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Updated Review and Meta-Analysis of Probiotics for the Treatment of Clinical Depression: Adjunctive vs. Stand-Alone Treatment.
Nikolova, VL, Cleare, AJ, Young, AH, Stone, JM
Journal of clinical medicine. 2021;10(4)
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Major depressive disorder is a common, complex, and heterogeneous illness that is characterized by persistent low mood and anhedonia, and a combination of sleep disturbances, changes in appetite, feelings of worthlessness or guilt, poor concentration, and suicidal ideation. The aim of this study was to identify and evaluate all current evidence from randomised controlled trials on the efficacy of probiotics in reducing depressive symptoms among people with clinical depression. This study is a review and meta-analysis of randomised controlled trials which included seven studies for qualitative and quantitative analysis. Results demonstrate that probiotics significantly reduce depressive symptoms after eight weeks of use, but only when used in addition to an approved antidepressant. Authors conclude that their findings support the clinical use of probiotics in depressed populations and provides an insight into the mode of administration more likely to yield antidepressant effects.
Abstract
Recent years have seen a rapid increase in the use of gut microbiota-targeting interventions, such as probiotics, for the treatment of psychiatric disorders. The objective of this update review was to evaluate all randomised controlled clinical trial evidence on the efficacy of probiotics for clinical depression. Cochrane guidelines for updated reviews were followed. By searching PubMed and Web of Science databases, we identified 546 new records since our previous review. A total of seven studies met selection criteria, capturing 404 people with depression. A random effects meta-analysis using treatment type (stand-alone vs. adjunctive) as subgroup was performed. The results demonstrated that probiotics are effective in reducing depressive symptoms when administered in addition to antidepressants (SMD = 0.83, 95%CI 0.49-1.17), however, they do not seem to offer significant benefits when used as stand-alone treatment (SMD = -0.02, 95%CI -0.34-0.30). Potential mechanisms of action may be via increases in brain-derived neurotrophic factor (BDNF) and decreases in C-reactive protein (CRP), although limited evidence is available at present. This review offers stronger evidence to support the clinical use of probiotics in depressed populations and provides an insight into the mode of administration more likely to yield antidepressant effects.
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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.