The Impact of Dietary Interventions on the Microbiota in Inflammatory Bowel Disease: A Systematic Review.

BACKGROUND AND AIMS: Diet plays an integral role in the modulation of the intestinal environment, with the potential to be modified for management of individuals with inflammatory bowel disease [IBD]. It has been hypothesised that poor 'Western-style' dietary patterns select for a microbiota that drives IBD inflammation and, that through dietary intervention, a healthy microbiota may be restored. This study aimed to systematically review the literature and assess current available evidence regarding the influence of diet on the intestinal microbiota composition in IBD patients, and how this may affect disease activity. METHODS: MEDLINE, EMBASE, Scopus, Web of Science, and Cochrane Library were searched from January 2013 to June 2023, to identify studies investigating diet and microbiota in IBD. RESULTS: Thirteen primary studies met the inclusion criteria and were selected for narrative synthesis. Reported associations between diet and microbiota in IBD were conflicting due to the considerable degree of heterogeneity between studies. Nine intervention studies trialled specific diets and did not demonstrate significant shifts in the diversity and abundance of intestinal microbial communities or improvement in disease outcomes. The remaining four cross-sectional studies did not find a specific microbial signature associated with habitual dietary patterns in IBD patients. CONCLUSIONS: Diet modulates the gut microbiota, and this may have implications for IBD; however, the body of evidence does not currently support clear dietary patterns or food constituents that are associated with a specific microbiota profile or disease marker in IBD patients. Further research is required with a focus on robust and consistent methodology to achieve improved identification of associations.

Assessing the Variability of the Twelfth Rib as a Landmark for Percutaneous Nephrolithotomy Using Computed Tomography.

Background: The variability in length of the twelfth rib is mentioned in the literature but has never been formally studied. The highly variable rib length provides a challenge for urologists seeking a consistent landmark for Percutaneous Nephrolithotomy (PCNL). We set out to determine whether the twelfth rib is safe to use as a consistent landmark for surgery. Methods: Single centre, cross-sectional retrospective observational study and analysis of CT scans of 100 adults who had imaging between 23rd March and 12th April 2020. The distance from the mid-sagittal line to the twelfth rib tip in the axial plane was measured as was the distance from the twelfth rib tip to the kidney, spleen and liver. Results: Length from the mid-sagittal line to the right twelfth rib tip varied from 46 (percentile 95% CI 40 to 57) to 136mm (percentile 95% CI 133 to 138). On the left, the distances varied from 55 (percentile 95% CI 50 to 64) to 134mm (percentile 95% CI 131 to 135). Twenty-three percent of people had an organ lying between the tip of the twelfth rib and the kidney on the right and 11% on the left. Conclusion: The twelfth rib is highly variable in length. Similar variability was recorded in the distance from the tip to intra-abdominal organs. Due to the frequency of organs lying between the tip of the rib and the kidney it should not be used as a landmark for accessing the kidney without prior knowledge of an individual patient's anatomy as seen on imaging.

Irritable bowel syndrome - controversies in diagnosis and management.

INTRODUCTION: The irritable bowel syndrome (IBS) is the best-recognized disorder of gut brain interactions (DGBI). However, it is controversial if the Rome IV criteria iteration for IBS diagnosis is fit for purpose. AREAS COVERED: This review critically evaluates Rome IV criteria for diagnosis of IBS and addresses clinical considerations in IBS treatment and management, including dietary factors, biomarkers, disease mimics, symptom severity, and subtypes. The role of diet in IBS is critically reviewed along with the influence of the microbiota, including small intestinal bacterial overgrowth. EXPERT OPINION: Emerging data suggest the Rome IV criteria are more suitable for identifying severe IBS and least useful for sub-diagnostic patients who are still likely to benefit from IBS treatment. Despite convincing evidence that IBS symptoms are diet-driven and often postprandial, a relationship to eating is not a Rome IV diagnostic criterion. Few IBS biomarkers have been identified, suggesting the syndrome is too heterogeneous to be measured by a single marker, and combined biomarker, clinical, dietary, and microbial profiling may be needed for objective characterization. With many organic diseases mimicking and overlapping with IBS, it's important clinicians are knowledgable about this to mitigate the risk of missing comorbid organic intestinal disease and to optimally treat IBS symptoms.

Dietitians' perspectives on the role of dietetics practice in 'gut health'.

AIMS: This study aimed to explore dietitians' perspectives on the evidence surrounding the relationship between diet and 'gut health' and the current and emerging role of dietetics practice in this area. METHODS: A qualitative descriptive methodology was used. Online semi-structured interviews were conducted with Australian dietitians, focused on the perspectives related to gut health management in dietetics practice. Inductive thematic analysis was employed, commencing with initial coding by two researchers, and further coding leading to development of emergent themes. Divergent data were discussed and considered in analysis. RESULTS: Fourteen interviews were conducted (2 males, 12 females). An overarching theme identified that current evidence is insufficient to direct dietetics practice change regarding gut health. Six subthemes on dietetics practice in 'gut health' emerged including (a) practice is multifaceted, (b) current practice aligns with dietary guidelines, (c) symptom management remains the primary concern, (d) evidence-based information is sought, (e) translational evidence is required for practice change and (f) there is a role for dietetics in gut health research and translation. CONCLUSIONS: Dietitians do not appear confident in their practice regarding gut microbiome-related management and recognise there is currently limited translatable research to inform practice. Evidence to date suggests that recommendations for positive gut health do not differ substantially from Australian Dietary Guidelines. Dietitians will need additional education if further evidence emerges, however they demonstrated a strong commitment to evidence-based practice.

Gut health, the microbiome and dietary choices: An exploration of consumer perspectives.

AIMS: To explore consumer perceptions regarding dietary behaviours related to the gut microbiome, to assist in effective translation of research to practice. METHODS: Online focus groups were conducted (adults with no formal medical or nutrition training). Semi-structured open-ended questioning explored perspectives related to gut health and dietary behaviours. A qualitative descriptive analysis approach was undertaken in duplicate. RESULTS: Fourteen focus groups were conducted (n = 38, 15 males, 23 females). Four overarching themes regarding consumer perceptions were identified. These were (a) gut health equates with wellbeing, (b) there are divergent perceptions of how diet influences gut health, (c) interest in scientific evidence does not necessarily influence dietary behaviour and (d) gastrointestinal symptoms influence dietary behaviour. CONCLUSIONS: Consumers are interested in gut health and understand that diet may be important. Given that current literature regarding diet and gut health does not differ from dietary guidelines, consumer interest may provide a timely slant to promote longstanding guidelines. Consumer education to limit scepticism around government messaging, including utilisation of social media by nutrition professionals, may be key to improving adherence to guidelines.

Establishing breast feeding in infants with Down syndrome: the FADES cohort experience.

OBJECTIVE: To describe breastfeeding prevalence and maternal experience in infants with trisomy 21. DESIGN: Longitudinal cohort study. SETTING: Participants from UK recruited through websites, social media and local collaborators: neonatologists, community paediatricians and research nurses. SUBJECTS: Infants under the age of 8 months with Down syndrome (DS) recruited to the Feeding and Autoimmunity in Down Syndrome Evaluation Study between 1 September 2014 and 31 August 2017. Seventy participants: median age 20 weeks (IQR 13-29 weeks) at initial questionnaire. MAIN OUTCOME MEASURE: Breastfeeding prevalence at 6 weeks and 6 months among infants with DS. RESULTS: The prevalence of exclusive breast feeding among study participants was similar to the general population (13/61, 21% vs 23% at 6 weeks, 2/54, 4% vs 1% at 6 months). However, the prevalence of breast feeding (exclusive or combination feeding) among the study participants was higher than the general population (39/61 64% vs 55% at 6 weeks, 32/59 54% vs 34% at 6 months). CONCLUSION: Although there may be challenges in establishing breast feeding in infants with DS, our data suggest that exclusive breast feeding is possible for some, and the prevalence of breast feeding is comparable to the prevalence in the general population. TRIAL REGISTRATION NUMBER: ISRCTN12415856.

Gut microbiome responses to dietary intake of grain-based fibers with the potential to modulate markers of metabolic disease: a systematic literature review.

CONTEXT: Cereal fiber modulates the gut microbiome and benefits metabolic health. The potential link between these effects is of interest.0. OBJECTIVE: The aim for this systematic review was to assess evidence surrounding the influence of cereal fiber intake on microbiome composition, microbiome diversity, short-chain fatty acid production, and risk factors for metabolic syndrome. DATA SOURCES AND EXTRACTION: The MEDLINE, PubMed, CINAHL, and Cochrane Library databases were searched systematically, and quality of studies was assessed using the Cochrane Risk of Bias 2.0 tool. Evidence relating to study design, dietary data collection, and outcomes was qualitatively synthesized on the basis of fiber type. DATA ANALYSIS: Forty-six primary publications and 2 secondary analyses were included. Cereal fiber modulated the microbiome in most studies; however, taxonomic changes indicated high heterogeneity. Short-chain fatty acid production, microbiome diversity, and metabolic-related outcomes varied and did not always occur in parallel with microbiome changes. Poor dietary data were a further limitation. CONCLUSIONS: Cereal fiber may modulate the gut microbiome; however, evidence of the link between this and metabolic outcomes is limited. Additional research is required with a focus on robust and consistent methodology. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42018107117.

Gut microbiome analysis by post: Evaluation of the optimal method to collect stool samples from infants within a national cohort study.

BACKGROUND: Understanding the role of the gut microbiome is pivotal for the future development of therapies for the prevention and management of autoimmune conditions such as type 1 diabetes when sampling during early life may be particularly important. The current standard methods for collecting gut microbiome samples for research is to extract fresh samples or freeze samples immediately after collection. This is often impractical however for population-based studies. The aim of this study was to determine the optimal method for the stabilization of stool bacterial DNA obtained from nappies and transported by post in ambient conditions to the research centre for a national birth cohort study. METHODS: Four methods to collect samples were compared to immediate freezing of samples: 1) collecting faeces onto a swab which was immediately frozen, 2) using a commercially available kit with stabilisation solution (OMNIgene•GUT kit) at ambient temperature, 3) collecting onto a swab and 4) collecting into a sterile plain tube. Samples 3) and 4) were returned to the laboratory by post at ambient temperatures. A Bland Altman analysis was used to assess the agreement between the different methods and the frozen standard. RESULTS: Stool samples were collected by parents. For samples transported in ambient conditions, the limits of agreement showed that the OMNIgene•GUT kit had the narrowest 95% limits of agreement with the frozen standard as measured by the number of operational taxonomic units and the Shannon diversity index. CONCLUSIONS: All methods assessed for preserving samples collected from nappies at a distance and delivered by post for gut microbiome analysis showed variation / disagreement from the frozen standard. Overall, the OMNIgene•GUT kit preserved the samples with minimal changes compared to other methods and was practical for parents to use.

What factors influence recruitment to a birth cohort of infants with Down's syndrome?

OBJECTIVE: To understand how to maximise recruitment of young infants with Down's syndrome (DS) into research through qualitative interviews with parents and care providers. In complex neonatal and genetic conditions such as DS, frequently diagnosed after birth, parents may go through a period of adaptation. These factors need consideration when overcoming barriers to recruitment. PARTICIPANTS AND DESIGN: Participants, who were drawn from health professionals and volunteers working with families experiencing DS, were recruited using a purposive sampling strategy. Semistructured telephone interviews were completed with nine paediatricians, three research nurses and six family support workers. Five of those interviewed had a child with DS. The interviews were transcribed and analysed thematically. RESULTS: A positive decision to take part in a 'from-birth' cohort study depends on factors such as the child's overall health, parent demographics (educational background and ethnicity), medical interactions that take place with the families (communication) and study logistics. The data suggest that recruitment methods need to take all these factors into consideration. Multiple recruitment methods should be considered including face to face, through parent and support groups, websites and social media. There also needs to be flexibility in the research timings to fit around the needs of the child and parents. CONCLUSION: Researchers need to be aware of the variable responses elicited by families to a diagnosis of DS for their baby and be sensitive to the child's current medical status. This does not preclude recruitment into studies, but to maximise uptake good communication and flexibility is essential.

Beta cell function and ongoing autoimmunity in long-standing, childhood onset type 1 diabetes.

AIMS/HYPOTHESIS: This study aimed to determine the frequency of residual beta cell function in individuals with long-standing type 1 diabetes who were recruited at diagnosis, and relate this to baseline and current islet autoantibody profile. METHODS: Two hour post-meal urine C-peptide:creatinine ratio (UCPCR) and islet autoantibodies were measured in samples collected from 144 participants (median age at diagnosis: 11.7 years; 47% male), a median of 23 years (range 12-29 years) after diagnosis. UCPCR thresholds equivalent to mixed meal-stimulated serum C-peptide >0.001 nmol/l, ≥0.03 nmol/l and ≥0.2 nmol/l were used to define 'detectable', 'minimal' and 'residual/preserved') endogenous insulin secretion, respectively. Autoantibodies against GAD (GADA), islet antigen-2 (IA-2A), zinc transporter 8 (ZnT8A) and insulin (IAA) were measured by radioimmunoassay. RESULTS: Endogenous C-peptide secretion was detectable in 51 participants (35.4%), including residual secretion in seven individuals (4.9%) and minimal secretion in 14 individuals (9.7%). In the 132 samples collected more than 10 years after diagnosis, 86 participants (65.2%) had at least one islet autoantibody: 42 (31.8%) were positive for GADA, 69 (52.3%) for IA-2A and 14 of 104 tested were positive for ZnT8A (13.5%). The level of UCPCR was related to age at diagnosis (p = 0.002) and was independent of diabetes duration, and baseline or current islet autoantibody status. CONCLUSIONS/INTERPRETATION: There is evidence of ongoing autoimmunity in the majority of individuals with longstanding diabetes. Endogenous insulin secretion continues for many years after diagnosis in individuals diagnosed with autoimmune-mediated type 1 diabetes above age 5. These findings suggest that some beta cells are protected from continued autoimmune attack in longstanding type 1 diabetes.