Impact of Cinnamon Supplementation on cardiometabolic Biomarkers of Inflammation and Oxidative Stress: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

To date, cinnamon supplementation has been investigated due to its antioxidant and anti-inflammatory properties. Several studies have confirmed the effects of cinnamon supplementation on several markers of cardiometabolic health. However, the effects of cinnamon supplementation on inflammation and oxidative stress levels warrant further investigation. Hence, the current meta-analysis was conducted to elucidate the impact of cinnamon supplementation on biomarkers of inflammation and oxidative stress. To perform this systematic review and meta-analysis, we employed the Preferred Reporting Items of Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The systematic search of available clinical trials was performed using the following databases: PubMed/MEDLINE, Scopus, Cochrane Library, Web of Science, Embase, and Google Scholar, up to January 2020. After removing the duplicates, 1145 studies were eligible for analysis and 12 of them were included in the meta-analysis. The dose of cinnamon powder investigated in the included trials ranged from 1.5 to 4 g/day. Cinnamon supplementation resulted in a significant reduction of C-reactive protein (CRP) (weight mean difference (WMD): -2.22 mg/L, 95 % CI: -3.74, -0.69, P = 0.004) and malondialdehyde (MDA) (WMD: -0.79 mmol/L, 95 % CI: -1.28, -0.29, P = 0.002), and marginally statistical significant decrease in interleukin-6 (IL-6) (WMD: -1.48 pg/mL, 95 % CI: -2.96, -0.01, P = 0.049). Moreover, it was associated with an increase in the total antioxidant capacity (TAC) (WMD: 0.34 mmol/L, 95 % CI: 0.04, 0.64, P = 0.026). However, the levels of intercellular adhesion molecule-1 (ICAM-1) (WMD: 1.53 ng/mL, 95 % CI: -12.03, 15.10, P = 0.82) did not change significantly following cinnamon supplementation. Cinnamon supplementation may be an adjuvant for reducing inflammation and oxidative stress levels in humans.

Zhu C ，Yan H ，Zheng Y ，Santos HO ，Macit MS ，Zhao K ... -  《-》

The effect of cinnamon consumption on lipid profile, oxidative stress, and inflammation biomarkers in adults: An umbrella meta-analysis of randomized controlled trials.

Cinnamon is a polyphenol-rich spice that has beneficial effects on markers of cardio metabolic health such as lipid profile, oxidative stress, and inflammation. Despite the accumulating evidence from meta-analyses on the effects of cinnamon on these markers, their findings are controversial. Thus, this umbrella meta-analysis was performed to evaluate the present evidence and provide a conclusive clarification. We searched the following international databases from inception to January 2022: PubMed, Scopus, Web of Science and Embase, and Google Scholar. Our findings of eleven meta-analyses showed that cinnamon consumption can significantly improve total cholesterol (TC) (WMD = -1.01 mg/dL; 95% CI: -2.02, -0.00, p = 0.049), low-density lipoprotein-cholesterol (LDL-C) (WMD = -0.82 mg/dL; 95% CI: -1.57, -0.07, p = 0.032), and high-density lipoprotein-cholesterol (HDL-C) (WMD = 0.47 mg/dL; 95% CI: 0.17, 0.77, p = 0.002) levels but not triglyceride (TG) levels (WMD = -0.13 mg/dL; 95% CI: -0.58, 0.32, p = 0.570). Our results did not show any significant effect of cinnamon on malondialdehyde (MDA) levels (WMD = -0.47; 95% CI: -0.99, 0.05, p = 0.078) and C-reactive protein (CRP) levels (WMD = -1.33; 95% CI: -2.66, 0.00, p = 0.051) but there was enhanced total antioxidant capacity (TAC) in patients with type 2 diabetes (T2DM) and polycystic ovary syndrome (PCOS) (WMD = 0.34; 95% CI: 0.04, 0.64, p = 0.026) and increased levels of interleukin-6 (WMD = -1.48; 95% CI: -2.96, -0.01, p = 0.049). Our results support the usefulness of cinnamon intake in modulating an imbalanced lipid profile in some metabolic disorders, particularly PCOS, as well as in improving TAC and interleukin-6. The review protocol was registered on PROSPERO as CRD42022358827.

Sarmadi B ，Musazadeh V ，Dehghan P ，Karimi E ... -  《-》

Antioxidant and anti-inflammatory effects of curcumin/turmeric supplementation in adults: A GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials.

Turmeric and its prominent bioactive compound, curcumin, have been the subject of many investigations with regard to their impact on inflammatory and oxidative balance in the body. In this systematic review and meta-analysis, we summarized the existing literature on randomized controlled trials (RCTs) which examined this hypothesis. Major databases (PubMed, Scopus, Web of Science, Cochrane Library and Google Scholar) were searched from inception up to October 2022. Relevant studies meeting our eligibility criteria were obtained. Main outcomes included inflammatory markers (i.e. C-reactive protein(CRP), tumour necrosis factorα(TNF-α), interleukin-6(IL-6), and interleukin 1 beta(IL-1β)) and markers of oxidative stress (i.e. total antioxidant capacity (TAC), malondialdehyde(MDA), and superoxide dismutase (SOD) activity). Weighted mean differences (WMDs) were reported. P-values < 0.05 were considered significant. Sixty-six RCTs were included in the final analysis. We observed that turmeric/curcumin supplementation significantly reduces levels of inflammatory markers, including CRP (WMD: -0.58 mg/l, 95 % CI: -0.74, -0.41), TNF-α (WMD: -3.48 pg/ml, 95 % CI: -4.38, -2.58), and IL-6 (WMD: -1.31 pg/ml, 95 % CI: -1.58, -0.67); except for IL-1β (WMD: -0.46 pg/ml, 95 % CI: -1.18, 0.27) for which no significant change was found. Also, turmeric/curcumin supplementation significantly improved anti-oxidant activity through enhancing TAC (WMD = 0.21 mmol/l; 95 % CI: 0.08, 0.33), reducing MDA levels (WMD = -0.33 µmol /l; 95 % CI: -0.53, -0.12), and SOD activity (WMD = 20.51 u/l; 95 % CI: 7.35, 33.67). It seems that turmeric/curcumin supplementation might be used as a viable intervention for improving inflammatory/oxidative status of individuals.

Dehzad MJ ，Ghalandari H ，Nouri M ，Askarpour M ... -  《-》

The effects of N-acetylcysteine on inflammatory and oxidative stress biomarkers: A systematic review and meta-analysis of controlled clinical trials.

Prolonged inflammation could be considered as the leading cause of chronic diseases such as cardiovascular disorders, type two diabetes, and obesity. N-acetylcysteine (NAC) is considered an antioxidant. The present meta-analysis aims to determine the efficacy of NAC in alleviating inflammation and oxidative stress. PubMed-Medline, SCOPUS, Web of Science and Embase databases and Google Scholar were searched up to Nov 2019. Random effect analysis was used to perform meta-analysis. Subgroup analyses were carried out to find heterogeneity sources. Meta-regression analysis was used to explore linear relationship between effect size and variables. Trim and fill analysis were performed in case of the presence of publication bias. Quality assessment was performed using Cochrane Collaboration's tool. A total of 28 studies were included in meta-analysis. NAC significantly decreased malondialdehyde (MDA) (SMD = -1.44 μmol/L; 95% CI: -2.05, -0.84; P < 0.001), IL-8 (WMD = -2.56 pg/ml; 95% CI: -3.89, -1.23; P < 0.001) and homocysteine (WMD = -1.45 pg/ml; 95% CI: -2.74, -0.17; P = 0.027) levels. There were no significant effects of NAC supplementation on CRP (SMD = -0.1 g/L; 95% CI: -0.52, 0.32; P = 0.647), TNF- α (WMD = -0.2 pg/ml; 95% CI: -0.65, 0.25; P = 0.378) and IL-6 (WMD = -0.41 pg/ml; 95% CI: -1.15, 0.32; P = 0.270) levels. However, NAC effects were significant in ameliorating TNF-α and IL-6 using sensitivity analysis. NAC significantly decreased MDA, IL-8, and homocysteine levels. The effects of NAC on amending TNF-α and IL-6 levels were significant after sensitivity analysis. No significant change was observed on CRP levels.

Faghfouri AH ，Zarezadeh M ，Tavakoli-Rouzbehani OM ，Radkhah N ，Faghfuri E ，Kord-Varkaneh H ，Tan SC ，Ostadrahimi A ... -  《-》

Effect of cinnamon (Cinnamomum Zeylanicum) supplementation on serum C-reactive protein concentrations: A meta-analysis and systematic review.

The effect of cinnamon (Cinnamomum Zeylanicum) on serum C-reactive protein (CRP), an acute phase protein commonly used as a marker of inflammation, is uncertain. Therefore, the objective of the present study was to conduct a systematic review and meta-analysis of published randomised controlled trials (RCTs) of cinnamon to determine the effect on levels of serum CRP, relative to controls. Studies were identified by a search of electronic databases including PubMed, Cochrane Library, Google Scholar and Scopus before August 2018. Combined and stratified analyses were used. Weighted mean differences (WMD) and its 95% confidence interval were estimated for net change in serum CRP by using random-effects model. The heterogeneity of meta-analysis was assessed by χ2 and I2 test. Six studies were identified, and data from 285 participants were included. Pooled analysis showed significant reductions in serum CRP (WMD: -0.81 mg/L, 95% CI: -1.36 to -0.26, p = 0.004), with significant heterogeneity between selected studies. Improvements in sub-group analysis were observed when baseline CRP levels were greater than 3 mg/dL, and in trials of >12 weeks duration. Doses <1500 mg/day and ≥1500 mg/day were effective in lowering serum CRP (WMD: -0.56 mg/dL, 95% CI: -1.01 to -0.10, p = 0.02 and WMD: -2.13 mg/dL, 95% CI: -4.08 to -0.19, p = 0.03), respectively, with significantly reduced heterogeneity in trials with lower doses of cinnamon <1500 mg/day (test for heterogeneity: P = 0.22 and I2 = 33%). No changes were found in controls. Cinnamon supplementation improves levels of serum CRP, particularly in chronic conditions, where basal CRP levels are raised. Further well-designed studies are warranted to confirm or not the above-mentioned findings.

Vallianou N ，Tsang C ，Taghizadeh M ，Davoodvandi A ，Jafarnejad S ... -  《-》