Post-Prandial Effects of High-polyphenolic Extra Virgin Olive Oil on Endothelial Function in Adults at Risk for Type 2 Diabetes: A Randomized Controlled Crossover Trial

Abstract

Abstract Objectives The effects of olive oil on cardiovascular risk have been controversial. We compared the effects of high-polyphenolic extra virgin olive oil (EVOO) and refined olive oil without polyphenols on endothelial function (EF) in adults at risk for Type 2 diabetes. Methods Randomized, controlled, double-blind, crossover trial of 20 adults (mean age 56.1 years; 10 women, 10 men) at risk for Type 2 diabetes (i.e., as defined by either prediabetes or metabolic syndrome) assigned to one of two possible sequence permutations of two different single dose treatments (50 mL of high-polyphenolic EVOO or 50 mL of refined olive oil without polyphenols), with 1-week washout. Participants received their olive oils in a smoothie consisting of ½ cup frozen blueberries and 1 cup (8oz) low fat yogurt (Crowley low-fat vanilla) blended together and served in a 20 oz. plastic cup. Our primary outcome measure was EF measured as flow-mediated dilatation. Blood pressure was a secondary outcome measure. Participants were evaluated before and 2 hours after ingestion of their assigned olive oil treatment. Results EVOO acutely improved endothelial as compared to refined olive oil (1.2 ± 6.5% versus −3.6 ± 3.8%; P = 0.0086). No significant effects on systolic or diastolic blood pressure (i.e., −0.9 ± 7.1 mmHg versus −0.6 ± 9.8 mmHg; P = 0.9122 and −1.6 ± 5.0 mmHg versus −1.1 ± 7.6 mmHg; P = 0.8061 respectively) were observed. Conclusions High-polyphenolic EVOO acutely enhanced endothelial function in the study cohort, whereas refined olive oil did not. Blood pressure effects were not observed. The vascular effects of olive oil ingestion should specify the characteristics of the oil. Funding Sources Cobram Estate Extra Virgin Olive Oil.