Effects of flaxseed supplementation on inflammatory biomarkers: A GRADE-assessed systematic review and meta-analysis of randomized controlled trials.

Several studies reported the benefits of flaxseed on inflammatory biomarkers, while others reported conflicting findings. Thus, the aim of this meta-analysis was to assess the impacts of flaxseed on inflammatory biomarkers in adults. Databases including Embase, PubMed, Scopus, and Web of Sciences were searched till February 2024. The 54 RCTs were included in the final analysis, which involved 3000 individuals from 12 countries. Overall, the flaxseed supplementation had a significant reduction in C-reactive protein (CRP) (SMD = -0.46; 95 % CI: -0.70, -0.23, P < 0.001; I2 = 82.9 %, P < 0.001), and interleukin 6 (IL-6) (SMD = -0.64, 95 % CI: -1.13, -0.16, P = 0.010; I2 = 92.7, P < 0.001). Furthermore, flaxseed did not significantly change the concentration of tumor necrosis factor α (TNF-α) (SMD = -0.17; 95 % CI: -0.63, 0.29, P = 0.467; I2 = 92, P < 0.001). Flaxseed supplementation significantly decreased serum concentrations of CRP and IL-6, but not TNF-a. Thus, this meta-analysis suggests that the current evidence supports the potential benefits of flaxseed in managing inflammatory conditions.

The effects of flaxseed (Linum usitatissimum) supplementation on anthropometric indices: An updated systematic review and meta-analysis of randomized clinical trials.

OBJECTIVE: Flaxseed (Linum usitatissimum) supplementation has shown promise as an anti-obesity agent in various clinical trials, although results have been inconsistent. To provide a more accurate assessment of the impact of flaxseed supplementation on anthropometric indices, a systematic review and meta-analysis was performed. METHODS: We searched several international databases until August 2023, including Scopus, PubMed, Web of Science, Embase, and Cochrane Library. Weighted mean differences (WMDs) were analyzed using a random-effects model. RESULTS: Sixty-four trials comprising 72 treatment arms were included. All studies reported the intervention types (Lignans, Whole flaxseed, and Flaxseed oil) and dosage. However, three studies did testing for purity, and 40 studies reported potency. Also, the risk of contamination with heavy metals was not mentioned in studies. Another limitation was the lack of blind evaluation in the studies. According to three trials included in the systematic review, flaxseed did not affect anthropometric indices. Our meta-analysis revealed significant reductions in body weight (WMD = -0.63 kg; 95 % CI: -1.00, -0.27, P < 0.001; I2 = 76.7 %, P < 0.001), body mass index (BMI) (WMD: -0.24 kg/m2, 95 % CI: -0.36, -0.11, P < 0.001; I2 = 78.5 %, P < 0.001) and waist circumference (WC) (WMD: -1.43 cm, 95 % CI: -2.06, -0.80, P < 0.001; I2 = 81.1 %, P < 0.001) following flaxseed supplementation. Subgroup analyses indicated that interventions lasting 10-20 weeks, and studies involving subjects with higher BMI (>30 kg/m2) showed more significant anti-obesity effects. Based on the GRADE evaluation, body weight, BMI, and WC results were considered as moderate-certainty evidence. CONCLUSION: Our systematic review and meta-analysis suggests that supplementation with flaxseed (Linum usitatissimum) leads to meaningful improvements in body weight, BMI, and WC. Therefore, flaxseed can be considered as an adjunctive therapeutic approach in improving obesity.

The effects of curcumin supplementation on biomarkers of inflammation, oxidative stress, and endothelial function: A meta-analysis of meta-analyses.

Numerous interventional studies have revealed the beneficial impact of curcumin supplementation on inflammation, oxidative stress, and endothelial function biomarkers, but the findings are still inconsistent. Thus, this study was conducted to investigate the effects of curcumin supplementation on inflammation, oxidative stress, and endothelial function biomarkers. A meta-analyses of randomized clinical trials was performed by searching PubMed, Embase, Scopus, and Web of Science up to March 31, 2024. Pooled estimates of 21 meta-analyses revealed that curcumin significantly reduced CRP (weighted mean difference (WMD) = -0.87; 95 % CI: - 1.14, - 0.59, P< 0.001), tumor-necrosis factor-alpha (TNF-α) (WMD = -2.72; 95 % CI: -4.05, -1.38; P< 0.001), interleukin-6 (IL-6) (WMD = -0.97, 95 % CI: -1.40, -0.54; P< 0.001), malondialdehyde (MDA) (Effect size (ES) = -0.81; 95 % CI: -1.39, -0.23, P = 0.006) and pulse wave velocity (PWV) (WMD = -45.60; 95 % CI: -88.16, -3.04, P = 0.036), and increased flow-mediated dilation (FMD) (WMD = 1.64, 95 % CI: 1.06, 2.22, P < 0.001), catalase (CAT) (WMD = 10.26; 95 % CI: 0.92, 19.61, P= 0.03), glutathione peroxidase (GPx) (WMD = 8.90; 95 % CI: 6.62, 11.19, P <0.001), and superoxide dismutase (SOD) levels (WMD = 20.51; 95 % CI: 7.35, 33.67, P= 0.002 and SMD = 0.82; 95 % CI: 0.27, 1.38, P= 0.004). However, curcumin did not significantly change total antioxidant capacity (TAC) (ES = 0.29; 95 % CI: -0.09, 0.66, P= 0.059). These results suggest that curcumin has a beneficial effect on CRP, IL-6, TNF-α, SOD, GPx, CAT, MDA, PWV, and FMD levels and may be an effective adjunctive therapy for improving inflammation, oxidative stress, and endothelial function. Registration number: PROSPERO, CRD42024539018.

The effects of policosanol supplementation on blood glucose: A systematic review and dose-response meta-analysis of randomized controlled trials.

Previous studies have assessed how supplementing with policosanol affects blood sugar levels. The outcomes, nevertheless, were not constant. Multiple electronic databases were searched including ISI Web of Science, Cochrane Library, PubMed, Google Scholar, and Scopus until February 9, 2023. To assess the effects of policosanol on glucose, we employed a random-effects or fixed-effects meta-analysis approach to examine the weighted mean differences (WMDs) and associated 95 % confidence intervals (CI) before and after policosanol and placebo administration. The final analysis comprised a total of 25 trials with 2680 participants. Compared to the control group, policosanol supplementation significantly reduced blood glucose levels (WMD: -2.24 mg/dl; 95 % CI: -4.05, -0.42, P = 0.01). Findings from subgroup analysis revealed a significant reduction of policosanol supplementation on glucose levels in period of less than 24 weeks, and in individuals below 50 years of age. Additionally, the reduction was statistically significant in dosage of 10 mg/day. Our dose-response analysis indicates no evidence of a non-linear relationship between policosanol dose and duration and changes in glucose levels (P-nonlinearity = 0.52, and P-nonlinearity = 0.52, respectively). Policosanol supplementation might improve blood glucose. Further trials with more complex designs are required to confirm the findings.

Effects of Nigella sativa supplementation on lipid profiles in adults: An updated systematic review and meta-analysis of randomized controlled trials.

BACKGROUND AND AIM: Several experiments have suggested that Nigella sativa (N. sativa) supplementation may have a beneficial effect on the lipid profile. However, the results from these trials have been inconclusive. Therefore, this study aimed to explore the impact of N. sativa supplementation on the lipid profile of adult participants. METHODS: We searched Scopus, Web of Science, PubMed, Cochrane, and Web of Science databases until December 2022. Random effects models were used, and pooled data were determined as standardized mean differences with a 95% confidence interval. RESULTS: The findings of 34 studies with 2278 participants revealed that N. sativa supplementation significantly reduced total cholesterol (TC) (SMD: -1.78; 95% CI: -2.20, -1.37, p < 0.001), triglycerides (TG) (SMD: -1.2725; 95% CI: -1.67, -0.83, p < 0.001), and low-density lipoprotein cholesterol (LDL-C) (SMD: -2.45; 95% CI: -3.06, -1.85; p < 0.001) compared to control groups. However, a significant increase was found in high-density lipoprotein cholesterol (HDL-C) (SMD: 0.79; 95% CI: 0.38, 1.20, p < 0.001). CONCLUSION: N. sativa has improved effects on TG, LDL-C, TC, and HDL-C levels. Overall, N. sativa may be suggested as an adjuvant anti-hyperlipidemic agent.

The effect of cinnamon supplementation on glycemic control in patients with type 2 diabetes mellitus: An updated systematic review and dose-response meta-analysis of randomized controlled trials.

Although many randomized controlled trials (RCTs) have revealed the benefits of cinnamon on type 2 diabetes mellitus (T2DM), the effects of cinnamon supplementation on glycemic control in patients with T2DM are inconclusive. Therefore, the aim of this meta-analysis of RCTs was to assess the effects of cinnamon supplementation in managing glycemic control in patients with T2DM. Scientific international databases including Scopus, Web of Sciences, PubMed, Embase, and the Cochrane Library were searched till December 2022. For net changes in glycemic control, standard mean differences (SMDs) were calculated using random-effects models. Findings from 24 RCTs revealed that cinnamon supplementation had a statistically significant reduction in fasting blood sugar (SMD: -1.32; 95% CI: -1.77, -0.87, p < 0.001), Homeostatic Model Assessment for Insulin Resistance (SMD: -1.32; 95% CI: -1.77, -0.87, p < 0.001), and hemoglobin A1C (SMD: -0.67; 95% CI: -1.18, -0.15, p = 0.011) compared with the control group in patients with T2DM. Additionally, cinnamon did not change the serum levels of insulin (SMD: -0.17; 95% CI: -0.34, 0.01, p = 0.058) significantly. Our analysis indicated that glycemic control indicators are significantly decreased by cinnamon supplementation. Together, these findings support the notion that cinnamon supplementation might have clinical potential as an adjunct therapy for managing T2DM.

The effect of curcumin supplementation on circulating adiponectin and leptin concentration in adults: a GRADE-assessed systematic review and meta-analysis of randomised controlled trials.

Curcumin is a phytocompound found in the root of turmeric, a common herbal ingredient in many Asian cuisines. The compound contains anti-inflammatory activity, which is mediated through an upregulation of adiponectin and reduction of leptin. Results of randomised controlled trials (RCT) have shown that the effects of curcumin on adipokines are conflicting. Therefore, the current systematic review and meta-analysis of RCT were conducted with the aim of elucidating the role of curcumin supplementation on serum adiponectin and leptin. The search included PubMed, Embase, Cochrane Library, Scopus, Web of Science and Google Scholar from inception to August 2023. For net changes in adipokines, standardised mean differences (SMD) were calculated using random effects models. Thirteen RCT with fourteen treatment arms were eligible for inclusion in this meta-analysis. Curcumin supplementation was effective in increasing serum adiponectin (SMD = 0·86, 95 % CI (0·33, 1·39), P < 0·001; I2 = 93·1 %, P < 0·001) and reducing serum leptin (SMD = -1·42, 95 % CI (-2·29, -0·54), P < 0·001; I2 = 94·7 %, P < 0·001). In conclusion, curcumin supplementation significantly increased circulating adiponectin and decreased leptin levels in adults.

The role of probiotic supplementation in inflammatory biomarkers in adults: an umbrella meta-analysis of randomized controlled trials.

OBJECTIVE: Despite the increasing evidence for probiotics' anti-inflammatory effects, the results of meta-analyses remain inconsistent. The present umbrella meta-analysis aimed to investigate the effects of probiotic supplementation on inflammatory biomarkers. METHODS: We performed a wide-ranging systematic search in several databases, including PubMed, Web of Science, Scopus, EMBASE, and Google Scholar up to April 2023. The overall effect sizes were calculated using effect size (ES) values and their corresponding confidence intervals (CI). RESULTS: Out of a total of 580 related articles, 39 studies were qualified for inclusion in the analysis. The results of the analysis revealed a significant reduction of C-reactive protein (CRP) (ES = -1.02; 95% CI: -1.23, -0.80, p < 0.001; I2: 94.1%, p < 0.001), TNF-α (ES = -0.35; 95% CI: -0.50, -0.20, p < 0.001; I2: 75.6%, p < 0.001), and interleukin-6 (IL-6) levels (ES = -0.36; 95% CI: -0.59, -0.13, p = 0.002; I2: 85.6%, p < 0.001), following probiotic supplementation. CONCLUSION: Probiotic supplementation significantly reduced serum concentrations of TNF-a, CRP, and IL-6. Thus, probiotic supplementation can be considered adjuvant therapy to alleviate inflammation in various inflammatory conditions.

The effect of L-carnitine supplementation on lipid profile in adults: an umbrella meta-analysis on interventional meta-analyses.

Introduction: Previous meta-analyses investigating the therapeutic effects of L-carnitine on lipid profiles have demonstrated inconsistent results. The present umbrella meta-analysis aimed to investigate the impact of efficacy of L-carnitine on lipid profiles in adults. Methods: Databases including PubMed, Scopus, and Embase, Web of Science, and Google Scholar were searched up to June 2023. Meta-analysis was performed using a random-effects model. Results: Our results from thirteen meta-analyses indicated that L-carnitine supplementation significantly total cholesterol (TC) (ES = -1.05 mg/dL, 95% CI: -1.71, -0.39; p = 0.002), triglycerides (TG) (ES = -2.51 mg/dL; 95% CI: -3.62, -1.39, p < 0.001), and low-density lipoprotein-cholesterol (LDL-C) (ES = -4.81 mg/dL; 95% CI: -6.04, -3.59; p < 0.001). It also increased high-density lipoprotein-cholesterol (HDL-C) (ES: 0.66 mg/dL, 95% CI: 0.20, 1.12, p = 0.005) levels. Conclusion: The present umbrella meta-analysis suggests supplementation with L-carnitine in a dosage of more than 2 g/day can improve lipid profile. Thus, L-carnitine supplementation can be recommended as an adjuvant anti-hyperlipidemic agent.

Alleviating effects of coenzyme Q10 supplements on biomarkers of inflammation and oxidative stress: results from an umbrella meta-analysis.

Introduction: Although several meta-analyses support the positive effect of coenzyme Q10 (CoQ10) on biomarkers of oxidative stress and inflammation, the results of some other studies reject such effects. Methods: Therefore, in this umbrella meta-analysis, we performed a comprehensive systematic search in such databases as Web of Science, PubMed, Scopus, Embase, and Google Scholar up to January 2023. Results: Based on standardized mean difference analysis, CoQ10 supplementation significantly decreased serum C-reactive protein (CRP) (ESSMD = -0.39; 95% CI: 0.77, -0.01, p = 0.042) and malondialdehyde (MDA) (ESSMD = -1.17; 95% CI: 1.55, -0.79, p < 0.001), while it increased the total antioxidant capacity (TAC) (ESSMD = 1.21; 95% CI: 0.61, 1.81, p < 0.001) and serum superoxide dismutase (SOD) activity (ESSMD = 1.08; 95% CI: 0.37, 1.79, p = 0.003). However, CoQ10 supplementation had no significant reducing effect on tumor-necrosis factor-alpha (TNF- α) (ESSMD = -0.70; 95% CI: 2.09, 0.68, p = 0.320) and interleukin-6 (IL-6) levels (ESSMD = -0.85; 95% CI: 1.71, 0.01, p = 0.053). Based on weighted mean difference analysis, CoQ10 supplementation considerably decreased TNF-α (ESWMD = -0.46, 95% CI: 0.65, -0.27; p < 0.001), IL-6 (ESWMD = -0.92, 95% CI: 1.40, -0.45; p < 0.001), and CRP levels (effect sizes WMD = -0.28, 95% CI: 0.47, -0.09; p < 0.001). Discussion: The results of our meta-analysis supported the alleviating effects of CoQ10 on markers of inflammation cautiously. However, CoQ10 had antioxidant effects regarding the improvement of all the studied antioxidant and oxidative stress biomarkers. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=323861, identifier CRD42022323861.

The effectiveness of treatment with probiotics in Helicobacter pylori eradication: results from an umbrella meta-analysis on meta-analyses of randomized controlled trials.

Background and aims: The purpose of this umbrella meta-analysis was to quantitatively summarize meta-analyses of randomized controlled trial (RCT) studies regarding the effects of probiotic supplementation on Helicobacter pylori (H. pylori) eradication. Methods: A thorough search of the electronic databases including PubMed, Web of Science, Embase, Scopus, and Google Scholar was carried out from the inception up to May 2022. For the evaluation of overall effect sizes, the pooled relative risk (RR) or odds ratio (OR) and their corresponding 95% confidence intervals (CI) were calculated. The random-effects model was used for the meta-analysis. Results: Overall, 18 eligible studies (47 278 participants in total) were included in the study. The findings revealed that probiotics have a beneficial impact on H. pylori eradication (pooled ESRR: 1.13; 95% CI: 1.11, 1.14, p < 0.01, and ESOR = 1.86, 95% CI: 1.70, 2.03, p < 0.01). Greater effects on H. pylori eradication were observed when higher doses (>10 × 1010 CFU) and mixed strains were supplemented. Conclusion: The present umbrella meta-analysis suggests that supplementation with probiotics may be considered as an efficient approach to ameliorate H. pylori complications, particularly probiotics with higher CFUs and mixed strains.

Antihypertensive effects of Nigella sativa supplementation: An updated systematic review and meta-analysis of randomized controlled trials.

Clinical studies have suggested that Nigella Sativa (N. sativa) supplementation may effectively reduce blood pressure, but the findings are controversial. Therefore, this study aimed to examine the effects of N. sativa on blood pressure in adults. PubMed, Cochrane Library, Web of Science, Scopus, Embase databases, and Google Scholar were searched till August 2022. To analyze weighted mean differences (WMDs), a random-effects model was utilized. Nonlinear dose-response analysis and a meta-regression were conducted. N. sativa supplementation was effective in reducing both systolic (WMD: -3.06 mmHg; 95% CI: -3.89 to -2.22, p < 0.001; I2 = 84.7%, p < 0.001) and diastolic blood pressure (WMD = -2.69 mmHg; 95% CI: -3.72, -1.66, p < 0.001; I2 = 97.3%, p < 0.001). The current meta-analysis suggests that N. sativa supplementation can improve blood pressure and claims that N. sativa could be used as an effective approach to blood pressure management.

The effect of Nigella sativa (black seed) on biomarkers of inflammation and oxidative stress: an updated systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: This study was conducted to assess the effect of Nigella sativa (N. sativa) supplementation on inflammatory and oxidative markers among the adult population. METHODS: We carried out a comprehensive, systematic search of Scopus, Embase, Cochrane Library, Web of Science, PubMed, and Google Scholar till December 2022. A random-effects model was used to estimate the overall effect size. RESULTS: In total, twenty trials consisting of 1086 participants were included in the meta-analysis. Findings from 20 RCTs included in the meta-analysis suggest that N. sativa supplementation could significantly reduce serum C-reactive protein (CRP) (SMD = - 2.28; 95% CI - 3.20, - 1.37, p < 0.001), tumour necrosis factor α (TNFα) (SMD = - 1.21; 95% CI - 2.15, - 0.26; p = 0.013), and malondialdehyde (MDA) (SMD = - 2.15; 95% CI - 3.37, - 0.93, p < 0.001) levels, and significantly improves total antioxidant capacity (TAC) (SMD = 2.28; 95% CI 1.29, 3.27, p < 0.001), glutathione peroxidase (GPx) (SMD = 1.23, 95% CI 0.25, 2.22; p = 0.014) and superoxide dismutase (SOD) (SMD = 2.05; 95% CI 1.22, 2.88, p < 0.001) levels. However, no significant reduction was found in interleukin 6 (IL-6) levels (SMD = - 1.13; 95% CI - 2.72, 0.46, p = 0.162). CONCLUSION: N. sativa supplementation had beneficial effects on CRP, TNF-α, MDA, SOD, GPx, and TAC. Thus, Nigella sativa can be recommended as an adjuvant anti-oxidant agent and anti-inflammatory.

Effect of vitamin D supplementation on type 2 diabetes biomarkers: an umbrella of interventional meta-analyses.

BACKGROUND: Vitamin D supplementation exerts several supporting effects on improving glycemic status, however, results are inconclusive. Thus, in the present study, we aimed to conduct an umbrella of meta-analysis regarding the impact of vitamin D on type 2 diabetes (T2DM) biomarkers. METHODS: The Scopus, PubMed, Web of Science, Embase, and Google Scholar online databases were searched up to March 2022. All meta-analyses evaluating the impact of vitamin D supplementation on T2DM biomarkers were considered eligible. Overall, 37 meta-analyses were included in this umbrella meta-analysis. RESULTS: Our findings indicated that vitamin D supplementation significantly decreased fasting blood sugar (FBS) (WMD = - 3.08; 95% CI: - 3.97, - 2.19, p < 0.001, and SMD = - 0.26; 95% CI: - 0.38, - 0.14, p < 0.001), hemoglobin A1c (HbA1c) (WMD = - 0.05; 95% CI: - 0.10, - 0.01, p = 0.016, and SMD = - 0.16; 95% CI: - 0.27, - 0.05, p = 0.004), insulin concentrations (WMD = - 2.62; 95% CI: - 4.11, - 1.13; p < 0.001, and SMD = - 0.33; 95% CI: - 0.56, - 0.11, p = 0.004), and homeostatic model assessment for insulin resistance (HOMA-IR) (WMD = - 0.67; 95% CI: - 1.01, - 0.32, p < 0.001, and SMD = - 0.31; 95% CI: - 0.46, - 0.16, p < 0.001). CONCLUSION: This umbrella meta-analysis proposed that vitamin D supplementation may improve T2DM biomarkers.

The effects of camelina sativa oil and high-intensity interval training on liver function and metabolic outcomes in male type 2 diabetic rats.

Objectives: The purpose of this study was to evaluate the independent and combined effects of camelina sativa oil and high-intensity interval training (HIIT) on liver function, and metabolic outcomes in streptozotocin-induced diabetic rats. Methods: Forty male Wistar rats were randomly assigned to five equal groups (8 per group): Normal control (NC), diabetic control (DC), diabetic + camelina sativa oil (300 mg/kg by oral gavage per day; D + CSO), diabetic + HIIT (running on a treadmill 5 days/week for 8 weeks; D + HIIT), diabetic + camelina sativa oil + HIIT (D + CSO + HIIT). Results: In all three intervention groups (D + CSO, D + HIIT, and D + CSO + HIIT) compared to the DC, hepatic TNF-α, MDA, and histopathology markers, decreased and hepatic PGC-1α, and PPAR-γ increased (p < 0.05). However, the effect of D + CSO was greater than D + HIIT alone. Hepatic TG decreased significantly in D + HIIT and D + CSO + HIIT compared to other groups (p < 0.001). Fasting plasma glucose in all three intervention groups (D + CSO, D + HIIT, and D + CSO + HIIT) and HOMA-IR in D + CSO and D + CSO + HIIT were decreased compared to DC (p < 0.001). Only hepatic TAC and fasting plasma insulin remained unaffected in the three diabetic groups (p < 0.001). Overall, D + CSO + HIIT had the largest effect on all outcomes. Conclusions: At the doses and treatment duration used in the current study, combination of CSO and HIIT was beneficial for reducing liver function and metabolic outcomes other than CSO and HIIT alone.

Effects of probiotics supplementation on blood pressure: An umbrella meta-analysis of randomized controlled trials.

AIMS: Several meta-analyses have revealed that probiotics could lower blood pressure (BP), but the findings were inconsistent. In this regard, an umbrella meta-analysis was carried out to provide a more accurate estimate of the overall impacts of probiotics supplementation on BP. DATA SYNTHESIS: We searched the following international databases till November 2021: PubMed, Scopus, EMBASE, Web of Science, and Google Scholar. A random-effects model was applied to evaluate the effects of probiotics on BP. Sensitivity analysis was performed by using the leave-one-out method. Grading of Recommendations Assessment, Development, and Evaluation (GRADE) was used to evaluate the certainty of evidence. Pooled effect size of 14 meta-analyses with 15,494 participants indicated significant decreases in both systolic (Weighted mean difference (WMD) = -1.96 mmHg; 95% confidence interval (CI): -2.78, -1.14, p < 0.001, and standardized mean difference (SMD) = -2.62; 95% CI: -4.96, -0.28, p < 0.001) and diastolic BP (WMD = -1.28 mmHg; 95% CI: -1.76, -0.79, p < 0.001, and SMD = -0.60 mmHg; 95% CI: -1.08, -0.12, p = 0.014) following probiotics supplementation. Greater effects on SBP were revealed in trials with a mean age of >50 years and the duration of intervention ≤10 weeks. DBP was also more reduced in studies with a dosage of ≥1010 colony forming unit (CFU), and SBP was decreased in patients with hypertension or diabetes analyzing WMD. CONCLUSION: The present umbrella meta-analysis suggests probiotics supplementation to improve BP and claims that probiotics could be used as a complementary therapy for controlling high BP. PROSPERO ID: CRD42022306560.

Profiling Inflammatory Biomarkers following Curcumin Supplementation: An Umbrella Meta-Analysis of Randomized Clinical Trials.

Objective: Several meta-analyses have shown that curcumin can reduce inflammatory biomarkers, but the findings are inconsistent. The objective of the present umbrella meta-analysis was to provide a more accurate estimate of the overall effects of curcumin on inflammatory biomarkers. Methods: The following international databases were systematically searched until March 20, 2022: PubMed, Scopus, Embase, Web of Science, and Google Scholar. A random-effects model was applied to evaluate the effects of curcumin on inflammatory biomarkers. Meta-analysis studies investigating the effects of curcumin supplementation on inflammatory biomarkers with corresponding effect sizes (ES) and confidence intervals (CI) were included in the umbrella meta-analysis. GRADE (Grading of Recommendations Assessment, Development, and Evaluation) was used to evaluate the certainty of evidence. Results: A meta-analyses of ten studies with 5,870 participants indicated a significant decrease in C-reactive protein (CRP) (ES = -0.74; 95% CI: -1.11, -0.37, p < 0.001; I2 = 62.1%, p=0.015), interleukin 6 (IL-6) (ES = -1.07; 95% CI: -1.71, -0.44, p < 0.001; I2 = 75.6%, p < 0.001), and tumour necrosis factor α (TNF-α) levels (ES: -1.92, 95% CI: -2.64, -1.19, p < 0.0; I2 = 18.1%, p=0.296) following curcumin supplementation. Greater effects on CRP and TNF-α were evident in trials with a mean age >45 years and a sample size >300 participants. Conclusion: The umbrella of meta-analysis suggests curcumin as a promising agent in reducing inflammation as an adjunctive therapeutic approach in diseases whose pathogenesis is related to a higher level of inflammatory biomarkers.

Vitamin D protects against depression: Evidence from an umbrella meta-analysis on interventional and observational meta-analyses.

Meta-analyses of interventional and observational studies investigating the efficacy and the relationship between vitamin D and depression provided inconsistent results. The current umbrella meta-analysis was conducted to assess the available evidence and provide a conclusive outcome in this regard. The following international databases were systematically searched till March 2022: PubMed, Scopus, Embase, Web of Science, and Google Scholar. Random-effects model was carried out to calculate the pooled point estimates and their respective 95 % confidence intervals (CI). Ten meta-analyses of randomised controlled trials (RCTs) revealed significant reduction in depression symptoms comparing participants on vitmain D supplements to those on placebo (Pooled standardised mean difference: - 0.40; 95 % CI: - 0.60, - 0.21, p < 0.01: I2 = 89.1 %, p < 0.01). Four meta-analyses of cohort studies (with one having two subgroups) revealed that participants with lower levels of serum vitamin D were at increased odds of depression than those with higher levels of serum vitamin D (Pooled odds ratio: 1.60; 95 % CI: 1.08, 2.36, p < 0.01; I2 = 91.3 %, p < 0.01). The present umbrella meta-analysis confirms the potential benefits of vitamin D supplementation and higher serum vitamin D levels in reducing the development and symptoms of depression.

Efficacy of vitamin D supplementation as an adjunct therapy for improving inflammatory and oxidative stress biomarkers: An umbrella meta-analysis.

BACKGROUND: Vitamin D supplementation has attracted a lot of attention as a potential modulator of inflammation and oxidative stress, while some studies have reported controversial findings. In this regard, the purpose of this study was to summarize existing systematic reviews and meta-analyses of clinical trials that determined the effects of supplementation with vitamin D on inflammatory and oxidative biomarkers. METHODS: The following international databases were systematically searched till March 20th, 2022: PubMed, Scopus, Embase, Web of Science, and Google Scholar. A random-effects model was applied to evaluate the effects of vitamin D on inflammatory and oxidative stress biomarkers. RESULTS: Overall, 23 meta-analyses were qualified in this umbrella meta-analysis. Our findings revealed that the vitamin D supplementation significantly reduced serum C-reactive protein (CRP) (ES = -0.42; 95% CI: -0.55, -0.29, p < 0.001), tumor necrosis factor-α (TNF-α) (ES = -0.27; 95% CI: -0.42, -0.12; p < 0.001), and malondialdehyde (MDA) concentrations (ES = -0.37; 95% CI: -0.48, -0.25, p < 0.001). However, no significant changes were illustrated regarding interleukin-6 (IL-6) (ES = -0.35, 95% CI: -0.80, 0.10; p = 0.125), total antioxidant capacity (TAC) (ES = 0.68; 95% CI: -0.31, 1.66, p = 0.179), and glutathione (GSH) activity (ES = 0.08; 95% CI: -0.44, 0.60, p = 0.757). CONCLUSION: The present umbrella meta-analysis indicated that supplementation of vitamin D in adults can improve CRP, TNF-α, and MDA levels under various health conditions. Vitamin D could be considered an adjuvant therapy for relieving inflammation and oxidative stress.