-
1.
Diets that differ in their FODMAP content alter the colonic luminal microenvironment.
Halmos, EP, Christophersen, CT, Bird, AR, Shepherd, SJ, Gibson, PR, Muir, JG
Gut. 2015;64(1):93-100
-
-
-
Plain language summary
A low FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols) diet is being increasingly recommended for the management of IBS. However, the FODMAP diet can be low in potential prebiotic and fermentable fibre which may have an adverse effect on gut bacteria diversity and other colonic health biomarkers. This study set out to identify how a low FODMAP diet affected the pH, short-chain fatty acid concentrations and bacterial abundance and diversity in comparison to a typical Australian diet. The randomised cross over study consisted of 27 IBS and 6 healthy subjects who were blinded to 21 days of a low FODMAP diet and then, following a washout period of 21 days following their usual diet they were crossed over to the typical Australian diet for 21 days. The study found increased faecal pH, similar short chain fatty acid concentrations, a greater microbial diversity and reduced bacterial abundancy in faecal samples whilst following the low FODMAP diet. It was concluded that caution should be used when reducing FODMAP intake in the long term and that a low FODMAP diet should not be recommended for asymptomatic populations.
Abstract
OBJECTIVE A low FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols) diet reduces symptoms of IBS, but reduction of potential prebiotic and fermentative effects might adversely affect the colonic microenvironment. The effects of a low FODMAP diet with a typical Australian diet on biomarkers of colonic health were compared in a single-blinded, randomised, cross-over trial. DESIGN Twenty-seven IBS and six healthy subjects were randomly allocated one of two 21-day provided diets, differing only in FODMAP content (mean (95% CI) low 3.05 (1.86 to 4.25) g/day vs Australian 23.7 (16.9 to 30.6) g/day), and then crossed over to the other diet with ≥21-day washout period. Faeces passed over a 5-day run-in on their habitual diet and from day 17 to day 21 of the interventional diets were pooled, and pH, short-chain fatty acid concentrations and bacterial abundance and diversity were assessed. RESULTS Faecal indices were similar in IBS and healthy subjects during habitual diets. The low FODMAP diet was associated with higher faecal pH (7.37 (7.23 to 7.51) vs. 7.16 (7.02 to 7.30); p=0.001), similar short-chain fatty acid concentrations, greater microbial diversity and reduced total bacterial abundance (9.63 (9.53 to 9.73) vs. 9.83 (9.72 to 9.93) log10 copies/g; p<0.001) compared with the Australian diet. To indicate direction of change, in comparison with the habitual diet the low FODMAP diet reduced total bacterial abundance and the typical Australian diet increased relative abundance for butyrate-producing Clostridium cluster XIVa (median ratio 6.62; p<0.001) and mucus-associated Akkermansia muciniphila (19.3; p<0.001), and reduced Ruminococcus torques. CONCLUSIONS Diets differing in FODMAP content have marked effects on gut microbiota composition. The implications of long-term reduction of intake of FODMAPs require elucidation. TRIAL REGISTRATION NUMBER ACTRN12612001185853.
-
2.
A diet low in FODMAPs reduces symptoms of irritable bowel syndrome.
Halmos, EP, Power, VA, Shepherd, SJ, Gibson, PR, Muir, JG
Gastroenterology. 2014;146(1):67-75.e5
-
-
-
Plain language summary
Although irritable bowel syndrome (IBS) is the most common gastrointestinal condition patients present with, little evidence exists on how to manage the varying symptoms. A diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) is often prescribed to manage IBS, however there is a large gap in evidence of the efficacy of the low FODMAP diet in this population. The aim of this crossover trial was to compare gastrointestinal symptoms of a low FODMAP diet with a typical Australian diet moderate in FODMAPs in 30 IBS patients and 8 healthy individuals. Participants were randomised and consumed the allocated diet for three weeks with a three week washout period. This study found that participants with IBS reported less overall gastrointestinal symptoms while on the low FODMAP diet compared with the typical Australian diet. Based on these results, the authors conclude that the low FODMAP diet has efficacy and should be used as a first-line therapy in patients with IBS.
Abstract
BACKGROUND & AIMS A diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) often is used to manage functional gastrointestinal symptoms in patients with irritable bowel syndrome (IBS), yet there is limited evidence of its efficacy, compared with a normal Western diet. We investigated the effects of a diet low in FODMAPs compared with an Australian diet, in a randomized, controlled, single-blind, cross-over trial of patients with IBS. METHODS In a study of 30 patients with IBS and 8 healthy individuals (controls, matched for demographics and diet), we collected dietary data from subjects for 1 habitual week. Participants then randomly were assigned to groups that received 21 days of either a diet low in FODMAPs or a typical Australian diet, followed by a washout period of at least 21 days, before crossing over to the alternate diet. Daily symptoms were rated using a 0- to 100-mm visual analogue scale. Almost all food was provided during the interventional diet periods, with a goal of less than 0.5 g intake of FODMAPs per meal for the low-FODMAP diet. All stools were collected from days 17-21 and assessed for frequency, weight, water content, and King's Stool Chart rating. RESULTS Subjects with IBS had lower overall gastrointestinal symptom scores (22.8; 95% confidence interval, 16.7-28.8 mm) while on a diet low in FODMAPs, compared with the Australian diet (44.9; 95% confidence interval, 36.6-53.1 mm; P < .001) and the subjects' habitual diet. Bloating, pain, and passage of wind also were reduced while IBS patients were on the low-FODMAP diet. Symptoms were minimal and unaltered by either diet among controls. Patients of all IBS subtypes had greater satisfaction with stool consistency while on the low-FODMAP diet, but diarrhea-predominant IBS was the only subtype with altered fecal frequency and King's Stool Chart scores. CONCLUSIONS In a controlled, cross-over study of patients with IBS, a diet low in FODMAPs effectively reduced functional gastrointestinal symptoms. This high-quality evidence supports its use as a first-line therapy. CLINICAL TRIAL NUMBER ACTRN12612001185853.
-
3.
The role of FODMAPs in irritable bowel syndrome.
Shepherd, SJ, Halmos, E, Glance, S
Current opinion in clinical nutrition and metabolic care. 2014;(6):605-9
Abstract
PURPOSE OF REVIEW Irritable bowel syndrome (IBS) is a condition affecting approximately 10-15% of Western populations. The Rome III criteria are applied to many studies to validate the diagnosis of IBS. The low fermentable oligo, di, monosaccharides and polyol (FODMAP) diet has been the subject of many robust clinical trials and is now used as the primary dietary therapy internationally. This review examines the current evidence for the role of the low FODMAP diet in IBS. RECENT FINDINGS Detailed commentary on original research involving FODMAPs and IBS symptoms from 2013 to 2014 is provided. SUMMARY The low FODMAP diet has been shown to be an efficacious therapy for reduction of functional gastrointestinal symptoms seen in IBS. Recent publications provide randomized controlled trial and prospective observational evidence in support of the diet for symptom management. The low FODMAP diet appears to be superior to a gluten-free diet in people with self-reported nonceliac gluten sensitivity. Although the low FODMAP diet has not been shown to reduce the prebiotic effect in the colon, total colonic bacterial load was reduced. Further research investigating the potential health implications of both this and the nutritional adequacy of the liberalized low FODMAP diet is required.
-
4.
Cognitive impairment in coeliac disease improves on a gluten-free diet and correlates with histological and serological indices of disease severity.
Lichtwark, IT, Newnham, ED, Robinson, SR, Shepherd, SJ, Hosking, P, Gibson, PR, Yelland, GW
Alimentary pharmacology & therapeutics. 2014;40(2):160-70
-
-
-
Free full text
-
Plain language summary
Coeliac disease (CD) is an inflammatory autoimmune disorder caused by the ingestion of gluten. While CD is known to primarily affect the bowel, there is reported evidence of potential neurological side effects. Cognition may be impaired in undiagnosed CD patients because of nutrient deficiencies, systemic inflammation and changes in the gut microbiome. CD patients often report a mild cognitive impairment, brain fog, characterised by difficulty concentrating, short-term memory and confusion. The aim of this study was to investigate the relationship between gut mucosal healing and cognitive function in eleven patients recently diagnosed with CD commencing a strict gluten-free diet. The findings of this study showed that in newly diagnosed CD patients, cognitive functioning improved with a gluten-free diet and was correlated with mucosal healing. Based on this study, the authors conclude that cognition is impaired in people with untreated coeliac disease and may affect the performance of everyday tasks. This finding also introduces the possibility of using cognitive tests to provide a marker of intestinal healing.
Abstract
BACKGROUND Mild impairments of cognition or 'Brain fog' are often reported by patients with coeliac disease but the nature of these impairments has not been systematically investigated. AIM: This longitudinal pilot study investigated relationships between cognitive function and mucosal healing in people with newly diagnosed coeliac disease commencing a gluten-free diet. METHODS Eleven patients (8 females, 3 males), mean age 30 (range 22-39) years, were tested with a battery of cognitive tests at weeks 0, 12 and 52. Information processing efficacy, memory, visuospatial ability, motoric function and attention were tested. Small bowel biopsies were collected via routine gastroscopy at weeks 12 and 52 and were compared to baseline Marsh scores. Cognitive performance was compared to serum concentrations of tissue transglutaminase antibodies, biopsy outcomes and other biological markers. RESULTS All patients had excellent adherence to the diet. Marsh scores improved significantly (P = 0.001, Friedman's test) and tissue transglutaminase antibody concentrations decreased from a mean of 58.4 at baseline to 16.8 U/mL at week 52 (P = 0.025). Four of the cognitive tests assessing verbal fluency, attention and motoric function showed significant improvement over the 12 months and strongly correlated with the Marsh scores and tissue transglutaminase antibody levels (r = 0.377-0.735; all P < 0.05). However, no meaningful patterns of correlations were found for nutritional or biochemical markers, or markers of intestinal permeability. CONCLUSIONS In newly diagnosed coeliac disease, cognitive performance improves with adherence to the gluten-free diet in parallel to mucosal healing. Suboptimal levels of cognition in untreated coeliac disease may affect the performance of everyday tasks.
-
5.
Design of clinical trials evaluating dietary interventions in patients with functional gastrointestinal disorders.
Yao, CK, Gibson, PR, Shepherd, SJ
The American journal of gastroenterology. 2013;(5):748-58
Abstract
Clear guiding principles for the design and conduct of dietary intervention trials in functional gastrointestinal disorders (FGID) are lacking. This narrative review examines the specific challenges associated with the design and reporting in dietary intervention trials. Dietary intervention trials need to address the collinearity between food, nutrients, and bioactive components that obscure the relationship between food and their effects in the gut. Randomized, double-blinded, placebo-controlled studies remain the gold standard for dietary trials, but are limited by difficulties in adequate masking of study food or inappropriate choice of placebo food/diets. Provision of study diets as the preferred delivery method can somewhat address these limitations, although allowing good adherence compared with education-based dietary interventions. Issues associated with participant expectancies and dietary behaviors can alter the true effectiveness of a diet. In addition, failure to adjust for or report baseline intake of nutrients of interest can reduce their magnitude of benefit. Bias in subjective reports and choice of measurement tools can preclude accurate assessment of food-intake data. In the design of elimination and rechallenge studies, sufficient time period and adequate exclusion of dietary triggers are essential to ensure symptoms are well-controlled before rechallenging. The route and frequency of challenging, design of test food, and/or placebo should match the aims of the rechallenge phase. Long-term efficacy data of such therapeutic diets has been poorly documented in most studies. Standardized guidelines that address many of the challenges outlined above are suggested to strengthen the quality of evidence for dietary therapies in FGID.
-
6.
Short-chain carbohydrates and functional gastrointestinal disorders.
Shepherd, SJ, Lomer, MC, Gibson, PR
The American journal of gastroenterology. 2013;(5):707-17
Abstract
Carbohydrates occur across a range of foods regularly consumed including grains such as wheat and rye, vegetables, fruits, and legumes. Short-chain carbohydrates with chains of up to 10 sugars vary in their digestibility and subsequent absorption. Those that are poorly absorbed exert osmotic effects in the intestinal lumen increasing its water volume, and are rapidly fermented by bacteria with consequent gas production. These two effects alone may underlie most of the induction of gastrointestinal symptoms after they are ingested in moderate amounts via luminal distension in patients with visceral hypersensitivity. This has been the basis of the use of lactose-free diets in those with lactose malabsorption and of fructose-reduced diets for fructose malabsorption. However, application of such dietary approaches in patients with functional bowel disorders has been restricted to observational studies with uncertain efficacy. As all dietary poorly absorbed short-chain carbohydrates have similar and additive effects in the intestine, a concept has been developed to regard them collectively as FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) and to evaluate a dietary approach that restricts them all. In patients with irritable bowel syndrome, there is now an accumulating body of evidence, based on observational and comparative studies, and on randomized-controlled trials that supports the notion that FODMAPs trigger gastrointestinal symptoms in patients with functional bowel disorders, and that a diet low in FODMAPs offers considerable symptom relief in the majority of patients who use it.
-
7.
Food choice as a key management strategy for functional gastrointestinal symptoms.
Gibson, PR, Shepherd, SJ
The American journal of gastroenterology. 2012;(5):657-66; quiz 667
Abstract
Recognition of food components that induce functional gut symptoms in patient's functional bowel disorders (FBD) has been challenging. Food directly or indirectly provides considerable afferent input into the enteric nervous system. There is an altered relationship between the afferent input and perception/efferent response in FBD. Defining the nature of food-related stimuli may provide a means of minimizing such an input and gut symptoms. Using this premise, reducing the intake of FODMAPs (fermentable oligo-, di-, and mono-saccharides and polyols)--poorly absorbed short-chain carbohydrates that, by virtue of their small molecular size and rapid fermentability, will distend the intestinal lumen with liquid and gas--improves symptoms in the majority of patients. Well-developed methodologies to deliver the diet via dietician-led education are available. Another abundant source of afferent input is natural and added food chemicals (such as salicylates, amines, and glutamates). Studies are needed to assess the efficacy of the low food chemical dietary approach. A recent placebo-controlled trial of FODMAP-poor gluten provided the first valid evidence that non-celiac gluten intolerance might actually exist, but its prevalence and underlying mechanisms require elucidation. Food choice via the low FODMAP and potentially other dietary strategies is now a realistic and efficacious therapeutic approach for functional gut symptoms.
-
8.
Gluten causes gastrointestinal symptoms in subjects without celiac disease: a double-blind randomized placebo-controlled trial.
Biesiekierski, JR, Newnham, ED, Irving, PM, Barrett, JS, Haines, M, Doecke, JD, Shepherd, SJ, Muir, JG, Gibson, PR
The American journal of gastroenterology. 2011;(3):508-14; quiz 515
Abstract
OBJECTIVES Despite increased prescription of a gluten-free diet for gastrointestinal symptoms in individuals who do not have celiac disease, there is minimal evidence that suggests that gluten is a trigger. The aims of this study were to determine whether gluten ingestion can induce symptoms in non-celiac individuals and to examine the mechanism. METHODS A double-blind, randomized, placebo-controlled rechallenge trial was undertaken in patients with irritable bowel syndrome in whom celiac disease was excluded and who were symptomatically controlled on a gluten-free diet. Participants received either gluten or placebo in the form of two bread slices plus one muffin per day with a gluten-free diet for up to 6 weeks. Symptoms were evaluated using a visual analog scale and markers of intestinal inflammation, injury, and immune activation were monitored. RESULTS A total of 34 patients (aged 29-59 years, 4 men) completed the study as per protocol. Overall, 56% had human leukocyte antigen (HLA)-DQ2 and/or HLA-DQ8. Adherence to diet and supplements was very high. Of 19 patients (68%) in the gluten group, 13 reported that symptoms were not adequately controlled compared with 6 of 15 (40%) on placebo (P=0.0001; generalized estimating equation). On a visual analog scale, patients were significantly worse with gluten within 1 week for overall symptoms (P=0.047), pain (P=0.016), bloating (P=0.031), satisfaction with stool consistency (P=0.024), and tiredness (P=0.001). Anti-gliadin antibodies were not induced. There were no significant changes in fecal lactoferrin, levels of celiac antibodies, highly sensitive C-reactive protein, or intestinal permeability. There were no differences in any end point in individuals with or without DQ2/DQ8. CONCLUSIONS "Non-celiac gluten intolerance" may exist, but no clues to the mechanism were elucidated.
-
9.
Manipulation of dietary short chain carbohydrates alters the pattern of gas production and genesis of symptoms in irritable bowel syndrome.
Ong, DK, Mitchell, SB, Barrett, JS, Shepherd, SJ, Irving, PM, Biesiekierski, JR, Smith, S, Gibson, PR, Muir, JG
Journal of gastroenterology and hepatology. 2010;(8):1366-73
Abstract
BACKGROUND AND AIM Reduction of short-chain poorly absorbed carbohydrates (FODMAPs) in the diet reduces symptoms of irritable bowel syndrome (IBS). In the present study, we aimed to compare the patterns of breath hydrogen and methane and symptoms produced in response to diets that differed only in FODMAP content. METHODS Fifteen healthy subjects and 15 with IBS (Rome III criteria) undertook a single-blind, crossover intervention trial involving consuming provided diets that were either low (9 g/day) or high (50 g/day) in FODMAPs for 2 days. Food and gastrointestinal symptom diaries were kept and breath samples collected hourly over 14 h on day 2 of each diet. RESULTS Higher levels of breath hydrogen were produced over the entire day with the high FODMAP diet for healthy volunteers (181 +/- 77 ppm.14 h vs 43 +/- 18; mean +/- SD P < 0.0001) and patients with IBS (242 +/- 79 vs 62 +/- 23; P < 0.0001), who had higher levels during each dietary period than the controls (P < 0.05). Breath methane, produced by 10 subjects within each group, was reduced with the high FODMAP intake in healthy subjects (47 +/- 29 vs 109 +/- 77; P = 0.043), but was not different in patients with IBS (126 +/- 153 vs 86 +/- 72). Gastrointestinal symptoms and lethargy were significantly induced by the high FODMAP diet in patients with IBS, while only increased flatus production was reported by healthy volunteers. CONCLUSIONS Dietary FODMAPs induce prolonged hydrogen production in the intestine that is greater in IBS, influence the amount of methane produced, and induce gastrointestinal and systemic symptoms experienced by patients with IBS. The results offer mechanisms underlying the efficacy of the low FODMAP diet in IBS.
-
10.
Evidence-based dietary management of functional gastrointestinal symptoms: The FODMAP approach.
Gibson, PR, Shepherd, SJ
Journal of gastroenterology and hepatology. 2010;(2):252-8
Abstract
BACKGROUND AND AIM Functional gastrointestinal symptoms are common and their management is often a difficult clinical problem. The link between food intake and symptom induction is recognized. This review aims to describe the evidence base for restricting rapidly fermentable, short-chain carbohydrates (FODMAPs) in controlling such symptoms. METHODS The nature of FODMAPs, their mode of action in symptom induction, results of clinical trials and the implementation of the diet are described. RESULTS FODMAPs are widespread in the diet and comprise a monosaccharide (fructose), a disaccharide (lactose), oligosaccharides (fructans and galactans), and polyols. Their ingestion increases delivery of readily fermentable substrate and water to the distal small intestine and proximal colon, which are likely to induce luminal distension and induction of functional gut symptoms. The restriction of their intake globally (as opposed to individually) reduces functional gut symptoms, an effect that is durable and can be reversed by their reintroduction into the diet (as shown by a randomized placebo-controlled trial). The diet has a high compliance rate. However it requires expert delivery by a dietitian trained in the diet. Breath hydrogen tests are useful to identify individuals who can completely absorb a load of fructose and lactose so that dietary restriction can be less stringent. CONCLUSIONS The low FODMAP diet provides an effective approach to the management of patients with functional gut symptoms. The evidence base is now sufficiently strong to recommend its widespread application.