Substantial Variability Across Individuals In The Vascular Response And Nutrigenomic Response To An Acute Intake Of Curcumin: A Randomised Controlled Trial

Objective: Curcumin exerts biological activities of interest in cardiovascular prevention. However, its vascular protective effect is still poorly investigated in humans. The present study aims to assess vascular effects of an acute intake of curcumin and its nutrigenomic impact in circulating immune cells. Design and method: In a randomised, double-blind, crossover design, eighteen healthy smokers consumed a placebo or a 5-gram of curcumin. Before and two hours after the intake, vascular function measurements were performed by using flow-mediated dilation (FMD). In addition, endothelial function in the microcirculation and blood pressure were evaluated. Plasma curcumin concentrations and changes in gene expression in peripheral blood mononuclear cells (PBMC) were analysed. Results: No significant effect of curcumin on FMD was observed when considering the entire study population (p = 0.08), mainly due to a high inter-individual variability. Interactions were found for gender and risk score, but not for plasma curcumin concentration, to explain this variability. A subgroup analysis according to the gender or the cardiovascular-risk score revealed a significant effect of curcumin on FMD in women (δ = 2.07 ± 2.59%, p < 0.001) and in subjects presenting lower cardiovascular risk (δ = 1.45 ± 0.97%; p < 0.001). Pulse pressure decreased significantly in men (δ = -5.06 ± 7.21 mmHg, p = 0.009) and in subjects presenting higher cardiovascular risk (δ = -4.81 ± 4.54 mmHg, p = 0.04). No change in gene expression was observed when data were analysed for all volunteers but changes in expression were observed when analyzed according to gender. Conclusions: This clinical trial highlights that a substantial variability in efficacy of curcumin exists across individuals, with potential positive effects on endothelial function and pulse pressure.