Effect of Curcumin on Diabetic Kidney Disease: A Systematic Review and Meta-Analysis of Randomized, Double-Blind, Placebo-Controlled Clinical Trials

Abstract

Background. Curcumin, a polyphenolic constituent from Curcuma longa, possesses antioxidant, hypolipidemic, and antidiabetic properties and has been reported to protect against diabetic kidney disease (DKD); however, the effect is inconsistent. Objective. This systematic review and meta-analysis aimed to investigate the effect of curcumin supplementation on renal function, lipid profile, blood pressure, and glycemic control in DKD. Methods. A systematic and comprehensive literature search of interrelated randomized controlled trials (RCTs) was conducted in PubMed, Embase, Cochrane Library, Web of Science, Scopus, and ClinicalTrials.gov from inception to July 30, 2021. Two investigators independently extracted data and assessed the risk of bias. Weighted mean differences (WMDs) with 95% confidence intervals (CIs) were calculated to describe the effect sizes using a fixed-effect model. Statistical analysis was performed using STATA 14.0 and RevMan 5.3. Results. Five RCTs involving 290 participants with DKD were included. Curcumin supplementation significantly improved the serum creatinine (WMD: −0.16 mg/dL, 95% CI: −0.3 to −0.02, P = 0.029, I2 = 0%, moderate certainty), total cholesterol (WMD: −10.13 mg/dL, 95% CI: −17.84 to −2.14, P = 0.01, I2 = 0%, moderate certainty), systolic blood pressure (WMD: 3.94 mmHg, 95% CI: 1.86 to 6.01, P < 0.01, I2 = 33.5%, moderate certainty), and fasting blood glucose (WMD: −8.29 mg/dL, 95% CI: −15.19 to −1.39, P = 0.019, I2 = 43.7%, moderate certainty) levels; however, it had no significant effects on blood urea nitrogen, proteinuria, triglyceride, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, and diastolic blood pressure levels. Conclusions. Curcumin may provide great potential effects against DKD. More large-scale and high-quality RCTs are required to confirm these findings.

The Effect of Curcumin on Renal Ischemia/Reperfusion Injury in Diabetic Rats

“…Fatih et al demonstrated, in a preclinical I/R study, that the use of curcumin reduced inflammatory process, oxidative stress and apoptosis by the semaphorin–plexin [ 30 ]. In a translational view, a meta-analysis of randomized, double-blind, placebo-controlled clinical trials about curcumin supplementation in patients with diabetic kidney disease (DRD) showed a significant improvement in serum creatinine corroborating the findings of this investigation [ 31 , 32 ].…”

Oxidative Stress and NRF2/KEAP1/ARE Pathway in Diabetic Kidney Disease (DKD): New Perspectives

“…Curcuma Longa Linn, of the Zingiberaceae family, contains a structure called rhizome, which is converted into a powder, known as turmeric, from which a natural component named curcumin is derived. Curcumin is part of the polyphenol group, known primarily for its use as a culinary spice [ 84 , 85 , 86 ]. It has many known biological roles that may influence the treatment of several oncological, neurological, cardiological and nephrological conditions [ 87 ].…”

“…It has many known biological roles that may influence the treatment of several oncological, neurological, cardiological and nephrological conditions [ 87 ]. Curcumin can modulate inflammation, the immune system, lipid and carbohydrate metabolism and prevent the development of DM-derived complications, including DKD [ 84 , 88 ]. It also plays a role in decreasing OS [ 7 ].…”

“…Further, curcumin has to be administered in high doses to exert its therapeutical roles. In the in vivo studies conducted on DKD animal models [ 95 , 96 , 97 ], the research team used curcumin 50–200 mg/kg per day, while in the clinical trials, reviewed by Jie et al [ 84 ], the patients who received unaltered curcumin were given a dose between 320 and 1670 mg per day. Last but not least, its absorption is limited, while its degradation and elimination are fast, posing more challenges in the medical use of curcumin [ 98 ].…”

A Glimpse of Inflammation and Anti-Inflammation Therapy in Diabetic Kidney Disease

“…In addition to TCM, nutraceuticals derived from Chinese herbal medicines could prevent DKD, for example, boswellic acid, curcumin and quercetin ( Lu et al, 2015 ; Lu et al, 2017 ; Asgharpour and Alirezaei, 2021 ). A systematic review and Meta-analysis revealed that curcumin supplementation significantly improved blood sugar, lipid and blood pressure control and decreased the serum creatinine in DKD patients ( Jie et al, 2021 ). Lu et al also found that curcumin could delay fibrosis progression in DKD mice by inhibiting the initiation of NLRP3 inflammasome and reduce the expression of IL-1β in renal tissue ( Lu et al, 2017 ).…”