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The aim of this meta-analysis was to determine the effect of curcumin on a range of health outcomes. PubMed, EMBASE, Scopus, and Web of Science were searched from inception until September 2023. Randomized clinical trials (RCTs) that compared the effect of Curcuma longa L. with placebo were considered eligible. The risk of bias and overall certainty of evidence were assessed using the Newcastle-Ottawa Scale and Grading of Recommendations Assessment, Development, and Evaluation (GRADE), respectively. We meta-analyzed the effect sizes across eligible studies using the random-effects model. In total, 103 RCTs on 42 outcomes were included, incorporating a total population of 7216 participants. Overall, 23 out of 42 (55%) outcomes reported statistically significant effect sizes. The credibility of the evidence was rated as high for fasting blood sugar (FBS), C-reactive protein (CRP), high-density lipoprotein (HDL), and weight. The remaining outcomes presented moderate (waist circumference [WC], hip circumference [HC], body mass index [BMI], insulin, Homeostatic Model Assessment for Insulin Resistance [HOMA-IR], quantitative insulin-sensitivity check index [QUICKI], leptin, gamma-glutamyl transferase [GGT], glutathione [GSH], and superoxide dismutase [SOD]), low (14 outcomes), or very low (14 outcomes) evidence. In conclusion, curcumin supplementation can modify FBS and some glycemic indices, lipid parameters, as well as inflammatory and oxidative parameters. This updated summary of the accumulated evidence may help inform clinicians and future guidelines regarding medical and scientific interest in curcumin. However, due to limitations in the methodological quality of the included studies, well-designed and long-term RCTs with large sample sizes are needed. Trial registration: PROSPERO: CRD42021251969., (© 2024 John Wiley & Sons Ltd.)

The present study sought to evaluate the effect of resveratrol supplementation on mRNA expression levels of peroxisome proliferator-activated receptor alpha (PPARα), p53, p21, p16, and serum levels of cluster of differentiation 163 (CD163) to TNF-like weak inducer of apoptosis (TWEAK) ratio in patients with type 2 diabetes. In this double-blind randomized controlled trial, 71 patients were randomly assigned to receive either 1,000 mg of trans-resveratrol or placebo (methyl cellulose) for 8 weeks. Expression levels of genes of interest, and serum levels of sCD163 and sTWEAK were assessed at baseline and at the end of the study. Resveratrol supplementation significantly increased mRNA expression levels of p53 and p21 genes, compared with the placebo group (fold change of p53 = 1.29, p = .04; fold change of p21 = 1.46, p = .006). However, no significant effect on expression levels of PPARα and p16 genes was observed after supplementation. In addition, resveratrol significantly reduced serum levels of sCD163/sTWEAK ratio compared with the placebo group (p = .003). Resveratrol supplementation resulted in significant changes in p53 and p21 genes expression, while serum levels of sCD163/sTWEAK ratio also improved in the resveratrol group, without any significant change in adjusted sCD163 levels. More research is needed to confirm the beneficial effects of resveratrol for patients with diabetes., (© 2021 John Wiley & Sons, Ltd.)

A wide variety of antioxidant properties are attributed to ginger (Zingiber officinale) and several randomized controlled trials (RCTs) have investigated the effect of ginger intake on major oxidative stress (OS) parameters. We conducted a systematic review and meta-analysis to evaluate the effects of using ginger to improve OS levels. Medline, Scopus, ISI Web of Science, EMBASE, and the Cochrane Central Register of Controlled Trials were systematically searched up until March 2020 to gather RCTs that evaluated the impact of ginger intake on the levels and activity of OS parameters in adult subjects. Means and standard deviations for relevant OS variables were extracted and evaluated to assess the quality of the trials based on the Cochrane risk-of-bias tool for randomized trials. The gathered data were pooled and expressed as standardized mean difference (SMD) with 95% Confidence Intervals (95% CI). Twelve trials were included in this review. Ginger intake was shown to significantly increase glutathione peroxidase (GPx) activity (SMD: 1.64; 95% CI: 0.43, 2.85; I 2  = 86.8%) and total antioxidant capacity (TAC) (SMD: 0.40; 95% CI: 0.06, 0.73; I 2  = 42.8%) and significantly decrease malondialdehyde (MDA) levels (SMD: -0.69; 95% CI: -1.26, -0.12; I 2  = 85.8%) compared to control groups. Ginger supplementation also non-significantly associated with an increase in CAT activity (SMD: 1.09; 95% CI: -0.07, 2.25; I 2  = 87.6%). This systematic review and meta-analysis presents convincing evidence supporting the efficacy of ginger supplementation on improving OS levels. PRACTICAL IMPLICATIONS: In health sciences, OS, due to its pivotal role in the pathophysiology of several chronic diseases, is a subject with a long history. Recent research strives for a safe, ideal, and effective antioxidant. Ginger is herbal medicine, which has been widely used in traditional and complementary medicine. Proving the antioxidant effect and potential benefit of ginger has positive clinical implications for the application of this practical herb., (© 2021 Wiley Periodicals LLC.)

Several clinical trials have identified glycemic-lowering effects of cinnamon, while other studies have reported conflicting findings. A comprehensive systematic search on Embase, PubMed, Scopus, Web of Science, and Cochrane Library was conducted using defined keywords in any language through June 2020. Studies that compared the effect of cinnamon with placebo on insulin resistance (IR) indices, as the primary outcome, in women with polycystic ovary syndrome (PCOS) were considered eligible. Standard Mean difference (SMD) (with 95% confidence intervals) for endpoints were calculated using the random-effects model. Finally, five RCTs which met the criteria were included in the meta-analysis. After pooling data, cinnamon supplementation significantly reduced homeostatic model assessment for insulin resistance (HOMA-IR) scores in women with PCOS (SMD: -0.84, 95% CI: -1.52, -0.16, p = .010). Cinnamon supplementation likely improves certain IR markers in patients with PCOS. PRACTICAL APPLICATIONS: There are controversies reports for cinnamon intake, which animal models have suggested that it decreases IR via promotion of insulin action, stimulating insulin signaling pathways, and enhancing insulin sensitivity. This study provides comprehensive information about the effect of cinnamon on insulin resistance (IR) indices in women with PCOS. In this regard, our results indicated that cinnamon supplementation significantly reduced homeostatic model assessment for insulin resistance (HOMA-IR) scores in women with PCOS. Therefore, consumption of cinnamon can be safe and this can be a useful recommendation for improving IR and promotion of healthy life which indeed are the potential or actual uses of this research., (© 2020 Wiley Periodicals LLC.)

Recent evidence indicates a beneficial effect of Melissa officinalis (MO) intake on several chronic diseases. However, the effects of MO intake have not yet been systematically reviewed. Therefore, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the effect of MO intake and focused on several cardiometabolic outcomes. MEDLINE, Scopus, EMBASE, Web of Science and the Cochrane Central Register of Controlled Trials were searched for MO-RCTs evaluating cardiometabolic outcomes. Random-effects meta-analyses estimated the pooled standardized mean differences (SMD) between intervention and control groups. Risk of bias was assessed with the Cochrane Collaboration's tool for assessing the risk of bias in RCTs. Seven RCTs were finally deemed eligible. MO intake was associated with a reduced total cholesterol (TC) (SMD: -0.26; 95% CI: -0.52, -0.01; I 2 = 13.7%; k = 6) and a reduced systolic blood pressure (SBP) (SMD: -0.56; 95% CI: -0.85, -0.27; I 2 = 00.0%; k = 3). MO intake was not associated with statistically significant changes in triglycerides, low-density lipoprotein, diastolic blood pressure, high sensitivity c-reactive protein levels, fasting blood sugar, HbA1c, insulin or high-density lipoprotein levels. No serious adverse events were reported. The risk of bias was high in a considerable amount of studies. Our study suggests that MO is a safe supplement with beneficial effects on TC and SBP. However, the findings of our study must be seen in the light of major limitations such as a low number of included studies and a serious risk of bias. High-quality RCTs are needed for firm conclusions concerning the effects of MO on cardiometabolic outcomes., (© 2020 John Wiley & Sons, Ltd.)