Evaluation of the effects of curcumin in patients with metabolic syndrome

Effect of nano-curcumin supplementation on cardiometabolic risk factors, physical and psychological quality of life, and depression in patients with coronary slow flow phenomenon: a randomized double-blind clinical trial

BACKGROUND

Extensive evidence has suggested the cardio-protective properties of the polyphenol curcumin. The aim of this study was to investigate the effects of a highly bioavailable curcumin supplement on cardiometabolic risk factors, health-related quality of life, and depression in patients with coronary slow flow phenomenon (CSFP).

METHODS

This randomized double-blind placebo-controlled clinical trial was conducted in 42 patients with CSFP (age 35-70 years, 25 ≤ body mass index < 40 kg/m2). Patients received either 80 mg/day nano-curcumin or placebo for 12 weeks. Serum levels of visfatin, high-sensitivity C-reactive protein (hs-CRP), and glycemic indices were measured before and after the intervention. The short form 36-item quality of life (SF-36) and Beck's Depression Inventory-II (BDI-II) questionnaires were assessed, as well.

RESULTS

No significant improvements were observed in circulating hs-CRP and visfatin following the intervention. A significant increase was observed in pre- to post-fasting blood glucose (- 0.9 ± 12.2 vs. 7.7 ± 12.4 mg/dl, p = 0.02) and hemoglobin A1C (- 0.1 ± 0.8 vs. 0.5 ± 0.8%, p = 0.04) levels, in the placebo compared with the intervention group. Physical (8.2 ± 8.1 vs. - 1.2 ± 6.5, p < 0.001) and mental (6.8 ± 11.8 vs. - 1.1 ± 10.4, p = 0.02) component summary scores were significantly improved in the nano-curcumin than the placebo group. Additionally, the number of patients with lower degrees of depression was significantly better in the intervention than the placebo group following the supplementation (p = 0.046).

CONCLUSION

Curcumin supplementation prevented deterioration of glycemic control and improved physical and psychological quality of life and depression in patients with CSFP.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials (IRCT20131125015536N8), June 19, 2019.

Is Curcumin Intake Really Effective for Chronic Inflammatory Metabolic Disease? A Review of Meta-Analyses of Randomized Controlled Trials

This review aimed to examine the effects of curcumin on chronic inflammatory metabolic disease by extensively evaluating meta-analyses of randomized controlled trials (RCTs). We performed a literature search of meta-analyses of RCTs published in English in PubMed®/MEDLINE up to 31 July 2023. We identified 54 meta-analyses of curcumin RCTs for inflammation, antioxidant, glucose control, lipids, anthropometric parameters, blood pressure, endothelial function, depression, and cognitive function. A reduction in C-reactive protein (CRP) levels was observed in seven of ten meta-analyses of RCTs. In five of eight meta-analyses, curcumin intake significantly lowered interleukin 6 (IL-6) levels. In six of nine meta-analyses, curcumin intake significantly lowered tumor necrosis factor α (TNF-α) levels. In five of six meta-analyses, curcumin intake significantly lowered malondialdehyde (MDA) levels. In 14 of 15 meta-analyses, curcumin intake significantly reduced fasting blood glucose (FBG) levels. In 12 of 12 meta-analyses, curcumin intake significantly reduced homeostasis model assessment of insulin resistance (HOMA-IR). In seven of eight meta-analyses, curcumin intake significantly reduced glycated hemoglobin (HbA1c) levels. In eight of ten meta-analyses, curcumin intake significantly reduced insulin levels. In 14 of 19 meta-analyses, curcumin intake significantly reduced total cholesterol (TC) levels. Curcumin intake plays a protective effect on chronic inflammatory metabolic disease, possibly via improved levels of glucose homeostasis, MDA, TC, and inflammation (CRP, IL-6, TNF-α, and adiponectin). The safety and efficacy of curcumin as a natural product support the potential for the prevention and treatment of chronic inflammatory metabolic diseases.

The effects of powdered drinks enriched with curcumin and probiotics on lipid profile and atherogenic indices in patients with metabolic syndrome: A randomized, double-blinded, placebo-controlled clinical trial

Cardiovascular disease is prevalent globally and is the most common complication of metabolic syndrome (MetS). Previous studies have suggested that curcumin and probiotics may improve the lipid profile, so we aimed to investigate the effects of the edible powder enriched with these substances on lipid profile level and atherogenic indices such as Atherogenic Coefficient (AC), Castelli Risk Index-I (CRI-I), Castelli Risk Index-II (CRI-II), and Atherogenic Index of Plasma (AIP). In the present parallel randomized double-blinded placebo-controlled clinical trial, 124 people with MetS with overweight or obesity were randomly allocated to 4 groups and were followed up for 8 weeks. The participants received a low-calorie diet and a daily sachet of enriched powder drink. The sachets contained either 109 CFU of probiotics or 1 g of curcumin, or probiotic + curcumin (pro + cur), or placebo, respectively. The fasting lipid profile and atherogenic indices were measured at the beginning and end of the study. One hundred and fourteen participants completed the study. At the end of the study, the within- and between-group comparisons showed no significant differences in lipid profile and atherogenic indices (p > .05). Based on the results of the current study, taking an oral powder containing 1 g curcumin and 109 CFU probiotics for 8 weeks had no effect on the lipid profile level and atherogenic indices; however, more studies are recommended.

Curcumin/turmeric supplementation could improve blood pressure and endothelial function: A grade-assessed systematic review and dose-response meta-analysis of randomized controlled trials

BACKGROUND AND PURPOSE

A number of studies have examined the impact of curcumin/turmeric on blood pressure and the factors allegedly responsible for hypertension. In this systematic review and meta-analysis, we tried to sum up the existing literature on randomized controlled trials (RCTs) investigating this hypothesis.

METHODS

Online databases (PubMed, Scopus, Web of Science Core Collection, Cochrane Library, and Google Scholar) were searched from inception up to October 2022. We used the cochrane quality assessment tool to evaluate the risk of bias. Outcomes of interest included systolic blood pressure (SBP), diastolic blood pressure (DBP), blood levels of vascular cell adhesion molecule-1 (VCAM-1) and intracellular adhesion molecule-1 (ICAM-1), flow-mediated vasodilation (FMD), and pulse-wave velocity (PWV). Weighted mean differences (WMDs) were derived and reported. In case of significant between-study heterogeneity, subgroup analyses were carried out. Significance level was considered as P-values<0.05.

RESULTS

Finally, 35 RCTs out of 4182 studies were included. Our findings suggested that curcumin/turmeric supplementation significantly improved SBP (WMD: -2.02 mmHg; 95 % CI: -2.85, -1.18), DBP (WMD: -0.82 mmHg; 95 % CI: -1.46, -0.18), VCAM-1 (WMD: -39.19 ng/mL; 95 % CI: -66.15, -12.23), and FMD (WMD: 2.00 %; 95 % CI: 1.07, 2.94). However, it did not significantly change levels of ICAM-1 (WMD: -17.05 ng/ml; 95 % CI: -80.79, 46.70), or PWV (WMD: -79.53 cm/s; 95 % CI: -210.38, 51.33).

CONCLUSION

It seems that curcumin/turmeric supplementation could be regarded as a complementary method to improve blood pressure and endothelial function. However, further research is needed to clarify its impact on inflammatory adhesion molecules in the circulation.

Curcumin-rich curry consumption and life expectancy: Singapore longitudinal ageing study

The therapeutic potential of curcumin for many diseases are intensively investigated. However, real-world observational data documenting health and longevity effects associated with dietary curcumin in turmeric from consuming curry in food is lacking. A prospective cohort study of 4551 adults aged 55 + assessed curry consumption (never or < once/year, ≥ once/year to < once/month, ≥ once/month to < once/week, ≥ once/week to < daily, ≥ once daily), prevalent health conditions, blood biomarker indexes of atherogenicity, insulin resistance, and inflammation at baseline, and mean (SD) 11.6 (3.8) year follow up of all-cause, CVS and cancer mortality. There were linear positive associations of increasing curry consumption with waist circumference, fasting blood glucose, TyG, AIP, CRI-1, CRI-2, central obesity and diabetes prevalence, and inverse association with eGFR. There were non-linear associations with FEV1/height2 and COPD prevalence, GDS score and depression, MMSE score and cognitive impairment, comorbidity count, serum albumin and haemoglobin, being most favourable with moderate consumption. The levels of NLR, PLR and SII indices of systemic and immune inflammation decreased linearly with curry consumption. Total mortality HR adjusted for baseline co-variables, decreased across curry consumption, 0.68 (95%CI 0.56-0.82), 0.54 (95%CI 0.43-0.69), 0.70 (0.52-0.93), and 0.62 (0.41-0.95), being lowest in the middle categories. Among participants with cardio-metabolic and vascular diseases (CMVD), at least occasional curry consumption was associated with decreased mortality risk by 39%, and increased life expectancy by 1.0 years. Among those without CMVD, the associated life expectancy increase was 1.9 years. Moderate curry consumption may confer meaningful longevity benefits.

Effects of curcumin on blood pressure: A systematic review and dose-response meta-analysis

AIMS

This systematic review and dose-response meta-analysis were conducted to summarize data from available clinical trials on the effects of curcumin supplementation on systolic BP (SBP) and diastolic BP (DBP).

DATA SYNTHESIS

Using related keywords, multiple databases, including the Web of Sciences, Scopus, Embase, PubMed, Cochrane Library, and Google Scholar, were searched until November 2022. We chose the studies that examined the effects of curcumin on systolic blood pressure (SBP) and diastolic blood pressure (DBP). Seventeen eligible studies with a total sample size of 1377 participants were included in the meta-analysis. The findings of the meta-analysis did not indicate any significant effect of curcumin on SBP (WMD = -0.06 mmHg, 95% CI: -0.62, 0.50, p = 0.85; I2 = 44.2%) and DBP (WMD = -0.18 mmHg, 95% CI: -1.17, 0.82, p = 0.62; I2 = 77.2%). Moreover, in our dose-response analysis, we found that the dose and duration of curcumin supplementation were non-significantly associated with the reduction of SBP and DBP. However, subgroup analysis revealed a significant reduction only in DBP levels (WMD: -0.76 mmHg, 95% CI: -1.46,-0.05; P = 0.03) but not in SBP in studies with ≥12-week supplementation. Also, a significant reduction in SBP (WMD: -1.55 mmHg, 95% CI: -2.85, -0.25; P = 0.01) and DBP (WMD: -1.73 mmHg, 95% CI: 2.67, -0.79; P < 0.01) was noticed by curcumin supplementation in studies performed on women.

CONCLUSIONS

The current study suggests that consuming curcumin may improve DBP when administered for long durations ≥12 weeks. However, more trials are required to confirm these findings.

Effects of curcumin/turmeric supplementation on glycemic indices in adults: A grade-assessed systematic review and dose-response meta-analysis of randomized controlled trials

INTRODUCTION

Glycemic control is of utmost importance both as a preventive measure in individuals at risk of diabetes and in the management of patients with disturbed glycemia. Turmeric/curcumin has been extensively studied in this field. In the present systematic review and meta-analysis, we aimed at investigating the impact of turmeric/curcumin supplementation on glycemic control.

METHODS

Major online databases (PubMed, Scopus, Web of Science, Cochrane Library and Google Scholar) were systematically searched from inception up to October 2022. Relevant randomized controlled trials (RCTs) meeting our eligible criteria were included. Weighted mean differences (WMDs) with confidence intervals (CIs) were expressed using a random-effect model. Subgroup analyses were conducted to find the sources of heterogeneities. To detect risk of bias in the included studies, we used the Cochrane risk-of-bias tool. The registration number was CRD42022374874.

RESULTS

Out of 4182 articles retrieved from the initial search, 59 RCTs were included. Our findings suggested that turmeric/curcumin supplementation was significantly effective in improving fasting blood sugar (WMD: 4.60 mg/dl; 95% CI: 5.55, -3.66), fasting insulin levels (WMD: 0.87 μIU/ml; 95% CI: 1.46, -0.27), hemoglobin A1c (HbA1c) (WMD: 0.32%; 95% CI: 0.45, -0.19), and homeostatic model assessment of insulin resistance (HOMA-IR) (WMD: 0.33; 95% CI: 0.43, -0.22).

CONCLUSION

Our results indicate that turmeric/curcumin supplementation can be considered as a complementary method in the management of disturbed glycemia.

Effects of turmeric (Curcuma longa) supplementation on glucose metabolism in diabetes mellitus and metabolic syndrome: An umbrella review and updated meta-analysis

AIMS

This study aims to comprehensively review the existing evidence and conduct analysis of updated randomized controlled trials (RCTs) of turmeric (Curcuma longa, CL) and its related bioactive compounds on glycemic and metabolic parameters in patients with type 2 diabetes (T2DM), prediabetes, and metabolic syndrome (MetS) together with a sub-group analysis of different CL preparation forms.

METHODS

An umbrella review (UR) and updated systematic reviews and meta-analyses (SRMAs) were conducted to evaluate the effects of CL compared with a placebo/standard treatment in adult T2DM, prediabetes, and MetS. The MEDLINE, Embase, The Cochrane Central Register of Control Trials, and Scopus databases were searched from inception to September 2022. The primary efficacy outcomes were hemoglobin A1C (HbA1C) and fasting blood glucose (FBG). The corrected covered area (CCA) was used to assess overlap. Mean differences were pooled across individual RCTs using a random-effects model. Subgroup and sensitivity analyses were performed for various CL preparation forms.

RESULTS

Fourteen SRMAs of 61 individual RCTs were included in the UR. The updated SRMA included 28 studies. The CCA was 11.54%, indicating high overlap across SRMAs. The updated SRMA revealed significant reduction in FBG and HbA1C with CL supplementation, obtaining a mean difference (95% confidence interval [CI]) of -8.129 (-12.175, -4.084) mg/dL and -0.134 (-0.304, -0.037) %, respectively. FBG and HbA1C levels decreased with all CL preparation forms as did other metabolic parameters levels. The results of the sensitivity and subgroup analyses were consistent with those of the main analysis.

CONCLUSION

CL supplementation can significantly reduce FBG and HbA1C levels and other metabolic parameters in T2DM and mitigate related conditions, including prediabetes and MetS.

TRIAL REGISTRATION

PROSPERO (CRD42016042131).

Effects of dietary polyphenol curcumin supplementation on metabolic, inflammatory, and oxidative stress indices in patients with metabolic syndrome: a systematic review and meta-analysis of randomized controlled trials

Objective

The aim was to conduct a systematic review and meta-analysis for assessing the effectiveness and safety of dietary polyphenol curcumin supplement on metabolic, inflammatory, and oxidative stress indices in patients with metabolic syndrome (MetS).

Methods

A comprehensive search for clinical trials was conducted in the following scientific databases: PubMed, SCOPUS, Cochrane Library, EMBASE, Web of Science, and China Biological Medicine. Randomized controlled trials (RCTs) evaluating the efficacy and safety of curcumin supplement for MetS were identified. A random-effects meta-analysis was performed using inverse variance, and efficacy was expressed as mean difference (MD) with 95% confidence interval (CI). The metabolic syndrome markers that were evaluated in the present study included waist circumference (WC), fasting blood sugar (FBS), systolic blood pressure (SBP), diastolic blood pressure (DBP), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), tumor necrosis factor-a (TNF-a), interleukin 6 (IL-6), C-reactive protein (CRP), ultrasensitive c-reactive protein (hsCRP), and malondialdehyde (MDA). By employing the Cochrane tool, RCTs were assessed for bias risk.

Results

A total of 785 participants from 13 RCTs were included, with intervention durations ranging from 4 to 12 weeks. Compared with the control group, the curcumin group had positive effects on WC (MD = -2.16, 95% CI: -3.78 to -0.54, p = 0.009, seven studies), FBS (MD = -8.6, 95% CI: -15.45 to -1.75, p = 0.01, nine studies), DBP (MD = -2.8, 95% CI: -4.53 to - 1.06, p = 0.002, five studies), HDL-C (MD = 4.98, 95% CI: 2.58 to 7.38, p < 0.0001, eight studies), TNF-a (MD = -12.97, 95% CI: -18.37 to -7.57, p < 0.00001, two studies), CRP (MD = - 1.24, 95% CI: -1.71 to -0.77, p < 0.00001, two studies), and MDA (MD = -2.35, 95% CI: -4.47 to -0.24, p = 0.03, three studies). These improvements were statistically significant. Meanwhile, there was no significant improvement in SBP (MD = -4.82, 95% CI: -9.98 to 0.35, p = 0.07, six studies), TG (MD = 1.28, 95% CI: -3.75 to 6.30, p = 0.62, eight studies), IL-6 (MD = -1.5, 95% CI: -3.97 to 0.97, p = 0.23, two studies), or hsCRP (MD = -1.10, 95% CI: -4.35 to 2.16, p < 0.51, two studies). FBS, SBP, HDL-C, IL-6, CRP, hsCRP, and MDA had a relatively high heterogeneity.

Conclusion

Curcumin exhibited promising potential in enhancing markers associated with metabolic syndrome, including inflammation. However, additional studies are required to confirm such findings since the included evidence is limited and has a relatively high heterogeneity.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier CRD42022362553.

Effects of curcumin/turmeric supplementation on lipid profile: A GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials

INTRODUCTION

Numerous approaches have been assigned to treat dyslipidemia (DLP). Turmeric/curcumin have been widely investigated with this regard. In the current study, we explored the effect of curcumin/turmeric supplementation on lipid profile.

METHODS

Online databases were searched up to October 2022. The outcomes included triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), apolipoprotein B (Apo-B), and apolipoprotein A (Apo-A). We used the Cochrane quality assessment tool to evaluate the risk of bias. The effect sizes were estimated as weighted mean difference (WMD) and 95% confidence intervals (CIs).

RESULTS

Out of 4182 articles retrieved from the initial search, 64 randomized clinical trials (RCTs) were included in the study. Between-study heterogeneity was significant. Meta-analysis showed that turmeric/curcumin supplementation exerts statistically significant improvements on blood levels of TC (WMD = -3.99mg/dL; 95% CI = -5.33, -2.65), TG (WMD = -6.69mg/dL; 95% CI = -7.93, -5.45), LDL-c (WMD = -4.89mg/dL; 95% CI = -5.92, -3.87), and HDL-c (WMD = 1.80mg/dL; 95% CI = 1.43, 2.17). However, turmeric/curcumin supplementation was not associated with improvements in blood levels of Apo-A or Apo-B. The studies did not thoroughly address the issues of potency, purity, or consumption with other foods.

CONCLUSION

Turmeric/curcumin supplementation seems to be effective in improving blood levels of TC, TG, LDL-c, and HDL-c; but may not be capable of improving their pertinent apolipoproteins. Since the evidence was assessed to be low and very low concerning the outcomes, these findings should be dealt with caution.

The effect of curcumin supplementation on weight loss and anthropometric indices: an umbrella review and updated meta-analyses of randomized controlled trials

BACKGROUND

Curcumin supplementation may promote weight loss and ameliorate obesity-related complications through its antioxidative and anti-inflammatory properties.

OBJECTIVE

An umbrella review and updated meta-analysis of randomized controlled trials (RCTs) was conducted to evaluate the effect of curcumin supplementation on anthropometric indices.

METHODS

Systematic reviews and meta-analyses (SRMAs) of RCTs were identified from electronic databases (Medline, Scopus, Cochrane, and Google Scholar) up to 31 March, 2022, without language restriction. SRMAs were included if they assessed curcumin supplementation on any of the following: BMI, body weight (BW), or waist circumference (WC). Subgroup analyses were performed, stratifying by patient types, severity of obesity, and curcumin formula. The study protocol was a priori registered.

RESULTS

From an umbrella review, 14 SRMAs with 39 individual RCTs were included with a high degree of overlap. In addition, searching was updated from the last search of included SRMAs in April 2021 up to 31 March, 2022, and we found 11 additional RCTs, bringing the total up to 50 RCTs included in the updated meta-analyses. Of these, 21 RCTs were deemed of high risk of bias. Curcumin supplementation significantly reduced BMI, BW, and WC with mean differences (MDs) of -0.24 kg/m2 (95% CI: -0.32, -0.16 kg/m2), -0.59 kg (95% CI: -0.81, -0.36 kg), and -1.32 cm (95% CI: -1.95, -0.69 cm), respectively. The bioavailability-enhanced form reduced BMI, BWs, and WC more, with MDs of -0.26 kg/m2 (95% CI: -0.38, -0.13 kg/m2), -0.80 kg (95% CI: -1.38, -0.23 kg) and -1.41 cm (95% CI: -2.24, -0.58 cm), respectively. Significant effects were also seen in subgroups of patients, especially in adults with obesity and diabetes.

CONCLUSIONS

Curcumin supplementation significantly reduces anthropometric indices, and bioavailability-enhanced formulas are preferred. Augmenting curcumin supplement with lifestyle modification should be an option for weight reduction. This trial was registered at PROSPERO as CRD42022321112 (https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022321112).

Role of Turmeric and Curcumin in Prevention and Treatment of Chronic Diseases: Lessons Learned from Clinical Trials

Turmeric (Curcuma longa) has been used for thousands of years for the prevention and treatment of various chronic diseases. Curcumin is just one of >200 ingredients in turmeric. Almost 7000 scientific papers on turmeric and almost 20,000 on curcumin have been published in PubMed. Scientific reports based on cell culture or animal studies are often not reproducible in humans. Therefore, human clinical trials are the best indicators for the prevention and treatment of a disease using a given agent/drug. Herein, we conducted an extensive literature survey on PubMed and Scopus following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The keywords "turmeric and clinical trials" and "curcumin and clinical trials" were considered for data mining. A total of 148 references were found to be relevant for the key term "turmeric and clinical trials", of which 70 were common in both PubMed and Scopus, 44 were unique to PubMed, and 34 were unique to Scopus. Similarly, for the search term "curcumin and clinical trials", 440 references were found to be relevant, of which 70 were unique to PubMed, 110 were unique to Scopus, and 260 were common to both databases. These studies show that the golden spice has enormous health and medicinal benefits for humans. This Review will extract and summarize the lessons learned about turmeric and curcumin in the prevention and treatment of chronic diseases based on clinical trials.

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.

Curcumin Formulations for Better Bioavailability: What We Learned from Clinical Trials Thus Far?

Curcumin has been credited with a wide spectrum of pharmacological properties for the prevention and treatment of several chronic diseases such as arthritis, autoimmune diseases, cancer, cardiovascular diseases, diabetes, hemoglobinopathies, hypertension, infectious diseases, inflammation, metabolic syndrome, neurological diseases, obesity, and skin diseases. However, due to its weak solubility and bioavailability, it has limited potential as an oral medication. Numerous factors including low water solubility, poor intestinal permeability, instability at alkaline pH, and fast metabolism contribute to curcumin's limited oral bioavailability. In order to improve its oral bioavailability, different formulation techniques such as coadministration with piperine, incorporation into micelles, micro/nanoemulsions, nanoparticles, liposomes, solid dispersions, spray drying, and noncovalent complex formation with galactomannosides have been investigated with in vitro cell culture models, in vivo animal models, and humans. In the current study, we extensively reviewed clinical trials on various generations of curcumin formulations and their safety and efficacy in the treatment of many diseases. We also summarized the dose, duration, and mechanism of action of these formulations. We have also critically reviewed the advantages and limitations of each of these formulations compared to various placebo and/or available standard care therapies for these ailments. The highlighted integrative concept embodied in the development of next-generation formulations helps to minimize bioavailability and safety issues with least or no adverse side effects and the provisional new dimensions presented in this direction may add value in the prevention and cure of complex chronic diseases.

Effects of curcumin/turmeric supplementation on obesity indices and adipokines in adults: A grade-assessed systematic review and dose-response meta-analysis of randomized controlled trials

In the present study, we explored the effect of curcumin/turmeric supplementation on anthropometric indices of obesity, leptin, and adiponectin. We searched PubMed, Scopus, Web of Science, Cochrane Library, and Google Scholar up to August 2022. Randomized clinical trials (RCTs) investigating the impact of curcumin/turmeric on obesity indices and adipokines were included. We applied the Cochrane quality assessment tool to evaluate the risk of bias. The registration number is CRD42022350946. Sixty eligible RCTs, with a total sample size of 3691 individuals were included for quantitative analysis. We found that supplementation with curcumin/turmeric significantly reduced body weight (WMD: -0.82 kg, 95% CI: -1.30, -0.35; p = 0.001), body mass index (WMD: -0.30 kg/m² , 95% CI: -0.53, -0.06, p = 0.013), waist circumference (WMD: -1.31 cm, 95% CI: -1.94, -0.69, p < 0.001), body fat percentage (WMD: -0.88%, 95% CI: -1.51, -0.25, p = 0.007), leptin (WMD = -4.46 ng/mL; 95% CI: -6.70, -2.21, p < 0.001), and increased adiponectin (WMD = 2.48 μg/mL; 95% CI: 1.34, 3.62, p < 0.001). Overall, our study shows that supplementation with curcumin/turmeric significantly improves anthropometric indices of obesity and adiposity-related adipokines (leptin and adiponectin). However, due to high between-studies heterogeneity, we should interpret the results with caution.

The effects of curcumin on anthropometric and cardiometabolic parameters of patients with metabolic related diseases: a systematic review and dose-effect meta-analysis of randomized controlled trials

Objective:To perform a meta-analysis of published randomized controlled trials (RCTs) to assess the effects of curcumin supplementation with different formulations on anthropometric and cardiometabolic indices in patients with metabolism-related diseases (MRDs). Methods: Six databases, including PubMed, Embase, Web of Science, China national knowledge internet (CNKI), Wanfang and China Biology Medicine (CBM), were systematically searched to find relevant articles from 2011 to July 2021. The effect sizes were expressed as weighted mean difference (WMD) with 95% confidence intervals (CI). Between-study heterogeneity was assessed using I2. Subgroup analysis was conducted to find possible sources of heterogeneity. Curcumin formulations in this study were divided as low bioavailability, high bioavailability and nanocurcumin. Results: Of the retrieved 1585 articles, 31 were included in the final analysis. Combined effect sizes suggested a significant effect of curcumin supplementation on reduced body weight (BW) (WMD: -0.94 kg, 95% CI: -1.40, -0.47) and body mass index (BMI) (WMD: -0.40 kg/m2, 95% CI: -0.60, -0.19), respectively. The results also showed significant improvements of fasting plasma glucose (FPG) (WMD: -0.50 mg/dL, 95% CI: -0.72, -0.28), glycosylated hemoglobin (Hb1Ac) (WMD: -0.42%, 95% CI: -0.57, -0.26), insulin (INS) (WMD: -1.70 μIU/mL, 95%CI: -2.03, -1.38), homeostasis model assessment-insulin resistance (HOMA-IR) (WMD: -0.71, 95%CI: -1.11, -0.31), high-density lipoprotein cholesterol (HDL-C) (WMD: 1.73 mg/dL, 95%CI: 0.78, 2.68) and high sensitivity C-reactive protein (Hs-CRP) (WMD: -1.11, 95%CI: -2.16, -0.05). Nanocurcumin showed a greater reduction in FPG (WMD: -1.78 mg/dL, 95% CI: -2.49, -1.07), INS (WMD: -1.66 μIU/mL, 95% CI: -3.21, -0.11), TC (WMD: -12.64 mg/dL (95% CI: -23.72, -1.57) and LDL-C (WMD: -8.95 mg/dL, 95% CI: -16.51, -1.38). The dose-effect analysis showed that there were trends of first rising and then falling between the supplemented curcumin dose and BW, BMI, LDL-C, Hb1Ac, which were clearly distinguished at 80 mg/d due to the strong effect of nanocurcumin on outcomes. A slow upward trend between the dose of curcumin supplementation and HDL-C. No relationships between dose and outcomes were found for FPG and insulin, except for nanocurcumin at 80 mg/d. Conclusions: Our study showed some significant beneficial effects of curcumin supplementation on improving BW, BMI, and the levels of FPG, Hb1Ac, HOMA-IR, HDL-C and Hs-CRP in patients with MRDs. Nanocurcumin may have a greater effect on the reduction of FPG, INS, TC and LDL-C than other curcumin formulations. Considering the potential bias and limitations of studies included, further quality studies with larger sample sizes are needed to confirm these results.

Effect of curcumin on C-reactive protein as a biomarker of systemic inflammation: An updated meta-analysis of randomized controlled trials

It has been suggested that curcumin is a potential agent for lowering the levels of C-reactive protein (CRP) and high-sensitivity CRP (hs-CRP), as markers of inflammation. In the current meta-analysis, we attempted to clarify the efficacy of curcumin supplementation in lowering the concentrations of CRP and hs-CRP in patients with autoinflammatory conditions. Nine studies were found evaluating the effect of curcumin on CRP levels, while 23 studies were identified for hs-CRP. CRP concentration was decreased significantly compared to the placebo (WMD = -3.67 mg/L, 95% CI = -6.96 to -0.38, p = 0.02). There was a significant effect of curcumin at dose ≤1,000 mg/day on the CRP concentration. CRP concentration significantly decreased after >10-week intervention compared with placebo.hs-CRP concentration in the intervention group was significantly lower than that of placebo group. A significant effect of curcumin consumption was detected on the serum level of hs-CRP in studies with prescribing ≤1,000 mg/day, and those with ≤10-week duration of intervention. Curcumin consumption resulted in a reduction of hs-CRP in a non-linear fashion with stronger effects with less than 2000 mg curcumin per day. Curcumin seems to be beneficial in decreasing the hs-CRP and CRP levels in proinflammatory settings.

The effects of nano-curcumin supplementation on glycemic control, blood pressure, lipid profile, and insulin resistance in patients with the metabolic syndrome: A randomized, double-blind clinical trial

Metabolic syndrome (MetS) is one of the most important health hazards. Curcumin is extracted from Curcuma longa (turmeric), which can affect the components of MetS. To increase the oral bioavailability of curcumin, nano-micelle curcumin is used instead of curcumin powder. In this randomized, double-blind, controlled clinical trial, 50 patients with MetS were randomly assigned to two groups to receive either 80 mg/day nano-curcumin (n = 25) or placebo (n = 25), for 12 weeks anthropometric measurements, blood pressure, and biochemical factors-including fasting blood sugar (FBS), Hemoglobin A1c (HbA1c), homeostatic model assessment (HOMA) for insulin resistance (HOMA-IR), pancreatic β cell function (HOMA-β) and lipid profile-were assessed at the baseline and the end of the study. Statistical analyses were done using SPSS software (Version 23). The analysis between the two groups has illustrated a significant reduction in the average change of triglyceride (TG) levels (-60.5 ± 121.7 vs. 13.1 ± 78.1 mg/dL; p < .05) and HOMA-β (-5.7 ± 48.2 vs. -4.01 ± 16.9; p < .05). But there were no significant differences in anthropometric measurements, blood pressure and biochemical factors-including FBS, HbA1c, HOMA-IR, HOMA-β, and lipid profile variables include (total cholesterol, LDL-C, and HDL-C) at the end of the study. In conclusion, supplementation with nano-micelle curcumin significantly improved serum TG in MetS patients.

Effects of Curcumin on Depression and Anxiety: A Narrative Review of the Recent Clinical Data

Depressive and anxiety disorders affect a significant proportion of the global population and constitute one of the highest disease burdens worldwide. Conventional pharmacological treatments are traditionally the first line of therapy for individuals affected by these conditions although these are only successful approximately half of the time and are often associated with undesirable side effects. This review describes the use of the natural substance curcumin as a potential alternative treatment of these mental disorders. With this in mind, we analyzed the effects of curcumin in eight clinical studies of depression and five studies of anxiety and assessed these using psychiatric symptom scores and molecular biomarker readouts.

The Effect of Curcumin Supplementation on Pulse Wave Velocity in Patients with Metabolic Syndrome: A Randomized, Double-Blind, Placebo-Controlled Trial

Cardiovascular disease is a leading cause of death in many societies. Arterial stiffness is an initial sign of structural and functional changes in the arterial wall. Pulse wave velocity (PWV) is the gold standard for non-invasive evaluation of aortic stiffness and a modifiable cardiovascular risk factor. Curcumin is a major component of turmeric with known anti-inflammatory and anti-oxidative effects. Since arterial stiffness is affected by inflammation and oxidative stress, it may be improved by curcumin supplementation. The purpose of this clinical trial was to investigate the potential effects of curcumin on improving arterial stiffness in patients with metabolic syndrome. This placebo-controlled, double-blind, randomized clinical trial was conducted among metabolic syndrome patients. Sixty-six eligible individuals were randomly assigned to active intervention or control groups. The active intervention group received curcumin supplement at a dose of 500 mg daily for 12 weeks, whereas the control group received placebo capsule. Physical activity, daily dietary energy intake, anthropometric body composition, and biochemical hemodynamic and arterial stiffness parameters were evaluated at baseline and at the end of the study. Body weight decreased significantly in the curcumin group compared to placebo. Also, curcumin intervention improved PWV, which remained significant after adjustment for potential confounding factors (p = 0.011). The current clinical trial demonstrated that daily intake of 500 mg of curcumin for 12 weeks can lead to the improvement of arterial stiffness and weight management among subjects with metabolic syndrome.

The Effects of Curcumin Plus Piperine Supplementation in Patients with Acute Myocardial Infarction: A Randomized, Double-Blind, and Placebo-Controlled Trial

BACKGROUND

Acute myocardial infarction (AMI) is a leading cause of death and disability worldwide. Previous investigations have demonstrated that curcumin has a cardioprotective effect and may improve myocardial injury. So this study was performed to assess whether supplementation with curcumin could diminish myocardial injury following AMI.

METHODS

To conduct this randomized, double-blinded, and placebo-controlled clinical trial, seventy-two patients with acute myocardial infarction, aged 18-75 years, were enrolled and randomly divided into the active intervention and control groups. The active intervention group (n = 38) received curcumin capsules with piperine supplement (500 mg/day, 95% curcuminoids) for 8 weeks, whereas the control group (n = 34) received a placebo capsule. At the baseline and end of the study, ejection fraction was assessed, and blood samples were taken from all patients to measure the levels of cardiac troponin I(cTnI), lipid profile, FBG, HbA1C, liver enzymes, renal function parameters, and electrolytes.

RESULTS

In this trial, curcumin supplementation significantly reduced the levels of HbA1C (-0.3 ± 2.2 vs. +1.1 ± 1.3, P = 0.002), LDL (-10.3 ± 20.7 vs. +0.2 ± 22.5, P = 0.039), ALT (-10.2 ± 28.5 vs. +7.3 ± 39.2, P = 0.029), and ALP (+6.4 ± 39.5 vs. +38.0 ± 69.0, P = 0.018) compared to the placebo group. Moreover, the serum concentration of HDL significantly improved in comparison with the placebo group (+4.5 ± 8.9 vs. -1.6 ± 7.7, P = 0.002). However, no substantial difference was perceived between the groups regarding the ejection fraction and serum levels of cTnI, FBG, renal function parameters, and electrolytes.

CONCLUSION

Our results indicated that daily intake of 500 mg of curcumin capsules with piperine supplement for 8 weeks modified lipid profile, liver enzymes, and glycemic status, but did not have any effect on ejection fraction and serum concentration of cardiac troponin I, renal function parameters, and electrolytes in acute myocardial infarction patients.

The effect of Curcumin/Turmeric on blood pressure modulation: A systematic review and meta-analysis

BACKGROUND AND AIM

Hypertension is a chronic condition that can lead to several health problems, such as cardiovascular diseases, myocardial infarction, stroke, retinopathy and renal failure. In the present study, a systematic review and meta-analysis was undertaken with the main aim of estimating the quantitative effect of curcumin/turmeric supplementation on blood pressure (BP).

METHODS

A systematic search was undertaken in Medline, Embase, Scopus, ISI Web of Science, Google Scholar and Cochrane library up to May 2019 to identify randomized clinical trials assessing the effect of curcumin/turmeric on systolic BP (SBP) and diastolic BP (DBP). A random-effects model was used to analyze the impact of combined trials. Cochrane Risk of Bias Tool was applied to assess potential risks of bias.

RESULTS

A total of 11 studies comprising 734 participants were eligible and included in the meta-analysis to estimate pooled effect size. Results of the meta-analysis did not indicate any significant effect of curcumin/turmeric on SBP (-0.69 mmHg; 95% CI: -2.01, 0.64; I2 = 18%) and DBP (0.28 mmHg; 95% CI: -1.12, 1.68; I2 = 53%). However, subgroup analysis revealed a significant reduction only in SBP levels (-1.24 mmHg; 95% CI: -2.26, -0.22; I2 = 0%) but not DBP (0.29 mmHg; 95% CI: -0.65, 1.22; I2 = 1%) in studies with ≥12-week supplementation. No favorable effect of curcumin administration on SBP or DBP levels was found after stratification according to either participant's condition or type of intervention (turmeric, crude curcumin and high-absorption curcumin).

CONCLUSION

The present meta-analysis suggests that consuming curcumin/turmeric may improve SBP when administered in long durations. However, more studies are needed to confirm these results.

Curcumin encapsulation and protection based on lysozyme nanoparticles

Curcumin possesses antioxidant, anti-inflammatory, and other properties. However, this compound exhibits low bioavailability because of its poor solubility and stability. In this paper, lysozyme nanoparticles were fabricated through solvent evaporation, and then, the solubilization and protection capability of curcumin were investigated. Lysozyme nanoparticles were characterized by dynamic light scattering technique, atomic force microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. The load capacity and stability in thermal environment were further explored. Results showed that the lysozyme nanoparticle displayed a spherical structure (127.9 ± 2.12 nm) with favorable distribution. The solubility of curcumin can increase to 22 μg/mL. After encapsulation by lysozyme nanoparticles, the retentive curcumin can reach up to 67.9% and 30.25% at 25°C and 50°C, respectively, significantly higher than that of free curcumin. Meanwhile, experiments on DPPH free radicals indicated the curcumin loaded by lysozyme nanoparticle possessed higher free radical scavenging activity than that of free curcumin with same treatments. The results confirmed that lysozyme nanoparticles exhibit potential applications in solubilizing and protecting the environment-sensitive hydrophobic functional components.

Metabolic benefits of curcumin supplementation in patients with metabolic syndrome: A systematic review and meta-analysis of randomized controlled trials

The finding of studies on the effect of curcumin extract on metabolic factor in patients with metabolic syndrome has had arguable results. This systematic review with meta-analysis of randomized controlled trials (RCT) aimed to analyze the effect of curcumin/turmeric on metabolic factors in patients with metabolic syndrome. The PICO strategy was used to establish the guiding question of this review. Several databases for RCT were searched until September 2018. Of the 144 articles initially identified, seven trials met the eligibility criteria. A random-effects model with a mean weight difference (WMD) and a 95% confidence interval was performed for quantitative data synthesis. Pooled estimates of WMD were calculated between intervention and control groups using random-effects model in the presence of high level of heterogeneity between the studies. The results showed significant improvement of fasting blood glucose (p = 0.01), triglycerides (p < 0.001), high-density lipoprotein cholesterol (p = 0.003), and diastolic blood pressure (p = 0.007) levels. Curcumin was not associated with a significant change in waist circumference measurement (p = 0.6) and systolic blood pressure level (p = 0.269). Curcumin supplementation improves some components of metabolic syndrome.

Hormetic effects of curcumin: What is the evidence?

Curcumin (diferuloylmethane), a component of the yellow powder prepared from the roots of Curcuma longa or Zingiberaceae (known as turmeric) is not only widely used to color and flavor food but also used as a pharmaceutical agent. Curcumin demonstrates anti-inflammatory, anticarcinogenic, antiaging, and antioxidant activity, as well as efficacy in wound healing. Notably, curcumin is a hormetic agent (hormetin), as it is stimulatory at low doses and inhibitory at high doses. Hormesis by curcumin could be also a particular function at low doses (i.e., antioxidant behavior) and another function at high dose (i.e., induction of autophagy and cell death). Recent findings suggest that curcumin exhibits biphasic dose-responses on cells, with low doses having stronger effects than high doses; examples being activation of the mitogen-activated protein kinase signaling pathway or antioxidant activity. This indicates that many effects induced by curcumin are dependent on dose and some effects might be greater at lower doses, indicative of a hormetic response. Despite the consistent occurrence of hormetic responses of curcumin in a wide range of biomedical models, epidemiological and clinical trials are needed to assess the nature of curcumin's dose-response in humans. Fortunately, more than one hundred clinical trials with curcumin and curcumin derivatives are ongoing. In this review, we provide the first comprehensive analysis supportive of the hormetic behavior of curcumin and curcumin derivatives.

The Effect of Curcumin on Serum Copper and Zinc and Zn/Cu Ratio in Individuals with Metabolic Syndrome: A Double-Blind Clinical Trial

Metabolic syndrome is a complex disorder with high socioeconomic costs and a high global prevalence. The serum concentrations of some trace elements are higher in people with metabolic syndrome compared to normal individuals. Curcumin is derived from turmeric and has antioxidant and anti-inflammatory properties. Curcumin may therefore have a potential role in the management of cardiovascular risk. The aim of this study was to investigate the effects of curcumin on serum copper (Cu), zinc (Zn), and Zn/Cu ratio levels in patients with metabolic syndrome. A double-blind clinical trial was designed in which 120 individuals with metabolic syndrome were randomly assigned to one of three groups: curcumin 1gr/day, phospholipidated curcumin 1gr/day, or a placebo, each taken for 6 weeks. Serum copper and zinc were measured before and after intervention. At baseline, in addition to obtaining the anthropometric characteristics of participants, a fasting blood sample was taken from each participant, and the concentrations of serum Cu and Zn were measured by atomic absorption (Varian AA 240 FS model). Serum Zn concentrations rose significantly in the phospholipidated curcumin and curcumin groups, being significantly higher (p <.001) in the phospholipidated curcumin group than in the curcumin group (p <.05). Serum Zn concentration fell in the control group (p <.05). Changes in serum Zn level from baseline to the levels after six weeks' intervention were significantly different between the groups, but changes in serum Cu from between baseline until after intervention were not significantly different. The serum Zn/Cu level in phospholipidated curcumin and curcumin groups after intervention was higher than for the control group, but it was more significant in the group taking phospholipidated curcumin (p <.001). Curcumin and phospholipidated curcumin complex, given at a dose of 1 g per day for six weeks, were associated with an increase in serum zinc and consequently zinc-to-copper ratio.