Summary
Background Functional gut symptoms are induced by inclusion and reduced by dietary restriction of poorly absorbed short‐chain carbohydrates (FODMAPs), but the mechanisms of action remain ...untested.
Aims To determine the effect of dietary FODMAPs on the content of water and fermentable substrates of ileal effluent.
Methods Twelve ileostomates without evidence of small intestinal disease undertook two 4‐day dietary periods, comprising diets differing only in FODMAP content in a randomized, cross‐over, single‐blinded intervention study. Daytime (14 h) ileal effluent was collected on day four of each diet. Patients rated effluent volume and consistency on a 10‐cm visual analogue scale. The FODMAP content of the diet and effluent was measured.
Results Ingested FODMAPs of 32% (range 6–73%) was recovered in the high FODMAP diet effluent. Effluent collection weight increased by a mean of 22% (95% CI, 5–39), water content by 20% (2–38%) and dry weight by 24% (4–43%) with the high compared to low FODMAP diet arm. Output increased by 95 (28–161) mL. Volunteers perceived effluent consistency was thicker (95% CI, 0.6–1.9) with the low FODMAP diet than with the high FODMAP diet (3.5–6.1; P = 0.006).
Conclusions These data support the hypothetical mechanism; FODMAPs increase delivery of water and fermentable substrates to the proximal colon.
Summary
Background
“Exercise‐induced gastrointestinal syndrome” refers to disturbances of gastrointestinal integrity and function that are common features of strenuous exercise.
Aim
To systematically ...review the literature to establish the impact of acute exercise on markers of gastrointestinal integrity and function in healthy populations and those with chronic gastrointestinal conditions.
Methods
Search literature using five databases (PubMed, EBSCO, Web of Science, SPORTSdiscus, and Ovid Medline) to review publications that focused on the impact of acute exercise on markers of gastrointestinal injury, permeability, endotoxaemia, motility and malabsorption in healthy populations and populations with gastrointestinal diseases/disorders.
Results
As exercise intensity and duration increases, there is considerable evidence for increases in indices of intestinal injury, permeability and endotoxaemia, together with impairment of gastric emptying, slowing of small intestinal transit and malabsorption. The addition of heat stress and running mode appears to exacerbate these markers of gastrointestinal disturbance. Exercise stress of ≥2 hours at 60% VO2max appears to be the threshold whereby significant gastrointestinal perturbations manifest, irrespective of fitness status. Gastrointestinal symptoms, referable to upper‐ and lower‐gastrointestinal tract, are common and a limiting factor in prolonged strenuous exercise. While there is evidence for health benefits of moderate exercise in patients with inflammatory bowel disease or functional gastrointestinal disorders, the safety of more strenuous exercise has not been established.
Conclusions
Strenuous exercise has a major reversible impact on gastrointestinal integrity and function of healthy populations. The safety and health implications of prolonged strenuous exercise in patients with chronic gastrointestinal diseases/disorders, while hypothetically worrying, has not been elucidated and requires further investigation.
Linked ContentThis article is linked to Uno and Costa et al papers. To view these articles visit https://doi.org/10.1111/apt.14330 and https://doi.org/10.1111/apt.14358.
Summary
Background
Crohn's disease recurs in the majority of patients after intestinal resection.
Aim
To compare the relative efficacy of thiopurines and anti‐TNF therapy in patients at high risk of ...disease recurrence.
Methods
As part of a larger study comparing post‐operative management strategies, patients at high risk of recurrence (smoker, perforating disease, ≥2nd operation) were treated after resection of all macroscopic disease with 3 months metronidazole together with either azathioprine 2 mg/kg/day or mercaptopurine 1.5 mg/kg/day. Thiopurine‐intolerant patients received adalimumab induction then 40 mg fortnightly. Patients underwent colonoscopy at 6 months with endoscopic recurrence assessed blind to treatment.
Results
A total of 101 patients 50% male; median (IQR) age 36 (25–46) years were included. There were no differences in disease history between thiopurine‐ and adalimumab‐treated patients. Fifteen patients withdrew prior to 6 months, five due to symptom recurrence (of whom four were colonoscoped). Endoscopic recurrence (Rutgeerts score i2–i4) occurred in 33 of 73 (45%) thiopurine vs. 6 of 28 (21%) adalimumab‐treated patients intention‐to‐treat (ITT); P = 0.028 or 24 of 62 (39%) vs. 3 of 24 (13%) respectively per‐protocol analysis (PPA); P = 0.020. Complete mucosal endoscopic normality (Rutgeerts i0) occurred in 17/73 (23%) vs. 15/28 (54%) (ITT; P = 0.003) and in 27% vs. 63% (PPA; P = 0.002). The most advanced disease (Rutgeerts i3 and i4) occurred in 8% vs. 4% (thiopurine vs. adalimumab).
Conclusions
In Crohn's disease patients at high risk of post‐operative recurrence adalimumab is superior to thiopurines in preventing early disease recurrence.
Summary
Background
Butyrate, propionate and acetate are short chain fatty acids (SCFA), important for maintaining a healthy colon and are considered as protective in colorectal carcinogenesis. ...However, they may also regulate immune responses and the composition of the intestinal microbiota. Consequently, their importance in a variety of chronic inflammatory diseases is emerging.
Aims
To review the physiology and metabolism of SCFA in humans, cellular and molecular mechanisms by which SCFA may act in health and disease, and approaches for therapeutic delivery of SCFA.
Methods
A PubMed literature search was conducted for clinical and pre‐clinical studies using search terms: ‘dietary fibre’, short‐chain fatty acids’, ‘acetate’, ‘propionate’, ‘butyrate’, ‘inflammation’, ‘immune’, ‘gastrointestinal’, ‘metabolism’.
Results
A wide range of pre‐clinical evidence supports roles for SCFA as modulators of not only colonic function, but also multiple inflammatory and metabolic processes. SCFA are implicated in many autoimmune, allergic and metabolic diseases. However, translating effects of SCFA from animal studies to human disease is limited by physiological and dietary differences and by the challenge of delivering sufficient amounts of SCFA to the target sites that include the colon and the systemic circulation. Development of novel targeted approaches for colonic delivery, combined with postbiotic supplementation, may represent desirable strategies to achieve adequate targeted SCFA delivery.
Conclusions
There is a large array of potential disease‐modulating effects of SCFA. Adequate targeted delivery to the sites of action is the main limitation of such application. The ongoing development and evaluation of novel delivery techniques offer potential for translating promise to therapeutic benefit.
Summary
Background While gluten‐free diet is an effective treatment for coeliac disease, the need for and goals of long‐term management of patients are poorly defined.
Aim To review systematically ...the complications and associations of coeliac disease, to identify potential risk factors, to define ways of assessing risk factors and to provide a strategy for management.
Methods Review of medical literature from 1975.
Results There is an increasing list of potential complications and/or conditions associated with coeliac disease, in particular, autoimmune disease, malignancy and bone disease. Risk factors that may predict or influence long‐term outcomes include genetic susceptibility, environmental factors predominantly gluten ingestion, persistent small intestinal inflammation/injury and nutritional deficiencies. Genotyping of patients is yet to have an established clinical role in long‐term management. Assessment of adherence to the gluten‐free diet largely relies upon skilled dietary history, but the ultimate test is duodenal histopathology, which is the only currently established means of assessing healing. Symptoms, serology or other non‐invasive means are poor predictors of healing and the likelihood of complications.
Conclusion Evidence (albeit limited) that adherence to a gluten‐free diet and mucosal healing prevent and/or ameliorate complications indicates that a planned long‐term strategy for follow‐up is essential.
Summary
Background
Beneficial effects of carbohydrate fermentation on gastrointestinal health are well established. Conversely, protein fermentation generates harmful metabolites but their relevance ...to gastrointestinal health is poorly understood.
Aim
To review the effects of increased protein fermentation on biomarkers of colonic health, factors influencing fermentative activity and potential for dietary modulation to minimise detrimental effects.
Methods
A literature search was performed in PubMed, Medline, EMBASE and Google scholar for clinical and pre‐clinical studies using search terms – ‘dietary protein’, ‘fermentation’, ‘putrefaction’, ‘phenols’, ‘sulphide’, ‘branched‐chain fatty acid’, ‘carbohydrate fermentation’, ‘gastrointestinal’.
Results
High protein, reduced carbohydrate diets alter the colonic microbiome, favouring a potentially pathogenic and pro‐inflammatory microbiota profile, decreased short‐chain fatty acid production and increased ammonia, phenols and hydrogen sulphide concentrations. These metabolites largely compromise the colonic epithelium structure, causing mucosal inflammation but may also directly modulate the enteric nervous system and intestinal motility. Increased protein fermentation as a result of a high‐protein intake can be attenuated by addition of oligosaccharides, resistant starch and nonstarch polysaccharides and a reduction in total protein or specifically, aromatic and sulphur‐containing amino acids. These factors may have clinical importance as novel therapeutic approaches to problems, in which protein fermentation may be implicated, such as malodorous flatus, irritable bowel syndrome, ulcerative colitis and prevention of colorectal cancer.
Conclusions
The direct clinical relevance of excessive protein fermentation in the pathogenesis of irritable bowel syndrome, malodorous flatus and ulcerative colitis are underexplored. Manipulating dietary carbohydrate and protein intake have potential therapeutic applications in such settings and warrant further clinical studies.
Background
Life‐long gluten‐free diet (GFD) is the only recognised treatment for coeliac disease (CD). The present study aimed to determine the nutritional adequacy of the ‘no detectable gluten’ ...diet.
Methods
Seven‐day prospective food intake was assessed in 55 patients who were adherent to a GFD for more than 2 years and in 50 newly‐diagnosed age‐ and sex‐matched patients (18–71 years, 24% male) studied prospectively over 12 months on GFD. Historical precoeliac intake was also assessed in the latter group. Intake was compared with Australian Nutritional Recommendations and the Australian population data.
Results
Nutritional intake was similar between groups. Of macronutrients, only starch intake fell over 12 months (26% to 23%, P = 0.04). Fibre intake was inadequate for all except in diet‐experienced men. More than one in 10 of both newly‐diagnosed and experienced women had inadequate thiamin, folate, vitamin A, magnesium, calcium and iron intakes. More than one in 10 newly‐diagnosed men had inadequate thiamin, folate, magnesium, calcium and zinc intakes. Inadequate intake did not relate to nutrient density of the GFD. Inadequacies of folate, calcium, iron and zinc occurred more frequently than in the Australian population. The frequency of inadequacies was similar pre‐ and post‐diagnosis, except for thiamin and vitamin A, where inadequacies were more common after GFD implementation.
Conclusions
Dietary intake patterns at 12 months on a GFD are similar to longer‐term intake. Dietary inadequacies are common and may relate to habitual poor food choices in addition to inherent deficiencies in the GFD. Dietary education should also address the achievement of adequate micronutrient intake. Fortification of GF foods also need to be considered.
The ERA‐40 re‐analysis Uppala, S. M.; KÅllberg, P. W.; Simmons, A. J. ...
Quarterly journal of the Royal Meteorological Society,
October 2005 Part B, Letnik:
131, Številka:
612
Journal Article
The fermentation of three arabinoxylan (AX) fractions from wheat by the human fecal microflora was investigated in vitro. Three AX fractions, with average molecular masses of 354, 278, and 66 kDa, ...were incorporated into miniature-scale batch cultures (with inulin as a positive prebiotic control) with feces from three healthy donors, aged 23−29. Microflora changes were monitored by the culture-independent technique, fluorescent in situ hybridization, and short chain fatty acid (SCFA) and lactic acid production were measured by high-performance liquid chromatography. Total cell numbers increased significantly in all treated cultures, and the fermentation of AX was associated with a proliferation of the bifidobacteria, lactobacilli, and eubacteria groups. Smaller but statistically significant increases in bacteroides and clostridia groups were also observed. All AX fractions had comparable bifidogenic impacts on the microflora at 5 and 12 h, but the 66 kDa AX was particularly selective for lactobacilli. Eubacteria increased significantly on all AX fractions, particularly on 66 kDa AX. As previously reported, inulin gave a selective increase in bifidobacteria. All supplemented cultures showed significant rises in total SCFA production, with a particularly high proportion of butyric acid being produced from AX fermentation. The prebiotic effect, that is, the selectivity of AX for bifidobacteria and lactobacilli groups, increased as the molecular mass of the AX decreased. This suggests that molecular mass may influence the fermentation of AX in the colon. Keywords: Prebiotics; in vitro fermentation; arabinoxylan; polysaccharide molecular mass
Summary
Background
The renin‐angiotensin system (RAS) is a homeostatic pathway widely known to regulate cardiovascular and renal physiology; however, little is known about its influence in ...gastrointestinal tissues.
Aim
To elicit the anatomical distribution and physiological significance of the components of the RAS in the gastrointestinal tract.
Methods
An extensive online literature review including Pubmed and Medline.
Results
There is evidence for RAS involvement in gastrointestinal physiology and pathophysiology, with all the components required for autonomous regulation identified throughout the gastrointestinal tract. The RAS is implicated in the regulation of glucose, amino acid, fluid and electrolyte absorption and secretion, motility, inflammation, blood flow and possibly malignant disease within the gastrointestinal tract. Animal studies investigating the effects of RAS blockade in a range of conditions including inflammatory bowel disease, functional gut disorders, gastrointestinal malignancy and even intestinal ischaemia have been encouraging to date. Given the ready availability of drugs that modify the RAS and their excellent safety profile, an opportunity exists for investigation of their possible therapeutic role in a variety of human gastrointestinal diseases.
Conclusions
The gastrointestinal renin‐angiotensin system appears to be intricately involved in a number of physiological processes, and provides a possible target for novel investigative and therapeutic approaches.
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