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The anxiolytic effect of probiotics: A systematic review and meta-analysis of the clinical and preclinical literature.
Reis, DJ, Ilardi, SS, Punt, SEW
PloS one. 2018;13(6):e0199041
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The microbiome-gut-brain axis in general and the possibility of altering the microbiome through administration of probiotics to support physical and mental health has received much attention in recent years. Here, a systematic review and meta-analysis were carried out to evaluate the clinical and preclinical evidence for the use of probiotics in anxiety. 22 preclinical (rodent) studies were included in the meta-analysis and showed an overall significant anxiolytic effect of probiotics in diseased, but not healthy, animals. Studies were heterogenous with regards to species and strains of probiotic used. Subgroup analysis showed that only Lactobacillus rhamnosus significantly reduced anxiety-like behaviour. 14 human studies were included in the meta-analysis and overall no anxiolytic effect was observed. Only three out of the 14 studies showed a positive effect (vs 12 out of the 22 animal studies), one of which used L. rhamnosus. Due to the small number of trials no subgroup analysis could be performed. Apart from the small number and heterogeneity of human studies, the authors discuss further possible reasons for the discrepancy between animal and human studies: • Dose: Dosages were typically 100 times higher (per kg) in animals than in humans. • Diseased vs healthy subjects: In animal studies, only those which investigated animals displaying anxiety related behaviour improved with probiotic administration. None of the human studies specifically recruited anxious individuals, eight of the studies included healthy subjects, the other six selected participants for other disorders, including four for irritable bowel syndrome. The authors conclude that more research into an anxiolytic effect of probiotics in humans is warranted, especially using L. rhamnosus, studying patients with anxiety, and using higher dosages and longer study duration.
Expert Review
Conflicts of interest:
None
Take Home Message:
- While preclinical animal studies suggest that probiotics may help reduce anxiety, such findings have not yet translated to clinical research in humans.
- Further investigation of probiotic treatment for clinically relevant anxiety is warranted, particularly with respect to the probiotic species L. rhamnosus.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
This review highlights how important it is for future studies to focus on clinically anxious patients and also to consider exploring the effects of differing doses of probiotics in this population.
Clinical practice applications:
Anxiety disorders affect as many as 3 in 10 people at some point during their lifetime. On that basis, it would be great to have a viable non-pharmaceutical option to help with some of the symptoms.
Considerations for future research:
If the results from the pre-clinical studies can be corroborated in human populations, this could have widespread clinical implications.
Abstract
BACKGROUND Probiotics have generated intensive research interest in recent years as a novel mode of treatment for physical and mental illness. Nevertheless, the anxiolytic potential of probiotics remains unclear. The present systematic review and meta-analysis aimed to evaluate the clinical and preclinical (animal model) evidence regarding the effect of probiotic administration on anxiety. METHODS The PubMed, PsycINFO, and Web of Science databases were reviewed for preclinical and clinical studies that met the defined inclusion and exclusion criteria. The effects of probiotics on anxiety-like behavior and symptoms of anxiety were analyzed by meta-analyses. Separate subgroup analyses were conducted on diseased versus healthy animals, specific preclinical probiotic species, and clinical versus healthy human samples. RESULTS Data were extracted from 22 preclinical studies (743 animals) and 14 clinical studies (1527 individuals). Overall, probiotics reduced anxiety-like behavior in animals (Hedges' g = -0.47, 95% CI -0.77 --0.16, p = 0.004). Subgroup analyses revealed a significant reduction only among diseased animals. Probiotic species-level analyses identified only Lactobacillus (L.) rhamnosus as an anxiolytic species, but these analyses were broadly under-powered. Probiotics did not significantly reduce symptoms of anxiety in humans (Hedges' g = -0.12, 95% CI -0.29-0.05, p = 0.151), and did not differentially affect clinical and healthy human samples. CONCLUSIONS While preclinical (animal) studies suggest that probiotics may help reduce anxiety, such findings have not yet translated to clinical research in humans, perhaps due to the dearth of extant research with clinically anxious populations. Further investigation of probiotic treatment for clinically relevant anxiety is warranted, particularly with respect to the probiotic species L. rhamnosus.
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Probiotic monotherapy and Helicobacter pylori eradication: A systematic review with pooled-data analysis.
Losurdo, G, Cubisino, R, Barone, M, Principi, M, Leandro, G, Ierardi, E, Di Leo, A
World journal of gastroenterology. 2018;24(1):139-149
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Helicobacter pylori (H-pylori) is a parasite that resides in the human stomach and is associated with the development of stomach ulcers, amongst other conditions. Conventional treatment relies on a combination of antibiotics and stomach acid suppressants, however failure rates for standard treatments have been rising and alternatives are required. Probiotics (live bacteria that provide health benefits to their host) have been used alongside antibiotic treatment for H-pylori in some cases to reduce medication side effects. This systematic review of 11 studies including 517 H-pylori infected patients, aimed to assess the effects of probiotic therapy alone on H-pylori status. The study found that the eradication rate of H-pylori with a variety of probiotic strains was 12-16%, compared to a 0% success rate in the placebo groups. Clinically, this rate is low, however the authors conclude that probiotics may have a role to play in a multi-therapy approach for the eradication of H-pylori.
Abstract
AIM: To define probiotic monotherapy effect on Helicobacter pylori (H. pylori) status by performing a systematic review. METHODS Methods of analysis and inclusion criteria were based on PRISMA recommendations. Relevant publications were identified by searching PubMed, MEDLINE, Science Direct, and EMBASE. The end-point was to estimate eradication rate and urea breath test delta value before and after probiotic monotherapy across all studies and, overall, with a pooled data analysis. Adverse events of probiotic therapy were evaluated. The data were expressed as proportions/percentages, and 95%CIs were calculated. For continuous variables, we evaluated the weighted mean difference. Odd ratios (ORs) were calculated according to the Peto method for the comparison of eradication rates between probiotics and placebo. RESULTS Eleven studies were selected. Probiotics eradicated H. pylori in 50 out of 403 cases. The mean weighted eradication rate was 14% (95%CI: 2%-25%, P = 0.02). Lactobacilli eradicated the bacterium in 30 out of 235 patients, with a mean weighted rate of 16% (95%CI: 1%-31%). Saccharomyces boulardii achieved eradication in 6 out of 63 patients, with a pooled eradication rate of 12% (95%CI: 0%-29%). Multistrain combinations were effective in 14 out of 105 patients, with a pooled eradication rate of 14% (95%CI: 0%-43%). In the comparison of probiotics vs placebo, we found an OR of 7.91 in favor of probiotics (95%CI: 2.97-21.05, P < 0.001). Probiotics induced a mean reduction in delta values higher than placebo (8.61% with a 95%CI: 5.88-11.34, vs 0.19% for placebo, P < 0.001). Finally, no significant difference in adverse events was found between probiotics and placebo (OR = 1, 95%CI: 0.06-18.08). CONCLUSION Probiotics alone show a minimal effect on H. pylori clearance, thus suggesting a likely direct role.
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Extra Dose of Vitamin C Based on a Daily Supplementation Shortens the Common Cold: A Meta-Analysis of 9 Randomized Controlled Trials.
Ran, L, Zhao, W, Wang, J, Wang, H, Zhao, Y, Tseng, Y, Bu, H
BioMed research international. 2018;2018:1837634
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The common cold poses a heavy burden worldwide, in terms of human health and economic losses. The aim of this meta-analysis was to evaluate whether vitamin C could be used for relieving symptoms, shortening the duration, or reducing the incidence of the common cold. Nine randomised controlled trials conducted between 1950 and 2001 were included in the meta-analysis. No statistically significant effects were found when vitamin C was only started at the onset of symptoms, but regular supplementation with therapeutic doses of vitamin C at the onset of illness shortened the duration of the common cold and the time confined indoors, and relieved the symptoms, including chest pain, fever and chills. Based on this meta-analysis the authors recommend a small daily dose of vitamin C (no more than 1.0g/day) to support immunity and a larger dose of vitamin C during the common cold (a larger dose than before, usually 3.0 g/day to 4.0 g/day) to better recover health.
Abstract
AIM: To investigate whether vitamin C is effective in the treatment of the common cold. METHOD After systematically searching the National Library of Medicine (PubMed), Cochrane Library, Elsevier, China National Knowledge Infrastructure (CNKI), VIP databases, and WANFANG databases, 9 randomized placebo-controlled trials were included in our meta-analysis in RevMan 5.3 software, all of which were in English. RESULTS In the evaluation of vitamin C, administration of extra therapeutic doses at the onset of cold despite routine supplementation was found to help reduce its duration (mean difference (MD) = -0.56, 95% confidence interval (CI) [-1.03, -0.10], and P = 0.02), shorten the time of confinement indoors (MD = -0.41, 95% CI [-0.62, -0.19], and P = 0.0002), and relieve the symptoms associated with it, including chest pain (MD = -0.40, 95% CI [-0.77, -0.03], and P = 0.03), fever (MD = -0.45, 95% CI [-0.78, -0.11], and P = 0.009), and chills (MD = -0.36, 95% CI [-0.65, -0.07], and P = 0.01). CONCLUSIONS Extra doses of vitamin C could benefit some patients who contract the common cold despite taking daily vitamin C supplements.
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Effect of probiotics on lipid profiles and blood pressure in patients with type 2 diabetes: A meta-analysis of RCTs.
He, J, Zhang, F, Han, Y
Medicine. 2017;96(51):e9166
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Type 2 diabetes mellitus (T2DM) is the most common metabolic disorder worldwide. Though many clinical studies have explored the effects of probiotics on T2DM they have concluded mixed results. The purpose of this meta-analysis was to evaluate all current randomised controlled trials and determine the effect of probiotics on lipid profiles and blood pressure in patients with T2DM. According to the existing literature, probiotic supplementation for patients with T2DM has a positive effect by lowering total cholesterol and increasing high-density lipoproteins (HDLs). While these beneficial effects on lipid profiles and blood pressure have been found, the authors conclude there is still a need for a multi-centre, longitudinal study to better understand the effects of probiotics on patients with T2DM.
Abstract
BACKGROUND This meta-analysis aimed to systematically evaluate the effects of probiotics on blood lipid and blood pressure among patients with type 2 diabetes mellitus (T2DM) based on the randomized controlled studies. METHODS PubMed, Cochrane, Embase, Wanfang, China National Knowledge Infrastructure, and VIP database were searched by the index words to identify the qualified randomized control trial. The latest research was done in the January 2017. Mean difference (MD) along with 95% confidence interval (CI) was used to analyze the included outcomes. RESULTS Ten trials were included at last with 297 patients in the treatment group and 294 patients in the control group. Probiotics significantly decreased the value of total cholesterol (SMD -0.57, 95% CI -0.92 to 0.21), triglyceride (SMD -0.66, 95% CI -0.93 to 0.39), low-density lipoprotein (SMD -0.40, 95% CI -0.79 to 0.01), systolic blood pressure (WMD -5.04, 95% CI -8.8 to 1.20), diastolic blood pressure (SMD -0.39, 95% CI -0.62 to 0.17), fasting blood glucose (FBG) (SMD 3.54, 95% CI 1.94-5.15) compared with the placebo treatment. Apart from this, probiotics could significantly improve the value of high-density lipoprotein (SMD 0.38, 95% CI 0.03-0.73). CONCLUSION Probiotics may decrease the indexes of lipid profile, blood pressure, and FBG in patients with T2DM; application of probiotics might be a new method for lipid profiles and blood pressure management in T2DM.
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Probiotics for prevention of radiation-induced diarrhea: A meta-analysis of randomized controlled trials.
Liu, MM, Li, ST, Shu, Y, Zhan, HQ
PloS one. 2017;12(6):e0178870
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Acute radiation-induced diarrhoea is a potentially fatal side effect of radiotherapy for abdominal or pelvic cancers. The mechanisms are not yet known, but effects of the radiation on the microbiota may be a factor and probiotic treatment may therefore be beneficial. The authors of this meta-analysis looked at randomised controlled trials of probiotics in the prevention of radiation-induced diarrhoea with probiotics (there were not enough trials to evaluate probiotics for the treatment of radiation-induced diarrhoea). Only six studies qualified for inclusion into this meta-analysis, with a total of 917 patients (490 receiving probiotics, 427 controls). Compared with placebo, patients receiving probiotics had a significantly lower risk of developing diarrhoea, but there was no significant reduction in anti-diarrhoea medication use or Bristol scale stool form. Most studies did not report adverse events from probiotic treatment. The meta-analysis was limited by several factors: variety of bacterial strains, dosages and timings used, differences in cancer treatment (dose of radiotherapy, radiotherapy alone or with chemotherapy), variability of patient populations and diseases, and diagnostic criteria for diarrhoea.
Abstract
BACKGROUND Radiotherapy is commonly used for abdominal or pelvic cancer, and patients receiving radiotherapy have a high risk developing to an acute radiation-induced diarrhea. Several previous studies have discussed the effect of probiotics on prevention of radiation-induced diarrhea, but the results are still inconsistent. OBJECTIVE We performed a meta-analysis of randomized controlled trials (RCTs) to evaluate the efficacy of probiotic supplementation for prevention the radiation-induced diarrhea. METHODS Relevant RCTs studies assessing the effect of probiotic supplementation on clinical outcomes compared with placebo were searched in PubMed, EMBASE, and the Cochrane Library databases (up to March 30 2016). Heterogeneity was assessed with I2 and H2, and publication bias was evaluated using sensitive analysis. RESULTS Six trials, a total of 917 participants (490 participants received prophylactic probiotics and 427 participants received placebo), were included in this meta-analysis. Compared with placebo, probiotics were associated with a lower incidence of radiation-induced diarrhea (RR: 0.55; 95% CI: 0.34-0.88; P = 0.01; I2: 87%; 95% CI: 75%-94%; H2: 2.8; 95% CI: 2.0-4.0). However, there is no significant difference in the anti-diarrheal medication use (RR: 0.68; 95% CI: 0.40-1.14; P = 0.14) or bristol scale on stool form (RR: 0.64; 95% CI: 0.35-1.17; P = 0.14). CONCLUSION Probiotics may be beneficial to prevent radiation-induced diarrhea in patients who suffered from abdominal or pelvic cancers during radiotherapy period.
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The Effect of Bifidobacterium animalis ssp. lactis HN019 on Cellular Immune Function in Healthy Elderly Subjects: Systematic Review and Meta-Analysis.
Miller, LE, Lehtoranta, L, Lehtinen, MJ
Nutrients. 2017;9(3)
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Elderly individuals are more susceptible to infections and cancer, due to lowered immune system function. The gut bacteria play a key role in human immune system function and there is an interest in a potential role for probiotics in strengthening the immune system through manipulation of the microbiome. This systematic review and meta-analysis of 4 randomised controlled trials aimed to examine the efficacy of Bifidobacterium animalis lactis HN019 on the cellular immune activity of healthy elderly adults age 60-70 years. The authors concluded that supplementation with this bacterial strain at a range of potencies for 3-6 weeks duration had a significant positive impact on the part of the immune system that is responsible for removing pathogens and cell debris (phagocytosis) and a lesser but nevertheless significant impact on natural killer cells responsible for tumour destruction.
Abstract
Elderly people have increased susceptibility to infections and cancer that are associated with decline in cellular immune function. The objective of this work was to determine the efficacy of Bifidobacterium (B.) animalis ssp. lactis HN019 (HN019) supplementation on cellular immune activity in healthy elderly subjects. We conducted a systematic review of Medline and Embase for controlled trials that reported polymorphonuclear (PMN) cell phagocytic capacity or natural killer (NK) cell tumoricidal activity following B. lactis HN019 consumption in the elderly. A random effects meta-analysis was performed with standardized mean difference (SMD) and 95% confidence interval between probiotic and control groups for each outcome. A total of four clinical trials were included in this analysis. B. lactis HN019 supplementation was highly efficacious in increasing PMN phagocytic capacity with an SMD of 0.74 (95% confidence interval: 0.38 to 1.11, p < 0.001) and moderately efficacious in increasing NK cell tumoricidal activity with an SMD of 0.43 (95% confidence interval: 0.08 to 0.78, p = 0.02). The main limitations of this research were the small number of included studies, short-term follow-up, and assessment of a single probiotic strain. In conclusion, daily consumption of B. lactis HN019 enhances NK cell and PMN function in healthy elderly adults.
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Saccharomyces cerevisiae CNCM I-3856 in irritable bowel syndrome: An individual subject meta-analysis.
Cayzeele-Decherf, A, Pélerin, F, Leuillet, S, Douillard, B, Housez, B, Cazaubiel, M, Jacobson, GK, Jüsten, P, Desreumaux, P
World journal of gastroenterology. 2017;23(2):336-344
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Irritable bowel syndrome (IBS) is a digestive disorder with various symptoms, affecting a significant number of the population. Gut bacteria are known to play a role in triggering the syndrome and research is exploring the manipulation of the gut microbiome in treating and managing symptoms. One yeast strain of interest is Saccharomyces Cerevisiae CNCM-I 3856. This meta-analysis of 2 randomised controlled trial, including 579 patients diagnosed with IBS, aimed to confirm previous conclusions on the effectiveness of supplementation of Saccharomyces Cerevisiae on typical IBS-C (constipation predominant IBS) symptoms. The pooled results showed a statistically significant improvement in abdominal pain, bloating and stool consistency when compared to placebo, after 2 months. It is important to note that positive effects were not reported after 1 month, but required 2 months of supplementation. When compiling nutrition protocols for IBS patients, Nutrition Practitioners need to take account of the length of intervention required to have the desired impact, as well as the choice of protocol itself.
Abstract
AIM: To confirm previous conclusions on Saccharomyces cerevisiae (S. cerevisiae) CNCM I-3856 for irritable bowel syndrome (IBS) management. METHODS An individual patient data meta-analysis was performed on two randomized clinical trials studying the effect of S. cerevisiae CNCM I-3856 supplementation on gastrointestinal (GI) symptoms in IBS subjects. A total of 579 IBS subjects were included. Outcomes were the daily Likert scale scores of abdominal pain/discomfort and bloating [area under the curve (AUC) and weekly means], responder status, and bowel movements (stool frequency and consistency). Statistical analyses were conducted in Intent to Treat (ITT) population, IBS-C subjects and IBS-C subjects with an abdominal pain/discomfort score higher than or equal to 2 at baseline ("IBS-C ≥ 2 subpopulation"). RESULTS S. cerevisiae CNCM I-3856 significantly improved abdominal pain/discomfort and bloating during the second month of supplementation [AUC (W5-W8)] with improvement up to the minimal clinically relevant threshold of 10%: a 12.3% reduction of abdominal pain/discomfort in the ITT population compared to the Placebo group (P = 0.0134) has been observed. In the IBS-C ≥ 2 subpopulation, there were a 13.1% reduction of abdominal pain/discomfort and a 14.9% reduction of bloating compared to the Placebo group (P = 0.0194 and P = 0.0145, respectively). GI symptoms significantly decreased during supplementation but no statistical differences were reported between groups at the end of the supplementation period. Responder status was defined as a subject who experienced a decrease of 1 arbitrary unit (a.u.) or 50% of the abdominal discomfort score from baseline for at least 2 wk out of the last 4 wk of the study. A significant difference between groups was reported in the ITT population, when considering the first definition: subjects in the Active group had 1.510 higher odds to be a responder (reduction of 1 a.u. of abdominal pain/discomfort) compared with subjects in the Placebo group (P = 0.0240). At the end of supplementation period, stool consistency in the Active group of the ITT population was significantly improved and classified as "normal" compared to Placebo (respectively 3.13 ± 1.197 a.u. vs 2.58 ± 1.020 a.u., P = 0.0003). Similar results were seen in the IBS-C ≥ 2 subpopulation (Active group: 3.14 ± 1.219 a.u. vs Placebo group: 2.59 ± 1.017 a.u., P = 0.0009). CONCLUSION This meta-analysis supports previous data linking S. cerevisiae I-3856 and improvement of GI symptoms, in IBS overall population and in the IBS-C and IBS-C ≥ 2 subpopulations.
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Impact of Probiotic Administration on Serum C-Reactive Protein Concentrations: Systematic Review and Meta-Analysis of Randomized Control Trials.
Mazidi, M, Rezaie, P, Ferns, GA, Vatanparast, H
Nutrients. 2017;9(1)
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C-reactive protein (CRP) is a blood marker of inflammation and is frequently elevated in chronic conditions such as heart disease, obesity and Type 2 diabetes. Some strains of probiotics (bacteria that exert health benefits) are thought to act as anti-inflammatory agents through various mechanisms. This systematic review and meta-analysis of 20 randomised controlled trials (RCTs) aimed to investigate the effects of probiotic supplementation on CRP levels as one measure of inflammation. The meta-analysis indicates that probiotic supplementation with various strains of bacteria has a significant impact on serum CRP levels, with a weighted mean difference of -1.35mg/l. Whilst positive impacts were also seen for interleukin-10 and tumour necrosis factor-alpha (other markers of inflammation) with probiotics, these did not reach significance. The authors of this study point out that the results need to be interpreted with caution owing to the wide variety of study types, study size, probiotic strains and health outcomes measured in the included RCTs. However, Nutrition Practitioners working with clients with raised CRP levels may want to investigate the use of certain probiotic strains as part of an anti-inflammatory protocol.
Abstract
We conducted this systematic review and meta-analysis of prospective studies to determine the effect of probiotic administration on serum C-reactive protein (CRP) concentrations. We searched PubMed-Medline, Web of Science, the Cochrane, and Google Scholar databases (until May 2016) to identify prospective studies evaluating the impact of probiotic administration on CRP. We used a random effects models and generic inverse variance methods to synthesize quantitative data, followed by a leave-one-out method for sensitivity analysis. The systematic review registration number was: CRD42016039457. From a total of 425 entries identified via searches, 20 studies were included in the final analysis. The meta-analysis indicated a significant reduction in serum CRP following probiotic administration with a weighted mean difference (WMD) of -1.35 mg/L, (95% confidence interval (CI) -2.15 to -0.55, I² 65.1%). The WMDs for interleukin 10 (IL10) was -1.65 pg/dL, (95% CI -3.45 to 0.14, I² 3.1%), and -0.45 pg/mL, (95% CI -1.38 to 0.48, I² 10.2%) for tumor necrosis factor alpha (TNF-α). These findings were robust in sensitivity analyses. This meta-analysis suggests that probiotic administration may significantly reduce serum CRP while having no significant effect on serum IL10 and TNF-α.
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Vitamin D receptor gene FokI but not TaqI, ApaI, BsmI polymorphism is associated with Hashimoto's thyroiditis: a meta-analysis.
Wang, X, Cheng, W, Ma, Y, Zhu, J
Scientific reports. 2017;7:41540
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Vitamin D is a vitamin that is involved in several immune processes within the body. It acts on immune cells through binding to vitamin D receptors (VDR) and modulating their activity. However genetic variations in VDRs is apparent amongst individuals, with the four most common being TaqI, ApaI, FokI and BsmI. The presence of any of these variations has been associated with the development of several different diseases. This systematic review and meta-analysis aimed to determine whether any of these variations in the VDR was associated with the development of Hashimoto’s thyroiditis (HT), a disease whereby the immune system does not recognise and attacks the body’s own tissues. The results showed that only the FokI variation was associated with the development of HT and only in individuals with Asian heritage. It was concluded that the FokI variation of the VDR is associated with an increased risk of HT in Asians but not Caucasians, however how this occurs is not fully understood. This study could be used by healthcare professionals to understand that genetic variations on the VDR may be indicative of risk of developing HT in individuals from Asian descent.
Abstract
Four VD receptor (VDR) gene polymorphisms (TaqI, ApaI, FokI and BsmI) have been reported to influence Hashimoto's thyroiditis (HT) risk. However, individual studies have produced inconsistent results. We conducted a comprehensive meta-analysis of eleven case-control studies to better understand roles of the four polymorphisms in HT development. The results showed only FokI polymorphism was significantly associated with the risk of HT (F vs f: OR = 1.44, 95% CI = 1.09-1.91, P = 0.010; FF vs Ff + ff: OR = 1.72, 95% CI = 1.09-2.70, P = 0.019). Subgroup analyses demonstrated the significant effect was only present in Asian population (F vs f: OR = 1.45, 95% CI = 1.07-1.95, P = 0.016; FF vs ff: OR = 1.64, 95% CI = 1.03-2.59, P = 0.036; FF + Ff vs ff: OR = 1.34, 95% CI = 1.00-1.80, P = 0.047; FF vs Ff + ff: OR = 1.64, 95% CI = 1.03-2.64, P = 0.039), but not in Caucasian. For TaqI, ApaI and BsmI polymorphisms, no significant association was found in any model comparison. Based on the current literature, it appears that only VDR FokI polymorphism is associated with HT risk in Asian population, but not in Caucasians; and the TaqI, ApaI and BsmI polymorphisms have not positive association neither in the overall population, nor when stratified by ethnicity. Further well-designed studies with larger sample sizes and different ethnic population are needed to clarify the present findings.
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Low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet improves symptoms in adults suffering from irritable bowel syndrome (IBS) compared to standard IBS diet: A meta-analysis of clinical studies.
Varjú, P, Farkas, N, Hegyi, P, Garami, A, Szabó, I, Illés, A, Solymár, M, Vincze, Á, Balaskó, M, Pár, G, et al
PloS one. 2017;12(8):e0182942
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Irritable bowel syndrome (IBS) is a common functional gut disorder causing a range of abdominal symptoms. A diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) is the main therapeutic approach for reducing IBS symptoms. The aim of this systematic review was to analyse the effects of a low-FODMAP diet on IBS symptoms and quality of life, based on the IBS Symptom Severity Score (IBS-SSS). Ten publications qualified for this meta-analysis and according to these studies, a low-FODMAP diet demonstrated a significant reduction in symptoms according to the IBS-SSS. Based on these results, the authors conclude there is high-grade evidence to recommend a low-FODMAP diet as a first-line therapeutic modality for IBS patients.
Abstract
BACKGROUND Irritable bowel syndrome (IBS) and functional digestive tract disorders, e.g. functional bloating, carbohydrate maldigestion and intolerances, are very common disorders frequently causing significant symptoms that challenge health care systems. A low Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols (FODMAP) diet is one of the possible therapeutic approaches for decreasing abdominal symptoms and improving quality of life. OBJECTIVES We aimed to meta-analyze data on the therapeutic effect of a low-FODMAP diet on symptoms of IBS and quality of life and compare its effectiveness to a regular, standard IBS diet with high FODMAP content, using a common scoring system, the IBS Symptom Severity Score (IBS-SSS). METHODS A systematic literature search was conducted in PubMed, EMBASE and the Cochrane Library as well as in the references in a recent meta-analysis. Adult patients diagnosed with IBS according to the Rome II, Rome III, Rome IV or NICE criteria were included in the analysis. STATISTICAL METHODS Mean differences with 95% confidence intervals were calculated from studies that contained means, standard deviation (SD) or mean differences and SD of differences and p-values. A random effect model was used because of the heterogeneity (Q test (χ2) and I2 indicator). A p-value of less than 0.05 was chosen to indicate a significant difference. RESULTS The literature search yielded 902 publications, but only 10 were eligible for our meta-analysis. Both regular and low-FODMAP diets proved to be effective in IBS, but post-diet IBS-SSS values were significantly lower (p = 0.002) in the low-FODMAP group. The low-FODMAP diet showed a correlation with the improvement of general symptoms (by IBS-SSS) in patients with IBS. CONCLUSIONS This meta-analysis provides high-grade evidence of an improved general symptom score among patients with irritable bowel syndrome who have maintained a low-FODMAP diet compared to those on a traditional IBS diet, therefore showing its superiority to regular IBS dietary therapy. These data suggest that a low-FODMAP diet with dietitian control can be a candidate for first-line therapeutic modality in IBS. Because of a lack of data, well-planned randomized controlled studies are needed to ascertain the correlation between improvement of separate key IBS symptoms and the effect of a low-FODMAP diet.