Evolution, adaptation, and new applications of the FODMAP diet.

The FODMAP diet has been a treatment of irritable bowel syndrome (IBS) for many years. Rigorous scientific evaluation and clinical application of the FODMAP diet have generated deep understanding regarding clinical efficacy, mechanisms of action, and potential adverse effects of this dietary approach. In turn, this knowledge has allowed fine-tuning of the diet to optimize treatment benefits and minimize risks, in the form of the traditional three-phase diet; the FODMAP-gentle approach, which is a less restrictive iteration; and a proposed FODMAP-modified, Mediterranean-style diet which endeavours to optimise both gastrointestinal symptoms and other health parameters. Furthermore, recognition that IBS-like symptoms feature in other conditions has seen the FODMAP diet tested in non-IBS populations, including in older adults with diarrhea and women with endometriosis. These areas represent new frontiers for the FODMAP diet and a space to watch as future research evaluates the validity of these novel clinical applications.

Presence and characteristics of disordered eating and orthorexia in irritable bowel syndrome.

INTRODUCTION: Orthorexia, a harmful obsession with eating healthily, may develop from illnesses characterized by dietary restriction, including irritable bowel syndrome (IBS) and eating disorders (ED). Evidence of disordered eating in IBS exists, but orthorexia has not been assessed. This cross-sectional study in adults (≥18 years) assessed presence and characteristics of disordered eating and orthorexia in IBS, compared to control subjects (CS) and ED. METHODS: IBS participants met Rome IV, and ED participants met DSM-5 criteria. Disordered eating was assessed using "sick, control, one-stone, fat, food" (SCOFF, ≥2 indicating disordered eating), and orthorexia by the eating habits questionnaire (EHQ). Secondary measures included stress (PSS); anxiety (HADS-A); food-related quality of life (Fr-QoL), and dietary intake (CNAQ). KEY RESULTS: In 202 IBS (192 female), 34 ED (34 female), and 109 CS (90 female), more IBS (33%) and ED (47%) scored SCOFF≥2 compared to CS (16%, p < 0.001, chi-square). IBS and ED had higher orthorexia symptom severity compared to CS (EHQ IBS 82.9 ± 18.1, ED 90.1 ± 19.6, and CS 73.5 ± 16.9, p < 0.001, one-way ANOVA). IBS and ED did not differ for SCOFF or EHQ (p > 0.05). Those with IBS and disordered eating had higher orthorexia symptom severity (EHQ 78.2 ± 16.6 vs. 92.4 ± 17.5, p < 0.001, independent t-test), worse symptoms (IBS-SSS 211.0 ± 78.4 vs. 244.4 ± 62.5, p = 0.008, Mann-Whitney U test), higher stress (p < 0.001, independent t-test), higher anxiety (p = 0.002, independent t-test), and worse FR-QoL (p < 0.001, independent t-test). CONCLUSIONS AND INFERENCES: Disordered eating and orthorexia symptoms occur frequently in IBS, particularly in those with worse gastrointestinal symptoms, higher stress, and anxiety. Clinicians could consider these characteristics when prescribing dietary therapies.

Proportion of unplanned tube replacements and complications following gastrostomy: A systematic review and meta-analysis.

AIMS: Gastrostomy feeding represents a vital component of supportive care provided to people with swallowing or feeding difficulties; however, the rate of specific long-term complications is currently unknown in the adult population. This study aimed to determine the prevalence of specific long-term gastrostomy-related complications and unplanned replacements in adults. METHODS: A prospective systematic review of Medline, CINAHL and Embase databases was performed. Key complications of hypergranulation, infection and displacement among studies relevant to percutaneous endoscopic gastrostomy tubes, radiologically inserted gastrostomy tubes and balloon replacement tubes were critically appraised by two independent reviewers. Results were synthesised quantitatively in a meta-analysis using random effects where the population and condition were sufficiently homogeneous. RESULTS: In total, 453 studies were identified, of which 17 met inclusion criteria. 8.5% of adults with a gastrostomy were found to have had an infection ≥42 days after initial tube insertion (p < 0.01), while 13% had hypergranulation (p < 0.01). Displacement occurred in 10.8% of adults (p < 0.01), with age (p < 0.001) and sex (p < 0.001) presenting as a risk factor (R2 = 75%) following meta-regression. CONCLUSIONS: Approximately 1 in 10 people with a gastrostomy will experience a complication related to either hypergranulation, infection or dislodgement. Age, in combination with sex, may provide a guide for risk of displacement among adult female cohorts, though further studies reporting prevalence of gastrostomy-related complications along with participant demographics are required.

Assessing the presence and motivations of orthorexia nervosa among athletes and adults with eating disorders: a cross-sectional study.

PURPOSE: Orthorexia nervosa involves restricting diet based on quality rather than quantity. Although orthorexia is well reported in many at-risk populations, limited data addresses its presence in individuals with eating disorder history (EDs) or athletes. We aimed to identify the presence and potential drivers of orthorexia in adults with EDs and endurance athletes, compared to control subjects. METHODS: Participants ≥ 18y included: people with a diagnosed eating disorder (ED as per DSM-5); endurance athletes (training/competing ≥ 5 h/week); or control subjects. Participants (n = 197) completed an online survey assessing orthorexia (eating habits questionnaire, EHQ), eating motivations (TEMS-B) and compulsive exercise (CET). RESULTS: ED had the highest orthorexia symptom severity (92.0 ± 3.02, n = 32), followed by athletes (76.2 ± 2.74, n = 54) and controls (71.0 ± 1.80, n = 111) (F (2) = 18.2, p < 0.001). A strong positive correlation existed between weight control motives and higher orthorexia symptom severity (r = 0.54, 95% CI [1.35, 2.36], p < 0.001), while a weak negative association existed between Hunger and Pleasure motives and higher orthorexia symptom severity (r = 0.23, 95% CI [- 2.24, - 0.34], p = 0.008; r = 0.26, 95% CI [- 2.11, - 0.47], p = 0.002, respectively). A moderate positive relationship was found between CET and orthorexia symptom severity (95% CI [1.52, 3.12], p < 0.001). CONCLUSION: Adults with ED history and endurance athletes have greater orthorexia symptom severity compared to control. Clinicians working with at-risk populations should screen patients and be aware of red-flags of orthorexic traits, desire to control weight, and compulsive exercise behavior. LEVEL OF EVIDENCE: III: Evidence obtained from cohort studies.

Time-Restricted Fasting Improves Liver Steatosis in Non-Alcoholic Fatty Liver Disease-A Single Blinded Crossover Trial.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is associated with visceral adiposity. We assessed the effectiveness of time-restricted fasting (TRF) for 16 h daily without calorie restrictions compared to standard care (SC; diet and lifestyle advice) in improving visceral adiposity and steatosis via controlled attenuation parameter (CAP). METHODS: In a prospective single-blind randomized controlled trial, 32 participants with NAFLD were randomly assigned to TRF or SC for 12 weeks. The secondary endpoints were changes in liver stiffness, anthropometry, blood pressure, and other metabolic factors. RESULTS: Twenty-eight participants completed the first arm of the study (TRF = 14, SC = 14), with 23 completing the crossover arm (TRF = 10, SC = 13). The baseline demographics were similar between the groups. Intermittent fasting caused a significant decrease in hepatic steatosis (p = 0.038), weight (p = 0.005), waist circumference (p = 0.001), and BMI (p = 0.005) compared to standard care. Intermittent fasting also resulted in additional within-group changes that were not seen in the standard care intervention. CONCLUSION: TRF offers superior improvements in patients with NAFLD, improving steatosis, weight, and waist circumference despite a lack of change in overall caloric intake. Time-restricted fasting should be considered as a primary weight loss intervention in the context of NAFLD. TRIAL REGISTRATION: ACTRN12613000935730.

Association between dietary factors, symptoms, and psychological factors in adults with dyspepsia: A cross-sectional study.

BACKGROUND: Evidence-based dietary management approaches for symptoms of dyspepsia are lacking. This study aimed to compare dietary factors, symptoms, quality of life (QOL) and salivary cortisol in dyspepsia participants and healthy controls. METHODS: A cross-sectional survey was completed by adults with dyspepsia (n = 121) meeting Rome IV criteria and healthy controls (n = 52). Outcome measures included self-reported questionnaires about dietary habits, triggers, restrictions, dietary management approaches, nutritional intake, psychological variables, QOL, gastrointestinal symptoms, and optional cortisol awakening response (CAR) via saliva samples. Data were analyzed using Chi-square or Mann-Whitney U. Cortisol awakening response data was analyzed using moderated regression controlling for age, gender and distress. KEY RESULTS: Fermentable carbohydrates (FODMAPs) (55%) were the most reported trigger in adults with dyspepsia. The dyspepsia group (88%) followed special diets more than controls (47%; p < 0.001), with a low FODMAP diet being most common (69%). The dyspepsia group consumed less fiber (p = 0.014), calcium (p = 0.015), and total FODMAPs (p < 0.001) than controls. There was a greater prevalence of comorbid anxiety (41%) and depression (31%) in dyspepsia compared to controls (15% and 12%, respectively, p < 0.001 and p = 0.006). The dyspepsia group had poorer QOL and greater gastrointestinal symptom severity than controls (p < 0.001). There was a negative association between anxiety and CAR (p = 0.001) in dyspepsia but not in controls. CONCLUSIONS & INFERENCES: Adults with dyspepsia follow special diets more than controls and perceive FODMAPs as a key dietary trigger. These findings highlight the importance of monitoring nutritional adequacy and QOL, and emphasize mechanisms of depleted stress response in dyspepsia, warranting further exploration.

Dietary monosodium glutamate increases visceral hypersensitivity in a mouse model of visceral pain.

BACKGROUND: Monosodium glutamate (MSG) has been identified as a trigger of abdominal pain in irritable bowel syndrome (IBS), but the mechanism is unknown. This study examined whether MSG causes visceral hypersensitivity using a water-avoidance stress (WAS) mouse model of visceral pain. METHODS: Mice were divided into four groups receiving treatment for 6 days: WAS + MSG gavage, WAS + saline gavage, sham-WAS + MSG gavage, and sham-WAS + saline gavage. The acute effects of intraluminal administration of 10 µM MSG on jejunal extrinsic afferent nerve sensitivity to distension (0-60 mmHg) were examined using ex vivo extracellular recordings. MSG was also applied directly to jejunal afferents from untreated mice. Glutamate concentration was measured in serum, and in the serosal compartment of Ussing chambers following apical administration. KEY RESULTS: Acute intraluminal MSG application increased distension responses of jejunal afferent nerves from mice exposed to WAS + MSG. This effect was mediated by wide dynamic range and high-threshold units at both physiologic and noxious pressures (10-60 mmHg, p < 0.05). No effect of MSG was observed in the other groups, or when applied directly to the jejunal afferent nerves. Serum glutamate was increased in mice exposed to WAS + MSG compared to sham-WAS + saline, and serosal glutamate increased using WAS tissue (p = 0.0433). CONCLUSIONS AND INFERENCES: These findings demonstrate that repeated exposure to MSG in mice leads to sensitization of jejunal afferent nerves to acute ex vivo exposure to MSG. This may contribute to visceral hypersensitivity reported in response to MSG in patients with IBS.

Orthorexia nervosa is a concern in gastroenterology: A scoping review.

There is concern that use of restrictive therapeutic diets, such as those used in disorders of the gut-brain interaction (DGBI), may increase disordered eating. In this issue of Neurogastroenterology and Motility, Burton Murray et al. and Peters et al. both demonstrate a high prevalence of disordered eating in patients with gastrointestinal conditions, particularly those with DGBI. Given these findings, it is likely that orthorexia is common in this patient group, although this was not directly examined in these studies. Orthorexia nervosa is described as an obsessive and unsafe focus on eating foods perceived as healthy. This mini-review therefore focuses on orthorexia by conducting a scoping review, as per the PRISMA extension for scoping reviews, aimed to assess the prevalence of orthorexia, and associations between orthorexia and restrictive eating practices. While a wide range of orthorexia prevalence has been reported (0%-97%) across the 57 studies included, no studies assessed prevalence specifically in gastrointestinal conditions. Four of eight studies describing diseases associated with specific dietary patterns suggested that participants who followed a diet for "digestive issues" or "food intolerances" were at higher orthorexia risk. These results suggest that dietary modifications may be a factor contributing to orthorexia. Additionally, we provide a commentary on the clinical implications of the findings for gastrointestinal conditions including a clinical flow chart. Clinicians should consider if a restrictive diet is appropriate for individuals with DGBI and include screening for disordered eating prior to implementation of dietary modifications. Future prospective studies should evaluate orthorexia within this patient group.

How to Implement the 3-Phase FODMAP Diet Into Gastroenterological Practice.

Background/Aims: The 3-phase fermentable oligo-, di-, mono-saccharides, and polyols (FODMAP) diet has shown a high level of efficacy in irritable bowel syndrome, largely based on dietitian delivered education. However, access to dietitians can be limited, and challenges exist when applying the diet to a wide range of cultures, such as limited FODMAP analysis of local foods. This review aims to discuss ways to optimally use the FODMAP diet in practice in a wide range of cultures, directed at gastroenterologists from a dietitian's perspective. Methods: Recent literature was analysed via search databases including Medline, CINAHL, PubMed and Scopus. Results: The dietetic process involves detailed assessment and follow-up through the 3 stages of the FODMAP diet (restriction, re-introduction, and long-term maintenance). Emerging evidence suggests the diet can be delivered by other health professionals such as the gastroenterologist or nurse, but training on how to do so successfully would be needed. Self-guided approaches through use of technology or specialised food delivery services may be an alternative when dietitians are not available, but efficacy data is limited. Regardless of delivery mode, nutritional and psychological risks of the diet must be mitigated. Additionally, culturally appropriate education must be provided, with accommodations necessary when the FODMAP content of local foods are unknown. Conclusion: While the diet has shown improved irritable bowel syndrome outcomes across studies, it is important to acknowledge the essential role of dietitians in implementing, tailoring, and managing the diet to achieve the best outcome for each individual.

The lived experience of irritable bowel syndrome: A focus on dietary management.

BACKGROUND: Irritable bowel syndrome (IBS) is a disorder of the gut-brain axis with a prevalence of 3.5% in Australia. The complexity of mechanisms underlying IBS means patients often respond poorly to treatment. There is encouraging evidence for the successful use of dietary strategies for short- and long-term management of IBS. OBJECTIVE: The aim of this narrative review was to explore the lived experience of IBS from the patient perspective with emphasis on dietary involvement and diet management of the condition. DISCUSSION: There are a number of dietary constituents implicated in IBS, and patients' main concerns are the trial-and-error nature of identifying triggers, uncertainty regarding food choices and reduced enjoyment of food. Despite this, dietary modifications are accepted by patients and healthcare professionals (HCPs) as an efficacious management strategy. A meaningful relationship with their HCP can improve patient adherence, treatment success and overall satisfaction for patients.

The Role of Food in the Treatment of Bowel Disorders: Focus on Irritable Bowel Syndrome and Functional Constipation.

Irritable bowel syndrome (IBS) and functional constipation (FC) are among the most common disorders of gut-brain interaction, affecting millions of individuals worldwide. Most patients with disorders of gut-brain interaction perceive food as a trigger for their gastrointestinal symptoms, and specific dietary manipulations/advice have now been recognized as a cornerstone therapeutic option for IBS and FC. We discuss in detail the 2 most common dietary interventions used for the management of IBS-general dietary advice based on the National Institute for Health and Care Excellence guidelines and a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs). We summarize the literature around the possible mechanisms of FODMAP-mediated IBS pathophysiology, the current 3-step, top-down approach of administering a low FODMAP diet (LFD) (restriction phase, followed by reintroduction and personalization), the efficacy data of its restriction and personalization phases, and possible biomarkers for response to an LFD. We also summarize the limitations and challenges of an LFD along with the alternative approach to administering an LFD (e.g., bottom-up). Finally, we discuss the available efficacy data for fiber, other dietary interventions (e.g., Mediterranean diet, gluten-free diet, and holistic dietary interventions), and functional foods (e.g., kiwifruit, rhubarb, aloe, and prunes) in the management of IBS and FC.

Low FODMAP diet beyond IBS: Evidence for use in other conditions.

The low FODMAP diet has shifted therapeutic guidelines for symptom management in irritable bowel syndrome. Given FODMAPs are involved in underlying pathological mechanisms of visceral hypersensitivity, research groups are exploring the use of the low-FODMAP diet as a potential management approach in several conditions outside of irritable bowel syndrome. Early data shows promise for functional dyspepsia, improving epigastric symptoms, and although evidence is scant, the diet has been proposed to assist in small intestinal bacterial overgrowth. Characterisation of sucrase-isomaltase deficiency may offer profiling for predicting response to the diet. Although encouraging, carefully controlled broader trials are needed across the conditions discussed to completely understand the effects of the low FODMAP diet on symptoms, safety, and efficacy in clinical practice.

Changes in signalling from faecal neuroactive metabolites following dietary modulation of IBS pain.

OBJECTIVE: Dietary therapies for irritable bowel syndrome (IBS) have received increasing interest but predicting which patients will benefit remains a challenge due to a lack of mechanistic insight. We recently found evidence of a role for the microbiota in dietary modulation of pain signalling in a humanised mouse model of IBS. This randomised cross-over study aimed to test the hypothesis that pain relief following reduced consumption of fermentable carbohydrates is the result of changes in luminal neuroactive metabolites. DESIGN: IBS (Rome IV) participants underwent four trial periods: two non-intervention periods, followed by a diet low (LFD) and high in fermentable carbohydrates for 3 weeks each. At the end of each period, participants completed questionnaires and provided stool. The effects of faecal supernatants (FS) collected before (IBS FS) and after a LFD (LFD FS) on nociceptive afferent neurons were assessed in mice using patch-clamp and ex vivo colonic afferent nerve recording techniques. RESULTS: Total IBS symptom severity score and abdominal pain were reduced by the LFD (N=25; p<0.01). Excitability of neurons was increased in response to IBS FS, but this effect was reduced (p<0.01) with LFD FS from pain-responders. IBS FS from pain-responders increased mechanosensitivity of nociceptive afferent nerve axons (p<0.001), an effect lost following LFD FS administration (p=NS) or when IBS FS was administered in the presence of antagonists of histamine receptors or protease inhibitors. CONCLUSIONS: In a subset of IBS patients with improvement in abdominal pain following a LFD, there is a decrease in pronociceptive signalling from FS, suggesting that changes in luminal mediators may contribute to symptom response.

Naturally-occurring dietary salicylates in the genesis of functional gastrointestinal symptoms in patients with irritable bowel syndrome: Pilot study.

BACKGROUND AND AIM: An elimination-rechallenge dietary approach targeting naturally-occurring bioactive chemicals has been proposed to alleviate functional gastrointestinal symptoms. A major focus of this approach is salicylates. This study aimed to address the potential role of dietary salicylates in the induction of symptoms in patients with irritable bowel syndrome (IBS). METHODS: A pilot, double-blind, randomized, cross-over trial of 2-week low- versus high-salicylate diets (6.6 and 27.9 g/day salicylate, respectively) was undertaken. All foods were provided containing minimal quantities of other potential food triggers. Gastrointestinal and extraintestinal symptoms were measured daily using a 100-mm visual-analogue-scale. RESULTS: Ten participants with IBS completed the study, including one with known aspirin-sensitivity. Overall, no differences in symptoms were observed (P = 0.625; Friedman test). However, clear symptom provocation was seen in the aspirin-sensitive participant, with all abdominal symptoms and tiredness worsening during the high-salicylate diet. A similar trend was seen in another participant, where abdominal symptoms gradually worsened during the high-salicylate diet. CONCLUSIONS: These results provide some evidence that food-related salicylates may influence the genesis of symptoms in a subset of patients with IBS. A larger cohort is needed to determine the incidence of salicylate-sensitivity and further evaluate the diet as a potential therapeutic target.The protocol was registered at www.anzctr.org.au (ACTRN12620001250921).

Evaluation of lactulose, lactose, and fructose breath testing in clinical practice: A focus on methane.

BACKGROUND AND AIM: Breath testing (BT) is used to identify carbohydrate malabsorption and small intestine bacterial overgrowth. Measuring methane alongside hydrogen is advocated to reduce false-negative studies, but the variability of methane production is unknown. The aim of this study is to examine the effect of high methane production on hydrogen excretion after ingesting lactulose, fructose, or lactose. METHODS: A retrospective audit was performed of patients with gastrointestinal symptoms who underwent BT. Following a low fermentable carbohydrate diet for 24-h, a fasting BT before consuming 35 ml lactulose, 35 g fructose, or lactose in 200 ml water, followed by BT every 10-15 min for up to 3-h, was performed. A positive test was defined as a ≥20 ppm rise of hydrogen or methane from baseline. A high methane producer had an initial reading of ≥5 ppm. Breath hydrogen and methane production were measured as area under the curve. Chi-squared tests were used to compare proportions of those meeting the cut-off criteria. RESULTS: Of patients, 26% (28/106) were high methane producers at their initial lactulose test. The test-retest repeatability of methane production was high, with the same methane production status before ingesting lactose in all (70/70) and before ingesting fructose in most (71/73). Methane production was highly variable during testing, with 38% (10/26) having ≥1 reading lower than baseline. Hydrogen produced by high or low methane producers did not differ (1528 [960-3645] ppm min vs 2375 [1810-3195] ppm min [P = 0.11]). Symptoms and breath test results were not positively related. CONCLUSION: The validity of including an increase of ≥20 ppm methane to identify carbohydrate malabsorption or small intestine bacterial overgrowth should be questioned due to the variability of readings during testing.

Implementation of the low FODMAP diet in functional gastrointestinal symptoms: A real-world experience.

BACKGROUND: The low FODMAP (fermentable oligo-, di-, monosaccharides, and polyols) diet reduces functional gastrointestinal symptoms (FGID) when implemented by dietitian-delivered education in clinical trials, but it is unknown how well the diet is followed in routine clinical care and if differences exist when implemented by physician or dietitian. This study aimed to evaluate the real-world experience of patients recommended the diet. METHODS: This case-series interviewed FGID patients attending a gastroenterology clinic with previous recommendation to trial the low FODMAP diet, examining who recommended the diet and what their percentage improvement was. To evaluate implementation of the diet's 3 phases, questions were constructed based on current literature and clinical guidelines regarding length of initial restriction and food knowledge (Phase-1), number of foods re-challenged (Phase-2) and food re-introduction as tolerated (Phase-3). The comprehensive nutrition assessment questionnaire provided daily FODMAP intake. Data were analyzed using chi-squared tests. KEY RESULTS: In 80 patients (21 male), the diet was recommended by the gastroenterologist in 53%, general practitioner 22%, dietitian 9% and other 15%. 30% saw a dietitian for guidance. 55% reported a ≥50% symptom improvement. The diet was followed appropriately during Phase-1 by 78% (with vs without a dietitian, 96% vs 71%; P = .02), Phase-2 by 48% (70% vs 39%; P = .02) and Phase-3 by 40% (65% vs 29%; P < .01). A FODMAP intake of <12 g/d (considered therapeutic) was achieved by 44% (72% vs 31%; P < .01). CONCLUSIONS & INFERENCES: Symptom improvement was reported in half of patients, but many did not reach the therapeutic FODMAP intake target, especially without dietitian education. Compliance was poor in Phase-2 and Phase-3 but improved with dietitian guidance.