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Effect of prebiotics, probiotics, synbiotics on depression: results from a meta-analysis.
Zhang, Q, Chen, B, Zhang, J, Dong, J, Ma, J, Zhang, Y, Jin, K, Lu, J
BMC psychiatry. 2023;23(1):477
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Major depressive disorder (MDD) is a mood disorder that impairs psychosocial function and quality of life. Recent studies show that prebiotics, probiotics, and synbiotics reveal a novel way to treat psychiatric disorders such as depression through the microbiota-gut-brain axis. The aim of this study was to evaluate the effectiveness of prebiotics, probiotics and synbiotics in alleviating depressive symptoms. This study was a meta-analysis of thirteen studies with a total of 786 participants who were allocated to the intervention group (n=427) and the placebo group (n=359). Results showed that the overall effects of probiotics, prebiotics and synbiotics on depressive symptoms were significantly superior to those of placebo. Additionally, biological sex was a vital factor that influenced patients’ responses to the treatment. Authors concluded that agents that manipulate gut microbiota might become a novel approach to treat patients with mild-to-moderate depression.
Abstract
Accumulating studies have shown the effects of gut microbiota management tools in improving depression. We conducted a meta-analysis to evaluate the effects of prebiotics, probiotics, and synbiotics on patients with depression. We searched six databases up to July 2022. In total, 13 randomized controlled trials (RCTs) with 786 participants were included. The overall results demonstrated that patients who received prebiotics, probiotics or synbiotics had significantly improved symptoms of depression compared with those in the placebo group. However, subgroup analysis only confirmed the significant antidepressant effects of agents that contained probiotics. In addition, patients with mild or moderate depression could both benefit from the treatment. Studies with a lower proportion of females reported stronger effects for alleviating depressive symptoms. In conclusion, agents that manipulate gut microbiota might improve mild-to-moderate depression. It is necessary to further investigate the benefits of prebiotic, probiotic and synbiotic treatments relative to antidepressants and follow up with individuals over a longer time before these therapies are implemented in clinical practice.
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Blood levels of circulating methionine components in Alzheimer's disease and mild cognitive impairment: A systematic review and meta-analysis.
Zhao, Y, Dong, X, Chen, B, Zhang, Y, Meng, S, Guo, F, Guo, X, Zhu, J, Wang, H, Cui, H, et al
Frontiers in aging neuroscience. 2022;14:934070
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Alzheimer’s disease (AD) is a chronic neurodegenerative disease that is characterized by progressive memory loss and cognitive deficits. Mild cognitive impairment (MCI) is a prodromal form of AD that is characterised by neurocognitive dysfunction. However, pathological changes associated with AD begin to occur in the brain at least 10 years before the onset of overt symptoms and clinical manifestations, making the discovery of early diagnostic methods and timely interventions important for AD management. The aim of this study was to determine the relationship between circulating methionine (Met) components and AD/MCI. This study is a systematic review and meta-analysis of thirty studies (10 case– control studies, 10 cohort studies, and 10 cross-sectional studies). Results show that: - individuals with AD compared with controls had significantly increased levels of homocysteine. - for people with MCI, there was no significant difference in blood homocysteine levels in the control group. - there were no differences in blood vitamin B12 levels between patients with AD or MCI and controls. Authors conclude that circulating Met components affect patients with AD compared to cognitively normal individuals, with patients exhibiting higher blood homocysteine levels. Additionally, high Met and S-adenosylmethionine levels are risk factors for AD, which supports the association between Met cycle components and AD/MCI.
Abstract
BACKGROUND Circulating methionine components have been reported to be associated with Alzheimer's disease (AD) and mild cognitive impairment (MCI), although outcomes are not always consistent. MATERIALS AND METHODS Database searching was conducted using PubMed, Embase, Cochrane Library, and Web of Science from inception to 26 December 2021. In this study, two reviewers independently identified eligible articles and extracted the data. We used Joanna Briggs Institute (JBI) Critical Appraisal tools to assess the overall quality of the included studies. STATA software was employed to perform meta-analysis evaluating the standardized mean difference (SMD) with its 95% confidence intervals (CIs) using random-effects models. Evidence quality was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria. RESULTS Totally, 30 observational studies were eligible for inclusion. Compared with cognitively normal controls, patients with AD had increased homocysteine (Hcy) levels in the blood [standardized mean difference (SMD) = 0.59, 95% confidence interval [CI]: 0.36-0.82, P = 0.000], plasma (SMD = 0.39, 95% CI: 0.23-0.55, P = 0.000), and serum (SMD = 1.56, 95% CI: 0.59-2.95, P = 0.002). Patients with MCI were not significantly different from controls (SMD = 0.26, 95% CI: -0.07-0.58, P = 0.127). Patients with AD or MCI did not significantly differ from controls of blood vitamin B12 levels, AD (SMD = -0.05, 95% CI: -0.19-0.08, P = 0.440), or MCI (SMD = 0.01, 95% CI: -0.16-0.17, P = 0.94). Some cohort studies have suggested that higher Hcy, methionine, and S-adenosylmethionine levels may accelerate cognitive decline in patients with MCI or AD, and vitamin B12 deficiency is a risk factor for the disease; however, the results of other studies were inconsistent. According to the GRADE system, all these outcomes scored very low to low quality, and no high-quality evidence was found. CONCLUSION Only Hcy levels in the plasma and serum were found to be inversely related to the risk of AD. However, due to the low quality of supporting these results, high-quality studies are needed to verify these findings. SYSTEMATIC REVIEW REGISTRATION http://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022308961.
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Effects of Fermented Milk Containing Lacticaseibacillus paracasei Strain Shirota on Constipation in Patients with Depression: A Randomized, Double-Blind, Placebo-Controlled Trial.
Zhang, X, Chen, S, Zhang, M, Ren, F, Ren, Y, Li, Y, Liu, N, Zhang, Y, Zhang, Q, Wang, R
Nutrients. 2021;13(7)
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Constipation is a common complaint among people with depression and may negatively affect their quality of life. In association with this, previous studies have shown a correlation between the reduction of Lactobacillus or Bifidobacterium strains in the gut of patients with major depressive disorder. Thus, this two-arm, parallel-design, randomised, double-blinded, placebo-controlled trial examined the effects of supplementing fermented milk with Lacticaseibacillus paracasei Strain Shirota or LcS (previously known as Lactobacillus casei strain Shirota) on constipation in people with depression. Symptoms of constipation, stool problems, and depressive symptoms improved after 9 weeks of consuming fermented milk containing LcS. The abundance of Adlercreutzia, Megasphaera, and Veillonella increased significantly in the intervention group. In contrast, the abundance of bacteria related to mental disorders such as Rikenellaceae_RC9_gut_group, Sutterella and Oscillibacter significantly decreased after the intervention. After 9 weeks of intervention with LcS, a significant reduction in serum proinflammatory cytokines such as IL-1β, IL-6, and TNF-α was observed in patients with depression. The intervention group also showed a decrease in inflammation-causing bacteria, Surrerella, which correlated with a reduction in proinflammatory cytokines. The mechanisms driving the changes in gut microbial composition, depression, and gastrointestinal symptoms after LcS intervention need to be evaluated in more robust studies. Healthcare professionals can use the results of the study to better understand how probiotics can reduce constipation and depression and improve gut microbial composition.
Abstract
Probiotics have been shown to benefit patients with constipation and depression, but whether they specifically alleviate constipation in patients with depression remains unclear. The aim of this study was to investigate the effect of Lacticaseibacillus paracasei strain Shirota (LcS), formerly Lactobacillus casei strain Shirota, on constipation in patients with depression with specific etiology and gut microbiota and on depressive regimens. Eighty-two patients with constipation were recruited. The subjects consumed 100 mL of a LcS beverage (108 CFU/mL) or placebo every day for 9 weeks. After ingesting beverages for this period, we observed no significant differences in the total patient constipation-symptom (PAC-SYM) scores in the LcS group when compared with the placebo group. However, symptoms/scores in item 7 (rectal tearing or bleeding after a bowel movement) and items 8-12 (stool symptom subscale) were more alleviated in the LcS group than in the placebo group. The Beck Depression Index (BDI) and Hamilton Depression Rating Scale (HAMD) scores were all significantly decreased, and the degree of depression was significantly improved in both the placebo and LcS groups (p < 0.05), but there was no significant difference between the groups. The LcS intervention increased the beneficial Adlercreutzia, Megasphaera and Veillonella levels and decreased the bacterial levels related to mental illness, such as Rikenellaceae_RC9_gut_group, Sutterella and Oscillibacter. Additionally, the interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) levels were significantly decreased in both the placebo and LcS groups (p < 0.05). In particular, the IL-6 levels were significantly lower in the LcS group than the placebo group after the ingestion period (p < 0.05). In conclusion, the daily consumption of LcS for 9 weeks appeared to relieve constipation and improve the potentially depressive symptoms in patients with depression and significantly decrease the IL-6 levels. In addition, the LcS supplementation also appeared to regulate the intestinal microbiota related to mental illness.