Effects of Curcumin/Turmeric Supplementation on Kidney Function in Individuals With Diabetes: A Systematic Review and Meta‐Analysis of Randomised Controlled Trials

BACKGROUND: Curcumin and turmeric are widely studied for their potential renoprotective effects, but evidence regarding their impact on kidney function in individuals with diabetes remains inconsistent. OBJECTIVE: To systematically evaluate the effects of curcumin/turmeric supplementation on kidney function parameters in subjects with diabetes. METHODS: PubMed, Web of Science and Scopus were searched from inception until August 2025. Randomised controlled trials (RCTs) assessing the effects of curcumin/turmeric on serum creatinine, blood urea nitrogen (BUN), uric acid, urea and albumin in diabetic populations were included. Data were pooled using random-effects models and reported as weighted mean differences (WMDs) with 95% confidence intervals (CIs). Subgroup, sensitivity, and meta-regression analyses were conducted. Risk of bias was assessed using the Cochrane RoB 2 tool, and evidence certainty was evaluated via GRADE. RESULTS: Twelve RCTs (n = 1303 participants) were included. Curcumin/turmeric supplementation did not significantly affect creatinine (WMD: -0.01 mg/dL, 95% CI: -0.03 to 0.01, p = 0.519) or BUN (WMD: -0.41 mg/dL, 95% CI: -3.15 to 2.33, p = 0.769). A trend toward reduction in uric acid was observed (WMD: -1.46 mg/dL, 95% CI: -2.93 to 0.02, p = 0.053). However, urea levels were significantly reduced (WMD: -2.53 mg/dL, 95% CI: -4.09 to -0.96, p = 0.002). No significant change was found in albumin (WMD: 0.07 g/dL, 95% CI: -0.02 to 0.17, p = 0.133). Subgroup analyses showed no significant moderating effects. Publication bias was detected for creatinine (Egger's p = 0.028). The certainty of evidence was moderate for creatinine, urea, and albumin, and low for BUN and uric acid. CONCLUSION: Curcumin/turmeric supplementation significantly reduces urea levels but does not significantly affect creatinine, BUN, uric acid or albumin in individuals with diabetes. Further high-quality, long-term RCTs are needed to clarify its renoprotective potential and optimal dosing.