"Let Food Be Thy Medicine": Diet and Supplements in Irritable Bowel Syndrome

Efficacy of diet restriction with or without probiotic for treatment of patients with IBS-D: Phase I-II clinical trial

BACKGROUND AND AIM

Diet is a major contributor to irritable bowel syndrome (IBS) and is also a powerful tool for treatment of IBS. This study compared two diets and explored the effectiveness of the diets when combined with a probiotic for treatment of IBS-D patients.

METHODS

Phase I, patients were randomized into groups; control, cold/spicy/fried restricted diet (CSF res diet), IgG positive restricted diet (IgG res diet), and a combination both diets (CSF + IgG res diet). Phase II, patients were randomized into IgG res diet + placebo and IgG res diet + probiotic. Both interventions were 12 weeks in duration. Symptom Severity Scale (IBS-D-SSS) and IgG titer were assessed at the beginning and the end of the study.

RESULTS

Totals of 214 and 167 patients completed the two parts of the study, respectively. After intervention, IBS-D-SSS and TIgG grade were significantly improved compared to baseline, with results similar to the control group. In general, there were decreases in IBS-D-SSS and TIgG grade that were significantly different among the groups. There were exceptions; no differences were observed for IBS-D-SSS between the IgG res diet and CSF + IgG res diet, or TIgG grade between the CSF res diet, IgG res diet, and CSF + IgG res diet. However, the CSF res diet and IgG res diet had a synergistic effect that decreased IBS-D-SSS and TIgG titer, with a greater contribution by the IgG res diet. Therefore, we evaluated the IgG res diet with either placebo or probiotic and found that IBS-D-SSS and TIgG grade decreased from baseline. There was a significant decrease in IBS-D-SSS with the probiotic but TIgG grade was not significantly different between the IgG diet + placebo and IgG diet + probiotic diet.

CONCLUSIONS

Both the CSF res diet and IgG res diet improved IBS symptoms and demonstrated synergy, although the IgG res diet had a greater contribution. Further, when intolerant foods cannot be eliminated from a diet, avoiding uncooked, cold, spicy, fried, and alcoholic foods is a superior choice. The IgG res diet combined with Bifidobacteria was the best dietary choice and may function though a non-IgG pathway.

Food as Medicine: How to Influence the Microbiome and Improve Symptoms in Patients with Irritable Bowel Syndrome

PURPOSE OF REVIEW

This review highlights effects of dietary interventions on the gut microbiome and gastrointestinal symptoms in those with irritable bowel syndrome (IBS).

RECENT FINDINGS

It is hypothesized that gut dysbiosis factors into the pathophysiology of IBS. Various diets that influence the microbiome and intestinal physiology may have therapeutic properties. At present, data suggests that implementation of personalized dietary interventions have a mixed, but overall positive effect on the gut microbiome and IBS symptoms. The effect of dietary modification on the gut microbiome and GI symptoms in patients with IBS is a topic that has garnered interest due to the increasing prevalence of IBS and heightened awareness of the importance of gut health. The composition of the gut microbiome may be modulated by promoting fiber intake and implementation of exclusionary diets and dietary supplements; however, additional studies are needed to provide evidence-based guidelines in this patient population.

Peppermint essential oil: its phytochemistry, biological activity, pharmacological effect and application

Mentha (also known as peppermint), a genus of plants in the taxonomic family Lamiaceae (mint family), is widely distributed throughout temperate regions of the world. Mentha contains various constituents that are classified as peppermint essential oil (PEO) and non-essential components. PEO, consisting mainly of menthol, menthone, neomenthol and iso-menthone, is a mixture of volatile metabolites with anti-inflammatory, antibacterial, antiviral, scolicidal, immunomodulatory, antitumor, neuroprotective, antifatigue and antioxidant activities. Mounting evidence indicates that PEO may pharmacologically protect gastrointestinal, liver, kidney, skin, respiratory, brain and nervous systems, and exert hypoglycemic and hypolipidemic effects. Clinically, PEO is used for gastrointestinal and dermatological diseases, postoperative adjuvant therapy and other fields. This review aims to address the advances in the extraction and isolation of PEO, its biological activities, pharmacological effects, toxicity and applications, with an emphasis on the efficacy of PEO on burn wounds and psoriasis, providing a comprehensive foundation for research, development and application of PEO in future.

Efficacy of a Restrictive Diet in Irritable Bowel Syndrome: A Systematic Review and Network Meta-analysis

BACKGROUND/AIMS

Dietary factors can aggravate the symptoms of irritable bowel syndrome (IBS). Many IBS patients try restrictive diets to relieve their symptoms, but the types of diets with an exacerbating factor are unknown. Therefore, this paper reports the results of a systematic review and network meta-analysis of randomized-controlled trials (RCTs) reviewing the efficacy of food restriction diets in IBS.

METHODS

The MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Clinicaltrials.gov databases were searched until July 21, 2021, to retrieve RCTs assessing the efficacy of restriction diets in adults with IBS. Two independent reviewers performed the eligibility assessment and data abstraction. RCTs that evaluated a restriction diet versus a control diet and assessed the improvement in global IBS symptoms were included. These trials reported a dichotomous assessment of the overall response to therapy.

RESULTS

A total of 1,949 citations were identified. After full-text screening, 14 RCTs were considered eligible for the systematic review and network meta-analysis. A starch- and sucrose-reduced diet and a diet with low-fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) showed significantly better results than a usual diet. Symptom flare-ups in patients on a gluten- free diet were also significantly lower than in those on high-gluten diets.

CONCLUSIONS

These findings showed that the starch- and sucrose-reduced, low FODMAP, and gluten-free diets had superior effects in reducing IBS symptoms. Further studies, including head-to-head trials will be needed to establish the effectiveness of dietary restrictions on IBS symptoms.

The Ketogenic Diet Improves Gut-Brain Axis in a Rat Model of Irritable Bowel Syndrome: Impact on 5-HT and BDNF Systems

Altered gut-brain communication can contribute to intestinal dysfunctions in the intestinal bowel syndrome. The neuroprotective high-fat, adequate-protein, low-carbohydrate ketogenic diet (KD) modulates the levels of different neurotransmitters and neurotrophins. The aim was to evaluate the effects of KD on levels of 5-HT, the receptors 5-HT_3B and 5-HT₄, the 5-HT transporter SERT, the neurotrophin BDNF, and its receptor TrkB in the colon and brain of a rat model of irritable bowel syndrome (IBS). Samples from Wistar rats exposed to maternal deprivation as newborns and then fed with a standard diet (IBS-Std) or KD (IBS-KD) for ten weeks were analyzed. As controls, unexposed rats (Ctrl-Std and Ctrl-KD) were studied. IBS-Std rats had a disordered enteric serotoninergic signaling shown by increased mucosal 5-HT content and reduced SERT, 5-HT_3B, and 5-HT₄ levels compared to controls. In the brain, these animals showed up-regulation of the BDNF receptor TrkB as a counteracting response to the stress-induced reduction of the neurotrophin. KD showed a dual effect in improving the altered 5-HT and BDNF systems. It down-regulated the increased mucosal 5-HT without affecting transporter and receptor levels. KD improved brain BDNF levels and established negative feedback, leading to a compensatory downregulation of TrkB to maintain a physiological steady state.