The effect of highly bioavailable forms of curcumin on lipoprotein(a) plasma levels: A systematic review and meta-analysis of randomized clinical studies

Abstract

Curcumin is a bioactive compound derived from the rhizome of Curcuma longa (turmeric) that has garnered increasing attention for its potential health benefits. However, its use in clinical practice is limited due to its generally poor bioavailability. This issue can be overcome using novel delivery systems that enhance curcumin’s solubility, extend its residence time in plasma, improve its pharmacokinetic profile, and increase its cellular uptake. Novel curcumin formulations with improved bioavailability have been suggested to elevate plasma concentrations of lipoprotein(a) (Lp(a)), but there is no definitive evidence of a causal relationship. To address this, a systematic literature search was conducted in multiple electronic databases to identify relevant randomized placebo-controlled clinical studies published without a time limit. A meta-analysis of data suggested that dietary supplementation with highly bioavailable forms of curcumin significantly reduces Lp(a) levels [Standardized Mean Difference (SMD)= -0.96 (95 % Confidence Interval (CI): −1.82, −0.11)]. The effect size was robust in the leave-one-out sensitivity analysis and was not primarily driven by any single study. Of course, the clinical significance of this observation should be more thoroughly evaluated in longer-term trials, where the combined metabolic and anti-inflammatory effects of curcumin have vascular protective effects.