Effects of Virgin Olive Oils Differing in Their Bioactive Compound Contents on Biomarkers of Oxidative Stress and Inflammation in Healthy Adults: A Randomized Double-Blind Controlled Trial. Sanchez-Rodriguez E, Biel-Glesson S, Fernandez-Navarro JR, et al. Nutrients. Vol. 11 (2019): 1-14. 

Key Findings: This randomized, crossover, controlled, double-blind trial study was conducted in 51 subjects. They received a daily dose of 30 ml (2 Tablespoons) of one of three different olive oils for 3 weeks with a 2-week washout period in between interventions: 1) an “optimized” virgin olive oil high in phenolic compounds, 2) a “functional” olive oil enriched with triterpenes (organic compounds found in olives), and 3) a virgin olive oil with reduced phenolic compounds. Triterpenes are a class of organic compounds found in plants. The olive oil polyphenols and tepenes decreased inflammation and DNA damage which is linked to heart disease. Taking extra amounts of these bioactive ingredients in a concentrated form could be beneficial for heart health. 

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Polyphenol Intake from a Mediterranean Diet Decreases Inflammatory Biomarkers Related to Atherosclerosis: A Substudy of the PREDIMED trial. Medina-Remón A, Casas R, Tressserra-Rimbau A, et al. British Journal of Clinical Pharmacology. Vol. 83 (2017): 114-128. 

Key Findings: Studies consistently suggest that the Mediterranean diet (MDiet), which includes olives and olive oil as primary components, is associated with a lower risk of cardiovascular diseases. This particular study showed that a MDiet can improve cardiovascular health by: 1) Improving blood lipids, specifically, increasing levels of HDL cholesterol and decreasing levels of LDL cholesterol; 2) Reducing both systolic and diastolic blood pressure; 3) Enhancing endothelial function, leading to better vasodilation and blood flow; and 4) Reducing inflammation and oxidative stress, both of which are key contributors to cardiovascular disease. 

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Platelet Aggregation Values in Patients with Cardiovascular Risk Factors are Reduced by Verbascoside Treatment. A Randomized Study. Campo G, Pavasini R, Biscaglia S. Pharmacological Research. Vol. 97 (2015): 1-6

Key Findings: This study examined whether a substance called verbascoside, a natural compound found in olives and in Olivino™, could prevent blood platelets from sticking together. Preventing “platelet aggregation” is important for heart health. In this study, researchers gave verbascoside to 100 people with at least one risk factor for heart disease, such as having diabetes, high blood pressure, smoking, high cholesterol, or being overweight. They split the participants into three groups: one group got a placebo (fake treatment), one group got a low verbascoside dose (50mg), and one group got a higher verbascoside dose (100mg). Participants' platelet activity was measured before and after 2 weeks of treatment. The higher dose of verbascoside (100mg) significantly reduced platelet activity.  

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Olive Oil Polyphenols Decrease LDL Concentrations and LDL Atherogenicity in Men in a Randomized Controlled Trial. Hernáez A, Remaley AT, Farràs M. Journal of Nutrition. Vol 145 (2015): 1692-1697.

Key Findings: This randomized controlled clinical trial involved 25 healthy European men aged 20-59. Participants were given 25 mL (1.7 Tablespoons) per day of olive oil either low in polyphenols or high in polyphenols for 3 weeks. The effects of these different types of olive oil on various aspects of cholesterol and heart health were then evaluated. Researchers found: 1) Consumption of olive oil with high polyphenol content led to a significant decrease in LDL cholesterol (bad cholesterol), compared to baseline levels. In contrast, the low polyphenol olive oil did not significantly change LDL cholesterol levels; 2) The study also measured the total number of LDL particles and the number of small LDL particles. Higher levels of small LDL particles are associated with increased cardiovascular risk. Participants who consumed olive oil with high polyphenol content experienced a significant decrease in both total LDL particles and small LDL particles compared to baseline levels. The study also examined LDL atherogenicity, which means the tendency of LDL cholesterol to form plaques in the arteries, leading to atherosclerosis (hardening of the arteries). The study found that consumption of olive oil with high polyphenol content resulted in a decrease in LDL atherogenicity. These findings support the notion that polyphenols in olive oil may play a role in reducing the risk of cardiovascular disease.

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Olive Oil Polyphenols Enhance High-Density Lipoprotein Function in Humans: A Randomized Controlled Trial. Hernáez A, Fernández-Castillejo S, Farràs M.  Arteriosclerosis, Thrombosis, and Vascular Biology. Vol. 34 (2014): 2115-2119.

Key Findings: This randomized, crossover, controlled trial included 47 healthy European men who ingested 25 mL/d (1.7 Tablespoon) of polyphenol-poor (2.7 mg/kg) or polyphenol-rich (366 mg/kg) olive oil in 3-week intervention periods, preceded by 2-week washout periods. HDL cholesterol efflux capacity significantly improved after consuming polyphenol-rich olive oil vs. the polyphenol-poor olive oil.  HDL cholesterol efflux refers to the ability of HDL cholesterol (the "good" cholesterol), to remove excess cholesterol from the cells in your body and transport it back to the liver, where it can be broken down and removed. This helps prevent the buildup of cholesterol in the walls of arteries, which can lead to heart disease. 

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Inverse Association Between Habitual Polyphenol Intake and Incidence of Cardiovascular Events in the PREDIMED study. Tresserra-Rimbau A, Rimm EB, Medina-Remón A, et al.  Nutrition, Metabolism and Cardiovascular Diseases. Vol. 24 (2014): 539-447.

Key Findings: The aim of this study was to evaluate the association between intakes of total polyphenol intake and the risk of major cardiovascular disease (CVD) events, including myocardial infarction, stroke or death from cardiovascular causes in the PREDIMED study. “PREDIMED” stands for “PREvención con DIeta MEDiterránea" (Prevention with Mediterranean Diet), a clinical trial conducted in Spain involving 7172 participants. After 4.3 years of follow-up, those who consumed the most polyphenols had 46% reduction in risk of CVD. 

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Antioxidant Activity of Olive Polyphenols in Humans: A Review. Raederstorff D.  International Journal of Vitamin and Mineral Research. Vol. 79 (2009): 152-165.

Key Findings:  Polyphenols found in olives have strong antioxidant abilities. These have been demonstrated in laboratory studies (in vitro) and studies on animals. Research involving humans has shown that olive polyphenols can decrease the levels of oxidized-Low Density Lipoprotein (LDL, a harmful form of cholesterol) in the bloodstream. Olive polyphenols also have positive effects on various markers of oxidative damage in the body. The antioxidant effects of olive polyphenols on LDL oxidation are noticeable with a daily dietary intake of about 10 mg.

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The Effect of Polyphenols in Olive Oil on Heart Disease Risk Factors: A Randomized Trial. Covas M-I, Nyyssönen K, Poulsen HE.  Annals of Internal Medicine. Vol. 145 (2006): 333-341.

Key Findings: This randomized, crossover, controlled trial involving 200 healthy male volunteers was conducted in 6 research centers from 5 European countries. Participants were randomly assigned to 3 sequences of daily administration of 25 mL (1.7 Tablespoons) of 3 different olive oils: 1)  Olive oil with low (2.7 mg/kg) medium (164 mg/kg), or high (366 mg/kg) phenolic content but otherwise similar. Intervention periods were 3 weeks preceded by 2-week washout periods. A linear increase in high-density lipoprotein (HDL) cholesterol levels was observed for low-, medium-, and high-polyphenol olive oil. Triglyceride levels decreased after consumption of all olive oils. Oxidative stress markers decreased linearly with increasing phenolic content. Researchers concluded that olive oil is more than a monounsaturated fat. Its phenolic content can also benefit plasma lipid levels and reduce oxidative damage.