Gut metabolome and microbiota signatures predict response to treatment with exclusive enteral nutrition in a prospective study in children with active Crohn's disease.

BACKGROUND: Predicting response to exclusive enteral nutrition (EEN) in active Crohn's disease (CD) could lead to therapy personalization and pretreatment optimization. OBJECTIVES: This study aimed to explore the ability of pretreatment parameters to predict fecal calprotectin (FCal) levels at EEN completion in a prospective study in children with CD. METHODS: In children with active CD, clinical parameters, dietary intake, cytokines, inflammation-related blood proteomics, and diet-related metabolites, metabolomics and microbiota in feces, were measured before initiation of 8 wk of EEN. Prediction of FCal levels at EEN completion was performed using machine learning. Data are presented with medians (IQR). RESULTS: Of 37 patients recruited, 15 responded (FCal < 250 µg/g) to EEN (responders) and 22 did not (nonresponders). Clinical and immunological parameters were not associated with response to EEN. Responders had lesser (µmol/g) butyrate [responders: 13.2 (8.63-18.4) compared with nonresponders: 22.3 (12.0-32.0); P = 0.03], acetate [responders: 49.9 (46.4-68.4) compared with nonresponders: 70.4 (57.0-95.5); P = 0.027], phenylacetate [responders: 0.175 (0.013-0.611) compared with nonresponders: 0.943 (0.438-1.35); P = 0.021], and a higher microbiota richness [315 (269-347) compared with nonresponders: 243 (205-297); P = 0.015] in feces than nonresponders. Responders consumed (portions/1000 kcal/d) more confectionery products [responders: 0.55 (0.38-0.72) compared with nonresponders: 0.19 (0.01-0.38); P = 0.045]. A multicomponent model using fecal parameters, dietary data, and clinical and immunological parameters predicted response to EEN with 78% accuracy (sensitivity: 80%; specificity: 77%; positive predictive value: 71%; negative predictive value: 85%). Higher taxon abundance from Ruminococcaceae, Lachnospiraceae, and Bacteroides and phenylacetate, butyrate, and acetate were the most influential variables in predicting lack of response to EEN. CONCLUSIONS: We identify microbial signals and diet-related metabolites in feces, which could comprise targets for pretreatment optimization and personalized nutritional therapy in pediatric CD.

Dose-dependent effects of enteral nutrition on the faecal microbiota and short chain fatty acids.

INTRODUCTION: Enteral nutrition (EN) involves replacing all or part of a person's habitual diet with a nutritional formula. The impact of varying doses of EN on the gut microbiome remains understudied. METHODS: Healthy adults replaced all (100% EN) or part (85% EN, 50% EN and 20% EN) of their energy requirements with EN for 7 days. Faecal samples were collected before and on day 7 of interventions. Faecal pH, short chain fatty acids (SCFAs), branched-chain fatty acids (BCFAs) and 16S rRNA sequencing were performed. Dietary assessment was performed with 7-day food diaries. RESULTS: Sixty-one participants (31 females; median (IQR) age: 24.7 (23.0-27.8) years) were recruited. A dose-dependent impact of EN on faecal microbiota, SCFAs, BCFAs) and pH was observed, with changes detectable at EN intakes of at least 50% of energy requirements. 100% and 85% EN reduced the abundance of fibre-fermenting taxa such as Agathobacter, Faecalibaterium, Succinivibrio and Acidaminococcus. In parallel, potentially harmful organisms like Eubacterium, Actinomyces, and Klebsiella increased. In the 50% EN group, adherence to a diet high in fish, vegetables, potatoes, non-alcoholic beverages, and fat spreads, and low in cereal products, milk, and meat negatively correlated with changes in microbiota structure (r = -0.75, P = 0.025). This signal was not observed when using compositional tools for microbiota analysis. CONCLUSIONS: EN detrimentally influences the faecal microbiota and diet-related bacterial metabolites in a dose-dependent manner, particularly at doses of at least 50%. The findings of this study have implications for the dietary management and counselling of patients receiving high volume EN.

Perceptions Toward Established and Novel Dietary Therapies for Crohn's Disease Management Among Adult Patients: Results From a Questionnaire Survey.

Background: Exclusive enteral nutrition (EEN) and partial enteral nutrition (PEN) remain the only established dietary therapies in Crohn's disease (CD) management. We conducted a questionnaire survey to evaluate the perceptions of adults with CD toward established and emerging food-based dietary therapies. Methods: A 26-question anonymous survey was mailed to 300 adults receiving biologic treatment. Two researchers independently conducted a thematic analysis of open-ended responses. Machine learning with the Random Forest-Recursive Feature Elimination algorithm identified predictors of willingness to try dietary therapies. Results: One hundred and sixty patients (53% female) completed and returned the survey. Forty-two percent were following some form of exclusion diet, with low-spice and low-fiber diets being the most popular. Although only a quarter of patients believed that EEN/PEN could help with their CD, more than half believed that diet could help, with another 13% already using diet for CD management. While half of the patients were willing to try EEN, the majority were willing to try PEN instead (51% vs. 79%; P < .001). Forty-two percent of patients preferred food-based dietary plans prepared at home over EEN/PEN options. The most important predictors for willingness to try dietary therapies were age (25-65 years), recent symptoms, previous exposure to EEN/PEN, and current exclusion diet use. The top concerns about PEN were taste/palatability, satiety/hunger, and taste fatigue. Conclusions: Most adults preferred to follow a food-based dietary therapy over EEN/PEN. The majority would try PEN though which allows for more flexibility to incorporate in habitual diet and may be easier to comply with than the EEN.

YouTube as a Source of Information for Food, Diet-Related Items, and Advisory Comments for the Management of Inflammatory Bowel Disease.

BACKGROUND: Patients with inflammatory bowel disease (IBD) often use the Internet to seek information beyond that received from healthcare professionals. This study assessed the perceptions of YouTube presenters on the role of diet in the management of IBD. METHODS: Videos discussing dietary aspects (food, diet-related items, and advisory comments [FODRIACs]) in the management of IBD were included. The perceptions of presenters toward each FODRIAC were labeled as positive, negative, or neutral/intermediate, and FODRIACs were classified according to their underlying role in the management of IBD (eg, symptom management, gut inflammation). Subgroup analysis was performed by type of video presenter (patients vs healthcare professionals), type of IBD (Crohn's disease vs ulcerative colitis), and reporting of scientific evidence supporting presenters' perceptions. RESULTS: We identified 122 FODRIACs within 160 videos. Patient videos received a higher number of likes (median 85 [interquartile range, 35-156]) than healthcare professional videos (median 44 [interquartile range, 16-1440]) (P = .01). Scientific evidence was cited in 2 (3%) of 76 patient videos compared with 25 (35%) of 71 healthcare professional videos (P < .001). Positive perceptions were expressed about avocadoes, salmon, bananas, white bread, and rice, whereas negative perceptions were reported for processed, high-fat and high-sugar foods and carbonated drinks. Fewer negative perceptions were expressed in videos supported by scientific evidence than in videos that lacked evidence (scientific: 4 positive, 0 negative vs nonscientific: 7 positive, 20 negative; P = .01). CONCLUSIONS: We have identified FODRIACs proposed as beneficial or detrimental in the management of IBD. The effect this information has on dietary practice as patients with IBD self-manage their condition needs further exploration.

Development and Validation of the Glasgow Exclusive Enteral Nutrition Index of Compliance.

BACKGROUND AND AIMS: Treatment adherence is key to the efficacy of exclusive enteral nutrition [100% EN] in active Crohn's disease [CD], but there are no biomarkers to objectively estimate this. We explored faecal parameters as biomarkers of compliance with 100% EN, and subsequently developed and validated the Glasgow Exclusive Enteral Nutrition Index of Compliance [GENIE]. METHODS: Healthy adults replaced all [100% EN] or part [85% EN, 50% EN, 20% EN] of their diet with a formula for 7 days. Faecal pH, water content, short chain fatty acids, and branched chain fatty acids [BCFAs] were measured before [D0] and after [D7] each intervention. Optimal biomarkers and threshold values were derived using receiver operating characteristic curve analyses and machine learning to develop the GENIE. The GENIE was then validated in 30 CD children, during and after 100% EN. RESULTS: In all, 61 adults were recruited. D7 faecal pH and the ratios of BCFAs to either acetate or butyrate performed the best to differentiate between patients on 100% EN from <100% EN. Two models were generated; one included faecal metabolites (Laboratory GENIE, L-GENIE; sensitivity, specificity, and positive predictive value [PPV] of 88%, 94%, and 92%) and a second one [Clinical Genie, C-GENIE] which considers only faecal pH [sensitivity, specificity, and PPV of 84%, 86%, and 81%]. Validation of GENIE in CD children found that C-GENIE outperformed L-GENIE, producing a sensitivity, specificity, and PPV of 85%, 88%, and 88%, respectively. CONCLUSIONS: GENIE can help predict adherence to 100% EN and may complement current conventional dietary assessment.

Muscle Activation Patterns of the Proximal Medial and Distal Biceps Femoris and Gluteus Maximus Among 6 Hip Extension and Knee Flexion Exercises in Trained Women.

The biceps femoris (BF) is a double-jointed muscle that performs both hip extension and knee flexion, making it a challenging muscle to train during common resistance training movements. An imbalance between the posterior and anterior chain increases the risk of lower-extremity injury. The purpose of this study was to compare BF proximal (BFprox), BF medial (BFmed), and BF distal (BFdist) peak and mean muscle activation among four hip hinging movements and two knee flexion movements. A secondary variable was gluteus maximus (GMax) muscle activation among the same six movements. Fifteen trained females completed three repetitions at 75% estimated 1-repetition max among the following exercises: Romanian-deadlift (RDL), step-up, hip-extension, kickbacks, Nordic hamstring curls (Nordics), and legcurls. Repetition voltage was normalized to percent maximal voluntary isometric contractions. Eight separate one-way repeated measures ANOVAs with Sidak post hoc analysis indicated the BFprox elicited greater voltage in the kickback, Nordic, and leg-curl exercise compared to the RDL, step-up and hip-extension (p < 0.05), BFmed voltage was higher in the hip-extension, kickback, Nordic, and leg-curl vs. the step-up and RDL (p < 0.05), BFdist voltage was greater during the kickback, Nordic, and leg-curl exercise vs. the RDL, step-up and hip-extension (p < 0.05), while the GMax elicited the lowest voltage during the leg-curl vs. the other five exercises (p < 0.05). All eight ANOVAs reached statistical significance (p < 0.01). The Nordic exercises consistently elicited the highest voltage among the six exercises. Coaches, trainers, and therapist can use these findings to target different aspects of the BF for training purposes and hamstring injury management.

Development of age-dependent micronutrient centile charts and their utility in children with chronic gastrointestinal conditions at risk of deficiencies: A proof-of-concept study.

BACKGROUND & AIMS: Interpretation of blood micronutrient levels requires age-appropriate reference intervals. This study developed age-dependent micronutrient centiles for healthy children (HC) and explored their utility in sick children. METHODS: 244 blood samples were collected from normal HC who underwent tests for acute illness. Age-dependent, centile charts were fitted for zinc, copper, magnesium and selenium in plasma and erythrocytes (RBC), and for vitamins B1, B2 and B6 in RBC. For 34 children with Crohn's disease (CrD) and 55 with coeliac disease (CoeD), Z-scores for the levels of these micronutrients were computed, using the new charts. Associations were explored between plasma and RBC micronutrient Z-scores, and in CrD with CRP and serum albumin. RESULTS: In HC, plasma zinc and selenium increased and plasma copper, magnesium and RBC vitamins B1, B2 and B6 decreased with age. In HC and in CrD, plasma and RBC Z-scores for copper, selenium and magnesium (all p < 0.001) were positively correlated, but not for zinc. In CrD, albumin was related with plasma zinc (rho = 0.62; p < 0.001) and selenium Z-scores (rho = 0.65; p < 0.001) and plasma copper Z-score with CRP (rho = 0.45; p = 0.02). A higher proportion of CrD children had low levels for B2 (21% vs 0%; p = 0.01) and B6 (18% vs 0%; p = 0.02) using the new centile charts than the local laboratory references. CONCLUSION: Age-dependent micronutrient centile charts enable tracking of micronutrient status, Z-score calculation and may prevent misdiagnosis and inappropriate treatment of deficiencies. In systemic inflammatory conditions, RBC measurements of certain micronutrients may be more reliable to use than measurements in plasma.

The Effects of Commonly Consumed Dietary Fibres on the Gut Microbiome and Its Fibre Fermentative Capacity in Adults with Inflammatory Bowel Disease in Remission.

Introduction: It has been suggested that the gut microbiome of patients with inflammatory bowel disease (IBD) is unable to ferment dietary fibre. This project explored the in vitro effect of fibre fermentation on production of short-chain fatty acids (SCFA) and on microbiome composition. Methods: Faecal samples were collected from 40 adults (>16 y) with IBD (n = 20 with Crohn's disease and n = 20 with ulcerative colitis) in clinical remission and 20 healthy controls (HC). In vitro batch culture fermentations were carried out using as substrates maize starch, apple pectin, raftilose, wheat bran, α cellulose and a mixture of these five fibres. SCFA concentration (umol/g) was quantified with gas chromatography and microbiome was profiled with 16S rRNA sequencing. Results: Fibre fermentation did not correct the baseline microbial dysbiosis or lower diversity seen in either patients with CD or UC. For all fibres, up to 51% of baseline ASVs or genera changed in abundance in HC. In patients with IBD, fermentation of fibre substrates had no effect on species or genera abundance. Production of SCFA varied among the different fibre substrates but this was not different between the two IBD groups and compared to HC after either 5 or 24 h fermentation. Conclusions: Despite extensive microbial dysbiosis, patients with IBD have a similar capacity to ferment fibre and release SCFA as HC. Fibre supplementation alone may be unlikely to restore to a healthy status the compositional shifts characteristic of the IBD microbiome.

Evaluation of Body Composition in Paediatric Osteogenesis Imperfecta.

Osteogenesis Imperfecta (OI) is a skeletal disorder characterised by a predisposition to recurrent fractures and bone deformities. Clinically OI is defined by features such as short stature, however, less is known regarding body composition. Assess body composition, both lean mass and fat mass, in a paediatric OI population. Children with OI attending the Bone service at the Royal Hospital for Children Glasgow were included; who had a dual-energy x-ray absorptiometry (DXA) scan performed 2015-2018. Height and body-mass-index (BMI) were converted to standard-deviation scores (SDS) using UK population references. DXA-derived lean mass and fat mass were used to generate lean-mass-index (LMI) and fat-mass-index (FMI) by dividing the covariates by height squared. LMI and FMI were converted to age-and-gender-adjusted SDS using DXA data from 198 local healthy children. Thirty-eight children (20 males) with median age 11.95 (range: 4.8, 18.3) years were included. Median height SDS was -1.08 (-3.64, 1.62) and was significantly lower than the healthy population (p<0.0001). Median BMI SDS was -0.10 (-2.31, 2.95), and not significantly different from the healthy population (p = 0.53). Median LMI SDS was -2.52 (-6.94, 0.77), and significantly lower than healthy controls (p<0.0001); 61% (23/38) had an SDS below -2.0. Median FMI SDS was 0.69 (-0.45, 2.72), significantly higher than healthy controls (p < 0.0001). BMI SDS cut-offs of -0.15 and 1.33, from ROC analysis, identified children with LMI SDS <-2, with a positive predictive value of 95% and a negative predictive value of 70%; and FMI SDS >2 with a positive predictive value of 44% and a negative predictive value of 100%. A contemporary population of children with ranging severities of OI present with significant reduction in height and lean mass, and relatively high fat mass. Standard BMI SDS cut-offs for identifying children with malnutrition and obesity have poor prognostic validity in OI.

Gut microbiota and its diet-related activity in children with intestinal failure receiving long-term parenteral nutrition.

BACKGROUND: This study characterized gut microbiota and its diet-related activity in children with intestinal failure (IF) receiving parenteral nutrition (PN) compared with those of healthy controls (HC) and in relation to disease characteristics. METHODS: The fecal microbiota and short-chain fatty acids (SCFAs) were measured in 15 IF patients (n = 68) and 25 HC (n = 25). RESULTS: Patients with IF had a lower bacterial load (P = .003), diversity (P < .001), evenness (P < .001) and richness (P = 0.006) than HC. Patients with surgical IF had lower diversity (P < .039) than those with functional IF. Propionic acid and butyric acid (p < .001) were lower and d-lactate and l-lactate were higher (p < 0.001) in IF patients than in HC. The energy supplied by PN (%PN) was negatively associated with microbiota diversity and SCFA profile. IF patients had more Escherichia-Shigella (P = .006), Cronobacter (P = .001), and Staphylococcus (Operational Taxonomic Unit 14, P < .001) and less Faecalibacterium (P < 0.001) and Ruminococcus 1 and 2 (P < .001). Duration of PN (P = .005), %PN (P = .005), and fiber intake (P = .011) were predictive of microbiota structure. Higher intake of enteral nutrition was associated with microbiota structure and function closer to those of HC. CONCLUSIONS: Microbiota composition and its diet-related function are altered in IF, with depletion of beneficial SCFAs and species and supraphysiological increase of potentially harmful pathobionts. The influence of this compositional and functional microbial dysbiosis on patients' outcomes and management warrants further exploration.

Dietary triggers of gut inflammation following exclusive enteral nutrition in children with Crohn's disease: a pilot study.

BACKGROUND: The anti-inflammatory effect of exclusive enteral nutrition on the gut of children with Crohn's disease is rapidly lost after food reintroduction. This study assessed disease dietary triggers following successful treatment with exclusive enteral nutrition. METHODS: Nutrient intake, dietary patterns and dietary biomarkers in faeces (gluten immunogenic peptides, undigestible starch, short chain fatty acids) were assessed in 14 children with Crohn's disease during early food reintroduction, following exclusive enteral nutrition. Groups above (Group A) and below (Group B) the median levels of faecal calprotectin after food reintroduction were assigned for comparative analysis. RESULTS: Intakes of fibre, gluten-containing cereals and red and processed meat were significantly higher in Group A than Group B; (median [Q1, Q3], g/day; Fibre: 12.1 [11.2, 19.9] vs. 9.9 [7.6, 12.1], p = 0.03; Red and processed meat: 151 [66.7, 190] vs. 63.3 [21.7, 67], p = 0.02; gluten-containing cereals: 289 [207, 402] vs. 203 [61, 232], p = 0.035). A diet consisting of cereals and meat products was predictive (92% accuracy) of higher faecal calprotectin levels after food reintroduction. In faeces, butyrate levels, expressed as absolute concentration and relative abundance, were higher in Group A than Group B by 28.4 µmol/g (p = 0.015) and 6.4% (p = 0.008), respectively. Levels of gluten immunogenic peptide and starch in faeces did not differ between the two groups. CONCLUSIONS: This pilot study identified potential dietary triggers of gut inflammation in children with Crohn's disease after food reintroduction following treatment with exclusive enteral nutrition. TRIAL REGISTRATION: Clinical trials.gov registration number: NCT02341248; Clinical trials.gov URL: https://clinicaltrials.gov/ct2/show/NCT02341248 (retrospectively registered).

Handgrip strength as a surrogate marker of lean mass and risk of malnutrition in paediatric patients.

BACKGROUND & AIMS: The use of handgrip strength (HGS) as a proxy of nutritional status in sick children has not been studied. This study created HGS centile charts in healthy children and explored the utility of HGS z-scores as markers of body composition and screening of malnutrition risk in sick children. METHODS: Data from 535 healthy children aged 5-16 years were used for the development of HGS centiles adjusted either for age or height. In 595 sick children, relationships between HGS z-scores with body composition, malnutrition risk (Paediatric Yorkhill Malnutrition Score-PYMS), length of hospital stay (LOS) and biomarkers of disease severity were explored. The use of HGS z-score to identify sick children in need of further dietetic assessment was investigated. RESULTS: Children scoring at high malnutrition risk with PYMS had lower HGS z-scores for age (by 0.51 SD, p < 0.001) and height (by 0.46 SD, p = 0.001) than those who scored low. A HGS z-score at cut-offs of -0.81 SD and -1.2 SD for age and height, respectively, was predictive of need for dietetic intervention in sick children with sensitivity of 79% and 70% and specificity of 56% and 69%, respectively. HGS z-scores were predictive of fat free mass (FFM) in sick and healthy (all p < 0.001) children, while fat mass was not. HGS z-scores were inversely related with plasma CRP (rho, age: -0.21; height: -0.23, both p = 0.001). HGS was not predictive of LOS. CONCLUSION: HGS is predictive of FFM, could compliment assessment of malnutrition risk, and may help identify children for further dietetic intervention on admission to hospital.

Stool metabolome-microbiota evaluation among children and adolescents with obesity, overweight, and normal-weight using 1H NMR and 16S rRNA gene profiling.

Characterization of metabolites and microbiota composition from human stool provides powerful insight into the molecular phenotypic difference between subjects with normal weight and those with overweight/obesity. The aim of this study was to identify potential metabolic and bacterial signatures from stool that distinguish the overweight/obesity state in children/adolescents. Using 1H NMR spectral analysis and 16S rRNA gene profiling, the fecal metabolic profile and bacterial composition from 52 children aged 7 to 16 was evaluated. The children were classified into three groups (16 with normal-weight, 17 with overweight, 19 with obesity). The metabolomic analysis identified four metabolites that were significantly different (p < 0.05) among the study groups based on one-way ANOVA testing: arabinose, butyrate, galactose, and trimethylamine. Significantly different (p < 0.01) genus-level taxa based on edgeR differential abundance tests were genus Escherichia and Tyzzerella subgroup 3. No significant difference in alpha-diversity was detected among the three study groups, and no significant correlations were found between the significant taxa and metabolites. The findings support the hypothesis of increased energy harvest in obesity by human gut bacteria through the growing observation of increased fecal butyrate in children with overweight/obesity, as well as an increase of certain monosaccharides in the stool. Also supported is the increase of trimethylamine as an indicator of an unhealthy state.

Assessment of Dietary Intake Using Food Photography and Video Recording in Free-Living Young Adults: A Comparative Study.

BACKGROUND: Conventional methods of dietary assessment are prone to recall bias and place burden on participants. OBJECTIVE: Our aim was to compare the performance of image-based dietary assessment (IBDA), including food photography (FP) and video recording (VR), with the criterion of weighed food records (WFR). DESIGN: In this comparative study, participants captured meals using FP and VR before and after consumption, over 2 days. Food type and portion size were assessed using the images and videos. Energy and nutrient intakes (mean of 2 days) were compared against WFR. PARTICIPANTS/SETTINGS: Eighty-four healthy adults (mean [standard deviation] age = 29 [8] years), recruited through advertisement in Glasgow, UK, between January and August 2016 were enrolled in the study. Eighty participants (95%) (mean [standard deviation] age = 28 [7] years) completed the study and were included in the analysis. MAIN OUTCOME MEASURES: Agreement in estimated energy and nutrient intake between WFR and IBDA. The IBDA method feasibility was evaluated using a questionnaire. Inter-rater and intra-rater reliability were assessed. STATISTICAL ANALYSIS PERFORMED: The performance of the IBDA methods against WFR and their inter and intra-rater reliability were tested with Bland-Altman plots and Spearman correlations. Intra-class agreement between methods was assessed using κ statistics. RESULTS: Inter-rater reliability was strong for both IBDA methods in estimating energy intake (ρ-coefficients: FP = 0.80; VR = 0.81). There was no difference in the agreement between the 2 assessors. Intra-rater reliability was high. FP and VR underestimated energy intake by a mean (95% agreement limits) of -13.3% (-56.4% and 29.7%) and -4.5% (-45.5% and 36.4%), respectively. IBDA demonstrated moderate-to-strong correlations in nutrient intake ranking, median ρ-coefficients for all nutrients: FP = 0.73 (interquartile range, 0.09) and VR = 0.82 (interquartile range, 0.02). Inter-class agreement of IBDA methods was moderate compared with the WFR in energy intake estimation. IBDA was more practical and enjoyable than WFR. CONCLUSIONS: IBDA and VR in particular demonstrated a moderate-to-strong ability to rank participants' dietary intake, and considerable group and inter-class agreement compared with the WFR. However, IBDA was found to be unsuitable for assessment in individuals.

The Acute Effect of Meal Timing on the Gut Microbiome and the Cardiometabolic Health of the Host: A Crossover Randomized Control Trial.

PURPOSE: The interaction of diet with gut microbiome has been implicated in the onset of cardiovascular disease. The gut microbiome displays diurnal rhythms, which may be influenced by meal timing. OBJECTIVE: This study aimed to investigate the effect of the timing of main meal consumption on the microbiome and cardiometabolic biomarkers of the host. METHODS: Seventeen healthy adults randomly consumed an isocaloric diet for 7 days, twice, by alternating lunch with dinner meals, and with a 2-week washout in-between. Sixty percent of the participants' daily energy requirements was consumed either as lunch or dinner, respectively. Meals were provided free to the participants. All fecal samples produced the last 3 days of each intervention were collected and analyzed for microbial profiling (16S rRNA gene amplicon sequencing), quantitative estimation of representative bacterial groups (qPCR) of the gut microbiome, and the output of short-chain fatty acids (SCFA) in feces. Fasted blood samples were analyzed for low-grade inflammatory biomarkers, blood lipids, insulin, and glucose levels. Cumulative energy loss in feces was measured over the collection period using bomb calorimetry. RESULTS: Meal timing had no significant effects on fecal SCFA output, energy loss in feces, microbial community profiling, and bacterial species relative abundance. The absolute concentration of Escherichia coli was significantly higher after the large lunch intervention (p = 0.02). No effects on blood biomarkers of cardiometabolic health were observed. CONCLUSIONS: In a well-controlled study, main meal timing displayed minimal acute effects on the gut microbiome composition, its diet-related function, and blood biomarkers of cardiometabolic health.

Alterations in Intestinal Microbiota of Children With Celiac Disease at the Time of Diagnosis and on a Gluten-free Diet.

BACKGROUND AND AIMS: It is not clear whether alterations in the intestinal microbiota of children with celiac disease (CD) cause the disease or are a result of disease and/or its treatment with a gluten-free diet (GFD). METHODS: We obtained 167 fecal samples from 141 children (20 with new-onset CD, 45 treated with a GFD, 57 healthy children, and 19 unaffected siblings of children with CD) in Glasgow, Scotland. Samples were analyzed by 16S ribosomal RNA sequencing, and diet-related metabolites were measured by gas chromatography. We obtained fecal samples from 13 children with new-onset CD after 6 and 12 months on a GFD. Relationships between microbiota with diet composition, gastrointestinal function, and biomarkers of GFD compliance were explored. RESULTS: Microbiota α diversity did not differ among groups. Microbial dysbiosis was not observed in children with new-onset CD. In contrast, 2.8% (Bray-Curtis dissimilarity index, P = .025) and 2.5% (UniFrac distances, P = .027) of the variation in microbiota composition could be explained by the GFD. Between 3% and 5% of all taxa differed among all group comparisons. Eleven distinctive operational taxonomic units composed a microbe signature specific to CD with high diagnostic probability. Most operational taxonomic units that differed between patients on a GFD with new-onset CD vs healthy children were associated with nutrient and food group intake (from 75% to 94%) and with biomarkers of gluten ingestion. Fecal levels of butyrate and ammonia decreased during the GFD. CONCLUSIONS: Although several alterations in the intestinal microbiota of children with established CD appear to be effects of a GFD, specific bacteria were found to be distinct biomarkers of CD. Studies are needed to determine whether these bacteria contribute to pathogenesis of CD.

Analysis of 61 exclusive enteral nutrition formulas used in the management of active Crohn's disease-new insights into dietary disease triggers.

BACKGROUND: Exclusive enteral nutrition (EEN) is an effective treatment for Crohn's disease. AIMS: To investigate the hypothesis that ingredients of EEN formulas are unlikely to initiate a disease flare and that their dietary elimination is not essential for disease amelioration. METHODS: We performed compositional analysis of EEN formulas with evidence of efficacy in management of active Crohn's disease. Macronutrient content was compared against the dietary reference values (DRV), the UK National Diet and Nutrition Survey (NDNS) and intake of Crohn's disease children. Food additives were cross-referenced against the FAO/WHO database. RESULTS: Sixty-one formulas were identified with variable composition (carbohydrates [22.8%-89.3%], protein [7.8%-30.1%], fat [0%-52.5%]). Maltodextrin, milk protein and vegetable/plant oils were the commonest macronutrient sources. Their n-6:n-3 fatty acid ratio varied from 0.25 to 46.5. 56 food additives were identified (median per formula: 11). All formulas were lactose-free, gluten-free, and 82% lacked fibre. The commonest food additives were emulsifiers, stabilisers, antioxidants, acidity regulators and thickeners. Food additives, implicated in Crohn's disease aetiology, were present in formulas (modified starches [100%], carrageenan [22%], carboxymethyl cellulose [13%] and polysorbate 80 [5%]). Remission rates did not differ between EEN formulas with and without those food additives. Analysis including only formulas from randomised controlled trials (RCTs) retained in the latest Cochrane meta-analysis produced similar findings. EEN formulas contained less energy from saturated fat than NDNS intake. CONCLUSION: We have identified food ingredients which are present in EEN formulas that are effective in Crohn's disease and challenge perceptions that these ingredients might be harmful.

The impact of food additives, artificial sweeteners and domestic hygiene products on the human gut microbiome and its fibre fermentation capacity.

PURPOSE: This study investigated the effect of food additives, artificial sweeteners and domestic hygiene products on the gut microbiome and fibre fermentation capacity. METHODS: Faecal samples from 13 healthy volunteers were fermented in batch cultures with food additives (maltodextrin, carboxymethyl cellulose, polysorbate-80, carrageenan-kappa, cinnamaldehyde, sodium benzoate, sodium sulphite, titanium dioxide), sweeteners (aspartame-based sweetener, sucralose, stevia) and domestic hygiene products (toothpaste and dishwashing detergent). Short-chain fatty acid production was measured with gas chromatography. Microbiome composition was characterised with 16S rRNA sequencing and quantitative polymerase chain reaction (qPCR). RESULTS: Acetic acid increased in the presence of maltodextrin and the aspartame-based sweetener and decreased with dishwashing detergent or sodium sulphite. Propionic acid increased with maltodextrin, aspartame-based sweetener, sodium sulphite and polysorbate-80 and butyrate decreased dramatically with cinnamaldehyde and dishwashing detergent. Branched-chain fatty acids decreased with maltodextrin, aspartame-based sweetener, cinnamaldehyde, sodium benzoate and dishwashing detergent. Microbiome Shannon α-diversity increased with stevia and decreased with dishwashing detergent and cinnamaldehyde. Sucralose, cinnamaldehyde, titanium dioxide, polysorbate-80 and dishwashing detergent shifted microbiome community structure; the effects were most profound with dishwashing detergent (R2 = 43.9%, p = 0.008) followed by cinnamaldehyde (R2 = 12.8%, p = 0.016). Addition of dishwashing detergent and cinnamaldehyde increased the abundance of operational taxonomic unit (OTUs) belonging to Escherichia/Shigella and Klebsiella and decreased members of Firmicutes, including OTUs of Faecalibacterium and Subdoligranulum. Addition of sucralose and carrageenan-kappa also increased the abundance of Escherichia/Shigella and sucralose, sodium sulphite and polysorbate-80 did likewise to Bilophila. Polysorbate-80 decreased the abundance of OTUs of Faecalibacterium and Subdoligranulum. Similar effects were observed with the concentration of major bacterial groups using qPCR. In addition, maltodextrin, aspartame-based sweetener and sodium benzoate promoted the growth of Bifidobacterium whereas sodium sulphite, carrageenan-kappa, polysorbate-80 and dishwashing detergent had an inhibitory effect. CONCLUSIONS: This study improves understanding of how additives might affect the gut microbiota composition and its fibre metabolic activity with many possible implications for human health.

In Vivo Function of the Lipid Raft Protein Flotillin-1 during CD8+ T Cell-Mediated Host Surveillance.

Flotillin-1 (Flot1) is an evolutionary conserved, ubiquitously expressed lipid raft-associated scaffolding protein. Migration of Flot1-deficient neutrophils is impaired because of a decrease in myosin II-mediated contractility. Flot1 also accumulates in the uropod of polarized T cells, suggesting an analogous role in T cell migration. In this study, we analyzed morphology and migration parameters of murine wild-type and Flot1-/- CD8+ T cells using in vitro assays and intravital two-photon microscopy of lymphoid and nonlymphoid tissues. Flot1-/- CD8+ T cells displayed significant alterations in cell shape and motility parameters in vivo but showed comparable homing to lymphoid organs and intact in vitro migration to chemokines. Furthermore, their clonal expansion and infiltration into nonlymphoid tissues during primary and secondary antiviral immune responses was comparable to wild-type CD8+ T cells. Taken together, Flot1 plays a detectable but unexpectedly minor role for CD8+ T cell behavior under physiological conditions.