Antihypertensive Effects of Curcumin/Turmeric Supplementation in Prediabetes and Diabetes: A Systematic Review and Meta‐Analysis of Randomised Controlled Trials

ABSTRACT Introduction Hypertension is a major cardiovascular risk factor in individuals with prediabetes and type 2 diabetes (T2D). Curcumin, with its anti‐inflammatory and antioxidant properties, has emerged as a potential adjunct therapy, but its effect on blood pressure in this population remains unclear. Aims This meta‐analysis aimed to evaluate the effects of curcumin or turmeric supplementation on systolic (SBP) and diastolic (DBP) blood pressure in adults with prediabetes or T2D. Methods A systematic search of PubMed, Scopus, and Web of Science was conducted until August 2025. Randomised controlled trials (RCTs) investigating curcumin/turmeric supplementation on blood pressure in adults with prediabetes or T2D were included. A meta‐analysis was performed using a random‐effects model. Results Fifteen RCTs comprising 16 treatment arms ( n = 855 participants) were included. Pooled results indicated that curcumin/turmeric supplementation significantly reduced SBP (WMD: −2.69 mmHg; 95% CI: −3.84 to −1.55; p < 0.001; I 2 = 30.1%) compared to control groups. A more substantial reduction in SBP (−3.41 mmHg) was observed in the subgroup of participants with baseline hypertension (SBP ≥ 130 mmHg). However, no significant effect was found on DBP (WMD: −1.20 mmHg; 95% CI: −2.84 to 0.44; p = 0.15; I 2 = 84.3%). Subgroup analyses showed significant reductions in SBP in individuals with T2D or prediabetes, in those who were overweight, and with interventions using nano‐curcumin, turmeric, or curcumin with piperine at doses > 1 g/day. In addition, subgroup analysis showed that curcumin/turmeric supplementation led to a significant reduction in DBP in individuals with T2D. Conclusions Curcumin/turmeric supplementation demonstrates a modest, yet significant reduction in SBP in individuals with prediabetes and diabetes, with a more pronounced effect in those with baseline hypertension. Further high‐quality RCTs are needed to confirm these findings and establish optimal dosing.