What Are Polyphenols and Why Should You Care?

The plant compounds in high-quality extra virgin olive oils provide important health benefits.

By Daniel Dawson
Dec. 30, 2021 12:27 UTC
13K reads

Extra vir­gin olive oil (EVOO) is cel­e­brated for being the health­i­est cook­ing oil.

Many would point to EVOO as a promi­nent source of monoun­sat­u­rated fats, which is asso­ci­ated with weight loss and low­er­ing the risk of car­dio­vas­cu­lar dis­ease, among other ben­e­fits.

See Also:Olive Oil Basics

However, Nasir Malik, a plant phys­i­ol­o­gist at the United States Department of Agriculture’s research ser­vice, said olive oil’s health ben­e­fits are almost entirely derived from a class of organic chem­i­cals known as phe­no­lic com­pounds – or polyphe­nols.

The health ben­e­fits of olive oil are 99 per­cent related to the pres­ence of the phe­no­lic com­pounds, not the oil itself,” he told the Washington Post in 2012.

What are polyphe­nols?

Polyphenol is an umbrella term for a large fam­ily of nat­u­rally occur­ring plant com­pounds com­pris­ing mul­ti­ple phe­nol units act­ing as antiox­i­dants.

There are 8,000 types of polyphe­nols and more than 100 dif­fer­ent types of foods with at least one mil­ligram of polyphe­nols per 100 grams or mil­li­liters of food or bev­er­age. These vary widely from fruits and veg­eta­bles to whole grains and seeds.

According to Phenol-Explorer, a data­base, 25 polyphe­nols are found in extra vir­gin olive oil. Of these 25, the most sig­nif­i­cant are tyrosols – includ­ing oleu­ropein, hydrox­y­ty­rosol and oleo­can­thal.

Polyphenols are found most abun­dantly in extra vir­gin olive oil, and some polyphe­nols are present in vir­gin olive oil.

See Also:5 Things Everyone Should Know About Olive Oil

Refined olive oil only has trace amounts of the polyphe­nols, which are removed dur­ing the refin­ing process and added back in when the refined oil is blended with small quan­ti­ties of vir­gin or extra vir­gin olive oil before it is bot­tled sold.

Polyphenols lower heart dis­ease risk

Polyphenols have been linked in hun­dreds of stud­ies to var­i­ous health ben­e­fits.

Chief among these health ben­e­fits is low­er­ing the risk of heart dis­ease, mainly due to their antiox­i­dant prop­er­ties. Antioxidants help reduce chronic inflam­ma­tion, the pri­mary risk fac­tor for heart dis­ease.


Two recent stud­ies – one pub­lished in the International Journal of Molecular Sciences and the other in the Journal of Oxidative Medicine and Cellular Longevity – linked polyphe­nol-enriched diets to lower blood pres­sure and LDL (low-den­sity lipid) cho­les­terol, col­lo­qui­ally known as bad cho­les­terol,’ and increased lev­els of HDL (high-den­sity lipid) cho­les­terol, or good’ cho­les­terol.

The con­sump­tion of polyphe­nols has also been asso­ci­ated with low­er­ing the risk of blood clots by pre­vent­ing excess platelet aggre­ga­tion.

Polyphenols decrease dia­betes risk

Along with pro­vid­ing ben­e­fits for heart health, polyphe­nols have also been shown to lower blood sugar lev­els, which decreases the risk of type 2 dia­betes.

A 2017 study pub­lished in the British Journal of Medicine found that par­tic­i­pants eat­ing large amounts of polyphe­nol-rich foods had a 57-per­cent lower chance of devel­op­ing type 2 dia­betes over two to four years than peo­ple who con­sumed very low amounts of polyphe­nols.

See Also:High-Polyphenol EVOO May Lower Risk of Vascular Diseases Associated with Diabetes

One rea­son may be that polyphe­nols help stim­u­late insulin secre­tion, which helps move sugar from the blood­stream and deposit it in the cells. This keeps blood sugar lev­els sta­ble.

Polyphenol-rich diets are also linked to lower fast­ing blood sugar lev­els and higher glu­cose tol­er­ance, which are essen­tial for reduc­ing the risk of con­tract­ing type 2 dia­betes.

Polyphenols may help can­cer and demen­tia patients

Though researchers are the first to admit that many more stud­ies need to be done on the sub­ject, polyphe­nols have also been linked to a lower risk of prostate and breast can­cer.

Some stud­ies con­ducted on the sub­ject sug­gest that polyphe­nols block the growth and devel­op­ment of these types of can­cer cells.

As a result, a sep­a­rate study sug­gested oleo­can­thal-based treat­ments may be effec­tive as part of tar­geted ther­apy for some types of breast can­cer patients.

See Also:Oleocanthal Regulates Abnormalities in Receptor Responsible for Alzheimer’s

The researchers behind this study also found that oleo­can­thal reg­u­lates abnor­mal­i­ties in a recep­tor respon­si­ble for the devel­op­ment of Alzheimer’s dis­ease.

In Alzheimer’s patients, the recep­tor becomes over-stim­u­lated and pro­motes inflam­ma­tion. Therefore, researchers hypoth­e­size that oleo­can­thal may reg­u­late the recep­tor and decrease inflam­ma­tion.

Polyphenols restore gut bac­te­ria

Along with help­ing pre­vent cer­tain chronic dis­eases, some sci­en­tific stud­ies also show that high-polyphe­nol extra vir­gin olive oil pro­motes the growth of ben­e­fi­cial gut bac­te­ria, which helps with diges­tion.

One study demon­strated that adher­ents to the Mediterranean diet, which includes polyphe­nols from sev­eral of its com­po­nents besides olive oil, had a more diverse gut bac­te­ria asso­ci­ated with bet­ter weight man­age­ment.

Polyphenols also add plenty of fla­vor to EVOO

Along with endow­ing extra vir­gin olive oil with its many health ben­e­fits, polyphe­nols also con­tribute to the fla­vor pro­files of the oil.

The pres­ence of polyphe­nols con­tributes to astrin­gency, bit­ter­ness and pun­gency. Depending on the types of olives and when they are har­vested will impact which of these attrib­utes can be sensed in an EVOO.

See Also:Certain Food Proteins Reduce Bitterness and Pungency of EVOO

Astringency is the puck­er­ing sen­sa­tion cre­ated by tan­nins, a type of polyphe­nol. Astringency is asso­ci­ated with early har­vested and robust extra vir­gin olive oils. Astringency is mostly noticed when tast­ing the oil on its own and is less appar­ent when cook­ing with an EVOO.

On the other hand, bit­ter­ness – due to oleu­ropein – is one of the less sought-after fla­vors in most foods but is an excel­lent indi­ca­tor that an EVOO has been made with fresh olives. As with cer­tain types of beer, choco­late and cof­fee, bit­ter­ness is an acquired taste, the appre­ci­a­tion of which comes over time.

Meanwhile, pun­gency is the sting­ing sen­sa­tion in the throat, mostly asso­ci­ated with oleo­can­thal. Occasionally the sen­sa­tion, sim­i­lar to that of chili pep­pers, is strong enough to force a cough.

Tips for select­ing high-polyphe­nol EVOO

While few brands list the polyphe­nol con­tents of their EVOOs directly on the label, there are a few tricks to find­ing high-polyphe­nol EVOO at any store or mar­ket.

The first is to check the label to see if the olives were har­vested early. Polyphenols accu­mu­late in the olives ear­lier than the oil and steadily decrease as the fruit matures. Therefore, an early har­vest EVOO has more of them.

Next, con­sumers should keep their eyes peeled for Coratina, Cornicabra, Maurino, Picual and Mission monocul­ti­vars or Tuscan blends. These olive vari­eties have the high­est lev­els of polyphe­nols.

Additionally, olives har­vested in tem­per­ate cli­mates instead of arid ones also have higher lev­els of polyphe­nols. This is likely due to the olives’ mat­u­ra­tion rate in these spe­cific cli­mates.

Finally, if none of this infor­ma­tion is read­ily avail­able, select robust EVOOs over mild or del­i­cate ones. The oils are robust (as pre­vi­ously dis­cussed) due to the pres­ence of polyphe­nols.

Where can I find the best extra vir­gin olive oil?

The retail finder on the Official Guide to the World’s Best Olive Oils makes it easy to find award-win­ning extra vir­gin olive oils near you or through online retail­ers.

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