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From probiotics to psychobiotics - the gut-brain axis in psychiatric disorders.
Zagórska, A, Marcinkowska, M, Jamrozik, M, Wiśniowska, B, Paśko, P
Beneficial microbes. 2020;(8):717-732
Abstract
This review aims to present a comprehensive state-of-the-art analysis of the bidirectional crosstalk between gut microbiota and the central nervous system (CNS). The literature concerning the potential effects of gut microbiota on psychiatric disorders through neural pathways comprising the 'gut-brain axis' were gathered. In addition, the influence of probiotics and prebiotics and dairy-rich diets combined with the intake of probiotics and prebiotics on gut microbiota and the subsequent relationship with brain function was reviewed. However, a meta-analysis on the effectiveness of probiotic supplementation in psychiatric disorders is lacking. Therefore, a systematic search of PubMed, Embase, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov databases from January 1969 to December 2019 was conducted. It led to the identification of a total of 844 research articles. Of these, a total of 23 studies met the meta-analysis criteria. Statistical analysis revealed that there was no significant difference in the symptoms of schizophrenia, stress, and anxiety between probiotic and placebo groups, post-intervention. Probiotic administration reduced depressive symptoms among patients with depression in a statistically significant manner (standardised mean difference (SMD) = -0.87; 95% confidence interval (95% confidence interval): -1.66, -0.99; P=0.03). Further evidence from larger and more rigorous studies with longer duration of probiotic administration, as well as well-defined populations, homogenous probiotic intervention and outcome measures, are needed to clarify the potential therapeutic effects of probiotics on psychiatric symptoms. Based on the current literature, it seems that not all probiotic-/prebiotic-/dairy-rich diet-based treatments exhibited a psychobiotic effect on the CNS. Among the parameters determining the success of the given treatment, the most significant were probiotic composition (multi-strain formulation), the quantity of ingested psychobiotics and the duration of the study.
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The effect of probiotics, prebiotics, and synbiotics on hormonal and inflammatory indices in women with polycystic ovary syndrome: a systematic review and meta-analysis.
Shamasbi, SG, Ghanbari-Homayi, S, Mirghafourvand, M
European journal of nutrition. 2020;(2):433-450
Abstract
INTRODUCTION Polycystic ovary syndrome (PCOS) is among the most prevalent endocrine disorders in women and can lead to many other disorders and chronic diseases. Thus, early diagnosis and treatment of this syndrome is important. Using probiotics, prebiotics, and synbiotics supplementations to treat PCOS seems appropriate because of their useful effects and low complications. AIMS To assess the effects of probiotics, prebiotics, and synbiotics on hormonal indices such as testosterone, dehydroepiandrosterone sulfate (DHEA-S), sex hormone binding globulin, Free Androgen Index (FAI), and inflammatory indices, such as high sensitive C reactive protein (hsCRP), malondialdehyde (MDA), total glutathione (GSH), nitric oxide (NO), and total antioxidant capacity (TAC) as the primary outcomes and the hirsutism score as the secondary outcome. METHODS All published articles from the beginning until 10 November 2018 in English (Cochrane Library, Web of Sciences, Google Scholar, PubMed, Scopus, and ProQuest) and Persian (SID and Magiran) databases were searched. The effect of interventions on the outcomes was reported with a standard mean difference (SMD) and confidence interval of 95%. In case of high heterogeneity, the random effect model was used instead of the fixed effect model. The statistical heterogeneity of the included clinical trials was tested using the Chi square test and I2. RESULTS Thirteen studies with 855 participants with PCOS(438 women in the intervention group and 417 women in the control group) were included in the meta-analysis. Results of the meta-analysis showed that the SHBG (SMD: 0.56; 95% CI 0.26-0.86; P = 0.0002) and NO (SMD: 0.38; 95% CI 0.09-0.68; P = 0.01) concentration increased significantly in the probiotics and synbiotics groups compared to the placebo group. FAI (SMD: - 0.58; 95% CI - 0.95 to - 0.21; P = 0.002) and MDA (SMD: - 0.76; 95% CI - 1.46 to - 0.05; P = 0.03) concentration in the probiotics and synbiotics groups reduced significantly compared to the placebo group. The results of meta-analyses on other hormonal and inflammatory indices such as testosterone, DHEAS, GSH, hsCRP, TAC, and hirsutism score showed that there were no significant differences between the intervention and control groups. CONCLUSION Using synbiotics and probiotics in women with polycystic ovary syndrome improve hormonal (FAI, SHBG) and inflammatory (NO, MDA) indices in these patients.
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Probiotics as an Adjunct Therapy for the Treatment of Halitosis, Dental Caries and Periodontitis.
Bustamante, M, Oomah, BD, Mosi-Roa, Y, Rubilar, M, Burgos-Díaz, C
Probiotics and antimicrobial proteins. 2020;(2):325-334
Abstract
Probiotics and prebiotics are popular among consumers worldwide as natural approaches to prevent gastrointestinal diseases. The effects of their consumption on the gastrointestinal system have been extensively investigated. Recently, the efficacy of probiotics and prebiotics has been evaluated against naturally developing microbiome imbalance in the human body, such as in the oral cavity, skin, female urogenital tract, and respiratory tract. This review examines the scientific data related to the effects of probiotics on the treatment of diseases occurring in the oral cavity. Probiotics can effectively prevent and treat some infectious diseases in the oral cavity, such as halitosis and periodontitis, and can reduce the development of dental caries and the concentration of harmful bacteria, according to clinical studies. The results of this meta-analysis also suggest the use of probiotics to treat halitosis and periodontitis. However, the evidence may be inconclusive due in part to the use of a wide range of probiotics, non-standardized study design, small population size, poor quality reports, and inconsistent data. Therefore, future studies should homogenize terms and definitions for primary and secondary outcomes, increase the number of volunteers/patients in in vitro tests and clinical studies, and include an evaluation of the combined use of pre- and probiotics.
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Efficacy of prebiotics and probiotics for functional dyspepsia: A systematic review and meta-analysis.
Zhang, J, Wu, HM, Wang, X, Xie, J, Li, X, Ma, J, Wang, F, Tang, X
Medicine. 2020;(7):e19107
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BACKGROUND Functional dyspepsia (FD) is a functional gastrointestinal disorder. Evidence suggests that disturbance of the gastrointestinal microbiota may be implicated in FD. We performed a systematic review and meta-analysis to examine the efficacy of prebiotics and probiotics for FD. METHODS MEDLINE, EMBASE, and the Cochrane Controlled Trials Register were searched (through September 2018). Randomized controlled trials (RCTs) that recruited adults with FD and that compared prebiotics, probiotics, or synbiotics with placebo or no therapy were eligible. Eligibility assessment and data extraction were performed by two independent researchers. Dichotomous symptom data were pooled to obtain a relative risk (RR) with a 95% confidence interval (CI) of remaining symptomatic after therapy. Continuous data were pooled using a standardized or weighted mean difference with a 95% CI. RESULTS The search strategy identified 1062 citations. Five RCTs were eligible for inclusion. The RR of FD symptoms improving with probiotics or probiotics vs placebo was 1.15 (95% CI 1.01-1.30). Probiotics and prebiotics had beneficial effects on symptom scores of FD. Data for synbiotics in the context of FD were sparse, and no definite conclusions could be drawn. ETHICS AND DISSEMINATION This study belongs to the category of systematic reviews, not clinical trials. Therefore, it does not require ethical approval. The results of this study will be published in influential international academic journals related to this topic. CONCLUSION Probiotics and prebiotics seemed to be effective treatments for FD, although the individual species and strains that are the most beneficial remain unclear. Using only probiotics failed to improve the symptoms of FD. Further evidence is required before the role of probiotics, prebiotics, and synbiotics in FD can be fully understood.
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Efficacy and Safety of Probiotics, Prebiotics and Synbiotics in the Treatment of Irritable Bowel Syndrome: A systematic review and meta-analysis.
Asha, MZ, Khalil, SFH
Sultan Qaboos University medical journal. 2020;(1):e13-e24
Abstract
Treatments that target alterations in gut microbiota may be beneficial for patients with irritable bowel syndrome (IBS). A systematic review and meta-analysis was conducted of randomised clinical trials (RCTs) evaluating the efficacy and safety of probiotics, prebiotics and synbiotics. Factors considered in the analysis included global IBS symptoms and/or abdominal pain, secondary symptoms and the frequency of adverse events. A total of 33 RCTs involving 4,321 patients were identified. Overall, probiotics significantly improved global IBS symptoms compared to placebos (standardised mean difference = -0.32, 95% confidence interval: -0.48 to -0.15; P <0.001), with significant heterogeneity between studies (I 2 = 72%; P <0.001). This remained apparent in both single- and multi-strain probiotic interventions as well as synbiotic formulations. However, evidence regarding prebiotics was scarce. There were no significant inter-group differences in terms of the frequency of adverse events. Future RCTs should address methodological limitations, including short follow-up periods and patient adherence.
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The Relationship between Prebiotic Supplementation and Anthropometric and Biochemical Parameters in Patients with NAFLD-A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Stachowska, E, Portincasa, P, Jamioł-Milc, D, Maciejewska-Markiewicz, D, Skonieczna-Żydecka, K
Nutrients. 2020;(11)
Abstract
We aim to systematically review the efficacy of prebiotics in reducing anthropometric and biochemical parameters in individuals with non-alcoholic fatty liver disease (NAFLD). A systematic search using PubMed/MEDLINE, Embase, clinicaltrials.gov, Cinahl, and Web of Science of articles published up to 20 March 2020 was performed for randomized controlled trials enrolling >20 adult patients. Random-effect meta-analysis for metabolic outcomes in NAFLD patients was performed for anthropometric data in addition to liver enzyme, carbohydrate, and lipid parameters. We found six trials (comprising a total of 242 patients) with NAFLD, with subjects aged 38-52 years. The mean time of fiber administration varied between 10 and 12 weeks. The main fiber types were psyllium (seeds or powder), Ocimum basilicum (seeds), and high-performance inulin and oligofructose powder at doses of either 10 or 16 g per day. The control group received either maltodextrin (powder or capsules) or crushed wheat (powder). Patients on the diet with added fiber had improvements in body mass index (BMI) (standardized mean difference (SMD) = -0.494, 95% confidence interval (CI): -0.864 to -0.125, p = 0.009); alanine aminotransferase (ALT) (SMD = -0.667, 95% CI: -1.046 to -0.288, p = 0.001); aspartate aminotransferase (AST) (SMD = -0.466, 95% CI: -0.840 to -0.091, p = 0.015); fasting insulin (SMD = -0.705, 95% CI: -1.115 to -0.295, p = 0.001); and homeostasis model assessment for insulin resistance (HOMA-IR) (SMD = -0.619, 95% CI: -1.026 to -0.211, p = 0.003). Hence, the results show that fiber supplements result in favorable changes as reflected in the measurement of anthropometric, metabolic, and liver-related biomarkers, i.e., body mass index (BMI), homeostasis model assessment for insulin resistance (HOMA-IR), insulin, alanine aminotransferase (ALT), and aspartate aminotransferase (AST). These effects suggest the potential benefits of fiber consumption for NAFLD populations. More prospective, controlled studies should be conducted to reveal specific details regarding the fiber type, dosage, and duration for optimal intervention.
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The Efficacy of Prebiotic, Probiotic, and Synbiotic Supplementation in Modulating Gut-Derived Circulatory Particles Associated With Cardiovascular Disease in Individuals Receiving Dialysis: A Systematic Review and Meta-analysis of Randomized Controlled Trials.
March, DS, Jones, AW, Bishop, NC, Burton, JO
Journal of renal nutrition : the official journal of the Council on Renal Nutrition of the National Kidney Foundation. 2020;(4):347-359
Abstract
OBJECTIVE This systematic review and meta-analyses provide an up-to-date synthesis on the effects of supplementation on circulating levels of toxic metabolites, markers of uremia and inflammation, blood lipids, and other clinical outcomes. METHODS Seventeen databases were searched, supplemented with internet and hand searching. Randomized controlled trials of adult end-stage renal-disease individuals receiving either hemodialysis or peritoneal dialysis were eligible. Trials were restricted to those which had administered a prebiotic, probiotic, or synbiotic as an oral supplement. Primary outcomes were measures of circulating endotoxin, indoxyl-sulphate, and p-cresyl sulfate. RESULTS Twenty-one trials were eligible (1152 randomized participants), of which 16 trials were considered to have a high risk of bias. The number of trials available for meta-analysis varied for each primary outcome. Synthesized data indicated that supplementation significantly reduced circulating levels of endotoxin (standardized mean difference, -0.61; 95% confidence interval, -1.03 to -0.20; P = .004; I2 = 0%), indoxyl-sulphate (-0.34; -0.64 to -0.04; P = .02; I2 = 0%), and p-cresyl sulfate (-0.34; -0.61 to -0.07; P = .01; I2 = 0%). For secondary outcomes, supplementation significantly reduced gastrointestinal symptoms (-0.54; -1.02 to -0.07; P = .02; I2 = 0%). CONCLUSIONS Supplementation reduces toxic metabolites associated with cardiovascular disease and mortality in individuals receiving dialysis. However, the majority of trials included were low in quality.
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Effects of prebiotics on sepsis, necrotizing enterocolitis, mortality, feeding intolerance, time to full enteral feeding, length of hospital stay, and stool frequency in preterm infants: a meta-analysis.
Chi, C, Buys, N, Li, C, Sun, J, Yin, C
European journal of clinical nutrition. 2019;(5):657-670
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BACKGROUND/OBJECTIVES Prebiotics are increasingly recognized as an effective measure to promote health and prevent adverse health outcomes in preterm infants. We aimed to systematically review the randomized controlled trials (RCTs) in this area. SUBJECTS/METHODS Relevant studies from January 2000 to June 2018 were searched and selected from PubMed, Medline, Scopus, and the Cochrane Library. RCTs were included if they involved preterm infant participants, included a prebiotic intervention group, measured incidence of sepsis, feeding intolerance, mortality, time to full enteral feeding, necrotizing enterocolitis (NEC), length of hospital stay, and stool frequency as outcomes. RESULTS Eighteen RCTs (n = 1322) were included in the final meta-analysis. Participants who took prebiotics showed significant decreases in the incidence of sepsis (with a risk ratio (RR) of 0.64, 95% CI: 0.51, 0.78), mortality (RR = 0.58. 95% CI: 0.36, 0.94), length of hospital stay (mean difference (MD): -5.18, 95% CI: -8.94, -1.11), and time to full enteral feeding (MD: -0.99, 95% CI: -1.15, 0.83). The pooled effects showed no significant differences between intervention and control groups in relation to the morbidity rate of NEC (RR = 0.79, 95% CI: 0.44, 1.44) or feeding intolerance (RR = 0.87, 95% CI: 0.52, 1.45). CONCLUSIONS The results showed that the use of prebiotics with preterm infants is safe and can decrease the incidence of sepsis, mortality, length of hospital stay, and time to full enteral feeding but not NEC.
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The effect of synbiotics in improving Helicobacter pylori eradication: A systematic review and meta-analysis.
Pourmasoumi, M, Najafgholizadeh, A, Hadi, A, Mansour-Ghanaei, F, Joukar, F
Complementary therapies in medicine. 2019;:36-43
Abstract
BACKGROUND Helicobacter pylori is a common human infection, presenting in half of the world's population. The failure of the Helicobacter pylori eradication rate necessitates the assessment of new options. The aim of the present meta-analysis was therefore to assess the role of synbiotics in Helicobacter pylori eradication therapy. METHODS A comprehensive literature search was conducted using PubMed, Google Scholar, Scopus, and Web of Knowledge up to June 2018 to identify all randomized controlled trials assessing the effect of synbiotics on the treatment of Helicobacter pylori. A random-effects model was applied for pooling analysis to compensate for the heterogeneity of included studies. The Cochrane Risk of Bias Tool was applied to assess potential bias risks. RESULTS A total of 6 randomized controlled trials were found which assessed the effect of synbiotics on Helicobacter pylori eradication rate. The pooled effect size of the intention-to-treat showed that synbiotics can improve eradication rate (RR: 1.28; 95% CI: 1.15-1.43; I2 = 0%). Also, common adverse events resulting from antibiotics therapy were significantly reduced by adding synbiotics to conventional antibiotics treatments (RR: 0.47; 95% CI: 0.25-0.90; I2 = 36%). However, no difference in eradication rate was observed from per-protocol treatment between intervention and control groups (RR: 0.90; 95% CI: 0.69-1.16; I2 = 88%). CONCLUSION The present systematic review and meta-analysis suggested synbiotics might improve Helicobacter pylori eradication rates, and reduce adverse effects. However, these findings assessed a low number of studies, and further high-quality studies are needed to confirm these results.
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Prebiotics in irritable bowel syndrome and other functional bowel disorders in adults: a systematic review and meta-analysis of randomized controlled trials.
Wilson, B, Rossi, M, Dimidi, E, Whelan, K
The American journal of clinical nutrition. 2019;(4):1098-1111
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BACKGROUND Irritable bowel syndrome (IBS) and other functional bowel disorders (FBDs) are prevalent disorders with altered microbiota. Prebiotics positively augment gut microbiota and may offer therapeutic potential. OBJECTIVES The aim of this study was to investigate the effect of prebiotics compared with placebo on global response, gastrointestinal symptoms, quality of life (QoL), and gut microbiota, via systematic review and meta-analysis of randomized controlled trials (RCTs) in adults with IBS and other FBDs. METHODS Studies were identified using electronic databases, back-searching reference lists, and hand-searching abstracts. RCTs that compared prebiotics to placebo in adults with IBS or other FBDs were included. Two reviewers independently performed screening, data extraction, and bias assessment. Outcome data were synthesized as ORs, weighted mean differences (WMDs) or standardized mean differences (SMDs) with the use of a random-effects model. Subanalyses were performed for type of FBD and dose, type, and duration of prebiotic. RESULTS Searches identified 2332 records, and 11 RCTs were eligible (729 patients). The numbers responding were 52/97 (54%) for prebiotic and 59/94 (63%) for placebo, with no difference between groups (OR: 0.62; 95% CI: 0.07, 5.69; P = 0.67). Similarly, no differences were found for severity of abdominal pain, bloating and flatulence, and QoL score between prebiotics and placebo. However, flatulence severity was improved by prebiotics at doses ≤6 g/d (SMD: -0.35; 95% CI: -0.71, 0.00; P = 0.05) and by non-inulin-type fructan prebiotics (SMD: -0.34; 95% CI: -0.66, -0.01; P = 0.04), while inulin-type fructans worsened flatulence (SMD: 0.85; 95% CI: 0.23, 1.47; P = 0.007). Prebiotics increased absolute abundance of bifidobacteria (WMD: 1.16 log10 copies of the 16S ribosomal RNA gene; 95% CI: 0.06, 2.26; P = 0.04). No studies were at low risk of bias across all bias categories. CONCLUSIONS Prebiotics do not improve gastrointestinal symptoms or QoL in patients with IBS or other FBDs, but they do increase bifidobacteria. Variations in prebiotic type and dose impacted symptom improvement or exacerbation. This review was registered at PROSPERO as CRD42017074072.