Health

Role of Olive Oil in Reducing Oxidative Stress

Extra virgin olive oil is a readily available antioxidant food source that helps reduce the effects of oxidative stress and therefore reduces the risk and progression of many diseases

Jun. 8, 2016
By Jedha Dening

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Environmental, phys­i­cal and mental stres­sors cause the pro­duc­tion of reac­tive oxygen species, also known as free rad­i­cals. The pro­duc­tion of free rad­i­cals leads to the human body being sub­ject to the pres­sures of oxida­tive stress.

Free rad­i­cals are highly reac­tive unsta­ble cells con­sist­ing of mol­e­cules that are unpaired with elec­trons. The cells don’t like to exist in this unpaired state and there­fore search the body to find stable, yet per­haps vul­ner­a­ble areas to steal elec­trons from. Free rad­i­cals don’t dis­crim­i­nate. They need to sta­bi­lize and will steal the elec­trons from wher­ever they find them avail­able.

Although free rad­i­cals do play an impor­tant role in the body and it’s immune defense and cell func­tion, too many free rad­i­cals lead to wide­spread damage. The oxida­tive stress pro­duced by free rad­i­cals has been linked to the devel­op­ment of dis­eases such as car­dio­vas­cu­lar dis­ease, cancer, and neu­rode­gen­er­a­tive dis­eases, among others.

Essentially, oxida­tive stress is as an imbal­ance between the oxi­dant and antiox­i­dant sys­tems of the body. Antioxidants sta­bi­lize free rad­i­cals by pro­vid­ing a supply of elec­trons to sta­bi­lize cells. Therefore, if we can aid the body by pro­vid­ing more antiox­i­dants, it makes sense that oxida­tive stress is reduced and there­fore, damage to organs and tis­sues is reduced also.

Foods are one of the best bioavail­able sources of antiox­i­dants for the human body, with extra virgin olive oil (EVOO) being one of the most stud­ied antiox­i­dant food sources. According to a study pub­lished in Food Chemistry, 2014, phe­no­lic acids, phe­no­lic alco­hols, sec­oiri­doids, lig­nans, and flavones are the four cat­e­gories iden­ti­fied in EVOO as the most impor­tant. Though it is likely due to the syn­er­gis­tic activ­ity of all olive oil (OO) com­pounds, accord­ing to research, phe­nols known as tyrosol and hydrox­y­ty­rosol and their frac­tions 3,4‑dihydroxyphenylethanol-elenolic acid (3,4‑DHPEA-EA) and 3,4‑dihydroxyphenylethanol-elenolic acid dialde­hyde (3,4‑DHPEA-EDA), are the com­pounds being iden­ti­fied as pro­vid­ing some of the great­est antiox­i­dant activ­i­ties.

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In the study pub­lished in Food Chemistry, researchers looked at a vari­ety of EVOOs to eval­u­ate their anti-rad­i­cal, lipid per­ox­ide inhi­bi­tion, H202 and nitrous oxide (NO) scav­eng­ing abil­i­ties — all antiox­i­dant scal­ing tests. No vari­a­tion for olive oils showed for H202 scav­eng­ing, all oils show­ing between 69.9 – 76.8 per­cent scav­eng­ing abil­ity. All the ana­lyzed frac­tions exhib­ited strong anti-rad­i­cal inhi­bi­tion but there was vari­a­tion in the sample rang­ing from 14.8 – 26.6 ug/ml. Inhibition of linoleic acid degra­da­tion ranged from 39 – 45 per­cent, and NO scav­eng­ing activ­ity ranged from 29.8 – 40.7 per­cent.

Another more recent study, pub­lished in the Journal of Food Composition and Analysis, 2015, looked at a range of 32 EVOOs from the Italian retail market to mea­sure their antiox­i­dant capac­ity. A test called ABTS assay is com­monly used to test the antiox­i­dant levels in foods. The aver­age ABTS antiox­i­dant activ­ity in the range of EVOOs was 32.4 u.mol Trolox equiv­a­lents. Only two of the sam­ples were sig­nif­i­cantly higher, at approx­i­mately 66 u.mol.

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 more antiox­i­dant value and indi­cates an indi­rect mea­sure of olive oil qual­ity.

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Although many stud­ies show that EVOO pro­vides a range of dif­fer­ent health ben­e­fits, in many cases the mech­a­nisms are still not fully under­stood. Still, much of the research sur­round­ing EVOO in rela­tion to dis­ease pre­ven­tion or risk rever­sal, fre­quently attrib­utes a reduc­tion in oxida­tive stress as one of the main mech­a­nisms.

A study, pub­lished in Food & Function, 2015, found that the polyphe­no­lic com­pounds in EVOO, 3,4‑DHPEA-EA and 3,4‑DHPEA-EDA sig­nif­i­cantly pro­tect red blood cells from oxida­tive stress. In regard to car­dio­vas­cu­lar dis­ease, EVOO has been shown to change the status of oxida­tive stress, inflam­ma­tion, lipid per­ox­i­da­tion, and lipid pro­file in coro­nary artery dis­ease. Researchers have even sug­gested that EVOO may be ben­e­fi­cial for pre­vent­ing oxida­tive stress related dis­eases such as retinopa­thy of pre­ma­tu­rity, bron­chopul­monary dys­pla­sia, periven­tric­u­lar leuko­ma­la­cia and necro­tiz­ing ente­ro­col­i­tis, in very low birth weight infants.

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The cen­tral ner­vous system (CNS) is par­tic­u­larly sus­cep­ti­ble to oxida­tive stress. As a study in Food Science and Technology explains, “This is mainly due to its high amounts of polyun­sat­u­rated fatty acids (PUFA) con­tent which con­sti­tute easily oxi­diz­able sub­strates and an inher­ently high flux of reac­tive oxygen species (ROS). Another reason of oxida­tive stress is the low level of endoge­nous antiox­i­dant enzymes in CNS rel­a­tive to other tis­sues, and its high oxygen con­sump­tion.”

EVOO has also been shown to exert a pos­i­tive influ­ence on CNS oxida­tive stress, in par­tic­u­lar brain lipid per­ox­ide levels and help­ing to restore brain fatty acid com­po­si­tion — espe­cially levels of docosa­hexaenoic acid (DHA). It’s also been shown to increase antiox­i­dant enzyme activ­i­ties to help mit­i­gate the oxida­tive damage that leads to neu­rode­gen­er­a­tive dis­or­ders such as Alzheimer and Parkinson dis­ease.

The role that EVOO plays in reduc­ing oxida­tive stress is extremely impor­tant. Clearly the research shows that EVOO does, in fact, pro­vide a cost effec­tive, read­ily avail­able antiox­i­dant food source that can be pre­scribed for con­sump­tion in the every­day diet to reduce the effects of oxida­tive stress and there­fore reduces the risk and pro­gres­sion of many dif­fer­ent dis­eases.