It is widely known that the short chain fatty acid butyrate, generated mainly through fermentation of dietary fibre by anaerobic bacteria, has beneficial effects on health. Less widely known is that butyrate, at the concentration (c20mM) typically found in the healthy colonic lumen, is toxic to colon epithelial cells. It is probably the presence of the continuous adherent mucus layer in the healthy colon that ensures that butyrate concentrations in contact with the epithelium fall below the levels (c>3mM) that are consistently toxic in in vitro or ex vivo studies. In active ulcerative colitis the adherent mucus layer is commonly weakened or absent. In this situation it is likely that the luminal butyrate concentration will be toxic to the epithelium. It follows that butyrate at concentrations typically present in the colon lumen is probably beneficial when colitis is in remission but harmful when colitis has relapsed. This may explain the largely negative results of butyrate therapy in ulcerative colitis and could also account for the recently reported benefit from total enteral nutrition. It also suggests that butyrate should be regarded as a target for therapy in active ulcerative colitis rather than a solution.

Symptoms associated with chronic inflammation have a negative impact on quality of life (QOL) in adults with inflammatory bowel disease (IBD). Dietary changes may assist in improving symptoms; however, they can be difficult to implement, causing increased stress and decreased QOL. The purpose of this narrative review was to investigate the impact of dietary interventions on QOL in adults with IBD. EBSCOhost was used to simultaneously search eight databases using the search terms ‘inflammatory bowel disease’ or ‘IBD’ or ‘ulcerative colitis’ or ‘Crohn’s disease’ AND ‘dietary interventions’ or ‘dietary advice’ or ‘dietary recommendations’. Inclusion criteria included adults with IBD and a validated QOL measure. After screening 1054 studies, 15 clinical trials were identified. Among these studies, dietary interventions included the low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet (n = 4), Immunoglobulin G (IgG) diet (n = 2), Anti-Inflammatory Diet (AID) (n = 1), highly restricted organic diet (n = 1), Autoimmune Protocol Diet (AIP) (n = 1), Dietary Modified Program (DMP) (n = 1), Dietary Modified Framework (DMF) (n = 1), Mediterranean diet (n = 2), and a high fibre diet (n = 2). QOL was measured using various validated questionnaires. Significant improvements in QOL were found in two of the low FODMAP diet studies, both IgG diet studies, the DMP, and one high fibre diet study. The Anti-inflammatory Diet, Dietary Modified Framework, Autoimmune Protocol Diet, highly restricted organic diet, and Mediterranean diet did not significantly improve QOL. Future research should focus on comparing dietary interventions, longer study durations, diet adherence and QOL. Due to the complexity in the various diets, dietitians with expertise in IBD are needed to assist with diet management.

Restorative proctocolectomy with ileal pouch-anal anastomosis is the surgical treatment of choice for patients with medically-refractory ulcerative colitis (UC) and familial adenomatous polyposis (FAP). Whilst quality of life is generally good, as many as 83% of patients associate dietary factors with the onset of symptoms(1) and around two-thirds employ some form of dietary restriction post-pouch creation(2,3). There is growing interest to understand the role of diet (as a whole) on pouch function and how it can be used therapeutically. It is imperative that we know the dietary characteristics of pouch patients before attempting to introduce strategies altering their food choice. Since there is good rationale to assess overall diet quality to identify potential avenues for targeting dietary strategies, this study aimed to examine the frequency of perceived food intolerances and diet quality in patients with an ileoanal pouch and the relationship between these two indices. In this cross-sectional study, patients with an ileoanal pouch completed a food intolerance questionnaire and a validated 297-item semi-quantitative food frequency questionnaire (Monash Comprehensive Nutritional Assessment Questionnaire). Dietary data was used to score diet quality using the 2013 Dietary Guidelines Index (DGI), a scoring system which compares how closely an individual’s dietary intake aligns with the Australian Dietary Guidelines (ADG). The DGI also comprises of 11 subcomponents (scored out of 10 respectively) based on each of the ADG guidelines and provides a total score of 110, with higher scores reflecting greater compliance to the ADG. In order to determine if perceived dietary intolerances was negatively associated with the intake of specific dietary factors, univariable and multivariable linear regression analysis of the correlation of intolerance and diet quality was performed. Of the 58 (10 FAP and 48 UC) patients studied, 81% of UC and 80% of FAP patients reported dietary intolerances. Mean total DGI score was 78 (95% CI: 74-80) of 110 in the overall pouch cohort with no differences across pouch sub-groups. However, only 5% of patients achieved a full score for food variety. Both uni- [OR −0.94 (−1.7,-0.10); p = 0.02] and multivariable analysis (adjusting for age and sex) showed that only intolerances to dairy products were associated with reduced intake of lactose-containing dairy [OR −0.29 (−1.8,-0.08); p=0.03]. No other significant correlations were found for overall or subcomponents of DGI scores. High rates of perceived food intolerances were observed in patients with an ileoanal pouch. However, only those with perceived dairy intolerances restricted their intake of lactose-containing dairy products. Additionally, patients with ileoanal pouch scored highly for overall diet quality but specific gaps in achieving better diet quality, particularly for diet variety were observed. These results provide some starting points for targeted dietary counselling to optimise nutritional health and potentially to improve pouch function these patients.

Ulcerative colitis (UC) is a chronic inflammatory disease involving the colon and rectum. One of the most modifiable environmental factors affecting UC severity is the patient’s dietary pattern. Although the role of dietary patterns on UC aetiology has been investigated previously, its relationship with disease severity has not yet been elucidated. This study examined the association between UC patients’ dietary patterns and disease severity. This cross-sectional study was conducted in 340 UC patients. Using an FFQ, food patterns were assessed. Twenty-five food categories were categorised based on the similarity of the nutrient composition of the food using the factor analysis method. A simple clinical colitis activity index was used to determine disease severity. Three dietary patterns were identified based on the factor analysis: healthy, unhealthy and Western dietary pattern. After adjusting for potential confounding factors, patients who were in the highest tertile of healthy dietary pattern compared with the lowest tertile were 92 % less likely to have severe UC (OR: 0·08; 95 % CI: 0·03, 0·22). Also, those in the highest tertile of the Western dietary pattern were 3·86 times more likely to have severe UC than those in the lowest tertile (OR: 3·86; 95 % CI: 1·86, 8·00). Even after controlling for confounding variables, unhealthy dietary pattern did not increase the risk of severe UC. Our data indicate the beneficial role of healthy dietary pattern in amelioration of disease severity in UC patients. To confirm this association, more studies are needed, especially prospective cohort studies.

Ulcerative Colitis (UC), a type of Inflammatory Bowel Disease (IBD), is a chronic, relapsing gastrointestinal condition with increasing global prevalence. The gut microbiome profile of people living with UC differs from healthy controls and this may play a role in the pathogenesis and clinical management of UC. Probiotics have been shown to induce remission in UC; however, their impact on the gut microbiome and inflammation is less clear. Anthocyanins, a flavonoid subclass, have shown anti-inflammatory and microbiota-modulating properties; however, this evidence is largely preclinical. To explore the combined effect and clinical significance of anthocyanins and a multi-strain probiotic, a 3-month randomised controlled trial will be conducted in 100 adults with UC. Participants will be randomly assigned to one of four groups: anthocyanins (blackcurrant powder) + placebo probiotic, probiotic + placebo fruit powder, anthocyanin + probiotic, or double placebo. The primary outcome is a clinically significant change in the health-related quality-of-life measured with the Inflammatory Bowel Disease Questionnaire-32. Secondary outcomes include shotgun metagenomic sequencing of the faecal microbiota, faecal calprotectin, symptom severity, and mood and cognitive tests. This research will identify the role of adjuvant anti-inflammatory dietary treatments in adults with UC and elucidate the relationship between the gut microbiome and inflammatory biomarkers in this disease, to help identify targeted individualised microbial therapies. ANZCTR registration ACTRN12623000630617.

Ulcerative colitis (UC) is an immune-mediated inflammation of the colonic mucosa. Gut microbiota dysbiosis may play a significant role in disease pathogenesis by causing shifts in metabolomic profiles within the gut. To identify differences and trends in the metabolomic profile of paediatric UC patients pre- and post-faecal microbiota transplants (FMT). Forty-six paediatric patients with mild-to-moderate UC and 30 healthy paediatric patients were enrolled in this study. Baseline stool samples were collected prior to FMT initiation and at months 1, 3, 6, and 12 post-FMT. Pediatric Ulcerative Colitis Activity Index (PUCAI) scores were calculated at baseline and months 1, 3, 6, and 12 after FMT. The average Bray–Curtis dissimilarities to healthy subjects decreased after FMT. In principal coordinate analysis plots, UC patients’ centroids drew nearer to healthy individuals. The variance explained by phenotype (Healthy versus UC) reduced and remained significant. From 1 to 3 months after FMT, PUCAI trends were statistically significant and decreasing. PUCAI scores remain flat starting 6 months after FMT. This study concludes that paediatric UC patients have a significantly different baseline metabolite profile than healthy controls. Although being time limited, FMT significantly altered these metabolite profiles and shifted them towards that of healthy controls.

In the UK, the incidence and prevalence of inflammatory bowel disease (IBD) is increasing in paediatric populations. Environmental factors including acute gastroenteritis episodes (AGE) may impact IBD development. Infant rotavirus vaccination has been shown to significantly reduce AGE. This study aims to explore the association between vaccination with live oral rotavirus vaccines and IBD development. A population-based cohort study was used, analysing primary care data from the Clinical Practice Research Datalink Aurum. Participants included children born in the UK from 2010 to 2015, followed from a minimum of 6 months old to a maximum of 7 years old. The primary outcome was IBD, and the primary exposure was rotavirus vaccination. Cox regression analysis with random intercepts for general practices was undertaken, with adjustment for potential confounding factors. In a cohort of 907,477 children, IBD was recorded for 96 participants with an incidence rate of 2.1 per 100,000 person-years at risk. The univariable analysis hazard ratio (HR) for rotavirus vaccination was 1.45 (95% confidence interval (CI) 0.93–2.28). Adjustment in the multivariable model attenuated the HR to 1.19 (95% CI 0.53–2.69). This study shows no statistically significant association between rotavirus vaccination and development of IBD. However, it provides further evidence for the safety of live rotavirus vaccination.

Time to evaluate diet quality and give dietary advice is limited in clinical inflammatory bowel disease (IBD) practice. The Eetscore is a web-based tool that assesses diet quality according to the Dutch dietary guidelines and provides personalised dietary advice. We aimed to assess diet quality of IBD patients using the Eetscore and to study changes in diet quality, health-related quality of life (HRQoL) and clinical disease activity over time. A prospective cohort study was performed in 195 adult IBD patients. Participants were invited to fill out questionnaires (Eetscore-FFQ, short Inflammatory Bowel Disease Questionnaire and Patient Harvey Bradshaw Index/Patient Simple Clinical Colitis Activity Index) at baseline and after 1 and 4 months. The Eetscore calculates diet quality based on sixteen food components (ten points per component, total score 0–160; the higher the better) and provides dietary advice per component based on the assessment. At baseline, mean diet quality was 98 (sd 19). Diet quality was positively associated with age, female sex and level of education. Component scores were highest for red meat, wholegrain products and sweetened beverages, and lowest for legumes, nuts and processed meat. Over time, diet quality increased to 107 (sd 21) at 4 months (P < 0·001). Each ten-point improvement in diet quality was associated with an increase in HRQoL (β = 0·4 (95 % CI (0·02, 0·7), P = 0·04). Clinical disease activity did not change. In conclusion, diet quality of IBD patients significantly improved following personalised dietary advice of the Eetscore. Improvement of diet quality was associated with a slight improvement in HRQoL. The Eetscore is a practical and useful tool to monitor and support a healthy diet in IBD patients.

The incidence rate of inflammatory bowel diseases is increasing in developed countries. As such there is an increasing demand for new therapies. The aim of this systematic review was to investigate whether there is evidence to support the use of helminth therapy for the management of Crohn's disease and ulcerative colitis. Four databases (PubMed, Embase, Medline and the Cochrane Central Register of Control Trials) were searched for primary evidence in the form of clinical studies. Nine studies were suitable for inclusion: five double-blind randomized control trials and four open-label studies. This review divided the results of the studies into two categories: (a) the efficacy of helminth therapy and (b) the safety of helminth therapy. Results regarding the efficacy were mixed and a conclusive answer could not be reached, as there was not enough evidence to rule out a placebo effect. More research is needed, particularly studies with control groups to address the possibility of a placebo effect. Despite this, all nine studies concluded helminth therapy was safe and tolerable, and therefore there is currently no evidence against further exploration of this treatment option.

The aetiology of inflammatory bowel disease (IBD) is multifactorial, with diet and gut microbiota playing an important role. Nonetheless, there are very few studies, particularly clinical research, which have explored the interaction between diet and gut microbiota. In the current review, we summarise the evidence from clinical trials exploring the interactions between the gut microbiota and diet in the management of IBD. Data from the effect of exclusive enteral nutrition (EEN) on the gut microbiota of children with active Crohn's disease (CD), receiving induction treatment, offer opportunities to understand the role of gut microbiota in underlying disease pathogenesis and develop novel dietary and pharmacological microbial therapeutics. In contrast, the evidence which links the effectiveness of food-based dietary therapies for IBD with mechanisms involving the gut microbiota is far less convincing. The microbial signals arising from these dietary therapies are inconsistent and vary compared to the effects of effective treatment with EEN in CD.

Inflammatory bowel disease (IBD) is a group of immune-mediated disorders characterised by a chronic, relapsing-remitting inflammation predominantly affecting the gastrointestinal tract. IBD is incurable, affecting people in their most productive years. IBD is historically seen as a disease of Westernised nations although in recent times other countries have seen an exponential rise in cases. Although the exact pathogenesis remains unclear, evidence suggests that microbiota changes play a critical role in IBD pathogenesis. Over the past two decades, IBD has become one of the most studied human conditions linked to the gut microbiota. However, deciphering the intricate link between the gut microbiota and therapeutic efficacy remains elusive. This review will summarise the current evidence relating to the gut microbiota and its involvement in IBD pathogenesis as well as the impact of IBD treatments including pharmaceutical-, nutraceutical- and microbial-focused regimens on the gut microbiota.

Extra virgin olive oil is often associated with anti-inflammatory and antioxidant properties. Its effects on inflammatory conditions such as ulcerative colitis (UC), however, have yet to be defined. As such, we aimed to conduct a systematic review and meta-analysis of studies investigating olive-based interventions in UC. A comprehensive database search for randomised controlled trials was performed between 9 July 2018 and 16 August 2018. Studies identified from search alerts were included up to 22 June 2020. Both individuals living with UC at any disease stage and murine models of UC were included in this review. No human trials meeting the eligibility criteria were identified, while nineteen animal studies comprised 849 murine models of UC were included in this review. Pooling of the data could not be performed due to heterogeneous outcomes; however, general trends favouring olive-based interventions were identified. Milder disease expression including weight maintenance, reduced rectal bleeding and well-formed stools favouring olive-based interventions was statistically significant in 16/19 studies, with moderate-to-large effect sizes (−0·66 (95 % CI −1·56, 0·24) to −12·70 (95 % CI −16·8, −8·7)). Olive-based interventions did not prevent the development of colitis-like pathologies in any study. In conclusion, effects of olive-based interventions on murine models of UC appear promising, with milder disease outcomes favouring the intervention in most trials and effect sizes suggesting potential clinical relevance. However, the lack of published randomised controlled human trials warrants further investigation to determine if these effects would translate to individuals living with UC.