compounds to PSA levels in men with indolent prostate cancer.

Methods

In a randomized controlled crossover study, men with prostate cancer (n = 24) consumed 485 gram of whole grain/bran rye and refined wheat foods for six weeks, with two weeks of washout in-between. The diets were isocaloric and contained the same amount of fiber by addition of cellulose in the refined wheat intervention. BXs in plasma samples were analyzed with HPLC- QTRAP/MS-ESI.

Results

Seventeen men finished the trial and were included in data analysis. For most BXs, the concentrations were significantly higher after the whole grain rye compared to the refined wheat intervention. The BXs or BXs metabolites HBOA-glc, HHPAA, HBOA-glcA, HPAA-glcA (∼19.4–0.4 nmol/L in plasma after interventions) were significantly inversely correlated to PSA level.

Conclusions

In men with indolent prostate cancer, most BXs were significantly higher after an intervention with whole grain rye compared to refined wheat. The inverse correlation between four BXs or BXs metabolites and PSA may indicate on an inhibitory effect on prostate cancer cell growth. This could open for new preventive food-based strategies, but results would need to be replicated.

Funding Sources

Independent Research Fund Denmark - Technology and Production Formas Swedish Research Council.

Obstructive sleep apnoea: patients' experiences of oral appliance treatment

Over the past few decades, there has been a pronounced increase in the number of patients being treated by general dental practitioners for obstructive sleep apnoea (OSA). The purpose of this study was to survey the care and patient experiences and the self-reported effectiveness of OSA treatment with an oral appliance (OA) incorporating mandibular advancement. The design was a retrospective, cross-sectional study, with follow-up between 6 months to 1 year after commencement of treatment. A survey form was posted to 1150 subjects, identified in the regional register over a 1-year period as having been treated with an OA for OSA. The questionnaire comprised 70 questions and assertions in various domains, such as general health/lifestyle, changes in symptoms/quality of life and sleep-related experiences, daytime sleepiness, changes in life situation, evaluation of treatment and the value of treatment. The overall response rate was 64% (n = 738). Treatment with OA gave relief of symptoms in 83% of the respondents. Quality of life, somatic and cognitive symptoms improved significantly in patients who used the appliance frequently (P < 0·001). Daytime sleepiness decreased significantly (P < 0·001). Treatment satisfaction and willingness to recommend the similar treatment to a friend were high (>85%). OA treatment of OSA by general dental practitioners is a safe procedure. Most of the survey respondents experienced relief of symptoms. Those who used their appliance frequently reported improvement in quality of life, somatic and cognitive symptoms. Excessive daytime sleepiness was reduced in the majority of the patients under treatment.

Changes in step-width during dual-task walking predicts falls

The aim was to evaluate whether gait pattern changes between single- and dual-task conditions were associated with risk of falling in older people. Dual-task cost (DTC) of 230 community living, physically independent people, 75 years or older, was determined with an electronic walkway. Participants were followed up each month for 1 year to record falls. Mean and variability measures of gait characteristics for 5 dual-task conditions were compared to single-task walking for each participant. Almost half (48%) of the participants fell at least once during follow-up. Risk of falling increased in individuals where DTC for performing a subtraction task demonstrated change in mean step-width compared to single-task walking. Risk of falling decreased in individuals where DTC for carrying a cup and saucer demonstrated change compared to single-task walking in mean step-width, mean step-time, and step-length variability. Degree of change in gait characteristics related to a change in risk of falling differed between measures. Prognostic guidance for fall risk was found for the above DTCs in mean step-width with a negative likelihood ratio of 0.5 and a positive likelihood ratio of 2.3, respectively. Findings suggest that changes in step-width, step-time, and step-length with dual tasking may be related to future risk of falling. Depending on the nature of the second task, DTC may indicate either an increased risk of falling, or a protective strategy to avoid falling.

Domestication effects on foraging strategies in fowl

Birds of two different breeds differing in degree of domestication were studied to reveal any differences in foraging strategies between them. The breeds were wild-type birds (crossing between red jungle fowl (Gallus gallus) and Swedish bantam (Gallus gallus domesticus) and domestic birds (Swedish bantam), breeds representing an increasing level of domestication. Bantam birds have not been selected for any specific characteristics. The birds were allowed to forage in an experimental pen containing two separate food patches, which depleted as a function of being exploited, to see how well the different breeds were able to assess costs and benefits as the distance between patches were changed (short distance between patches compared to long distance between patches). Both breeds behaved in accordance with some general predictions of optimal foraging theory, i.e. moved between patches, left patches before these were empty and stayed for a shorter time in more depleted patches. Wild-type birds responded more than domestic birds to an increase of distance between patches, by spending longer average time in patch when there was a long distance between them compared to when there was a short distance. The wild-type birds adopted what seemed to be a more costly foraging strategy, moving more between patches than the domestic birds without ingesting more feed. During domestication, in the protected environment provided by man, individuals using less costly behavioural strategies may have gained increased fitness over those spending more energy on foraging. Although domestic birds still possessed the ability to respond adaptively to environmental conditions, the differences between the wild-type and the domestic breed might be a result of the reduction of the natural selection pressure which accompanies domestication.