Manolis Makaris Cardiologist, Director of the Cardiology Clinic of Messinia General Hospital, MSc Nanomedicine
The cardioprotective properties of polyphenolic olive oil


Cardiovascular diseases are the leading cause of death in the developed world. Especially in Greece, an increase in cardiovascular diseases has been observed, probably due to the change in eating habits and the adoption of the western way of eating. This is also evident from the ranking of Greece in the moderate risk countries for cardiovascular events according to the European Society of Cardiology, even though until recently it was in the low risk category.

There are many studies that demonstrate the cardioprotective effect of the Mediterranean diet. A landmark study on cardiovascular diseases and olive oil is considered the PREDIMED study. This particular multicenter study was published in 2014 and involved 7,447 volunteer participants with high cardiovascular risk who were put on three different diets for 4.8 years.

The first diet was the Mediterranean with the addition of four tablespoons of extra virgin olive oil daily. The second diet was also Mediterranean with 30 grams of nuts per day, and the third diet was a low-fat diet. This study showed that the Mediterranean diet with extra virgin olive oil offered cardiovascular protection after reducing the combined risk of heart attack, stroke, or cardiovascular death by 31% compared to the low-lipid diet.




In conclusion, the PREDIMED study has opened a new path and even showed the value of the Mediterranean diet and extra virgin olive oil for the prevention of cardiovascular diseases, but also the superiority, as we said, of the Mediterranean diet with extra virgin olive oil in relation to the low-fat diet.




At the same time, another primary prevention study proves that the long-term intake of extra virgin olive oil in the diet leads to a 15% reduction in cardiovascular diseases and a reduction in overall cardiovascular mortality, while the replacement of animal fats, butter, margarine and mayonnaise in the diet with extra virgin olive oil offers a 5 to 7% lower risk of coronary heart disease and cardiovascular morbidity.

Similar intervention studies with the adoption of the Mediterranean diet with the addition of olive oil also exist for the secondary prevention of cardiovascular diseases in patients with coronary artery disease. One such study is CORDIOPREV. In this particular study, it was shown that the Mediterranean diet enriched with extra virgin olive oil compared to the low-fat diet leads to a reduction in the progression of atherosclerosis as determined by ultrasound imaging in the common carotid artery (reduction in the thickness of the intima-media and the height of the atherosclerotic plaque).




A key component of the Mediterranean diet is olive oil. There are different categories of olive oil depending on the acidity and the presence or absence of polyphenols. The composition of the extra virgin olive oil is 98% saponified fraction (monounsaturated and polyunsaturated fatty acids) and 2% unsaponified fraction. The saponified fraction is dominated by oleic acid, while the unsaponified fraction includes polyphenols.

The beneficial properties of olive oil have been known since ancient times. In fact, Dioskouridis recommended taking oil from unripe olives for better health results and better endurance over time. The health-promoting properties of extra virgin olive oil (EVOO) are basically due to these two ingredients for which there has been an official health claim from the European Food Safety Authority (EFSA).

For olive oil polyphenols, EFSA accepts the benefits of a daily intake of olive oil rich in polyphenols corresponding to 5mg of hydroxytyrosol or its derivatives per 20g of olive oil, to prevent the oxidation of cholesterol particles in the general population.

At the same time, there has been a corresponding health claim for oleic acid that requires the replacement of saturated fats with unsaturated fats such as oleic acid. The FDA has approved the labeling of oils with >70% oleic acid (mainly olive oil) that consuming 20g (1.5 tablespoons) of it per day probably reduces heart attacks. In order not to increase body weight, this amount must replace an equal amount of saturated fat.

Various mechanisms have been proposed through which extra virgin olive oil leads to the reduction of cardiovascular diseases such as improving endothelial functionality, reducing inflammation, reducing platelet aggregation, reducing oxidative stress, improving lipid metabolism and reduction of clotting factors. The cardiovascular protection of polyphenols is closely related to their antioxidant activity. Oxidative stress is caused by the imbalance between intracellular levels of reactive oxygen radicals (ROS) and antioxidants and has been proposed as the main aetiological mechanism of atherosclerosis and cardiovascular disease.

The four most abundant polyphenols in EVOO in the Greek territory are oleocanthal, oleacein, ligstroside and oleuropein aglycone. These polyphenols show important in vitro biological activities, participating in various cellular and biochemical processes.





A reliable method of measuring the substances of the regulation has been developed which provides the necessary certificates to support the health claim. Oleocanthal, the main polyphenol in Greek EVOO, is responsible for the burning sensation in the throat when eating and is an inhibitor of cyclooxygenase 1 and 2, having an anti-inflammatory effect similar to non-steroidal anti-inflammatory drugs such as ibuprofen. At the same time, it can slow down Alzheimer's disease in laboratory animals. Oleasin is a 5-lipoxygenase inhibitor, has a strong antioxidant and anti-inflammatory effect and possibly helps against atherosclerosis and aging. The aglycone ligstroside has an anti-inflammatory effect, while the oleuropein aglycone in probably has an antimetastatic and antioxidant effect. Hydroxytyrosol inhibits atherosclerosis in the early stages (inhibition of LDL oxidation and proinflammatory gene expression).





Due to its importance, the Mediterranean diet was included in the representative list of the Intangible Cultural Heritage of Humanity of UNESCO in 2013 after the submission of a file by Cyprus, Croatia, Spain, Greece, Italy, Morocco and Portugal with the respective emblematic communities, in this case, from Greece were the Koroni of Messinia.




In a clinical study of the Cardiology Clinic of the Kalamata Hospital in collaboration with Prokopis Mayatis. professor of the School of Pharmacy of the University of Athens, we aimed to investigate the effect of polyphenolic olive oil on the cardiovascular system, the lipid profile and the vascular endothelial function of patients with hyperlipidemia and compared the preparations with different polyphenol content.




Specifically, we took 60 volunteers who had hyperlipidemia over 18 years of age and divided them into two groups, one group received for one month 8mL daily of olive oil with a high content of polyphenols (about 1000mg of polyphenols per kg) and group B which received 20 mL of polyphenol olive oil containing 400mg of polyphenols per kg. In a series of parameters before and after the month period we had the following:


•    improved diastolic blood pressure,
•    improved lipid profile in biochemical tests,
•    better left ventricular diastolic function in terms of diamitral flow and left ventricular filling pressure in
     echocardiography,
•    improvement in maximal exercise performance with longer duration of fatigue, up to maximal fatigue and
•    lower heart rate at the same stage of fatigue in the fatigue test.
•    We also saw an improvement in markers of vascular endothelial function meaning better oxygen uptake in
      brachial artery flow measurement (FMD).




Also, the comparison between the two groups clearly showed that the high polyphenol olive oil further improved some of these indicators compared to the lower polyphenol olive oil. In conclusion, polyphenolic extra virgin olive oil appears to have a beneficial effect on lipid profile, vascular endothelial function and cardiac function in hyperlipidemic patients.




Olive oil with a higher amount of polyphenols seems to have an even better effect. Extra virgin olive oil is the basis of the Mediterranean diet and its important contribution to its cardioprotective properties has been proven. Especially the category of polyphenolic olive oil can be the flagship of the Mediterranean diet.


The article was published in the scientific journal ATHIROMA of the Hellenic Society of Lipidiology and Atherosclerosis and Vascular Disease

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