Phenols More Important than MUFA Content for EVOO Health Benefits, Research Suggests

The phenols in extra virgin olive oil are more important for decreasing blood pressure, improving insulin sensitivity, and promoting weight loss than its fats.
By Thomas Sechehaye
Jul. 12, 2023 16:15 UTC

A research review pub­lished in the sci­en­tific jour­nal Nutrients con­firms that phe­no­lic com­pounds play a crit­i­cal role in the health ben­e­fits asso­ci­ated with extra vir­gin olive oil that are not asso­ci­ated with other olive oil grades.

The sin­gle most impor­tant thing to under­stand is that extra vir­gin olive oil is a unique food,” Mary Flynn, the lead author and an asso­ciate pro­fes­sor of med­i­cine at Brown University, told Olive Oil Times.

This review indi­cates that approx­i­mately two table­spoons per day for extra vir­gin olive oil can improve a range of chronic dis­ease risk fac­tors in as lit­tle as three weeks.- Mary Flynn, asso­ciate pro­fes­sor of med­i­cine, Brown University

Compared to other oils, refined and non-extra vir­gin olive oil, or low-fat diet, daily use will improve sev­eral risk fac­tors for chronic dis­eases, such as decreas­ing blood pres­sure, blood glu­cose, oxi­da­tion, and LDL and increas­ing HDL,” she added. There is no other food, or med­i­cine for that mat­ter, that can improve such a range of risk fac­tors.”

The researchers con­ducted a sys­tem­atic review of stud­ies pub­lished between 2000 and 2003 that com­pared extra vir­gin olive oil to low-fat diets, other oils and oils listed as olive oils’ in the stud­ies.

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The nar­ra­tive review sys­tem­at­i­cally sum­ma­rized the lat­est evi­dence on the pro­tec­tive effects of extra vir­gin olive oil on dis­ease risk fac­tors.

A cri­te­rion included in this review was that the study had to state extra vir­gin olive oil was used. Most of the pub­lished stud­ies pro­vided lim­ited infor­ma­tion on the extra vir­gin olive oil used. Of 281 retrieved arti­cles, 34 arti­cles ful­filled the inclu­sion cri­te­ria for the study.

Based on cur­rent test­ing in most coun­tries, an oil could meet a stan­dard for extra vir­gin,’ but it might not have phe­nols, and it is the phe­nols that pro­vide the health ben­e­fits,“ Flynn said.

Flynn, who is also the founder of The Olive Oil Health Initiative of the Miriam Hospital, added that one of the goals of the research was to sep­a­rate olive oil’s health ben­e­fits asso­ci­ated with phe­no­lic com­pounds and those that may come from its high con­tent of monoun­sat­u­rated fatty acids.

I find it very hard to believe that there are still peo­ple who think it is the monoun­sat­u­rated fat con­tent that pro­vides the health ben­e­fits,” she said. While there are no stud­ies that sup­port monoun­sat­u­rated fats pro­vid­ing any ben­e­fits, there are many stud­ies, some of which are in our review, that clearly show the [monoun­sat­u­rated fatty acid] con­tent is not the rea­son for health ben­e­fits.

If it were, then both refined olive oil and canola oil would have health ben­e­fits, and they do not,” Flynn added.

Catherine Itsiopoulos, a co-author and pro­fes­sor at RMIT University in Australia, added that extra vir­gin olive oil is the key­stone ingre­di­ent behind the health ben­e­fits asso­ci­ated with the Mediterranean diet.

Extra vir­gin olive oil is one of the most impor­tant sta­ples and a highly ranked dis­tinc­tive ingre­di­ent of a tra­di­tional Mediterranean diet,” she told Olive Oil Times. Our study shows that extra vir­gin olive oil, due to its rich source of polyphe­nols with anti-inflam­ma­tory and anti-oxi­dant poten­tial, con­fers these health ben­e­fits and not just any type of olive oil.”

The researchers found extra vir­gin olive oil to be supe­rior for decreas­ing blood pres­sure, LDL‑c, LDL oxi­da­tion, fast­ing blood glu­cose, and improv­ing insulin sen­si­tiv­ity. Extra vir­gin olive oil also was deter­mined to increase HDL‑c and improve HDL func­tion.

One of the more inter­est­ing find­ings was evi­dence of a dis­tinct advan­tage of extra vir­gin olive oil for weight loss,” said Flynn.

More research is needed to bet­ter under­stand which phe­nols are most pro­tec­tive and the amount of phe­nol needed in the olive oil to see the ben­e­fit,” she added.

In the mean­time, the researchers hope these find­ings can help inform pub­lic health pol­icy sur­round­ing nutri­tion, which they believe to be out­dated.


I have been research­ing oil for the past 25 years,” Flynn said. I’ve long been frus­trated that health guide­lines around the world do not dis­tin­guish the dif­fer­ent types of oils.”

Extra vir­gin olive oil is the juice of the olive and pro­vides unique health ben­e­fits, espe­cially com­pared to other oils,” she added. The con­sumer needs to know they are using extra vir­gin olive oil that has health ben­e­fits, mean­ing it has at least 150 mil­ligrams per deciliter of total phe­nols. Simply pass­ing the chem­i­cal tests is not suf­fi­cient.”

Itsiopoulos said more work also needs to be done to dis­pel com­mon myths about cook­ing with extra vir­gin olive oil.

Extra vir­gin olive oil, due to its high antiox­i­dant nutri­ent con­tent, is highly sta­ble dur­ing cook­ing, dis­pelling the myth that you can­not fry with extra vir­gin olive oil,” she said.

Despite the work that still needs to be done, both researchers said the review gives con­sumers plenty of rea­sons to pre­fer extra vir­gin olive oil over other grades of olive oil and cook­ing oils.

This review indi­cates that approx­i­mately two table­spoons per day for extra vir­gin olive oil can improve a range of chronic dis­ease risk fac­tors in as lit­tle as three weeks,” Flynn said.

From olive oil pro­duc­ers, Flynn would like to see phe­nol con­tent fea­tured promi­nently on label­ing and web­sites. The phe­nol con­tent of olive oil is high­est when first pro­duced. Fresher vir­gin olive oil has a higher phe­nol con­tent and there­fore offers more health ben­e­fits.

She added that pro­duc­ers should also men­tion har­vest dates on their olive oils and spec­ify the amount of time from the har­vest to the trans­for­ma­tion process. This infor­ma­tion would help con­sumers know which com­pa­nies are pro­duc­ing the fresh­est olive oil with max­i­mum health ben­e­fits.

In many food-based dietary guide­lines around the world, extra vir­gin olive oil is cat­e­go­rized in the oils, spreads and added fats sec­tion with the rec­om­men­da­tion to con­sume spar­ingly,” Itsiopoulos added. Given the evi­dence on the health ben­e­fits of extra vir­gin olive oil as pre­sented in this paper, its place in food pyra­mids or plate mod­els needs to be more promi­nent.”

Looking ahead at future stud­ies, Flynn said more research into the rela­tion­ship between extra vir­gin olive oil con­sump­tion and type 2 dia­betes should be done.

I was sur­prised how few stud­ies there are test­ing the ben­e­fits of extra vir­gin olive oil for type 2 dia­bet­ics,” she said. Studies have shown that lifestyle changes have more ben­e­fits for type 2 dia­bet­ics com­pared to med­ica­tions.”

We reviewed some stud­ies show­ing extra vir­gin olive oil can improve insulin resis­tance (that is, the abil­ity of insulin to store nutri­ents includ­ing glu­cose), and insulin resis­tance is the root cause of type 2 dia­betes and meta­bolic syn­drome,” Flynn added. If more stud­ies could con­firm this find­ing, that would be very impor­tant infor­ma­tion.”

Flynn pre­dicts future stud­ies could test how quickly daily use of extra vir­gin olive oil could improve blood glu­cose con­trol.”

Based on the cur­rently avail­able stud­ies, it is likely two table­spoons per day in as lit­tle as three weeks, but future stud­ies could exam­ine if the ben­e­fits increase over time,” she con­cluded.


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