Summary:
Diabetes mellitus is a widespread chronic condition characterised by impaired glucose regulation and long-term metabolic dysfunction. Diabetes contributes directly to millions of deaths each year, many occurring before older age, highlighting its role in premature mortality. The disease includes several forms, most commonly type 1 diabetes, which involves destruction of insulin-producing cells, and type 2 diabetes, which is driven by insulin resistance and deficiency. Hypertension frequently occurs with diabetes and significantly increases the risk of cardiovascular disease, stroke, and other vascular complications. Persistently elevated blood glucose and metabolic abnormalities accelerate damage to both large and small blood vessels, leading to complications such as heart disease, kidney disease, and vision loss. Effective diabetes management therefore requires not only glycaemic control but also blood pressure regulation and lifestyle-based strategies to reduce long-term risk. There is growing interest in the use of natural compounds to support cardiometabolic health. Curcumin, the primary bioactive compound in turmeric, has been widely studied for its anti-inflammatory and antioxidant properties. Research suggests that curcumin may influence metabolic pathways relevant to diabetes, including inflammation, lipid metabolism, insulin sensitivity, and vascular function. This study, a systematic review and meta-analysis of randomised controlled trials involving 855 participants, aimed to evaluate the effect of curcumin or turmeric supplementation on blood pressure in adults with prediabetes or type 2 diabetes. Findings showed that curcumin or turmeric supplementation was associated with a statistically significant reduction in systolic blood pressure compared with control conditions. The reduction was greater among participants with elevated baseline blood pressure. No overall significant effect was observed for diastolic blood pressure, although further analyses suggested potential benefits in individuals with type 2 diabetes. Greater systolic blood pressure reductions were also observed in participants who were overweight, those receiving higher doses, and those using enhanced formulations such as curcumin combined with piperine. In summary, this study suggests that curcumin or turmeric supplementation may reduce systolic blood pressure in adults with prediabetes or diabetes, particularly in those with hypertension at baseline.
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.
Article Publication Date: 12/12/2025
DOI: 10.1002/edm2.70145
