Effect of oleocanthal-rich olive oil on postprandial oxidative stress markers of patients with type 2 diabetes mellitus.

BACKGROUND: Type 2 diabetes mellitus (T2DM) is characterized by postprandial dysmetabolism, which has been linked to post-meal redox disturbances. Oleocanthal (OO), one of the most potent bioactive phenols of extra virgin olive oil, has shown redox modulating properties in vitro. However, its acute, in vivo antioxidant properties have never been studied before. OBJECTIVE: The aim of this study was to investigate the kinetics of five redox markers (Thiobarbituric acid-reactive substances [TBARS] and glutathione peroxidase activity in serum-GPx3 and erythrocytes (GPx1), protein carbonyls in serum) after the consumption different meals. DESIGN: Five different isocaloric meals comprised of white bread and butter (BU) or butter plus ibuprofen (BU-IBU) or olive oil poor in OO or olive oils containing 250 and 500 mg/Kg of oleocanthal (OO250 and OO500, respectively). We hypothesized that OO-rich olive oil will reduce postprandial oxidative stress in T2DM patients compared to other lipid sources. This study involved 10 patients with T2DM and had a cross-over design. RESULTS: The comparison of incremental Area Under Curves (iAUCs) has shown that OO-rich olive oils were able to alleviate the increments of thiobarbituric acid-reactive substances (TBARS) and GPx3 and induce a higher red blood cells (RBCs) GPx1 activity compared to OO (P < 0.05). The effect was dose and redox marker depended. Correlation analysis in the pooled sample demonstrated a positive association between postprandial ex vivo platelet sensitivity to ADP and iAUC TBARS. In conclusion, our study has shown that OO-rich olive oils can favorably modulate lipid peroxidation and RBC GPx activity in T2DM patients when consumed as part of a carbohydrate meal. DISCUSSION: This study demonstrates for the first time that, apart from its anti-inflammatory and antiplatelet properties, OO can also exert acute antioxidant effects. CONCLUSION: This finding emphasizes the health benefits of extra virgin olive oil, particularly those with a high OO content, for T2DM patients.