Fiber and functional gastrointestinal disorders

Irritable Bowel Syndrome: What Treatments Really Work

Irritable bowel syndrome (IBS) is present in patients with symptoms of chronic abdominal pain and altered bowel habits but no identifiable organic etiology. Rome IV classification groups patients based on predominant stool pattern. Low-FODMAP diets have been helpful in providing symptom relief, as have cognitive behavioral and mind-body techniques that help patients manage symptoms. Targeted symptomatic relief for the patient's predominant symptoms provides relief in addition to effective older medications that are inexpensive and reliable. Newer treatments for IBS-D, such as eluxadoline, and IBS-C, with linaclotide, lubiprostone, plecanatide, also can provide durable relief.

Impact of plant extracts upon human health: A review

With the increase in evidences directly linking diet and health, several foodstuffs, such as phenolic rich fruits and vegetables, have emerged as possessing potential health benefits. Plants, given their fiber and phenolic content (and their intrinsic biological potential), have long been considered as contributing to health promotion. Therefore, the present work aimed to review the existing evidences regarding the various potential benefits of plant extracts' and plant extract-based products' consumption, with emphasis on in vivo works and epidemiological studies whenever available. Overall, the information available supports that, while there are indications of the potential benefits of plant extracts' consumption, further human-based studies are still needed to establish a true cause-effect.

Gut microbiota correlates with fiber and apparent nutrients digestion in goose

To explore the relationship among the level of fiber, gut microbiota, and nutritional substances, we applied the next generation sequencing technology for the identification of the composition and structure of microbiota in the gastrointestinal tract. In this study, a total of 25 phyla and 298 genera were identified from the gastrointestinal tract; Firmicutes, Bacteroidetes, and Proteobacteria were the predominant phyla. The ability of cecum in carbohydrate metabolism was significantly higher than that of the gizzard and ileum (P < 0.05). The bacterial community structure in various stages of the development of the cecum was different. In the different growth stages of cecum, the increase in the microbiota structure of the fiber level elevates the ability of carbon hydration. Second, the apparent metabolic rates of the other nutrients were affected by the fiber and period except for acid detergent fiber (P < 0.05); the apparent utilization rate of the nutrients increased with time. However, with the increase in the fiber level, the apparent utilization of nutrients was initially increased, followed by a decrease. Therefore, a correlation was established between the fiber level and gastrointestinal microbiota and apparent nutrient utilization rate of the 3 phyla. Our results suggest that the fiber level and growth stages could impact the composition of gut microbiota.

Gluten-free and low-FODMAP sourdoughs for patients with coeliac disease and irritable bowel syndrome: A clinical perspective

Wheat- and gluten-containing products are often blamed for triggering a wide range of gastrointestinal symptoms, and this has fueled demand for gluten-free products worldwide. The best studied 'gluten intolerance' is coeliac disease, an auto-immune disease that affects the small intestine. Coeliac disease occurs in 1% of the population and requires strict, life-long avoidance of gluten-containing foods as the only medical treatment. There is a larger group of individuals (around 10-15% of the population) who report a wide-range of gastrointestinal symptoms that respond well to a 'gluten-free diet', but who do not have coeliac disease - so called 'non-coeliac gluten sensitivity (NCGS)'. The team at Monash University has identified other factors in gluten-containing foods that may be responsible for symptoms in this group of individuals with so-called, NCGS. We have evidence that certain poorly absorbed short chain carbohydrates (called FODMAPs) present in many gluten-containing food products, induce symptoms of abdominal pain, bloating, wind and altered bowel habit (associated with irritable bowel syndrome, IBS). Our research has shown that FODMAPs, and not gluten, triggered symptoms in NCGS. Going forward, there are great opportunities for the food industry to develop low FODMAP products for this group, as choice of grain variety and type of food processing technique can greatly reduce the FODMAP levels in foods. The use of sourdough cultures in bread making has been shown to reduce the quantities of FODMAPs (mostly fructan), resulting in bread products that are well tolerated by patients with IBS. Greater interaction between biomedical- and food-scientists will improve understanding about the clinical problems many consumers face, and lead to the development of food products that are better tolerated by this group.

Resistant Maltodextrin and Metabolic Syndrome: A Review

Resistant maltodextrin is a non-viscous dietary fiber that is fermentable in the colon by colonic bacteria. The objective of this review is to summarize the studies of resistant maltodextrin and its effect on metabolic profile, such as blood glucose, lipid profile, and body weight. Several studies support the idea that resistant maltodextrin may improve blood glucose, insulin sensitivity, lipid profile, and obesity. However, the use of resistant maltodextrin should be limited to minimize the adverse effect on the gastrointestinal system. This review provides information regarding the benefits of resistant maltodextrin on metabolic health as well as its proposed mechanism to enhance the knowledge of this novel fiber. Key teaching points Resistant maltodextrin is a novel non-viscous dietary fiber classified as resistant starch type V that is produced by debranching of the starch structure. Resistant maltodextrin is fermentable in the colon and thus produces short-chain fatty acid. Resistant maltodextrin helps to maintain blood and lipid profiles as well as promote satiety and reducing food intake. High intake of resistant maltodextrin may cause gastrointestinal discomfort due to the gas production and increased osmotic pressure.

Irritable bowel syndrome: the clinical approach

Irritable bowel syndrome (IBS) is a chronic and debilitating functional gastrointestinal disorder which presents with abdominal pain associated with alteration of bowel habits. IBS is a common condition affecting 9-23% of the general population, being the 80% female, with considerable impact on quality of life and health care costs. The exact pathogenesis of IBS remains elusive, but is clearly multifactorial and includes environmental and host factors. Management of patients with IBS is challenging since diagnosis and treatment could require several approaches with unsatisfactory results. In any case, the diagnosis of IBS is based on the positive identification of symptoms consistent with this condition and by excluding an underling organic disease. Before choosing therapeutic options, a strong reassuring physician-patient relationship is crucial. The therapeutic approach of IBS may consist of both non-pharmacological therapies and pharmacotherapy and should be based on prevalent symptomatology. Lifestyle modifications such as stress reduction and increased physical activity seem to be useful to improve symptoms and should be encouraged. The same for dietary modifications that represent an important first-line therapeutic option. The pharmacological treatment should take into account the predominant symptom and test one drug at a time with a predefined time point for effectiveness evaluation and dosage adjustment. This clinical review offers an updated overview on epidemiology, pathogenesis, diagnosis and treatment of IBS.

In healthy adults, resistant maltodextrin produces a greater change in fecal bifidobacteria counts and increases stool wet weight: a double-blind, randomized, controlled crossover study

Dietary fiber stimulates the growth of potentially beneficial bacteria (eg, bifidobacteria), yet most Americans do not meet daily fiber recommendations. Resistant maltodextrin (RMD), a fermentable functional fiber, may help individuals meet total fiber recommendations and potentially increase bifidobacteria. It was hypothesized that fecal bifidobacteria counts/ng fecal DNA would increase after adding 25 g RMD to inadequate fiber diets of healthy adults. In this double-blind, controlled crossover study, 51 participants (26.3 ± 6.8 years, mean ± SD) were randomized to consume 0, 15, and 25 g RMD daily for 3 weeks followed by a 2-week washout. Participants collected all stools for 2 days at weeks 0 and 3 of each intervention for stool wet weight (WW) measurements and fecal bifidobacteria counts. Weekly 24-hour dietary recalls assessed total fiber intake. Only 25 g RMD resulted in a change (final minus baseline) in bifidobacteria that was significant compared with 0 g (0.17 ± 0.09 vs -0.17 ± 0.09 log₁₀[counts], respectively, mean ± SEM, P = .008). Stool WW increased only with 25 g (150 ± 11 vs baseline 121±11 g/d; P = .011). Mean daily total fiber intake (including RMD) was significantly higher (both P< .001) with 15 g (17.8 ± 0.6 g/1000 kcal or 4184 kJ) and 25 g (25.3 ± 1.1 g/1000 kcal) compared with 0 g RMD (8.4±0.4 g/1000 kcal). Mean daily total fiber intakes exceeded recommendations (14 g/1000 kcal) with 15 and 25 g of RMD, and 25 g RMD increased fecal bifidobacteria counts and stool WW, suggesting health benefits from increasing total fiber intake.

Postprandial glucose-lowering effect of premeal consumption of protein-enriched, dietary fiber-fortified bar in individuals with type 2 diabetes mellitus or normal glucose tolerance

AIMS/INTRODUCTION

Protein preload improves postprandial glycemia by stimulating secretion of insulin and incretin hormones. However, it requires a large dose of protein to produce a significant effect. The present study was carried out to investigate the postprandial glucose-lowering effect of a premeal protein-enriched, dietary fiber-fortified bar (PFB), which contains moderate amounts of protein, in individuals with type 2 diabetes mellitus or normal glucose tolerance (NGT).

MATERIALS AND METHODS

The participants (15 type 2 diabetes mellitus and 15 NGT) were randomly assigned to either a premeal or postmeal PFB group and underwent two mixed meal tolerance tests, 1 week apart in reverse order. Plasma levels of glucose, insulin, glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide were measured.

RESULTS

During the mixed meal tolerance tests, the incremental area under the curve from 0 to 180 min of plasma glucose levels was lower with premeal PFB than with postmeal PFB in the type 2 diabetes mellitus (14,723 ± 1,310 mg min/dL vs 19,642 ± 1,367 mg min/dL; P = 0.0002) and NGT participants (3,943 ± 416 mg min/dL vs 4,827 ± 520 mg min/dL, P = 0.0296). In the type 2 diabetes mellitus participants, insulinogenic index and the incremental area under the curve from 0 to 180 min of plasma total glucagon-like peptide-1 levels were higher with premeal PFB than with postmeal PFB, but not in the NGT participants. There was no difference in postprandial glucose-dependent insulinotropic polypeptide levels between premeal and postmeal PFB in both groups.

CONCLUSIONS

Acute administration of premeal PFB decreased postprandial glucose excursion in both type 2 diabetes mellitus and NGT participants. In the type 2 diabetes mellitus participants, premeal PFB augmented the early-phase insulin secretion, possibly through enhancing glucagon-like peptide-1 secretion.

Combined exercise improves gastrointestinal motility in psychiatric in patients

AIM

To examine the effect of combined exercise on colonic transit time (CTT) in admitted psychiatric patients.

METHODS

Over a 6-mo period, consecutive in patients with mental illness were recruited from the Somang Hospital Psychiatry Unit. A combined exercise program that included 60 min per day of exercise 3 d per week for 12 wk was performed. Physical fitness and CTT of the patients were measured twice before and twice after the exercise program. CTT was measured using a multiple marker technique with a radio-opaque marker. Changes in the exercising patients’ CTT and weight-, cardiovascular- and fitness-related parameters were statistically assessed.

RESULTS

After the 12-wk combined exercise intervention, decreased intestinal transit time was observed in all CTTs of the exercise group, including the right CTT (exercise: 15.6 ± 15.2 vs 9.2 ± 11.9, control: 13.1 ± 10.4 vs 10.9 ± 18.7), left CTT (exercise: 19.7 ± 23.5 vs 10.4 ± 13.2, control: 19.2 ± 19.0 vs 16.9 ± 19.8), recto-sigmoid CTT (exercise: 14.3 ± 16.7 vs 6.7 ± 7.9, control: 15.0 ± 14.4 vs 19.3 ± 30.3), and total colonic transit time (TCTT) (exercise: 50.2 ± 38.1 vs 27.1 ± 28.0, control: 47.4 ± 34.6 vs 47.3 ± 47.3). After the 12-wk combined exercise period, TCTT was significantly shortened in the exercise group compared with that in the control group. In addition to eating habits, water intake, and fiber intake, the increased physical activity level as a result of the 12-wk combined exercise program reduced the CTT.

CONCLUSION

The CTT of the psychiatric patients was reduced due to increased physical activity via a 12-wk combined exercise program.

Clinical utility of plecanatide in the treatment of chronic idiopathic constipation

Constipation is an important health burden that reduces the quality of life for countless millions of people. Symptom-centric therapeutics are often used to treat constipation due to unknown etiology, but in many cases, these drugs are either inadequate or have significant side effects. More recently, synthetic peptide agonists for epithelial guanylyl cyclase C (GC-C) have been developed which are effective at treating constipation in a sub-population of adult constipation patients. The first to market was linaclotide that is structurally related to the diarrheagenic enterotoxin, but this was followed by plecanatide, which more closely resembles endogenous uroguanylin. Both the drugs exhibit almost identical clinical efficacy in about 20% of patients, with diarrhea being a common side effect. Despite the potential for reduced side effects with plecanatide, detailed analysis suggests that clinically, they are very similar. Ongoing clinical and preclinical studies with these drugs suggest that treating constipation might be the tip of the iceberg in terms of clinical utility. The expression of cGMP signaling components could be diagnostic for functional bowel disorders, and increasing cGMP using GC-C agonists or phosphodiesterase inhibitors has huge potential for treating enteric pain, ulcerative colitis, and for the chemoprevention of colorectal cancer.

Association Between Ultra-Processed Food Consumption and Functional Gastrointestinal Disorders: Results From the French NutriNet-Santé Cohort

OBJECTIVES

Ultra-processed foods (UPF) consumption has increased over the last decades and is raising concerns about potential adverse health effects. Our objective was to assess the association between UPF consumption and four functional gastrointestinal disorders (FGIDs): irritable bowel syndrome (IBS), functional constipation (FC), functional diarrhea (FDh), and functional dyspepsia (FDy), in a large sample of French adults.

METHODS

We analyzed dietary data of 33,343 participants from the web-based NutriNet-Santé cohort, who completed at least three 24 h food records, prior to a Rome III self-administered questionnaire. Proportion (in weight) of UPF in the diet (UPFp) was computed for each subject. The association between UPFp quartiles and FGIDs was estimated by multivariable logistic regression.

RESULTS

Participants included in the analysis were mainly women (76.4%), and the mean age was 50.4 (SD = 14.0) years. UPF accounted for 16.0% of food consumed in weight, corresponding to 33.0% of total energy intake. UPF consumption was associated with younger age, living alone, lower incomes, higher BMI, and lower physical activity level (all p < 0.0001). A total of 3516 participants reported IBS (10.5%), 1785 FC (5.4%), 1303 FDy (3.9%), and 396 FDh (1.1%). After adjusting for confounding factors, an increase in UPFp was associated with a higher risk of IBS (_aOR _{Q4 vs. Q1} [95% CI]: 1.25 [1.12-1.39], p-trend < 0.0001).

CONCLUSIONS

This study suggests an association between UPF and IBS. Further longitudinal studies are needed to confirm those results and understand the relative impact of the nutritional composition and specific characteristics of UPF in this relationship.

Review article: short chain fatty acids as potential therapeutic agents in human gastrointestinal and inflammatory disorders

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.

Dietary fiber intervention on gut microbiota composition in healthy adults: a systematic review and meta-analysis

Background

Dysfunction of the gut microbiota is frequently reported as a manifestation of chronic diseases, and therefore presents as a modifiable risk factor in their development. Diet is a major regulator of the gut microbiota, and certain types of dietary fiber may modify bacterial numbers and metabolism, including short-chain fatty acid (SCFA) generation.

Objective

A systematic review and meta-analysis were undertaken to assess the effect of dietary fiber interventions on gut microbiota composition in healthy adults.

Design

A systematic search was conducted across MEDLINE, EMBASE, CENTRAL, and CINAHL for randomized controlled trials using culture and/or molecular microbiological techniques evaluating the effect of fiber intervention on gut microbiota composition in healthy adults. Meta-analyses via a random-effects model were performed on alpha diversity, prespecified bacterial abundances including Bifidobacterium and Lactobacillus spp., and fecal SCFA concentrations comparing dietary fiber interventions with placebo/low-fiber comparators.

Results

A total of 64 studies involving 2099 participants were included. Dietary fiber intervention resulted in higher abundance of Bifidobacterium spp. (standardized mean difference (SMD): 0.64; 95% CI: 0.42, 0.86; P < 0.00001) and Lactobacillus spp. (SMD: 0.22; 0.03, 0.41; P = 0.02) as well as fecal butyrate concentration (SMD: 0.24; 0.00, 0.47; P = 0.05) compared with placebo/low-fiber comparators. Subgroup analysis revealed that fructans and galacto-oligosaccharides led to significantly greater abundance of both Bifidobacterium spp. and Lactobacillus spp. compared with comparators (P < 0.00001 and P = 0.002, respectively). No differences in effect were found between fiber intervention and comparators for α-diversity, abundances of other prespecified bacteria, or other SCFA concentrations.

Conclusions

Dietary fiber intervention, particularly involving fructans and galacto-oligosaccharides, leads to higher fecal abundance of Bifidobacterium and Lactobacillus spp. but does not affect α-diversity. Further research is required to better understand the role of individual fiber types on the growth of microbes and the overall gut microbial community. This review was registered at PROSPERO as CRD42016053101.

Quality Improvement and Antioxidant Activity of Sugar-Snap Cookies Prepared Using Blends of Cereal Flour

In this study, we investigated the changes in quality and antioxidant activity of sugar-snap cookies prepared with different blends of refined wheat (WHF) and oat flour (OAF). The crude protein contents of OAF and WHF were 12.24% and 7.17%, respectively, and the fiber contents of were 3.45% and 0.31%, respectively; both were increased by adding OAF. However, the total starch contents were decreased by adding OAF. The β-glucan content of the samples increased considerably upon the addition of OAF. The water-holding capacity was increased after adding OAF compared to WHF (79.21%). Water binding in wet gluten contents decreased on the addition of OAF. Final viscosity increased on the addition of OAF. Antioxidant activity and total phenolic acid were increased upon the addition of OAF. The thickness of cookies prepared with OAF, WHF, 20% of WHF with OAF (WOB20), and WOB40 were 11.28, 12.35, 9.74, and 9.81 mm, respectively. The hardness of cookies prepared with WHF and WOF20 did not differ significantly, and analysis of the appearance of cookies showed that the cookies were increasingly cracked as the OAF content increased. Therefore, substituting WHF with OAF improved the quality and nutrient value of the cookies.

Beyond Irritable Bowel Syndrome: The Efficacy of the Low Fodmap Diet for Improving Symptoms in Inflammatory Bowel Diseases and Celiac Disease

BACKGROUND AND AIM

To evaluate the usefulness of a low FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) diet on patients with irritable bowel syndrome (IBS), non-active inflammatory bowel diseases (IBD), and celiac disease (CD) on a gluten-free diet (GFD).

METHODS

Dietetic interventional prospective study. IBS, IBD, and CD subjects were evaluated to check if they fulfilled the Rome III criteria. Each subject was educated to follow a low FODMAP diet after being evaluated by filling out questionnaires that assessed the quality of life (QoL) and symptoms experienced (IBS-SSS and SF-36), and was reevaluated after 1 and 3 months.

RESULTS

One hundred twenty-seven subjects were enrolled: 56 with IBS, 30 with IBD, and 41 with CD. IBS-SSS showed that abdominal symptoms improved after 1 and 3 months of diet in all subjects, with significant difference among the 3 groups at T0 (average scores IBS: 293 ± 137, IBD: 206 ± 86, CD: 222 ± 65, p < 0.001), but no difference at T3 (IBS: 88 ± 54, IBD: 73 ± 45, CD: 77 ± 49, p = ns). By analyzing the SF-36 questionnaire, we did not observe any difference between the 3 groups, in terms of response to diet (p = ns), we observed a clinical improvement from T0 to T3 for most of the questionnaire's domains.

CONCLUSIONS

A low FODMAP diet could be a valid option to counter -abdominal symptoms in patients with IBS, non-active IBD, or CD on a GFD, and thus, improve their QoL and social -relations.

Modulation of colonic hydrogen sulfide production by diet and mesalazine utilizing a novel gas-profiling technology

Excessive hydrogen sulfide (H₂S) production from gut microbial metabolism may have clinically important relevance in the pathogenesis of gut disorders, including ulcerative colitis. However, little is known regarding factors that alter its production. Using a newly-designed in vitro gas-profiling technology, the study aimed to verify real-time H₂S measurement reproducibility and thereafter, assess its production following exposure to dietary factors and 5-aminosalicylate acid (5-ASA). Measurements of H₂S, carbon dioxide, hydrogen and methane measurements were compared between gas-profiling systems. Homogenized slurries were prepared from freshly-passed healthy human feces. Fifty ml slurries were aliquoted into separate fermentation chambers and substrates added including 1 g highly fermentable fructo-oligosaccharides (FOS) or resistant starch Hi-Maize (RS), or minimally fermentable psyllium or sterculia, 1 g cysteine, 0.9 g sodium sulfate or 1.2 mL of 1 M 5-ASA alone or in combinations. H₂S release was sampled every 5 mins over 4-h and expressed relative to unspiked controls. RS suppressed H₂S production by a mean 89.0 (SEM 4.8)% and FOS by 82.2 (6.2)% compared to <35 (17)% by psyllium and sterculia (p<0.001, two-way ANOVA). Cysteine stimulated H₂S production by 1557 (532)%. The addition of FOS to slurries containing cysteine significantly suppressed H₂S by 90 (2)% over the addition of 5-ASA (0.3 (2)%, p<0.001). Sulfate and 5-ASA had minimal overall effects. In conclusion, the H₂S-profiling technology is a reproducible tool. Production of H₂S is greatly enhanced by sulfur-amino acids but not inorganic sulfate, and is effectively suppressed by readily fermentable fibers. These findings inform potential designs of dietary therapies to reduce H₂S production in vivo.

Fecal microbiota transplantation for managing irritable bowel syndrome

Irritable bowel syndrome (IBS) is a widespread gastrointestinal disorder affecting 11.2% of the world adult population. The intestinal microbiome is thought to play a pivotal role in the pathophysiology of IBS. The composition of the fecal microbiome in IBS patients differs from that in healthy individuals, but the exact bacteria species involved in the development of IBS remain to be determined. There is also an imbalance between useful and harmful bacteria (dysbiosis) in the intestinal microbiome in patients with IBS. Consuming prebiotics, probiotics, or synbiotics has a limited effect on IBS symptoms. In contrast, fecal microbiome transplantation (FMT) in IBS patients reverses the dysbiosis to normobiosis and reduces the IBS symptoms in about 70% of patients, and is not associated with any serious adverse events. Area covered: The available data on the microbiome and FMT in IBS regarding the efficacy of FMT in managing IBS were found using a PubMed search of these topics. Expert commentary: FMT is a promising tool for managing irritable syndrome. It appears to be effective, easy, and inexpensive procedure. However, more controlled studies involving larger cohorts of IBS are needed before FMT can be used as a routine procedure in the clinic.

Prevalence of Fructose Malabsorption in Patients With Irritable Bowel Syndrome After Excluding Small Intestinal Bacterial Overgrowth

Background/Aims

Fructose malabsorption (FM) mimics symptoms of irritable bowel syndrome (IBS), and its prevalence has increased. Diagnosing FM in IBS is challenging because of its overlap with small intestinal bacterial overgrowth (SIBO). We assessed the prevalence of FM by comparing patients with IBS with asymptomatic control individuals after excluding SIBO using the glucose hydrogen breath test (HBT).

Methods

Patients diagnosed with IBS and asymptomatic control individuals were enrolled prospectively. Dietary habits were assessed with the Food Frequency Questionnaire. After excluding SIBO, participants underwent HBTs with both 15 g and 25 g of fructose.

Results

Thirty-five patients with IBS and 35 age- and sex-matched asymptomatic control individuals were enrolled. The 15-g fructose HBT yielded positive results in 7 of the 35 (20.0%) patients with IBS and in 2 of 35 (5.7%) controls (P = 0.070). The 25-g fructose HBT was positive in 16 of the 35 (45.7%) patients with IBS and in 8 of the 35 (22.9%) controls (P = 0.040). Analysis of the Food Frequency Questionnaire responses showed no significant differences between the 2 groups in dietary intake, although patients with IBS showed a significantly higher mean fiber intake than controls (21.24 ± 11.35 g vs 15.87 ± 7.07 g, respectively, P = 0.040).

Conclusions

The 25-g fructose HBT identified FM in a significantly higher percentage of SIBO-negative patients with IBS than in asymptomatic control individuals, suggesting that FM may correlate with IBS. Education regarding dietary control of foods containing fructose may be useful for the management of patients with IBS.

Functional abdominal pain disorders in children

Chronic abdominal pain is a common problem in pediatric practice. The majority of cases fulfill the Rome IV criteria for functional abdominal pain disorders (FAPDs). At times, these disorders may lead to rather serious repercussions. Area covered: We have attempted to cover current knowledge on epidemiology, pathophysiology, risk factors related to pathophysiology, clinical evaluation and management of children with FAPDs. Expert commentary: FAPDs are a worldwide problem with a pooled prevalence of 13.5%. There are a number of predisposing factors and pathophysiological mechanisms including stressful events, child maltreatment, visceral hypersensitivity, altered gastrointestinal motility and change in intestinal microbiota. It is possible that the environmental risk factors intricately interact with genes through epigenetic mechanisms to contribute to the pathophysiology. The diagnosis mainly depends on clinical evaluation. Commonly used pharmacological interventions do not play a major role in relieving symptoms. Centrally directed, nonpharmacological interventions such as hypnotherapy and cognitive behavioral therapy have shown both short and long term efficacy in relieving pain in children with FAPDs. However, these interventions are time consuming and need specially trained staff and therefore, not currently available at grass root level. Clinicians and researchers should join hands in searching for more pragmatic and effective therapeutic modalities to improve overall care of children with FAPDs.

The Mexican consensus on chronic constipation

INTRODUCTION

Significant advances have been made in the knowledge and understanding of the epidemiology, pathophysiology, diagnosis, and treatment of chronic constipation, since the publication of the 2011 guidelines on chronic constipation diagnosis and treatment in Mexico from the Asociación Mexicana de Gastroenterología.

AIMS

To present a consensus review of the current state of knowledge about chronic constipation, providing updated information and integrating the new scientific evidence.

METHODS

Three general coordinators reviewed the literature published within the time frame of January 2011 and January 2017. From that information, 62 initial statements were formulated and then sent to 12 national experts for their revision. The statements were voted upon, using the Delphi system in 3 voting rounds (2 electronic and one face-to-face). The statements were classified through the GRADE system and those that reached agreement >75% were included in the consensus.

RESULTS AND CONCLUSIONS

The present consensus is made up of 42 final statements that provide updated knowledge, supplementing the information that had not been included in the previous guidelines. The strength of recommendation and quality (level) of evidence were established for each statement. The current definitions of chronic constipation, functional constipation, and opioid-induced constipation are given, and diagnostic strategies based on the available diagnostic methods are described. The consensus treatment recommendations were established from evidence on the roles of diet and exercise, fiber, laxatives, new drugs (such as prucalopride, lubiprostone, linaclotide, plecanatide), biofeedback therapy, and surgery.

The Role of Bacteria, Probiotics and Diet in Irritable Bowel Syndrome

Irritable bowel syndrome is a highly prevalent gastrointestinal disorder that threatens the quality of life of millions and poses a substantial financial burden on healthcare systems around the world. Intense research into the human microbiome has led to fascinating discoveries which directly and indirectly implicate the diversity and function of this occult organ in irritable bowel syndrome (IBS) pathophysiology. The benefit of manipulating the gastrointestinal microbiota with diet and probiotics to improve symptoms has been demonstrated in a wealth of both animal and human studies. The positive and negative mechanistic roles bacteria play in IBS will be explored and practical probiotic and dietary choices offered.

Dietary therapies for functional bowel symptoms: Recent advances, challenges, and future directions

BACKGROUND

Functional gastrointestinal symptoms in irritable bowel syndrome (IBS) and quiescent inflammatory bowel disease (IBD) cause significant morbidity and a reduction in quality of life. Multiple dietary therapies are now available to treat these symptoms, but supporting evidence for many is limited. In addition to a further need for studies demonstrating efficacy and mechanism of action of dietary therapies, the risk of nutritional inadequacy, alterations to the microbiome and changes in quality of life are key concerns requiring elucidation. Identifying predictors of response to dietary therapy is an important goal as management could be tailored to the individual to target specific dietary components, and thereby reduce the level of dietary restriction necessary.

PURPOSE

This review discusses the available dietary therapies to treat symptoms in patients with IBS and patients with quiescent IBD suffering from IBS symptoms, with the aim to understand where current dietary evidence lies and how to move forward in dietary research in this field.

Irritable bowel syndrome diagnosis and management: A simplified algorithm for clinical practice

BACKGROUND

Effective management of irritable bowel syndrome (IBS), a common functional gastrointestinal disorder, can be challenging for physicians because of the lack of simple diagnostic tests and the wide variety of treatment approaches available.

OBJECTIVE

The objective of this article is to outline a simple algorithm for day-to-day clinical practice to help physicians navigate key stages to reaching a positive IBS diagnosis and guidance on how to prioritise the use of specific management strategies.

METHODS

This algorithm was based on the opinion of an expert panel evaluating current evidence.

RESULTS

The key principles forming the foundation of this evidence-supported algorithm are: confidently naming and explaining an IBS diagnosis for the patient, followed by assessment of key patient characteristics likely to influence the choice of therapy, such as predominant symptoms, and exploring the patient agenda and preferences. Consultation should always include education and reassurance with an explanatory model of IBS tailored to the patient. Individualised lifestyle changes, dietary modifications, pharmacological therapies, psychological strategies or a combination of interventions may be used to optimise treatment for each patient.

CONCLUSION

The simple visual tools developed here navigate the key stages to reaching a positive diagnosis of IBS, and provide a stepwise approach to patient-centred management targeted towards the most bothersome symptoms. Establishing a strong patient-physician relationship is central to all stages of the patient journey from diagnosis to effective management.

Opioid-Induced Constipation and Bowel Dysfunction: A Clinical Guideline

OBJECTIVE

To formulate timely evidence-based guidelines for the management of opioid-induced bowel dysfunction.

SETTING

Constipation is a major untoward effect of opioids. Increasing prescription of opioids has correlated to increased incidence of opioid-induced constipation. However, the inhibitory effects of opioids are not confined to the colon, but also affect higher segments of the gastrointestinal tract, leading to the coining of the term "opioid-induced bowel dysfunction."

METHODS

A literature search was conducted using Medline, EMBASE, and EMBASE Classic, and the Cochrane Central Register of Controlled Trials. Predefined search terms and inclusion/exclusion criteria were used to identify and categorize relevant papers. A series of statements were formulated and justified by a comment, then labeled with the degree of agreement and their level of evidence as judged by the Strength of Recommendation Taxonomy (SORT) system.

RESULTS

From a list of 10,832 potentially relevant studies, 33 citations were identified for review. Screening the reference lists of the pertinent papers identified additional publications. Current definitions, prevalence, and mechanism of opioid-induced bowel dysfunction were reviewed, and a treatment algorithm and statements regarding patient management were developed to provide guidance on clinical best practice in the management of patients with opioid-induced constipation and opioid-induced bowel dysfunction.

CONCLUSIONS

In recent years, more insight has been gained in the pathophysiology of this "entity"; new treatment approaches have been developed, but guidelines on clinical best practice are still lacking. Current knowledge is insufficient regarding management of the opioid side effects on the upper gastrointestinal tract, but recommendations can be derived from what we know at present.

Association between self-reported vegetarian diet and the irritable bowel syndrome in the French NutriNet cohort

BACKGROUND

There is growing interest in using diet counselling in the management of patients with irritable bowel syndrome (IBS). Among new emerging diets, vegetarian diets (VD) seem to be experiencing an important popularity, partly because of their alleged health benefits. A recent study performed among a rural Indian population showed that predominant VD could be associated with IBS.

OBJECTIVE

This cross-sectional study aimed at assessing the association between the VD and IBS, among a large French cohort, the NutriNet-santé study.

METHODS

Subjects participating in the NutriNet-Santé cohort study completed a questionnaire based on Rome III criteria (N = 41,682). Anthropometrics, socio-demographical and lifestyle data, including VD, were collected prior to the completion of Rome III questionnaire via self-administered questionnaires. Association between VD and IBS and its subtypes was investigated through multivariate logistic regression.

RESULTS

The included subjects were mainly women (78.0%) and the mean age was 49.8±14.3 years. Among these individuals, 2,264 (5.4%) presented an IBS, and 805 (1.9%) reported a VD. Overall, VD was not associated with IBS or subtypes. A stable VD (i.e. self-declared at least three times) was associated with IBS (aOR 2.60 95%CI [1.37-4.91]), IBS mixed (aOR 2.97 95%CI [1.20-7.36]) and IBS diarrhoea (aOR 2.77 95%CI [1.01-7.59]).

CONCLUSIONS

This study suggests that a long term VD could be associated with IBS. Nevertheless, further studies are needed to confirm these results, and investigate the multiple aspects of the vegetarian diet, possibly related to the IBS.

Adherence to the Mediterranean diet is associated with the gut microbiota pattern and gastrointestinal characteristics in an adult population

This study aimed to explore the potential associations of adherence to the Mediterranean diet with gut microbiota characteristics and gastrointestinal symptomatology in an adult population. Other long-term dietary habits (e.g. consumption of snacks and junk food or stimulant intake) were also evaluated in terms of the gut microbiota profile. Participants (n 120) underwent anthropometric, dietary, physical activity and lifestyle evaluation. Adherence to the Mediterranean diet was assessed using a Mediterranean diet score, the MedDietScore, and subjects were classified into three tertiles according to individual adherence scoring. Gut microbiota composition was determined using quantitative PCR and plate-count techniques, and faecal SCFA were analysed using GC. Gastrointestinal symptoms were also evaluated. Participants with a high adherence to the Mediterranean diet had lower Escherichia coli counts (P=0·022), a higher bifidobacteria:E. coli ratio (P=0·025), increased levels and prevalence of Candida albicans (P=0·039 and P=0·050, respectively), greater molar ratio of acetate (P=0·009), higher defaecation frequency (P=0·028) and a more pronounced gastrointestinal symptomatology compared with those reporting low adherence. A lower molar ratio of valerate was also observed in the case of high adherence to the Mediterranean diet compared with the other two tertiles (Pfor trend=0·005). Positive correlations of MedDietScore with gastrointestinal symptoms, faecal moisture, total bacteria, bifidobacteria:E. coli ratio, relative share of Bacteroides, C. albicans and total SCFA, as well as negative associations with cultivable E. coli levels and valerate were indicated. Fast food consumption was characterised by suppressed representation of lactobacilli and butyrate-producing bacteria. In conclusion, our findings support a link between adherence to the Mediterranean diet and gut microbiota characteristics.

Gastrointestinal neuroendocrine peptides/amines in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic recurrent condition whose etiology is unknown, and it includes ulcerative colitis, Crohn’s disease, and microscopic colitis. These three diseases differ in clinical manifestations, courses, and prognoses. IBD reduces the patients’ quality of life and is an economic burden to both the patients and society. Interactions between the gastrointestinal (GI) neuroendocrine peptides/amines (NEPA) and the immune system are believed to play an important role in the pathophysiology of IBD. Moreover, the interaction between GI NEPA and intestinal microbiota appears to play also a pivotal role in the pathophysiology of IBD. This review summarizes the available data on GI NEPA in IBD, and speculates on their possible role in the pathophysiology and the potential use of this information when developing treatments. GI NEPA serotonin, the neuropeptide Y family, and substance P are proinflammatory, while the chromogranin/secretogranin family, vasoactive intestinal peptide, somatostatin, and ghrelin are anti-inflammatory. Several innate and adaptive immune cells express these NEPA and/or have receptors to them. The GI NEPA are affected in patients with IBD and in animal models of human IBD. The GI NEPA are potentially useful for the diagnosis and follow-up of the activity of IBD, and are candidate targets for treatments of this disease.

Dietary fiber in irritable bowel syndrome (Review)

Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disorder. It is widely believed that IBS is caused by a deficient intake of dietary fiber, and most physicians recommend that patients with IBS increase their intake of dietary fiber in order to relieve their symptoms. However, different types of dietary fiber exhibit marked differences in physical and chemical properties, and the associated health benefits are specific for each fiber type. Short-chain soluble and highly fermentable dietary fiber, such as oligosaccharides results in rapid gas production that can cause abdominal pain/discomfort, abdominal bloating/distension and flatulence in patients with IBS. By contrast, long-chain, intermediate viscous, soluble and moderately fermentable dietary fiber, such as psyllium results in a low gas production and the absence of the symptoms related to excessive gas production. The effects of type of fiber have been documented in the management of IBS, and it is known to improve the overall symptoms in patients with IBS. Dietary fiber acts on the gastrointestinal tract through several mechanisms, including increased fecal mass with mechanical stimulation/irritation of the colonic mucosa with increasing secretion and peristalsis, and the actions of fermentation byproducts, particularly short-chain fatty acids, on the intestinal microbiota, immune system and the neuroendocrine system of the gastrointestinal tract. Fiber supplementation, particularly psyllium, is both safe and effective in improving IBS symptoms globally. Dietary fiber also has other health benefits, such as lowering blood cholesterol levels, improving glycemic control and body weight management.

Low fermentable, oligo-, di-, mono-saccharides and polyol diet in the treatment of irritable bowel syndrome: A systematic review and meta-analysis

OBJECTIVES

The aim of this review was to systematically assess and meta-analyze the effects of a low fermentable, oligo-, di-, mono-saccharides and polyol (FODMAP) diet (LFD) on the severity of symptoms, quality of life, and safety in patients with irritable bowel syndrome (IBS).

METHODS

The MEDLINE/PubMed, Scopus, and Cochrane Library databases were screened through January 19, 2016. Randomized controlled trials (RCTs) that compared LFD to other diets were included if they assessed symptoms of IBS or abdominal pain in patients with IBS. Safety, quality of life, anxiety, depression, and effect on gut microbiota were defined as secondary outcomes. Standardized mean difference (SMD) and 95% confidence interval (CI) were calculated.

RESULTS

Nine RCTs with a total of 596 subjects were included. Three RCTs compared LFD with a habitual diet, two RCTs provided all meals and compared LFD with a western diet, one RCT each compared LFD with a diet high in FODMAPs or a sham diet, and two RCTs compared with other diet recommendations for IBS. A meta-analysis revealed significant group differences for LFD compared with other diets with regard to gastrointestinal symptoms (SMD = -0.62; 95% CI = -0.93 to -0.31; P = 0.0001), abdominal pain (SMD = -0.50; 95% CI = -0.77 to -0.22; P = 0.008), and health-related quality of life (SMD = 0.36; 95% CI = 0.10-0.62; P = 0.007). Three studies reported a significant reduction in luminal bifidobacteria after LFD. Adverse events were assessed in three RCTs only and no intervention-related adverse events were reported.

CONCLUSIONS

This meta-analysis found evidence of the short-term efficacy and safety of LFD in patients with IBS. However, only a preliminary recommendation for LFD can be made until long-term effects are investigated.

The Effects of Bariatric Procedures on Bowel Habit

BACKGROUND

Bariatric procedures are increasingly being used to combat the rising obesity epidemic. The aim of this study was to assess the effect of these interventions on bowel habit.

METHODS

We recruited obese adults listed for a bariatric procedure. Demographic data, medical history, medications and anthropometric measurements were recorded. Bowel habit was characterized using a 7-day Bristol Stool Form Scale (BSFS) diary. A validated food frequency questionnaire (FFQ) was used to assess diet.

RESULTS

Twenty-six patients were assessed pre-operatively and at a median of 6.4 months post-operatively. Nineteen had a Roux-en-Y gastric bypass (RYGB), five had a sleeve gastrectomy (SG) and two had an intra-gastric balloon (IGB) with median percentage excess weight loss (% EWL) of 67.9, 52.4 and 31.3 %, respectively. Dietary fibre intake decreased from 24.4 (±12.1) g/day pre-operatively to 17.5 (±7.3) g/day post-operatively (P = 0.008). Frequency of bowel motions decreased from 8.6 (±3.5) to 5.7 (±3.5) motions/week (P = 0.001). Mean usual BSFS score decreased (towards firmer stool) from 4.1 (±1.3) pre-operatively to 3.1 (±1.9) post-operatively (P = 0.016). Constipation increased from 8 to 27 %, but this did not reach statistical significance (P = 0.125).

CONCLUSIONS

Constipation is a common problem after bariatric surgery. The decrease in bowel motion frequency and change towards firmer stools suggest prolonged intestinal transit time after bariatric procedures. Reduction in dietary fibre intake is likely to be a contributory factor.

Influence of roasting on the chemopreventive potential of in vitro fermented almonds in LT97 colon adenoma cells

The consumption of almonds may contribute to the prevention of colon cancer due to their unique composition of health promoting compounds. Since almonds are often consumed roasted, the impact of different roasting (R) conditions (R1 = 139.2 °C/25 min, R2 = 161.5 °C/20 min and R3 = 170.8 °C/15 min) on chemopreventive effects of in vitro-fermented almonds was analysed in LT97 colon adenoma cells. Fermentation supernatants (FS) of raw and roasted almonds had no genotoxic effects. FS obtained from raw or mildly roasted almonds (R1) significantly increased mRNA levels of CAT (4.6-fold), SOD2 (5.6-fold) and GSTP1 (3.9-fold) but not of GPx1. FS of almonds significantly reduced the growth of LT97 cells in a time- and dose-dependent manner. Treatment with 5% almonds FS increased the number of early apoptotic cells (17.4%, on average) and caspase-3 activity (4.9-fold, on average). The results indicate a chemopreventive potential of in vitro-fermented almonds which is largely independent of the roasting process.

Probiotics, fibre and herbal medicinal products for functional and inflammatory bowel disorders

Functional bowel disorders (FBD), mainly irritable bowel syndrome (IBS) and functional constipation (FC, also called chronic idiopathic constipation), are very common worldwide. Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, although less common, has a strong impact on patients' quality of life, as well as being highly expensive for our healthcare. A definite cure for those disorders is still yet to come. Over the years, several therapeutic approaches complementary or alternative to traditional pharmacological treatments, including probiotics, prebiotics, synbiotics, fibre and herbal medicinal products, have been investigated for the management of both groups of diseases. However, most available studies are biased by several drawbacks, including small samples and poor methodological quality. Probiotics, in particular Saccharomyces boulardii and Lactobacilli (among which Lactobacillus rhamnosus), synbiotics, psyllium, and some herbal medicinal products, primarily peppermint oil, seem to be effective in ameliorating IBS symptoms. Synbiotics and fibre seem to be beneficial in FC patients. The probiotic combination VSL#3 may be effective in inducing remission in patients with mild-to-moderate ulcerative colitis, in whom Escherichia coli Nissle 1917 seems to be as effective as mesalamine in maintaining remission. No definite conclusions can be drawn as to the efficacy of fibre and herbal medicinal products in IBD patients due to the low number of studies and the lack of randomized controlled trials that replicate the results obtained in the individual studies conducted so far. Thus, further, well-designed studies are needed to address the real role of these therapeutic options in the management of both FBD and IBD.

LINKED ARTICLES

This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.

Is a low FODMAP diet beneficial for patients with inflammatory bowel disease? A meta-analysis and systematic review

BACKGROUND & AIMS

To assess the current evidence regarding the benefit of a low fermentable oligosaccharides, disaccharides, monosaccharides, and polyol (FODMAP) diet in the treatment of patients with inflammatory bowel disease (IBD).

METHODS

Databases such as PubMed, Web of Science, Medline were comprehensively searched for relevant studies through January 2017. The pooled odds ratio (OR) and weighted mean difference (WMD) with 95% confidence intervals (CIs) were used to analyze the dichotomous variables (diarrhea response, abdominal pain and bloating, etc.) and the continuous variables. Random- and fixed-effects models were chosen according to heterogeneity.

RESULTS

Two RCTs and four before-after studies with a total of 319 patients (96% in remission) were identified. Except for the constipation response, there was a significant improvement in other symptoms: diarrhea response (OR: 0.24, 95% CI: 0.11-0.52, p = 0.0003), satisfaction with gut symptoms (OR: 26.84, 95% CI: 4.6-156.54, p < 0.00001), abdominal bloating (OR: 0.10, 95% CI: 0.06-0.16, p < 0.00001), abdominal pain (OR: 0.24, 95% CI: 0.16-0.35, p < 0.00001), fatigue (OR: 0.40, 95% CI: 0.24-0.66, p = 0.0003) and nausea (OR: 0.51, 95% CI: 0.31-0.85, p = 0.009).

CONCLUSIONS

The present meta-analysis offers proof to support that a low FODMAP diet is beneficial for reducing gastrointestinal symptoms in patients with quiescent IBD. With the inherent limitations, the findings of this analysis remain to be confirmed and updated by further high-volume, well-designed and long-term follow-up studies.

Functionality and nutritional aspects of microcrystalline cellulose in food

Microcrystalline cellulose (MCC) is among the most commonly used cellulose derivatives in the food industry. In order assess the recent advances of MCC in food product development and its associated nutraceutical implications, google scholar and database of journals subscribed by Jiangnan university, China were used to source literature. Recently published research articles that reported physicochemical properties of MCC for food application or potential application in food and nutraceutical functions were reviewed and major findings outlined. The selected literature reviewed demonstrated that the material has been extensively explored as a functional ingredient in food including meat products, emulsions, beverages, dairy products, bakery, confectionary and filling. The carbohydrate polymer also has many promising applications in functional and nutraceutical food industries. Though widely used as control for many dietary fiber investigations, MCC has been shown to provide positive effects on gastrointestinal physiology, and hypolipidemic effects, influencing the expression of enzymes involved in lipid metabolism. These techno-functional and nutraceutical properties of MCC are influenced by the physicochemical of the material, which are defined by the raw material source and processing conditions. Apart from these functional properties, this review also highlighted limitations and gaps regarding the application of material in food and nutritional realms. Functional, Nutritional and health claims of MCC.

Low FODMAP in 2017: Lessons learned from clinical trials and mechanistic studies

Given the prevalence of irritable bowel syndrome (IBS) and the suboptimal response to most therapeutic approaches, there has been increasing interest in and adoption of dietary treatment strategies, such as the low Fermentable Oligo-, Di-, & Mono-Saccharides and Polyols (FODMAP) diet. FODMAPs are a diverse group of carbohydrates that exert effects in the gastrointestinal tract not only via fermentation but likely via alterations in the microbiota, metabolome, permeability, and intestinal immunity as well. Clinical evidence for efficacy of this diet is mounting, but there are significant questions regarding short- and long-term safety and effects on the microbiota and nutrition that remain unanswered. This review article interprets the recent findings reported in this issue of Neurogastroenterology and Motility and summarizes the mechanistic and clinical efficacy data of the low FODMAP diet in IBS patients to date.

Fiber supplements and clinically proven health benefits: How to recognize and recommend an effective fiber therapy

BACKGROUND

Only 5% of adults consume the recommended level of dietary fiber. Fiber supplements appear to be a convenient and concentrated source of fiber, but most do not provide the health benefits associated with dietary fiber.

PURPOSE

This review will summarize the physical effects of isolated fibers in small and large intestines, which drive clinically meaningful health benefits.

DATA SOURCES

A comprehensive literature review was conducted (Scopus and PubMed) without limits to year of publication (latest date included: October 31, 2016).

CONCLUSIONS

The physical effects of fiber in the small intestine drive metabolic health effects (e.g., cholesterol lowering, improved glycemic control), and efficacy is a function of the viscosity of gel-forming fibers (e.g., psyllium, β-glucan). In the large intestine, fiber can provide a laxative effect if (a) it resists fermentation to remain intact throughout the large intestine, and (b) it increases percentage of water content to soften/bulk stool (e.g., wheat bran and psyllium).

IMPLICATIONS FOR PRACTICE

It is important for nurse practitioners to understand the underlying mechanisms that drive specific fiber-related health benefits, and which fiber supplements have rigorous clinical data to support a recommendation.

CLINICAL PEARL

For most fiber-related beneficial effects, "Fiber needs to gel to keep your patients well."

Dietary Interventions and Irritable Bowel Syndrome: A Review of the Evidence

Irritable bowel syndrome (IBS) is the best studied of the functional gastrointestinal disorders. It is a highly prevalent disorder characterized by symptoms of abdominal pain, bloating, and disordered bowel habits, which may include constipation, diarrhea, or both. IBS has a significant negative impact on patients, both financially and with regard to their quality-of-life. At present, there is no cure for IBS, and while there are a number of pharmacological therapies available to treat IBS symptoms, they are not uniformly effective. For this reason, many patients and providers are turning to dietary interventions in an attempt to ameliorate IBS symptoms. At first glance, this approach appears reasonable as dietary interventions are generally safe and side effects, including potential adverse reactions with medications, are rare. However, although dietary interventions for IBS are frequently recommended, there is a paucity of data to support their use. The goals of this article are to answer key questions about diets currently recommended for the treatment of IBS, using the best available data from the literature.