New insights into the pathogenesis and treatment of irritable bowel syndrome

Painful neurotrophins and their role in visceral pain

Beyond their well-known role in embryonic development of the central and peripheral nervous system, neurotrophins, particularly nerve growth factor and brain-derived neurotrophic factor, exert an essential role in pain production and sensitization. This has mainly been studied within the framework of somatic pain, and even antibodies (tanezumab and fasinumab) have recently been developed for their use in chronic somatic painful conditions, such as osteoarthritis or low back pain. However, data suggest that neurotrophins also exert an important role in the occurrence of visceral pain and visceral sensitization. Visceral pain is a distressing symptom that prompts many consultations and is typically encountered in both 'organic' (generally inflammatory) and 'functional' (displaying no obvious structural changes in routine clinical evaluations) disorders of the gut, such as inflammatory bowel disease and irritable bowel syndrome, respectively. The present review provides a summary of neurotrophins as a molecular family and their role in pain in general and addresses recent investigations of the involvement of nerve growth factor and brain-derived neurotrophic factor in visceral pain, particularly that associated with inflammatory bowel disease and irritable bowel syndrome.

Irritable bowel syndrome: a review of the general aspects and the potential role of vitamin D

Irritable Bowel Syndrome (IBS) is a bowel disorder leading to symptoms such as abdominal pain, modifications in the motility and bowel habits, distention, bloating, and gas. Vitamin D (VD) may interfere in a plethora of cellular mechanisms, and act directly or indirectly in the regulation of the microbiome, the release of anti-microbial peptides, modulation of the immune system and inflammation processes; which in turn, may positively interfere with the altered gut function. The main purpose of this review was to survey studies involving the impacts of VD on IBS. Area covered: Eligible studies including the term VD and IBS were searched in the MEDLINE-PubMed and EMBASE (2009-2018). VD may act direct or indirectly in the regulation of the gut microbiome, immune response, and psychosocial factors that may be included in the list of IBS triggering factors. Expert opinion: Once VD plays an essential role in many processes associated with IBS, its deficiency may be associated with IBS, and the supplementation could help in the therapeutic approach for this condition. For these reasons, the understanding of the association of VD in IBS is indispensable for the development of new strategies that could improve the quality of life of the patient.

Cow milk protein allergy and other common food allergies and intolerances

The prevalence of food allergy and food intolerance is increasing and it is an important public health problem affecting children. Food allergy results from an immunological reaction to certain food(s) and affects numerous organs in the body. Food intolerances are non-immunological reactions including metabolic, toxic, pharmacological and undefined mechanisms. Cow milk is the most common cause of food allergy and food intolerance, especially in young children. Food intolerance can present with similar symptoms to those of food allergy. Health-care personnel, patients and their caregivers often confuse food intolerance with food allergy. This review focuses on the clinical manifestations, diagnostic evaluation, treatment and prevention of food allergy and food intolerance.

Lacto-fermented sauerkraut improves symptoms in IBS patients independent of product pasteurisation - a pilot study

Lacto-fermented sauerkraut contains a natural variety of lactic acid bacteria (LAB) and has not previously been studied in the treatment of irritable bowel syndrome (IBS) patients. The present study investigated the effect of a daily lacto-fermented sauerkraut supplement in relation to IBS patients' gastrointestinal symptoms and gut microbiota composition. A randomized double-blinded intervention was conducted with 34 Norwegian IBS patients. The patients were consuming either pasteurized sauerkraut (PS; n = 15) or unpasteurized sauerkraut (UPS; n = 19) as a supplement to their daily diet for 6 weeks. The differences in change of symptoms were assessed using the questionnaire IBS-Symptom Severity Score (IBS-SSS) measured at the baseline, and at weeks 2, 4, 6 and 8 (follow-up). The gut microbiota composition was analysed using 16S rRNA gene amplicon sequencing of faecal samples from the baseline and week 6. The mean change in IBS-SSS was -38.57 ± 17.08 PS vs. -56.99 ± 16.92 UPS and was significantly improved in both groups (P < 0.04), while the improvement in symptoms was not different between the intervention groups. The sauerkraut intervention (pasteurized or not) also led to significant gut microbiota compositional changes as determined by 16S rRNA gene amplicon sequencing (un-weighted UniFrac: P = 0.001, weighted UniFrac: P = 0.001). Sauerkraut related LAB in feces (Lactobacillus plantarum and Lactobacillus brevis) were significantly more often present in the UPS-group. In conclusion lacto-fermented sauerkraut had an effect on IBS patients' symptoms and gut microbiota even though the study was underpowered. Our results indicate that the observed effect to a larger extent can be attributed to the potential prebiotics in lacto-fermented sauerkraut rather than the viable LAB. Future studies with greater statistical power are needed to clarify the possible effects of LAB from lacto-fermented sauerkraut in the treatment of IBS patients.

The impact of peppermint oil on the irritable bowel syndrome: a meta-analysis of the pooled clinical data

Background

Peppermint oil (PO) has intrinsic properties that may benefit patients with irritable bowel syndrome (IBS) symptoms. The study objective was to determine the effect of peppermint oil in the treatment of the IBS.

Methods

We systematically searched MEDLINE (PubMed), Cochrane Central Register of Controlled Trials (Cochrane CENTRAL), ClinicalTrials.gov, EMBASE (Ovid), and Web of Science for randomized controlled trials (RCTs) of PO for IBS. We appraised the eligible studies by the Cochrane risk of bias tool. We performed random-effects meta-analysis on primary outcomes including global improvement in IBS symptoms and abdominal pain. A PRISMA-compliant study protocol is registered in PROSPERO Register [2016, CRD42016050917].

Results

Twelve randomized trials with 835 patients were included. For global symptom improvement, the risk ratio (RR) from seven RCTs for the effect of PO (n = 253) versus placebo (n = 254) on global symptoms was 2.39 [95% confidence interval (CI): 1.93, 2.97], I² = 0%, z = 7.93 (p < 0.00001). Regarding abdominal pain, the RR from six RCTs for the effect of PO (n = 278) versus placebo (n = 278) was 1.78 [95% CI: 1.43, 2.20], I² = 0%, z = 5.23 (p < 0.00001). Overall, there were no differences in the reported adverse effects: PO (32 events, 344 total, 9.3%) versus placebo (20 events, 327 total, 6.1%) for eight RCTs; RR 1.40 [95% CI: 0.87, 2.26] I² = 0%, z = 1.39 (p = 0.16). The number needed to treat with PO to prevent one patient from having persistent symptoms was three for global symptoms and four for abdominal pain.

Conclusions

In the most comprehensive meta-analysis to date, PO was shown to be a safe and effective therapy for pain and global symptoms in adults with IBS.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2409-0) contains supplementary material, which is available to authorized users.

Serum cholinesterase activity is elevated in female diarrhea-predominant irritable bowel syndrome patients compared to matched controls

BACKGROUND

Micro-inflammation is involved in the pathogenesis of irritable bowel syndrome (IBS). The parasympathetic nervous system, via acetylcholine (ACh), and its hydrolytic enzymes, plays a role in regulating inflammation. Increased serum cholinesterase activity, named cholinergic Status (CS), is associated with decreased inflammatory inhibition (ie, pro-inflammation). We assessed the association between IBS diarrhea-predominant (IBS-D) symptoms, CS, and inflammatory biomarkers.

METHODS

Women with IBS-D were prospectively recruited. Serum acetylcholinesterase (AChE), CS, and high-sensitivity C-reactive protein (hs-CRP) levels were analyzed and fecal calprotectin (FC) in a subgroup of patients. The control group included women attending routine health checkups (matched by age and BMI).

KEY RESULTS

Ninety-four women with IBS-D were compared to matched controls (1:1). Serum CS, AChE, and the AChE/butyrylcholinesterase (BChE) ratios were significantly increased in the IBS-D group compared to matched controls (P = 0.018, P = 0.001, and P = 0.004, respectively). Using a multiple logistic regression model, IBS-D was almost twice as likely in women with high CS compared to women with low CS (adjusted OR=1.84 (95% CI: 1.01-3.33), P = 0.045). Furthermore, IBS-D patients with higher hs-CRP levels demonstrated lower CS and BChE activity and elevated AChE and AChE/BChE ratios compared to patients with lower hs-CRP levels (P = 0.026, P = 0.036, P = 0.002; and P = 0.0007, respectively). CS was not correlated with the IBS symptoms score.

CONCLUSIONS AND INFERENCES

This is the first study to explore the potential role of serum CS in IBS-D. The findings emphasize the possible role of the autonomic nervous system and its anti-inflammatory properties in IBS.

Adipose Tissue-Derived Biomarkers of Intestinal Barrier Functions for the Characterization of Diarrhoea-Predominant IBS

Background

Alterations of the small-intestinal permeability (s-IP) might play an essential role in a subgroup of diarrhoea-predominant IBS (D-IBS) patients.

Goals

(a) To analyse in D-IBS patients the symptom profile in relation to the altered (+) or not (−) s-IP using the Gastrointestinal Symptom Rating Scale (GSRS). (b) To assess the circulating levels of the adipokines IL-6, IL-8, TNF-α, leptin, and adiponectin, along with LPS, TLR-4, neurotensin, and brain-derived neurotrophic factor (BDNF). The frequency distribution of SNPs at the loci for the investigated molecules and leptin receptor was evaluated.

Study

The study included 34 D-IBS patients and 17 healthy controls (HC). s-IP permeability was assayed by high-performance liquid chromatography determination in the urine of the lactulose to mannitol ratio. Concentrations of IL-6, IL-8, TNF-α, LPS, TLR-4, leptin, adiponectin, neurotensin, and BDNF were assayed by ELISA. Screening of genetic variants was done employing the restriction fragment length polymorphism-polymerase chain reaction method.

Results

D-IBS(−) patients had a significantly higher GSRS cluster pain and diarrhoea profile than D-IBS(+) ones. Significant correlations were found between the symptoms clusters and immune activation and inflammation markers. The levels of adipo(cyto)kines in D-IBS(+) patients were higher than those of controls, and IL-6 levels correlated with those of LPS. Leptin and BDNF were significantly higher, and neurotensin levels were significantly lower in D-IBS(+) than in controls. No differences were found in the frequency distribution of genotypes among the study groups.

Conclusions

Results from this study could be of some help in the characterization of the D-IBS and highlight the contribution of an altered intestinal barrier in the pathogenesis of this syndrome. Besides, a role could be ascribed to molecules secreted by the visceral adipose tissue that can impact on barrier functions.

A Retrospective Study on Dietary FODMAP Intake in Celiac Patients Following a Gluten-Free Diet

Our aim was to evaluate the intake of foods containing fermentable oligo/di/mono-saccharides and polyols (FODMAP) as a possible factor that induces gastrointestinal symptoms in treated celiac disease (CD) patients. We collected seven-day weighed food records for 104 CD patients and 91 healthy volunteers. All evaluated food items were from sources with high and low content of FODMAP, which were divided into cereals and sweets, sweeteners and soft drinks, fruits, dried fruits, and vegetables. Nutrient intake was calculated using the food database of the European Institute of Oncology. The symptoms reported were assessed by a Rome IV Irritable bowel syndrome (IBS) diagnostic questionnaire and by specific questions for the evaluation of functional gastrointestinal disorders (FGIDs). The 12% of CD patients met IBS symptoms criteria as opposed to 6% of controls (p = 0.09) and 27% of patients reported FGIDs symptoms vs. 22% of healthy controls (p = 0.42). The intake by CD patients was significantly higher than healthy volunteers for: sweeteners and sugars with low content of FODMAP (p = 0.0007), fruits, dried fruits, and vegetables high in FODMAP (p = 0.003) and low in FODMAP (p = 0.04) when compared to controls. CD patients had a lower intake of cereals and sweets with a high content of FODMAP (p = 0.00001). Healthy volunteers consumed significantly higher alcoholic beverages and fats high in FODMAP (both p < 0.044). The mean daily intake of other food categories did not differ between both groups. Even though CD patients had a low intake of gluten-free cereals high in FODMAP, they still consumed a significant amount of fruits and vegetables high in FODMAP. The clinical effect of a concomitant gluten-free diet and low-FODMAP diet should be prospectively evaluated as a supportive therapy in CD patients.

Fecal incontinence in people with self-reported irritable bowel syndrome: Prevalence and quality of life

Irritable bowel syndrome (IBS) is a common functional gastrointestinal (GI) disorder characterized by recurrent abdominal pain and altered bowel habits. IBS is a risk factor for fecal incontinence (FI), the unintentional passage of solid or liquid stool. FI can substantially interfere with health related quality of life (HRQL), leading to heightened anxiety and avoidance behavior. Nevertheless, relatively little research has been conducted on the prevalence of FI in IBS patients. This study evaluated the prevalence of FI in people with self-reported IBS and the relationship between FI and HRQL. 703 people who reported a diagnosis of IBS completed questionnaires on IBS symptom severity, FI symptom severity, HRQL, fear of food, anxiety about visceral sensations, and GI specific catastrophizing. Overall, 60% of people with IBS reported experiencing at least one lifetime episode of FI. In a subsample of 360 people who met strict Rome IV criteria and reported no other GI related co-morbidities, 62% reported experiencing at least one lifetime episode. While people who experienced FI more frequently had worse HRQL statistically, the differences in HRQL between people who had experienced FI and those who had not were not clinically significant. Rather than frequency of FI or physical symptom severity, quality of life was mostly determined by psychological variables, such as fear of food, anxiety, and catastrophizing. This study suggests that FI is quite prevalent in IBS patients, but that the best way to improve HRQL for IBS patients with FI may be to focus on reducing anxiety, catastrophizing and avoidance.

Eph/ephrin signalling serves a bidirectional role in lipopolysaccharide‑induced intestinal injury

A growing body of evidence has demonstrated that Eph/ephrin signalling may serve a central role in intestinal diseases. However, whether erythropoietin-producing hepatocellular (Eph)/ephrin signalling is associated with the development of post-infectious irritable bowel syndrome (PI-IBS) is still unknown. In the present study, the role of Eph/Ephrin signalling in lipopolysaccharide (LPS)-induced intestinal injury was evaluated in vivo and in vitro. LPS treatment significantly increased the levels of proinflammatory mediators [monocyte chemoattractant protein-1, tumour necrosis factor α, interleukin (IL)-1β, IL-6, intercellular adhesion molecule 1 and vascular cell adhesion molecule-1], activated the EphA2-Ephrin A1, protein kinase B (Akt)-nuclear factor (NF)-κB, Src-NF-κB and Wnt/β-catenin signalling pathways, and inhibited EphB1-Ephrin B3 signalling in colon tissues, and primary cultured enteric neuronal and glial cells. Notably, EphA2 monoclonal antibody (mAb) treatment or Ephrin B3 overexpression could partially alleviate the LPS-induced upregulation of proinflammatory mediators, and Akt-NF-κB, Src-NF-κB and Wnt/β-catenin signalling pathways. In addition, EphA2 mAb treatment could partially inhibit LPS-induced inactivation of EphB-Ephrin B3 signalling, while Ephrin B3 overexpression could abrogate LPS-induced activation of EphA2-Ephrin A1 signalling. EphB1/Ephrin B3 signalling may antagonise the EphA2/Ephrin A1-dependent pathway following LPS treatment. The results associated with the EphA2 signaling pathway, indicated that Eph/ephrin signalling may serve a bidirectional role in LPS-induced intestinal injury. Eph/ephrin signalling may be a novel therapeutic target for LPS-induced intestinal injury and potentially PI-IBS.

Irritable bowel syndrome in children: Current knowledge, challenges and opportunities

Irritable bowel syndrome (IBS) is a common and troublesome disorder in children with an increasing prevalence noted during the past two decades. It has a significant effect on the lives of affected children and their families and poses a significant burden on healthcare systems. Standard symptom-based criteria for diagnosis of pediatric IBS have changed several times during the past two decades and there are some differences in interpreting symptoms between different cultures. This has posed a problem when using them to diagnose IBS in clinical practice. A number of potential patho-physiological mechanisms have been described, but so far the exact underlying etiology of IBS is unclear. A few potential therapeutic modalities have been tested in children and only a small number of them have shown some benefit. In addition, most of the described patho-physiological mechanisms and treatment options are based on adult studies. These have surfaced as challenges when dealing with pediatric IBS and they need to be overcome for effective management of children with IBS. Recently suggested top-down and bottom-up models help integrating reported patho-physiological mechanisms and will provide an opportunity for better understanding of the diseases process. Treatment trials targeting single treatment modalities are unlikely to have clinically meaningful therapeutic effects on IBS with multiple integrating patho-physiologies. Trials focusing on multiple combined pharmacological and non-pharmacological therapies are likely to yield more benefit. In addition to treatment, in the future, attention should be paid for possible prevention strategies for IBS.

Does a low FODMAPs diet reduce symptoms of functional abdominal pain disorders? A systematic review in adult and paediatric population, on behalf of Italian Society of Pediatrics

BACKGROUND

Despite the rising of the Functional Gastrointestinal Disorders (FGIDs)' incidence in the last years, the etio-pathogenesis of FGIDs remains unclear. The diet seems to play an important role in these disorders. Indeed, at least two thirds of adult patients with Irritable Bowel Syndrome (IBS) and of children with FGIDs perceive their GI symptoms to be food-related. In particular, in the last years, more interest has been focused in the low Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyol (FODMAPs) diet.

AIMS

To provide a systematic review on the efficacy of a low FODMAPs diet in reducing symptoms associated with functional abdominal pain disorders.

METHODS

Cochrane Library, MEDLINE (via Pubmed), and EMBASE databases from inception to June 2017 were searched. We included randomized controlled trials (RCTs), prospective and retrospective studies, systematic reviews and meta-analyses, reporting the efficacy of the FODMAPs diet intervention in FGIDs patients.

RESULTS

Nineteen studies were eligible. A FODMAPs-restricted diet is beneficial in 12/13 intervention trials. The low FODMAPs diet improves overall GI symptoms, especially abdominal pain and bloating. In children, only one study reported positive results of a low FODMAPs diet. No effect was found for the lactose free diet whilst fructose-restricted diet was effective in 3/4 studies. The duration of the intervention was very different among the studies, ranging from 2 days to 16 months, and from 3 and 9 weeks for the RCTs. The majority of the trials presented differences in symptoms scoring scales, diet, food diaries, and food frequencies questionnaire.

CONCLUSIONS

The FODMAPs-restricted diet may be an effective dietary intervention for reducing IBS symptoms in adults. In children, there are promising data, although only one randomized double-blind study exists and further data are needed to better clarify the role of FODMAPs and fructose-restricted diet in IBS. The current evidence does not support the use of a lactose-restricted diet in children with FGIDs.

Effect of acupuncture and its influence on visceral hypersensitivity in IBS-D patients: Study protocol for a randomized controlled trial

BACKGROUND

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder associated with visceral hypersensitivity. Increased expression of colonic TRPV1 and decreased expression of microRNA-199 are implicated in the pathogenesis of visceral hypersensitivity in IBS-D patients. Acupuncture is one of the frequently used complementary and alternative therapies for the treatment of IBS. The existing clinical studies mostly use IBS-SSS or other subjective scales, so there is a lack of objective biochemical evidence regarding the effect of acupuncture on IBS. Therefore, we designed this study to investigate whether acupuncture alleviate visceral hypersensitivity by influencing the expression of TRPV1 and microRNA-199.

METHOD

This study is a randomized, sham-controlled trial involving 40 patients and 10 healthy volunteers. A total of 40 eligible patients with IBS-D will be randomly assigned to a traditional acupuncture group or sham acupuncture group in a 1:1 ratio. Patients will receive 3 acupuncture treatment sessions per week for 12 consecutive weeks, for a total of 36 sessions during the study. The primary outcome measure is the IBS-Symptom Severity Score (IBS-SSS). Secondary outcomes are Visceral Pain Scale and levels of TRPV1 and microRNA-199 in colonic tissues. Healthy volunteers will not receive any clinical intervention. The safety of interventions will be assessed at every visit.

DISCUSSION

The purpose of this trial is to evaluate the efficacy of acupuncture for IBS-D through IBS-SSS and Visceral Pain Scale. Furthermore, we want to explore the intervention mechanism of acupuncture in improving visceral hypersensitivity by analyzing the colonic TRPV1 and microRNA-199.

TRIAL REGISTRATION

This trial is registered with Chinese Clinical Trials Register, ChiCTR-IOR- 17010860(http://www.chictr.org.cn/showproj.aspx?proj=18445).

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.

A Novel EphA2 Inhibitor Exerts Beneficial Effects in PI-IBS in Vivo and in Vitro Models via Nrf2 and NF-κB Signaling Pathways

Though the detailed pathological mechanism of post-infectious irritable bowel syndrome (PI-IBS) remains unclear, accumulating evidence indicates that oxidative stress and inflammation are implicated in the process of PI-IBS. Oxidative stress and inflammation are regulated by Nrf2 and NF-κB signaling pathways, respectively. EphA2, a member of Eph receptor family, promotes oxidative stress and inflammatory responses via regulation of Nrf2 and NF-κB signaling pathways in various types of human diseases. Understanding the mechanisms by which EphA2 regulate oxidative stress and inflammation in PI-IBS is important for the development of new strategies to treat PI-IBS. However, the effects of ALW-II-41-27, a novel EphA2 inhibitor on PI-IBS and the underlying molecular mechanisms have never been studied. In the present study, we showed that ALW-II-41-27 decreased gastrointestinal motility and abdominal withdrawal reflex (AWR) scores, markedly reduced the levels of oxidative stress markers [4-hydroxy-2-nonenal (4-HNE), protein carbonyl, and 8-hydroxy-2-de-axyguanine (8-OHdG)] and proinflammatory cytokines (TNF-α, IL-6, IL-17, and ICAM-1), and remarkably increased the level of anti-inflammatory cytokine (IL-10) in serum and colon of Trichinella spiralis-infected mice. Moreover, ALW-II-41-27 was effective in suppressing oxidative stress and inflammation in LPS-treated NCM460 colonic cells. Treatment of ALW-II-41-27 reversed the activation of NF-κB and inactivation of Nrf2 in LPS-treated NCM460 cells. Importantly, these protective effects of ALW-II-41-27 were partially inhibited by EphA2 KO and abolished by EphA2 overexpression. In conclusion, EphA2 may represent a promising therapeutic target for patients with PI-IBS and ALW-II-41-27 might function as a novel therapeutic agent for PI-IBS.

Vitamin D supplementation in adolescents with irritable bowel syndrome: Is it useful? A randomized controlled trial

BACKGROUND/AIM

Vitamin D deficiency is common in irritable bowel syndrome (IBS). There is growing interest in the role of vitamin D in pediatric IBS. We aimed to evaluate the effect of vitamin D supplementation in adolescents with IBS and vitamin D deficiency.

PATIENTS AND METHODS

One hundred and twelve adolescents with IBS and vitamin D deficiency were randomly divided into two groups of matched age and sex. The first group received oral vitamin D3 2000IU/day for 6 months and the second group received placebo for 6 months. Vitamin D status as well as different IBS score systems (IBS-SSS, IBS-QoL, and total score) were evaluated before and 6 months after treatment.

RESULTS

IBS patients who received vitamin D supplementation for 6 months showed significant improvement in IBS-SSS (P < 0.001), IBS-QoL (P < 0.001), and total score (P = 0.02) compared to IBS placebo group. IBS patients treated with vitamin D showed two folds increase in their serum vitamin D levels (from 17.2 ± 1.3 to 39 ± 3.3) ng/ml with P < 0.001. While in the placebo group, their serum vitamin D levels were not significantly changed (P = 0.66). Vitamin D was tolerated well without any recorded adverse effects during the study period.

CONCLUSION

Vitamin D supplementation can be effective in treating adolescents with IBS and vitamin D deficiency.

The Vagus Nerve at the Interface of the Microbiota-Gut-Brain Axis

The microbiota, the gut, and the brain communicate through the microbiota-gut-brain axis in a bidirectional way that involves the autonomic nervous system. The vagus nerve (VN), the principal component of the parasympathetic nervous system, is a mixed nerve composed of 80% afferent and 20% efferent fibers. The VN, because of its role in interoceptive awareness, is able to sense the microbiota metabolites through its afferents, to transfer this gut information to the central nervous system where it is integrated in the central autonomic network, and then to generate an adapted or inappropriate response. A cholinergic anti-inflammatory pathway has been described through VN's fibers, which is able to dampen peripheral inflammation and to decrease intestinal permeability, thus very probably modulating microbiota composition. Stress inhibits the VN and has deleterious effects on the gastrointestinal tract and on the microbiota, and is involved in the pathophysiology of gastrointestinal disorders such as irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) which are both characterized by a dysbiosis. A low vagal tone has been described in IBD and IBS patients thus favoring peripheral inflammation. Targeting the VN, for example through VN stimulation which has anti-inflammatory properties, would be of interest to restore homeostasis in the microbiota-gut-brain axis.

Reducing the maternal dietary intake of indigestible and slowly absorbed short-chain carbohydrates is associated with improved infantile colic: a proof-of-concept study

BACKGROUND

To investigate if a low fermentable oligo-, di- and mono-saccharides and polyols (FODMAP) diet consumed by breastfeeding mothers may be associated with reduced symptoms of infantile colic.

METHODS

Exclusively breastfeeding mothers and their typically-developing healthy infants who met the Wessel Criteria for infantile colic were recruited from the community, to this single-blind, open-label, interventional study. After a 3-day qualifying period, mothers were provided a low FODMAP 7-day diet. On days 5, 6 and 7 mothers completed a Baby Day Diary. At baseline and at the end of the 7-day dietary intervention, breast milk was analysed for FODMAP content and infant faecal samples for pH.

RESULTS

Eighteen breastfeeding mothers (aged 27-40 years) adhered (100%) to the low FODMAP diet. Infants were of gestational age 37-40.3 weeks and aged 2-17 weeks. At entry, crying durations were a mean [95% CI] of 142 [106-61] min and fell by 52 [178-120] min (P = 0.005; ancova). Combined crying-fussing durations fell by 73 [301-223] min (n = 13; P = 0.007), as did crying episodes (P = 0.01) and fussing durations (P = 0.011). Infant sleeping, feeding, or awake-and-content durations did not change. Infant faecal pH did not change. Breast milk lactose content was stable and other known FODMAPs were not detected. At end of study, mothers reported their baby 'is much more content' and 'can be put down without crying'.

CONCLUSIONS

Maternal low FODMAP diet may be associated with a reduction in infant colic symptoms. A randomized controlled study is warranted to determine if a maternal low FODMAP diet is effective in reducing symptoms.

Diet in irritable bowel syndrome: What to recommend, not what to forbid to patients!

A substantial proportion of patients with irritable bowel syndrome (IBS) associate their symptoms with the ingestion of specific foods. Therefore, in recent years, scientific research has increasingly focused on the role of diet in IBS and dietary management is now considered an important tool in IBS treatment. This article reviews the main dietary approaches in IBS emphasizing evidence from experimental and observational studies and summarizing the main diet and lifestyle recommendations provided by dietary guidelines and scientific literature. Despite the limited evidence for a beneficial role, general advice on healthy eating and lifestyle is recommended as the first-line approach in the dietary management of IBS. Standard recommendations include adhering to a regular meal pattern, reducing intake of insoluble fibers, alcohol, caffeine, spicy foods, and fat, as well as performing regular physical activity and ensuring a good hydration. Second-line dietary approach should be considered where IBS symptoms persist and recommendations include following a low FODMAP diet, to be delivered only by a healthcare professional with expertise in dietary management. The efficacy of this diet is supported by a growing body of evidence. In contrast, the role of lactose or gluten dietary restriction in the treatment of IBS remains subject to ongoing research with a lack of high-quality evidence. Likewise, further clinical trials are needed to conclude the efficacy of probiotics on IBS symptoms.