Effect of Probiotic Use on Adverse Events in Adult Patients with Inflammatory Bowel Disease: a Retrospective Cohort Study

Rosemary (Rosmarinus officinalis L.) polyphenols and inflammatory bowel diseases: Major phytochemicals, functional properties, and health effects

Major polyphenols in Rosmarinus officinalis L. primarily consist of phenolic acids, phenolic diterpenes, and flavonoids, all of which have pharmacological properties including anti-inflammatory and antibacterial characteristics. Numerous in vitro and animal studies have found that rosemary polyphenols have the potential to decrease the severity of intestinal inflammation. The beneficial effects of rosemary polyphenols were associated with anti-inflammatory properties, including improved gut barrier (increased mucus secretion and tight junction), increased antioxidant enzymes, inhibiting inflammatory pathways and cytokines (downregulation of NF-κB, NLRP3 inflammasomes, STAT3 and activation of Nrf2), and modulating gut microbiota community (increased core probiotics and SCFA-producing bacteria, and decreased potential pathogens) and metabolism (changes in SCFA and bile acid metabolites). This paper provides a better understanding of the anti-inflammatory properties of rosemary polyphenols and suggests that rosemary polyphenols might be employed as strong anti-inflammatory agents to prevent intestinal inflammation and lower the risk of inflammatory bowel disease and related diseases.

Microbiota and IBD: Current knowledge and future perspectives

Inflammatory Bowel Disease (IBD) is a chronic relapsing-remitting disease with a remarkable increase in incidence worldwide and a substantial disease burden. Although the pathophysiology is not fully elucidated yet an aberrant immune reaction against the intestinal microbiota and the gut microbial dysbiosis have been identified to play a major role. The composition of gut microbiota in IBD patients is distinct from that of healthy individuals, with certain organisms predominating over others. Differences in the microbial dysbiosis have been also observed between Crohn Disease (CD) and Ulcerative Colitis (UC). A disruption of the microbiota's balance can lead to inflammation and intestinal damage. Microbiota composition in IBD can be affected both by endogenous (i.e., interaction with the immune system and intestinal epithelial cells) and exogenous (i.e., medications, surgery, diet) factors. The complex interplay between the gut microbiota and IBD is an area of great interest for understanding disease pathogenesis and developing new treatments. The purpose of this review is to summarize the latest evidence on the role of microbiota in IBD pathogenesis and to explore possible future areas of research.

Perioperative Considerations for the Surgical Treatment of Crohn's Disease with Discussion on Surgical Antibiotics Practices and Impact on the Gut Microbiome

Crohn's disease, a chronic inflammatory process of the gastrointestinal tract defined by flares and periods of remission, is increasing in incidence. Despite advances in multimodal medical therapy, disease progression often necessitates multiple operations with high morbidity. The inability to treat Crohn's disease successfully is likely in part because the etiopathogenesis is not completely understood; however, recent research suggests the gut microbiome plays a critical role. How traditional perioperative management, including bowel preparation and preoperative antibiotics, further changes the microbiome and affects outcomes is not well described, especially in Crohn's patients, who are unique given their immunosuppression and baseline dysbiosis. This paper aims to outline current knowledge regarding perioperative management of Crohn's disease, the evolving role of gut dysbiosis, and how the microbiome can guide perioperative considerations with special attention to perioperative antibiotics as well as treatment of Mycobacterium avium subspecies paratuberculosis. In conclusion, dysbiosis is common in Crohn's patients and may be exacerbated by malnutrition, steroids, narcotic use, diarrhea, and perioperative antibiotics. Dysbiosis is also a major risk factor for anastomotic leak, and special consideration should be given to limiting factors that further perturb the gut microbiota in the perioperative period.

A critical review on inflammatory bowel diseases risk factors, dietary nutrients regulation and protective pathways based on gut microbiota during recent 5 years

The treatment of inflammatory bowel diseases (IBDs) has become a worldwide problem. Intestinal flora plays an important role in the development and progression of IBDs. Various risk factors (psychology, living habits, dietary patterns, environment) influence the structure and composition of the gut microbiota and contribute to the susceptibility to IBDs. This review aims to provide a comprehensive overview on risk factors regulating intestinal microenvironment which was contributed to IBDs. Five protective pathways related to intestinal flora were also discussed. We hope to provide systemic and comprehensive insights of IBDs treatment and to offer theoretical guidance for personalized patients with precision nutrition.

Change in the Gut Microbiome and Immunity by Lacticaseibacillus rhamnosus Probio-M9

With the exploding growth of the global market for probiotics and the rapid awakening of public awareness to manage health by probiotic intervention, there is still an active debate about whether the consumption of probiotics is beneficial for nonpatients, which is due to the lack of systematic analysis based on time series multiomics data sets. In this study, we recruited 100 adults from a college in China and performed a random case-control study by using a probiotic (Lacticaseibacillus rhamnosus Probio-M9) as an intervention for 6 weeks, aiming to achieve a comprehensive evaluation and understanding of the beneficial effect of Probio-M9 consumption. By testing advanced blood immunity indicators, sequencing the gut microbiome, and profiling the gut metabolome at baseline and the end of the study, we found that although the probiotic intervention has a limited impact on the human immunity and the gut microbiome and metabolome, the associations between the immunity indicators and multiomics data were strengthened, and further analysis of the gut microbiome's genetic variations revealed inhibited generation of single nucleotide variants (SNVs) by probiotic consumption. Taken together, our findings indicated an underestimated influence of the probiotic, not on altering the microbial composition but on strengthening the association between human immunity and commensal microbes and stabilizing the genetic variations of the gut microbiome. IMPORTANCE Although the global market for probiotics is growing explosively, there is still an active debate about whether the consumption of probiotics is beneficial for nonpatients. In this study, we recruited 100 adults from a college in China and performed 6 weeks of intervention for half of the volunteers. By analyzing the time series multiomics data in this study, we found that the probiotic intervention (i) has a limited effect on human immunity or the global structure of the gut microbiome and metabolome, (ii) can largely influence the correlation of the development between multiomics data and immunity, which was not able to be discovered by conventional differential abundance analysis, and (iii) can inhibit the generation of SNVs in the gut microbiome instead of promoting it.

Manipulation of Gut Microbiota as a Key Target for Crohn's Disease

Crohn's disease (CD) is an inflammatory bowel disease (IBD) sub-type characterized by transmural chronic inflammation of the gastrointestinal tract. Research indicates a complex CD etiology involving genetic predisposition and immune dysregulation in response to environmental triggers. The chronic mucosal inflammation has been associated with a dysregulated state, or dysbiosis, of the gut microbiome (bacteria), mycobiome (fungi), virome (bacteriophages and viruses), and archeaome (archaea) further affecting the interkingdom syntrophic relationships and host metabolism. Microbiota dysbiosis in CD is largely described by an increase in facultative anaerobic pathobionts at the expense of strict anaerobic Firmicutes, such as Faecalibacterium prausnitzii. In the mycobiome, reduced fungal diversity and fungal-bacteria interactions, along with a significantly increased abundance of Candida spp. and a decrease in Saccharomyces cerevisiae are well documented. Virome analysis also indicates a significant decrease in phage diversity, but an overall increase in phages infecting bacterial groups associated with intestinal inflammation. Finally, an increase in methanogenic archaea such as Methanosphaera stadtmanae exhibits high immunogenic potential and is associated with CD etiology. Common anti-inflammatory medications used in CD management (amino-salicylates, immunomodulators, and biologics) could also directly or indirectly affect the gut microbiome in CD. Other medications often used concomitantly in IBD, such as antibiotics, antidepressants, oral contraceptives, opioids, and proton pump inhibitors, have shown to alter the gut microbiota and account for increased susceptibility to disease onset or worsening of disease progression. In contrast, some environmental modifications through alternative therapies including fecal microbiota transplant (FMT), diet and dietary supplements with prebiotics, probiotics, and synbiotics have shown potential protective effects by reversing microbiota dysbiosis or by directly promoting beneficial microbes, together with minimal long-term adverse effects. In this review, we discuss the different approaches to modulating the global consortium of bacteria, fungi, viruses, and archaea in patients with CD through therapies that include antibiotics, probiotics, prebiotics, synbiotics, personalized diets, and FMT. We hope to provide evidence to encourage clinicians and researchers to incorporate these therapies into CD treatment options, along with making them aware of the limitations of these therapies, and indicate where more research is needed.

Postbiotics as the new frontier in food and pharmaceutical research

Food is the essential need of human life and has nutrients that support growth and health. Gastrointestinal tract microbiota involves valuable microorganisms that develop therapeutic effects and are characterized as probiotics. The investigations on appropriate probiotic strains have led to the characterization of specific metabolic byproducts of probiotics named postbiotics. The probiotics must maintain their survival against inappropriate lethal conditions of the processing, storage, distribution, preparation, and digestion system so that they can exhibit their most health effects. Conversely, probiotic metabolites (postbiotics) have successfully overcome these unfavorable conditions and may be an appropriate alternative to probiotics. Due to their specific chemical structure, safe profile, long shelf-life, and the fact that they contain various signaling molecules, postbiotics may have anti-inflammatory, immunomodulatory, antihypertensive properties, inhibiting abnormal cell proliferation and antioxidative activities. Consequently, present scientific literature approves that postbiotics can mimic the fundamental and clinical role of probiotics, and due to their unique characteristics, they can be applied in an oral delivery system (pharmaceutical/functional foods), as a preharvest food safety hurdle, to promote the shelf-life of food products and develop novel functional foods or/and for developing health benefits, and therapeutic aims. This review addresses the latest postbiotic applications with regard to pharmaceutical formulations and commercial food-based products. Potential postbiotic applications in the promotion of host health status, prevention of disease, and complementary treatment are also reviewed.

The Gut Microbiota in Inflammatory Bowel Disease

Epidemiological surveys indicate that the incidence of inflammatory bowel disease (IBD) is increasing rapidly with the continuous growth of the economy. A large number of studies have investigated the relationship between the genetic factors related to the susceptibility to IBD and the gut microbiota of patients by using high-throughput sequencing. IBD is considered the outcome of the interaction between host and microorganisms, including intestinal microbial factors, abnormal immune response, and a damaged intestinal mucosal barrier. The imbalance of microbial homeostasis leads to the colonization and invasion of opportunistic pathogens in the gut, which increases the risk of the host immune response and promotes the development of IBD. It is critical to identify the specific pathogens related to the pathogenesis of IBD. An in-depth understanding of various pathogenic factors is of great significance for the early detection of IBD. This review highlights the role of gut microbiota in the pathogenesis of IBD and provides a theoretical basis for the personalized approaches that modulate the gut microbiota to treat IBD.

Clinical Efficacy of Probiotic Therapy on Bowel-Related Symptoms in Patients with Ulcerative Colitis during Endoscopic Remission: An Observational Study

Background

A substantial percentage of patients with ulcerative colitis (UC) have irritable bowel syndrome- (IBS-) like symptoms despite adequate treatment and endoscopic remission. In this study, we evaluated the clinical efficacy of probiotic therapy for residual IBS-like symptoms in patients with UC in endoscopic remission.

Methods

We conducted a multicenter, observational study between April 2018 and December 2020 across two university hospitals in Korea. Patients with UC whose IBS-like symptoms persisted during endoscopic remission were included in this study. Endoscopic remission was defined as a Mayo endoscopic score ≤ 1, and IBS-like symptoms were defined as those meeting the ROME-IV diagnostic criteria. A Biotop capsule® (Lactobacillus acidophilus, 75 mg; Clostridium butyricum TO-A, 25 mg; Bacillus mesentericus TO-A, 25 mg; and Streptococcus faecalis T-110, 5 mg) was administered three times daily for one month. All patients completed bowel-related symptom questionnaires and short inflammatory bowel disease questionnaires (SIBDQs) at the start and end of the 4-week treatment period.

Results

A total of 43 patients were enrolled and analyzed. Statistically significant improvements from baseline were observed at the end of the 4-week treatment. The total SIBDQ score improved from 50.6 to 53.6 (P = 0.005). SIBDQ scores of bowel function (P = 0.018), systemic function (P = 0.040), and social function (P = 0.005) improved. Stool frequency and Bristol stool scale scores improved after probiotic therapy (P < 0.05).

Conclusion

This study showed that probiotic administration improved bowel-related symptoms and quality of life in patients with UC whose IBS-like symptoms persisted during endoscopic remission. As this is an observational study and has no placebo-controlled arm, further prospective randomized controlled trials are needed to confirm these results.

Microbial pathogenesis in inflammatory bowel diseases

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal system. Previously, it is considered the disease of the western world but now the incidence and prevalence of IBD are increasing globally with urbanization and modernization. Additionally, the major problem is the highest incidence of IBD among children and adolescents. The precise etiology of IBD is unknown and there is no cure for IBD, which is also the reason for increasing the number of cases worldwide. The IBD is a complex interplay of environment, immune system, and microbiota in a genetically susceptible host. Among these factors, the alteration in intestinal microbiota has been detected in IBD patients. The bacterial species associated with IBD include Mycobacterium paratuberculosis, adherent-invasive E. coli (AIEC), Helicobacter pylori, and Campylobacter concisus. Moreover, the efficacy of antibiotics and probiotics further suggests the role of microbes in IBD. However, no study confirmed the bacterial species as a cause of IBD as per Koch's postulates. Thus, still controversies exist regarding the role of microbes in IBD. Therefore, this paper aims to review the current literature to evaluate the role of microbes in IBD that would be a useful inventory of researchers working in this area.

The significant role of nutraceutical compounds in ulcerative colitis treatment

Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD) mainly affecting the colon and the rectum. Its main characters are represented by relapsing and remitting mucosal inflammation, starting in the rectum and typically extending continuously proximally through part or the entire colon. UC pathogenesis depends on multiple factors, such as genetic predisposition, defects in the epithelial barrier, dysregulated immune responses, and environmental causes. The most frequent symptoms are abdominal pain, weight loss, mucus discharge, bloody diarrhoea, incontinence, nocturnal defecations, fever, and anemia. Existing therapies for UC include 5-aminosalicylic acid (5-ASA) and its derivatives, steroids, immunosuppressants and biological drugs. However, limited efficacy and unwanted adverse effects hardly limit these strategies of treatment. In the last decades, research studies have been driven towards complementary and alternative medicines for the treatment of UC. Various nutraceuticals have exhibited promising results in modulating intestinal inflammation meanwhile improving symptoms. These compounds possess a wide spectrum of positive health effects evidenced by in vitro studies, characterized by their involvement in antioxidant defenses, cell proliferation, and gene expression. The present review analyzes the available data about the different types of nutraceuticals and their potential effectiveness as adjuvant therapy of IBD, with particular emphasis to UC.

Prebiotics, Probiotics, Synbiotics, Paraprobiotics and Postbiotic Compounds in IBD

The increasing incidence of inflammatory bowel diseases (IBD) and the increasing severity of the course of these diseases create the need for developing new methods of therapy. The gut microbiome is extensively studied as a factor influencing the development and course of IBD. The composition of intestinal microbiota can be relatively easily modified by diet (i.e., prebiotics, mainly dietary fibers) and bacterial supplementation using beneficial bacteria strains called probiotics. Additionally, the effects of the improved microbiome could be enhanced or gained by using paraprobiotics (non-viable, inactivated bacteria or their components) and/or postbiotics (products of bacterial metabolism or equal synthetic products that beneficially modulate immunological response and inflammation). This study summarizes the recent works on prebiotics, probiotics, synbiotics (products merging pre- and probiotics), paraprobiotics and postbiotics in IBD.

Evaluation of Microbiome Alterations Following Consumption of BIOHM, a Novel Probiotic

Gastrointestinal microbiome dysbiosis may result in harmful effects on the host, including those caused by inflammatory bowel diseases (IBD). The novel probiotic BIOHM, consisting of Bifidobacterium breve, Saccharomyces boulardii, Lactobacillus acidophilus, L. rhamnosus, and amylase, was developed to rebalance the bacterial–fungal gut microbiome, with the goal of reducing inflammation and maintaining a healthy gut population. To test the effect of BIOHM on human subjects, we enrolled a cohort of 49 volunteers in collaboration with the Fermentation Festival group (Santa Barbara, CA, USA). The profiles of gut bacterial and fungal communities were assessed via stool samples collected at baseline and following 4 weeks of once-a-day BIOHM consumption. Mycobiome analysis following probiotic consumption revealed an increase in Ascomycota levels in enrolled individuals and a reduction in Zygomycota levels (p value < 0.01). No statistically significant difference in Basidiomycota was detected between pre- and post-BIOHM samples and control abundance profiles (p > 0.05). BIOHM consumption led to a significant reduction in the abundance of Candida genus in tested subjects (p value < 0.013), while the abundance of C. albicans also trended lower than before BIOHM use, albeit not reaching statistical significance. A reduction in the abundance of Firmicutes at the phylum level was observed following BIOHM use, which approached levels reported for control individuals reported in the Human Microbiome Project data. The preliminary results from this clinical study suggest that BIOHM is capable of significantly rebalancing the bacteriome and mycobiome in the gut of healthy individuals, suggesting that further trials examining the utility of the BIOHM probiotic in individuals with gastrointestinal symptoms, where dysbiosis is considered a source driving pathogenesis, are warranted.

Microbiota-targeted therapeutics in gastrointestinal diseases

In recent years, more and more diseases have been found to be related to dysbiosis. In particular, some disruptive discoveries in the past five years have made gut microbiota a hot topic in the field of health and diseases. As an important coordinator of biological processes and a common participant in the occurrence and development of multiple diseases, coupled with the plasticity of its composition and function, the gut microbiota has gradually become an attractive target for the intervention and management of diseases, arousing great attention of researchers. In this paper, we summarize the relationship between gut microbiota and irritable bowel syndrome, inflammatory bowel disease, and colorectal cancer. Then, we introduce the current status of microbiota-targeted therapeutics in gastrointestinal diseases.

Clinically relevant thyroid disorders and inflammatory bowel disease are inversely related: a retrospective case-control study

OBJECTIVES

The risk of thyroid disorders (TDs) in inflammatory bowel disease (IBD) is still controversial. The aim of this retrospective, single-center, case-control study was to explore the association between clinically relevant functional TDs and IBD.

METHODS

Consecutive individuals for a total of 313 IBD patients [90 Crohn's disease (CD); 223 ulcerative colitis (UC)], and 833 individuals undergoing colonoscopy for screening without IBD were collected. In the study, subject's information on thyroid status were retrieved. Thyroid disorders were classified, according to the functional status, as hypothyroidism or hyperthyroidism. Patients with TDs (cases) were compared with 941 without (controls) according to IBD exposure. Unadjusted and adjusted odds ratios (ORs) and their 95% confidence interval (CI) were calculated.

RESULTS

Clinically relevant TDs were detected in 205 (17,9%) patients and the prevalence was significantly lower in IBD patients compared with subjects without (8.3% vs 12.9%; p = 0.029). After adjusting for potential confounders, a higher TDs risk was confirmed in female (OR 2.72; 95%CI 1.88‒3.92) and older subjects (OR 1.01; 95%CI 1.00‒1.03), and a lower risk in IBD (OR 0.51; 95%CI 0.34‒0.76), especially for hypothyroidism (OR 0.33; 95%CI 0.17‒0.66) in UC. Among four thyroid cancers, only one was detected in IBD patients.

CONCLUSIONS

Overall, in our study, the risk of TDs was lower in IBD patients. To assess routinely hormones and/or thyroid gland imaging in the absence of clinical signs or symptoms seems unnecessary in IBD patients, at least in our geographic area.

The effects of probiotics, prebiotics and synbiotics on the reduction of IBD complications, a periodic review during 2009-2020

AIMS

To perform a systematic review on randomized controlled trials to examine the efficacy of probiotics, prebiotics and synbiotics in the treatment of IBD.

METHODS AND RESULTS

PubMed, Web of science, Scopus and Google Scholar were systematically searched from January 2009 to January 2020 using the following keywords: 'Inflammatory Bowel Disease', 'Probiotics' and 'Clinical trial'. The statistical analysis was performed using SPSS software version 24.0. A total of 1832 articles were found during the initial search and 21 clinical trials were eligible. Studies comparing the effects of probiotics and placebo among patients with active ulcerative colitis (UC) showed a significant difference in clinical outcomes. Moreover, probiotics improved the overall induction of remission rates among patients with Crohn's disease (CD). Probiotics significantly decreased the IL-1β, TNF-α and IL-8 levels. Also, the need for systemic steroids, hospitalization, surgery, as well as histological score and disease activity index significantly decreased in patients who used probiotic or pro-/synbiotics.

CONCLUSIONS

The use of probiotics, as food supplements, can induce anti-inflammatory reactions, balance the intestinal homeostasis and induce remission in IBD. The efficacy of probiotics on remission induction is more reported in UC rather than CD. Larger well-designed clinical trials are needed to further determine whether probiotics are of clear benefits for remission in IBD.

An Overview of Gut Microbiota and Colon Diseases with a Focus on Adenomatous Colon Polyps

It is known and accepted that the gut microbiota composition of an organism has an impact on its health. Many studies deal with this topic, the majority discussing gastrointestinal health. Adenomatous colon polyps have a high prevalence as colon cancer precursors, but in many cases, they are hard to diagnose in their early stages. Gut microbiota composition correlated with the presence of adenomatous colon polyps may be a noninvasive and efficient tool for diagnosis with a high impact on human wellbeing and favorable health care costs. This review is meant to analyze the gut microbiota correlated with the presence of adenomatous colon polyps as the first step for early diagnosis, prophylaxis, and treatment.

The Rundown of Dietary Supplements and Their Effects on Inflammatory Bowel Disease-A Review

Inflammatory bowel diseases, including Crohn's disease and ulcerative colitis, are a life-long, chronic, and relapsing problem affecting 11.2 million people worldwide. To date, there is pharmacological therapy to treat symptoms such as diarrhea, constipation, and abdominal cramping/pain. These medications also help to alleviate everyday discomfort; however, there are no curative therapies. Recent studies have investigated the combination of pharmacological treatment along with nutritional interventions to improve quality of life and risk of disease relapse. Dietary supplements, specifically probiotics, polyphenols, fibers, fatty acids and low fermentable oligosaccharide, disaccharide, monosaccharide, and polyol diets (FODMAP diets), have been closely looked at to determine their effect, if any, on the development of inflammatory bowel disease and its course of progression. Approximately 30 studies were carefully reviewed and analyzed to appreciate the value of these above-mentioned supplements and their influence on this gastrointestinal disease. After analysis, it has been demonstrated that by implementing fibers, polyphenols, and fatty acids, as well as keeping a low-saccharide diet for those patients with Crohn's disease and ulcerative colitis can improve quality of life and invoke clinical remission. Some polyphenols, specifically curcumin and resveratrol, have proved to decrease disease activity in studies reviewed. Although these studies have become a topic of recent interest, it would be of great value to doctors and patients alike, to continue in this direction of research and to improve the findings for best treatment substances and dosages. This would lead to increased quality of life and disease control leading to fewer complications in the future.

The Rundown of Dietary Supplements and Their Effects on Inflammatory Bowel Disease-A Review

Inflammatory bowel diseases, including Crohn's disease and ulcerative colitis, are a life-long, chronic, and relapsing problem affecting 11.2 million people worldwide. To date, there is pharmacological therapy to treat symptoms such as diarrhea, constipation, and abdominal cramping/pain. These medications also help to alleviate everyday discomfort; however, there are no curative therapies. Recent studies have investigated the combination of pharmacological treatment along with nutritional interventions to improve quality of life and risk of disease relapse. Dietary supplements, specifically probiotics, polyphenols, fibers, fatty acids and low fermentable oligosaccharide, disaccharide, monosaccharide, and polyol diets (FODMAP diets), have been closely looked at to determine their effect, if any, on the development of inflammatory bowel disease and its course of progression. Approximately 30 studies were carefully reviewed and analyzed to appreciate the value of these above-mentioned supplements and their influence on this gastrointestinal disease. After analysis, it has been demonstrated that by implementing fibers, polyphenols, and fatty acids, as well as keeping a low-saccharide diet for those patients with Crohn's disease and ulcerative colitis can improve quality of life and invoke clinical remission. Some polyphenols, specifically curcumin and resveratrol, have proved to decrease disease activity in studies reviewed. Although these studies have become a topic of recent interest, it would be of great value to doctors and patients alike, to continue in this direction of research and to improve the findings for best treatment substances and dosages. This would lead to increased quality of life and disease control leading to fewer complications in the future.

Side Effects Associated with Probiotic Use in Adult Patients with Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Probiotics demonstrated to be effective in the treatment of inflammatory bowel disease (IBD). However, the safety profile of probiotics is insufficiently explored. In the present systematic review and meta-analysis, we examined the occurrence of side effects related to probiotic/synbiotic use in randomized controlled trials (RCTs) of IBD patients as compared with placebo. Eligible RCTs in adult patients with IBD were identified by accessing the Medline database via PubMed, EMBASE, CENTRAL and the Cochrane central register of controlled trials up to December 2018. Occurrence of side effects was retrieved and recorded. Data were pooled and the relative risks (RRs) with their 95% confidence intervals (CIs) were calculated. The low-moderate study heterogeneity, assessed by the I² statistic, allowed to use of a fixed-effects modelling for meta-analysis. Nine RCTs among 2337, including 826 patients (442 treated with probiotics/symbiotic and 384 with placebo) were analyzed. Eight were double-blind RCTs, and six enrolled ulcerative colitis (UC) patients. Although the risk for the overall side effects (RR 1.35, 95%CI 0.93–1.94; I² = 25%) and for gastrointestinal symptoms (RR 1.78, 95%CI 0.99–3.20; I² = 20%) was higher in IBD patients taking probiotics than in those exposed to placebo, statistical significance was achieved only for abdominal pain (RR 2.59, 95%CI 1.28–5.22; I² = 40%). In conclusion, despite the small number of RCTs and the variety of probiotic used and schedule across studies, these findings highlight the level of research effort still required to identify the most appropriate use of probiotics in IBD.