A red yeast rice-olive extract supplement reduces biomarkers of oxidative stress, OxLDL and Lp-PLA(2), in subjects with metabolic syndrome: a randomised, double-blind, placebo-controlled trial

BACKGROUND: Metabolic syndrome (MetS) refers to clustered cardiovascular risk factors (abdominal obesity, pre-diabetes, high blood pressure, dyslipidaemia). Therapies targeting oxidative stress may delay progression to atherosclerosis and diabetes. We investigated the anti-oxidative effect of a supplement combining red yeast rice and olive extract in patients with MetS. METHODS: A double-blind, placebo-controlled, randomised trial was conducted with 50 patients with MetS as defined by National Cholesterol Education Program Adult Treatment Panel III criteria. Forty-nine subjects randomly assigned to red yeast rice-olive extract (RYR-olive extract; 10.82 mg of monacolins and 9.32 mg of hydroxytyrosol per Cholesfytolplus capsule) or placebo completed the 8-week trial. Whereas effects on cardiovascular risk parameters of MetS have been reported recently, the observed significant 20% increase in oxidised low-density lipoprotein (OxLDL) prompted us to investigate other oxidative stress-related parameters: malondialdehyde (MDA), lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) and 8-hydroxy-2′-deoxyguanosine (8-OHdG). Statistical calculations included univariate quantitative analysis, multivariate linear regression and correlation analysis. RESULTS: The updated results indicate that an RYR-olive extract supplement significantly reduced Lp-PLA(2) by 7% (p < 0.001), but it failed to show a significant decrease in plasma MDA and 8-OHdG (p > 0.05). Reductions in OxLDL (20%) and Lp-PLA(2) (7%) were associated with each other (r = 0.740, p < 0.001). CONCLUSIONS: RYR-olive extract significantly reduced Lp-PLA(2) in correlation with the marked reduction in plasma OxLDL, which may lead to a reduced risk for cardiovascular disease in patients with MetS. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02065180. Registered on 13 February 2014. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13063-017-2058-5) contains supplementary material, which is available to authorized users.