Miranda Lomer

Review article: lactose intolerance in clinical practice – myths and realities

Background  Approximately 70% of the world population has hypolactasia, which often remains undiagnosed and has the potential to cause some morbidity. However, not everyone has lactose intolerance, as several nutritional and genetic factors influence tolerance.

Fermentable Carbohydrate Restriction Reduces Luminal Bifidobacteria and Gastrointestinal Symptoms in Patients with Irritable Bowel Syndrome

Preliminary studies indicate that dietary restriction of fermentable short-chain carbohydrates improves symptoms in irritable bowel syndrome (IBS). Prebiotic fructo-oligosaccharides and galacto-oligosaccharides stimulate colonic bifidobacteria. However, the effect of restricting fermentable short-chain carbohydrates on the gastrointestinal (GI) microbiota has never been examined. This randomized controlled trial aimed to investigate the effects of fermentable carbohydrate restriction on luminal microbiota, SCFA, and GI symptoms in patients with IBS. Patients with IBS were randomized to the intervention diet or habitual diet for 4 wk. The incidence and severity of symptoms and stool output were recorded for 7 d at baseline and follow-up. A stool sample was collected and analyzed for bacterial groups using fluorescent in situ hybridization. Of 41 patients randomized, 6 were withdrawn. At follow-up, there was lower intake of total short-chain fermentable carbohydrates in the intervention group compared with controls (P = 0.001). The total luminal bacteria at follow-up did not differ between groups; however, there were lower concentrations (P < 0.001) and proportions (P < 0.001) of bifidobacteria in the intervention group compared with controls when adjusted for baseline. In the intention-to-treat analysis, more patients in the intervention group reported adequate control of symptoms (13/19, 68%) compared with controls (5/22, 23%; P = 0.005). This randomized controlled trial demonstrated a reduction in concentration and proportion of luminal bifidobacteria after 4 wk of fermentable carbohydrate restriction. Although the intervention was effective in managing IBS symptoms, the implications of its effect on the GI microbiota are still to be determined.

Comparison of symptom response following advice for a diet low in fermentable carbohydrates (FODMAPs) versus standard dietary advice in patients with irritable bowel syndrome

BACKGROUND Emerging evidence indicates that the consumption of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) may result in symptoms in some patients with irritable bowel syndrome (IBS). The present study aimed to determine whether a low FODMAP diet is effective for symptom control in patients with IBS and to compare its effects with those of standard dietary advice based on the UK National Institute for Health and Clinical Excellence (NICE) guidelines. METHODS Consecutive patients with IBS who attended a follow-up dietetic outpatient visit for dietary management of their symptoms were included. Questionnaires were completed for patients who received standard (n = 39) or low FODMAP dietary advice (n = 43). Data were recorded on symptom change and comparisons were made between groups. RESULTS In total, more patients in the low FODMAP group reported satisfaction with their symptom response (76%) compared to the standard group (54%, P = 0.038). Composite symptom score data showed better overall symptom response in the low FODMAP group (86%) compared to the standard group (49%, P < 0.001). Significantly more patients in the low FODMAP group compared to the standard group reported improvements in bloating (low FODMAP 82% versus standard 49%, P = 0.002), abdominal pain (low FODMAP 85% versus standard 61%, P = 0.023) and flatulence (low FODMAP 87% versus standard 50%, P = 0.001). CONCLUSIONS A low FODMAP diet appears to be more effective than standard dietary advice for symptom control in IBS.

Distinct microbial populations exist in the mucosa-associated microbiota of sub-groups of irritable bowel syndrome

Background  There is increasing evidence to support a role for the gastrointestinal microbiota in the etiology of irritable bowel syndrome (IBS). Given the evidence of an inflammatory component to IBS, the mucosa‐associated microbiota potentially play a key role in its pathogenesis. The objectives were to compare the mucosa‐associated microbiota between patients with diarrhea predominant IBS (IBS‐D), constipation predominant IBS (IBS‐C) and controls using fluorescent in situ hybridization and to correlate specific bacteria groups with individual IBS symptoms.

British Dietetic Association evidence-based guidelines for the dietary management of irritable bowel syndrome in adults.

BACKGROUND  Irritable bowel syndrome (IBS) is a chronic debilitating functional gastrointestinal disorder. Diet and lifestyle changes are important management strategies. The aim of these guidelines is to systematically review key aspects of the dietary management of IBS, with the aim of providing evidence-based guidelines for use by registered dietitians. METHODS Questions relating to diet and IBS symptom management were developed by a guideline development group. These included the role of milk and lactose, nonstarch polysaccharides (NSP), fermentable carbohydrates in abdominal bloating, probiotics and empirical or elimination diets. A comprehensive literature search was conducted and relevant studies from January 1985 to November 2009 were identified using the electronic database search engines: Cinahl, Cochrane Library, Embase, Medline, Scopus and Web of Science. Evidence statements, recommendations, good practice points and research recommendations were developed. RESULTS Thirty studies were critically appraised. A dietetic care pathway was produced following a logical sequence of treatment and formed the basis of these guidelines. Three lines of dietary management were identified. first line: Clinical and dietary assessment, healthy eating and lifestyle management with some general advice on lactose and NSP. Second line: Advanced dietary interventions to improve symptoms based on NSP, fermentable carbohydrates and probiotics. Third line: Elimination and empirical diets. Research recommendations were also identified relating to the need for adequately powered and well designed randomised controlled trials. CONCLUSIONS These guidelines provide evidence-based details of how to achieve the successful dietary management of IBS.

Efficacy and tolerability of a low microparticle diet in a double blind, randomized, pilot study in Crohn's disease.

Background Ultrafine and fine particles are potent adjuvants in antigen-mediated immune responses, and cause inflammation in susceptible individuals. Following recent findings that microparticles accumulate in the phagocytes of intestinal lymphoid aggregates, this study is the first investigation of whether their reduction in the diet improves the symptoms of Crohns disease. Methods In a double blind study, 20 patients with active corticosteroid-treated ileal or ileo-colonic Crohns disease randomly received either a low microparticle diet (trial group;n = 10) or a control diet (n = 10) for 4 months. Crohns disease activity index (CDAI) and corticosteroid requirements were compared. Results One patient in each group was withdrawn. In the trial group there was a progressive decrease in CDAI from entry (392 ± 25) to month 4 (145 ± 47) (P = 0.002 vs control group) and seven patients were in remission (CDAI < 150). In contrast, the control group had returned to baseline levels (302 ± 28 on entry and 295 ± 25 at month 4), with none in remission. Corticosteroid intake was reduced more in the trial group although this did not reach significance. Conclusions A low microparticle diet may be effective in the management of ileal Crohns disease and could explain the efficacy of elemental diets, which similarly are low in microparticles.

Improvement in orofacial granulomatosis on a cinnamon- and benzoate-free diet.

Background: Orofacial granulomatosis (OFG) is a chronic inflammatory disorder presenting characteristically with lip swelling but also affecting gingivae, buccal mucosa, floor of mouth, and a number of other sites in the oral cavity. Although the cause remains unknown, there is evidence for involvement of a dietary allergen. Patch testing has related responses to cinnamon and benzoate to the symptoms of OFG, with improvement obtained through exclusion diets. However, an objective assessment of the effect of a cinnamon‐ and benzoate‐free diet (CB‐free diet) as primary treatment for OFG has not previously been performed. Thus, this study was undertaken to investigate the benefits of a CB‐free diet as first‐line treatment of patients with OFG. Materials and Methods: Thirty‐two patients with a confirmed diagnosis of OFG were identified from a combined oral medicine/gastroenterology clinic. All had received a CB‐free diet as primary treatment for a period of 8 weeks. Each patient underwent a standardized assessment of the oral cavity to characterize the number of sites affected and the type of inflammation involved before and after diet. Results: There was a significant improvement in oral inflammation in patients on the diet after 8 weeks. Both global oral and lip inflammatory scores improved (P < 0.001), and there was significant improvement in both lip and oral site and activity involvement. However, improvement in lip activity was less marked than oral activity. Response to a CB‐free diet did not appear to be site specific. A history of OFG‐associated gut involvement did not predict a response to the diet. Conclusions: The impact of dietary manipulation in patients with OFG can be significant, particularly with regard to oral inflammation. With the disease most prevalent in the younger population, a CB‐free diet can be recommended as primary treatment. Subsequent topical or systemic immunomodulatory therapy may then be avoided or used as second line.

Lack of efficacy of a reduced microparticle diet in a multi-centred trial of patients with active Crohn's disease.

Background and aims Dietary microparticles, which are bacteria-sized and non-biological, found in the modern Western diet, have been implicated in both the aetiology and pathogenesis of Crohns disease. Following on from the findings of a previous pilot study, we aimed to confirm whether a reduction in the amount of dietary microparticles facilitates induction of remission in patients with active Crohns disease, in a single-blind, randomized, multi-centre, placebo controlled trial. Methods Eighty-three patients with active Crohns disease were randomly allocated in a 2×2 factorial design to a diet low or normal in microparticles and/or calcium for 16 weeks. All patients received a reducing dose of prednisolone for 6 weeks. Outcome measures were Crohns disease activity index, Van Hees index, quality of life and a series of objective measures of inflammation including erythrocyte sedimentation rate, C-reactive protein, intestinal permeability and faecal calprotectin. After 16 weeks patients returned to their normal diet and were followed up for a further 36 weeks. Results Dietary manipulation provided no added effect to corticosteroid treatment on any of the outcome measures during the dietary trial (16 weeks) or follow-up (to 1 year); e.g., for logistic regression of Crohns disease activity index based rates of remission (P=0.1) and clinical response (P=0.8), in normal versus low microparticle groups. Conclusions Our adequately powered and carefully controlled dietary trial found no evidence that reducing microparticle intake aids remission in active Crohns disease.

Distinguishing orofacial granulomatosis from crohn's disease: Two separate disease entities?

Background: Orofacial granulomatosis (OFG) is a rare chronic inflammatory disease of unknown etiology sharing histological features with Crohns disease (CD). This study aimed to 1) define the clinical presentation of OFG, 2) establish differentiating features for those with CD, 3) examine if onset of OFG is predictive of CD, and 4) establish differentiating features for children. Methods: Data were extracted from medical notes (n = 207) for demographics, clinical features, blood parameters, diagnosis of CD, and treatments for patients with OFG. Results: Ninety‐seven patients (47%) were female. The lips (184/203; 91%) and buccal mucosa (151/203; 74%) were mainly affected. Forty‐six (22%) had intestinal CD. Ulcers (24/46; 46% versus 29/159; 15%, P = <0.001) were more common in patients with CD as was a raised C‐reactive protein (24/33; 73% versus 60/122; 49%, P = 0.016) and abnormal full blood count (19/41; 46% versus 35/150; 23%). The buccal‐sulcus (12/44; 27% versus 20/158; 13%, P = 0.019) was more often affected in those with CD. Half the patients with CD were diagnosed prior to onset of OFG. The remainder were diagnosed after. The incidence of CD is similar for children (16/69; 23%) and adults (29/132; 22%), although oral onset in childhood is more likely to occur prior to diagnosis of CD. Conclusions: OFG mainly presents in young adults with lip and buccal involvement. Abnormalities in inflammatory markers, hematology and oral features of ulceration, and buccal‐sulcal involvement are factors more commonly associated with CD. Initial presentation of OFG does not necessarily predict development of CD, although this is more likely in childhood. (Inflamm Bowel Dis 2011;)

British Dietetic Association systematic review and evidence‐based practice guidelines for the dietary management of irritable bowel syndrome in adults (2016 update)

BACKGROUND The first British Dietetic Association (BDA) guidelines for the dietary management of irritable bowel syndrome (IBS) in adults were published in 2012. Subsequently, there has been a wealth of new research. The aim of this work was to systematically review the evidence for the role of diet in the management of IBS and to update the guidelines. METHODS Twelve questions relating to diet and IBS were defined based on review of the previous guideline questions, current evidence and clinical practice. Chosen topics were on healthy eating and lifestyle (alcohol, caffeine, spicy food, elimination diets, fat and fluid intakes and dietary habits), milk and dairy, dietary fibre, fermentable carbohydrates, gluten, probiotics and elimination diets/food hypersensitivity. Data sources were CINAHL, Cochrane Register of Controlled Trials, Embase, Medline, Scopus and Web of Science up to October 2015. Studies were assessed independently in duplicate using risk of bias tools specific to each included study based on inclusion and exclusion criteria for each question. National Health and Medical Research Council grading evidence levels were used to develop evidence statements and recommendations, in accordance with Practice-based Evidence in Nutrition Global protocol used by the BDA. RESULTS Eighty-six studies were critically appraised to generate 46 evidence statements, 15 clinical recommendations and four research recommendations. The IBS dietary algorithm was simplified to first-line (healthy eating, provided by any healthcare professional) and second-line [low FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) to be provided by dietitian] dietary advice. CONCLUSIONS These guidelines provide updated comprehensive evidence-based details to achieve the successful dietary management of IBS in adults.