How olive oil helps against cancer, cardiovascular disease, Parkinson’s and Alzheimer’s has been studied extensively. Olive oil initially helps to reduce free radicals, which increase oxidative stress in the human body. In particular, free radicals are highly reactive and unstable compounds, which are composed of molecules that are not electron-paired. These compounds are usually created both by metabolic processes that occur in the human body and by external factors such as poor nutrition, alcohol, smoking, environmental pollution, stress, etc. Free radicals have the ability to damage human cells causing oxidative stress in the body which plays an important role in chronic damage and premature aging. The non-paired electrons at the outer shell of the atom, make the free radical to search for other electrons to creates bond. Therefore, they are looking for somewhere in the body to find “stable”, perhaps even vulnerable areas from which they can “steal” electrons. This process can cause damage to the human body. Free radicals can oxidize and damage vital biological molecules such as fats, proteins and DNA.
How olive oil contributes to the fight against free radicals?
Plant-derived food is one of the best bioavailable source of antioxidants for the human body, with Extra Virgin Olive Oil (EVOO) being one of the most powerful in this area.
According to a study published in 2014 in the Journal of Food Chemistry, phenolic acids, phenolic alcohols, lignans and flavones are the four elements that olive oil has and are considered very important. Although it is likely to be due to the synergistic action of all olive oil compounds, according to research, its phenols (tyrosol and hydroxytyrosol) and their fractions (3,4-DHPEA-EA and 3,4-DHPEA-EDA) are compounds recognized as the most powerful antioxidants.
In a study published in Food Chemistry, researchers tested many varieties of olive oil to evaluate their antioxidant properties. All the olive oils analyzed showed strong anti-free radical activity.
Another, more recent study, published in 2015 in the Journal of Food Composition and Analysis, examined a series of 32 extra virgin olive oils to measure their antioxidant capacity. Overall, the total antioxidant activity in this sample of EVOOs was attributed to the polyphenol hydroxytyrosol along with the alpha-tocopherol content.
Another interesting observation was that the bitterness of the samples was an attribute of the higher quality oils. Therefore, choosing an olive oil with bitter pungent notes will deliver most probably more antioxidant value and indicates an indirect measure of olive oil quality.
Moreover, a study published in 2015 in the Journal of Food & Function showed that polyphenolic compounds in olive oil (3,4-DHPEA-EA and 3,4-DHPEA-EDA) significantly protect red blood cells from oxidative stress.
With regard to cardiovascular disease, extra virgin olive oil has been proven to regulate oxidative stress, inflammation, lipid peroxidation and lipid profile in coronary heart disease.
Researchers have found that extra virgin olive oil can also be beneficial in the prevention of diseases such as retinopathy, bronchopulmonary dysplasia, peripheral leukemia and necrotic enterocolitis in infants with very low birth weight.
How olive oil helps the central nervous system?

A study in Food Science and Technology states: “This is mainly due to high amounts of polyunsaturated fatty acids and an inherently high flow of reactive oxygen species (ROS).
Another reason for oxidative stress is the low level of endogenous antioxidant enzymes in the central nervous system compared to other tissues, and the high consumption of oxygen.”
Extra virgin olive oil has also been shown to have a positive influence on the oxidative stress of the central nervous system, in particular on the levels of lipid peroxide in the brain, contributing to the better synthesis of fatty acids in it (especially docosahexaenoic acid).
It has also been shown to increase the antioxidant activities of enzymes, which mitigate oxidative damage leading to neurodegenerative disorders, such as Alzheimer’s and Parkinson’s.
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References:
- Phenolic compounds and antioxidant capacity of virgin olive oil
- Nutritional quality assessment of extra virgin olive oil from the Italian retail market: Do natural antioxidants satisfy EFSA health claims?
- Effects of the olive oil phenol metabolite 3,4-DHPEA-EDAH2 on human erythrocyte oxidative damage
- Exclusive olive oil consumption has a protective effect on coronary artery disease; overview of the THISEAS study
- Neonatal Outcomes of very low birth weight infants who received enteral nutrition with and without olive oil support
- Extra virgin olive oil modulates brain docosahexaenoic acid level and oxidative damage caused by 2,4-Dichlorophenoxyacetic acid in rats