The miraculous composition of extra virgin olive oil

Extra virgin olive oil (EVOO) is a vegetable oil obtained directly from the fruits of Olea Europea, commonly known as olive tree, with the use of mechanical means. It is consumed with no further processing and has distinct aroma and flavor which are largely determined by its chemical composition. The latter consists of major and minor components, many of which are bioactive phytochemicals^[1].  

Major components include glycerols and represent more than 98% of olive oil’s total weight. These form what is known as the saponifiable or glyceride fraction of olive oil, which is responsible for its greasy texture. Triacylglycerols, esters of glycerol with 3 fatty acids, dominate olive oil’s composition. Fatty acids exploited for the formation of triglycerides are simple structures made up of long chains of various numbers of carbon atoms. Depending on the number of double bonds found between their carbon atoms, fatty acids can be saturated (all the carbon atoms attached by single bonds), monounsaturated (one double bond joining two of the carbon atoms) and polyunsaturated (two or more double bonds). Triacylglycerols of monounsaturated fatty acids represent 55-83% of the total triacylglycerols’ number in extra virgin olive oil (EVOO), with oleic acid having the lion’s share. Following years of scientific research, monounsaturated fatty acids have proven to have a strong beneficial impact on our health^[2],  thus are considered far superior to polyunsaturated fatty acids - found in widely used vegetable oils such as soybean oil and sunflower oil - and most certainly, to saturated fatty acids that dominate animal fats and have been connected with increased risk of coronary heart diseases, strokes and cancer tumors. 

Despite amounting to a modest 2% of olive oil’s total weight, minor components are of critical importance as they are considered responsible for several of the olive oil’s health benefits, while they hugely impact its sensory properties. More than 230 chemical compounds combine to form the non-saponifiable fraction of olive oil, including sterols, aliphatic and triterpenic alcohols, hydrocarbons, phenols, flavonoids, carotenoids, vitamins and others. The proportions of these minor compounds depend on the manufacturing process of oil.  Even though each one of the aforementioned facilitate one way or another the fine function of human body, a special mention should be made to phenolic compounds and their antioxidative action.

Olive tree’s characteristic capability of surviving on minimum resources is largely attributed to a number of defence mechanisms developed by the tree for self-protection. One the most important of those mechanisms are the antioxidants, which guarantee the chemical stability of both the olive tree and the olive oil. Now as far as the human body is concerned, antioxidants provide an invaluable service as they protect cells from oxidative stress, active oxygen and free radicals. While most of the oxygen we inhale is used for the production of energy in our system, there is a 2-3% which is converted in the so-called free radicals. The latter when produced in large quantities and for a long period of time, expose our system to the so-called oxidative stress which speeds up the aging process and act as a precursor for several serious diseases. In addition, free radicals have proven to damage the structure of our DNA molecules, largely hampering the production process of enzymes, hormones and antibodies. Inevitably, genes are also distorted and as soon as the cell division takes place, the new cell is inferior to its generator. That implies an increased risk of the new-born cell turning into a cancer cell, since the DNA molecule was not passed on intact.   

Extra virgin olive oil (EVOO) is rich in several types of phenolic compounds ( e.g. oleuropein, α-tocopherol, tyrosol, hydroxytyrosol), thus its consumption implies a strong antioxidative protection.  Hydrophilic phenols, such as phenolic alcohols, phenolic acids, flavonoids, lignans and most importantly secoiridoids, are the most abundant natural antioxidants found in EVOO. Importantly, secoiridoids(oleuropein, demethyloleuropein etc.), which are the prevalent phenols in EVOO, are found exclusively in plants originating from the Family of Oleaceae, which includes Olea europaea (the olive tree). Apart from hydrophilic phenols, important antioxidants found in EVOO are tocopherols (vitamin E) and carotens. A-tocopherol is the most biologically active tocopherol and extra virgin olive oil contains it in large proportions. Apart from its antioxidative activity, vitamin E is important for the proper function of human reproductive system, while it can also contribute to the restoration of damages in our neurological and muscular system. 

Apart from the phenolic compounds contained in EVOO, it is important to mention two additional types of chemical compounds, namely sterols and hydrocabons. Phytosterols found in EVOO and other plant products, have been known to decrease the cholesterol levels, while there are indications (especially for β-sitosterol) that they might also have anticancer activity. The hydrocarbon squalene is found in EVOO in greater proportion than in any other vegetable oil (136-708mg in 100gr of EVOO). Based on epidemiological studies and scientific experiments conducted on animals^[3], squalene appears to have a strong and multidimensional anti-cancer activity. Although that potential still remains to be explored on human subjects, indications are rather encouraging. 

Caution!

Concluding on the chemical composition of EVOO, it is necessary to set one thing straight. The chemical compounds mentioned above strictly refer to extra virgin and virgin olive oil which is obtained directly from the olive fruit with the use of mechanical means and no further processing. The refinement process (involves an extensive use of chemicals) that olive oil and pomace olive oil has to go through in order to become edible, wipes out the beneficial compounds described above, practically annihilating all those important properties passed down from the olive tree to the olive fruit. Keep that in mind for most conscious and properly informed olive oil purchases.