ABSTRACT
BACKGROUND: Oxidative stress and inflammation play critical roles in the pathogenesis of many chronic diseases. Dark chocolate (DC)/cocoa, as a rich source of polyphenols like flavonoids, has anti-inflammatory and antioxidant properties that may confer health benefits, but findings in this context are inconsistent. OBJECTIVE: This systematic review and dose-response meta-analysis aimed to provide a comprehensive overview of the controlled trials (CTs) that have examined the effects of DC/cocoa on oxidative stress and inflammation biomarkers in adults. SEARCH METHODS: Databases including PubMed, Web of Science, and Scopus, were searched for relevant studies through April 2024. SELECTION CRITERIA: Studies assessed C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), malondialdehyde (MDA), nitric oxide (NO), P-selectin, E-selectin and thiobarbituric acid reactive substances (TBARS) in adults were included. DATA ANALYSIS: Based on the random-effects model, we calculated WMDs, SMDs and 95 % confidence intervals (CIs). Sensitivity, sub-group, meta-regression and dose-response analyses were also conducted. RESULTS: Thirty-three eligible CTs with 1379 participants were included. All studies reported the intervention types (cocoa powder, beverages and chocolate bars) and dosage. However, sixteen studies didn't do/report testing for purity and potency by independent groups. Also, none of the studies mentioned the risk of contamination with heavy metals. Another limitation was the lack of blinding assessment in studies. DC/cocoa significantly reduced MDA (SMD: -0.69, 95 %CI: -1.17, -0.2, p = 0.005) and increased NO levels (SMD: 2.43, 95 %CI: 1.11,3.75, p < 0.001); However, it has no significant effects on the other outcomes. Greater anti-inflammatory effects occurred at higher flavonoid doses (>450 mg/day) and for shorter durations (≤4 weeks) in the non-healthy participants. Non-linear dose-response relationships between cocoa dosage and CRP level and also between flavonoid dosage and IL-6 level were observed. Based on the GRADE evaluation, just CRP and MDA results were considered as high certainty evidence and the other outcomes results were categorized as very low to moderate certainty. CONCLUSIONS: DC/cocoa may improve systemic oxidative status and inflammation in adults. However, further studies should be performed to determine its benefits.
ABSTRACT
Osteoarthritis (OA) is one of the most prevalent degenerative joint diseases. Several meta-analyses have shown that curcumin could improve the function of the knee and alleviate pain in OA, while some meta-analyses demonstrate controversial results. Hence, we assessed curcumin's effects on knee OA in an umbrella meta-analysis. PubMed, Scopus, Embase, and Web of Science databases were employed to find English-language meta-analyses of randomized controlled trials investigating the effect of curcumin supplementation on OA outcomes up to September 2023. The visual analog scale (VAS), Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain, function, and stiffness scales were analyzed. Effect sizes and 95% confidence intervals were utilized to obtain the overall effect size. A random-effects model was applied to perform the meta-analysis. Heterogeneity was determined by I2 statistics and the Cochrane Q-test. The pooled effect of the 11 included meta-analyses showed that curcumin could significantly decrease the VAS score (weighted mean difference [WMD] and standardized mean difference [SMD]), WOMAC-total (SMD and WMD), WOMAC-Function (SMD and WMD), WOMAC-Pain (SMD), and WOMAC-Stiffness scores (SMD) (p ≤ 0.001, ≤0.001, ≤0.001, 0.007, ≤0.001, 0.002, ≤0.001, ≤0.001, respectively). The results strongly support curcuminoid supplementation in relieving pain, improving joint mobility and stiffness, and shortening medication usage of OA patients.
Subject(s)
Curcumin , Osteoarthritis, Knee , Curcumin/therapeutic use , Humans , Osteoarthritis, Knee/drug therapy , Randomized Controlled Trials as Topic , Pain Measurement , Osteoarthritis/drug therapyABSTRACT
CONTEXT: Hypertension (HTN) is regarded as a serious public health issue throughout the world. High blood pressure (BP) may be improved by carotenoid supplementation; however, randomized controlled trials (RCTs) provide conflicting evidence. OBJECTIVE: The aim of this study was to evaluate the effects of carotenoid supplementation on BP in RCTs by systematically review and meta-analysis. DATA SOURCES: A comprehensive literature search was performed in the Scopus, PubMed, and Web of Science databases until October 2023, with no limitation on the date or language of publication. DATA EXTRACTION: Studies that evaluated the net effects of carotenoids in the form of supplements on BP in adults were selected. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated on the basis of a fixed or random-effects model. Sensitivity analysis, meta-regression, publication bias, and heterogeneity were assessed using standard methods. Cochrane quality assessments were used to evaluate the included studies' bias risks. Evidence certainty was calculated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework). DATA ANALYSIS: Reports on a total of 19 RCTs involving 1151 participants were included in this review. Carotenoid supplementation significantly reduced the systolic BP (SBP) (WMD, -2.492 mmHg; 95%CI, -4.52, -0.47; P = 0.016) and diastolic BP (DBP) (WMD, -1.60 mmHg; 95%CI, -2.73, -0.47; P = 0.005). Greater effects were observed in Asian participants, those aged >50 years, nonhealthy participants, and participants with a baseline SBP ≥130 mmHg and DBP ≥80 mmHg, at dose >10 mg. Dose-response analysis showed that carotenoid supplementation decreased SBP and DBP levels at doses of, respectively, 0-25 and 0-20 mg/d. Evidence for all SBP, DBP, and heart rate values was high quality. CONCLUSIONS: Carotenoid supplementation had a beneficial effect on BP parameters, especially in nonhealthy study participants with high BP baseline levels. PROSPERO REGISTRATION NO: CRD42023402740.
ABSTRACT
OBJECTIVE: To summarize available findings on the effect of Chlorella vulgaris supplementation on lipid profile in adults. DESIGN: Systematic review and meta-analysis of randomized controlled trials (RCTs). SETTING: This study followed 2020 PRISMA guideline. We performed a systematic search in the online databases to identify relevant articles and then, extracted required data from each paper for the meta-analysis. Random-effects models were used to obtain overall mean difference (MD) comparing Chlorella vulgaris supplementation with a control group. MAIN OUTCOME MEASURES: Blood lipids including triglyceride (TG), total cholesterol (TC), LDL-C, and HDL-C. RESULTS: In total, 10 RCTs with a total sample size of 539 adults (264 in the Chlorella vulgaris group and 275 in the control group) were included. Of the 10 RCTs, four had a low risk of bias for all aspects of the Cochrane risk of bias tool. Also, only two studies determined the chlorella content, purity, potency, and contamination of the supplements used in the intervention. Combining results from these studies showed a summary MD of -2.11 mg/dL (95% CI: -7.28 to 3.06) for TG, -7.47 mg/dL (95% CI: -12.98 to -1.96) for TC, -7.71 mg/dL (95% CI: -14.05 to -1.37) for LDL-C, and -0.45 mg/dL (95% CI: -0.67 to 1.57) for HDL-C, indicating a beneficial effect of Chlorella vulgaris supplementation on TC and LDL-C levels. Based on the dose-response analysis, the reducing effect of Chlorella vulgaris supplementation on LDL-C levels was seen at the dosages between zero and 1500 mg/d (P for non-linearity= 0.01), whereas in higher amounts, this effect was not significant. CONCLUSION: We found that Chlorella vulgaris supplementation had a beneficial effect on TC and LDL-C levels with no significant effect on TG and HDL-C levels.
