The effect of curcumin (Curcuma longa L.) on circulating levels of adiponectin in patients with metabolic syndrome

In modern societies, metabolic syndrome (MetS) is a highly common disease, which is closely associated with the increased risk of cardiovascular disease (CVD). Metabolic syndrome is usually accompanied by low levels of adiponectin, which is a key regulator of insulin sensitivity and reduced inflammation of the tissue. Adiponectin also reduces systemic insulin resistance and predicts cardiovascular disease. Curcumin has several beneficial effects on risk factors of metabolic syndrome. This polyphenol can affect almost all components of metabolic syndrome including insulin resistance, hypertension and obesity. According to the low oral bioavailability of curcumin, several phospholipid-complex formulations have been developed to address this issue. The present study aims to evaluate the impact of unformulated curcumin and a phospholipid complex of curcumin on serum adiponectin in subjects with metabolic syndrome. Subjects (n = 120) with metabolic syndrome were randomly assigned to three groups which received capsules of phospholipidated curcumin (1 g/day), (n = 40), unformulated curcumin (n = 40) and placebo (n = 40) for a period of 6 weeks. The serum concentrations of adiponectin were measured at baseline and at the end of study using ELISA. The results showed a significant elevation of serum adiponectin concentrations in the curcumin group (mean change 28.9 ± 30.5) in comparison to both curcumin-phospholipid complex (mean change 4.1 ± 15.4) and placebo (mean change −3.5 ± 20.4) groups. Curcumin supplementation increased serum adiponectin concentrations, but this effect was not caused by phospholipid-curcumin complex.