Effects of curcumin supplementation on homocysteine levels: a systematic review and meta-analysis of randomized controlled trials

Why clinicians should know about it

• Picked for Physiology (medical) (top studies of the week, 2 August 2026).

Abstract

BACKGROUND: Homocysteine (Hcy) is an established cardiovascular risk factor, and dietary modulation via nutraceuticals represents a promising preventive strategy. Curcumin, a bioactive polyphenol from Curcuma longa L., exhibits pleiotropic biological activities; however, its capacity to reduce circulating Hcy remains uncertain. OBJECTIVES: To systematically evaluate the effect of curcumin supplementation on Hcy levels. METHODS: Eight databases were searched from inception to November 2025 for RCTs investigating curcumin and Hcy outcomes. Risk of bias was assessed using Cochrane RoB 2.0. A random-effects model was applied. RESULTS: Three randomized controlled trials (RCT) with a total of 110 subjects were included in this study. Due to physiologically implausible Hcy values in one study (Rezaei 2024), the primary meta-analysis was restricted to two RCTs with interpretable data (Ghaffari 2017 and Campbell 2019). The results of Meta-analysis showed that compared with the control group, the pooled standardized mean difference SMD = -2.08, 95% confidence interval was -4.67 to 0.51, P = 0.116, there was no statistically significant difference between the two groups. There was a high degree of heterogeneity among the included studies (I2 = 91.6%, P = 0.001). Risk of bias assessment (RoB 2.0) rated one study as low risk, one as some concerns, and one as high risk (selective reporting). Sensitivity analysis that included the study with implausible data (Rezaei 2024) gave a similar non-significant pooled estimate (SMD = -1.23, 95% CI -2.82 to 0.36, P = 0.13; I2 = 91.9%). CONCLUSION: Current RCT evidence does not support a statistically significant Hcy-lowering effect of curcumin. The overall certainty of evidence is very low due to small sample size, extreme heterogeneity, and risk of bias. Curcumin should not be recommended as a standalone intervention for lowering Hcy. Its potential role, if any, requires confirmation in well-powered trials using optimized, high-bioavailability formulations.

Abstract as published, via PubMed.