`Use Any Olive Oil You Like, "As Long as it's Green and Bitter"


Use Any Olive Oil You Like, "As Long as it's Green and Bitter"

May. 11, 2011
Julie Butler

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The Euro­pean Food Safety Author­ity (EFSA) last month approved the claim that con­sump­tion of olive oil polyphe­nols con­tributes to the pro­tec­tion of blood lipids from oxida­tive dam­age.”

Here we speak to the leader of the research team whose inves­ti­ga­tion of EVOO’s health ben­e­fits was piv­otal to the approval.

Dr. María-Isabel Covas is head of the Car­dio­vas­cu­lar Risk and Nutri­tion Research Group at the IMIM-Research Insti­tute, Hos­pi­tal del Mar in Barcelona, Spain. She is also head inves­ti­ga­tor of the CIBER of Obe­sity and Nutri­tion (CIBEROBN) a Net­work of Research Groups of Excel­lence in Spain. Last week she won an inau­gural Cata­lan olive oil DOPs prize in recog­ni­tion of her out­stand­ing research.

Dr. Covas explains why lipid oxi­da­tion mat­ters and that the key to ben­e­fit­ing from EVOO is not to take it as a med­i­cine. You must enjoy it.”

Please tell us about the research that led to the EFSA approval.


Our research started about twelve years ago and focuses on the health ben­e­fits of olive oil, in par­tic­u­lar the effects of its polyphe­nols on the heart. Until 2004, it had been known that olive oil was good for you but there was a con­tro­versy over the in vivo antiox­i­dant power (in humans) of the polyphe­nols.

We started sev­eral stud­ies with Cata­lan olive oil and our hypothe­ses were suc­cess­ful but we needed full proof, because in this area of sci­ence, for a health pro­fes­sional to be able to say, take this, it is good for you,” you need evi­dence from ran­dom­ized and con­trolled stud­ies with humans. You also need to be very accu­rate when you deter­mine the aver­age daily dose nec­es­sary to get suf­fi­cient quan­ti­ties of polyphe­nols, because the effect will be not a phar­ma­co­log­i­cal one but phys­i­o­log­i­cal.

We there­fore held an ini­tial trial with Cata­lan olive oil involv­ing about 30 healthy indi­vid­u­als here in Cat­alo­nia. We also did another study here with 38 peo­ple with sta­ble coro­nary heart dis­ease. Then, in order to have defin­i­tive clin­i­cal proof, we orga­nized a Euro­pean study, the EUROLIVE Study, encom­pass­ing 200 healthy indi­vid­u­als from five Euro­pean Coun­tries. They con­sumed 25ml/day of three types of olive oil that were sim­i­lar but dif­fer­ent in polyphe­nol con­tent.

What were the results of these stud­ies?

We were able to prove that there was an increase in lev­els of high den­sity lipopro­tein (HDL), the good cho­les­terol, and that this was directly pro­por­tional to the olive oil polyphe­nol con­tent. There was also a proven decrease in lipid oxi­da­tion, one of the main risk fac­tors for car­dio­vas­cu­lar dis­ease, and this risk was shown to be inversely related to the polyphe­nol con­tent of the olive oil.

All this work paid off on April 8 when EFSA con­cluded that a cause and effect rela­tion­ship had been estab­lished between the con­sump­tion of olive oil polyphe­nols and pro­tec­tion of low den­sity lipopro­tein (LDL- the bad” cho­les­terol) par­ti­cles from oxida­tive dam­age, and that this was a ben­e­fi­cial phys­i­o­log­i­cal effect. This was mainly based on our study and we were really happy about it.

How much EVOO must we con­sume each day to ben­e­fit from this antiox­i­dant effect?

EFSA says that 5mg of hydrox­y­ty­rosol and its deriv­a­tives (e.g. oleu­ropein com­plex and tyrosol) in olive oil should be con­sumed daily.

That means tak­ing 25ml/day of a vir­gin olive oil that con­tains 300mg/kg of polyphe­nols, or 30ml/day of a vir­gin olive oil con­tain­ing 200mg/kg of polyphe­nols. (Vir­gin olive oils have an aver­age con­cen­tra­tion of around 250mg/kg of phe­no­lic com­pounds.)

These amounts, if pro­vided by mod­er­ate amounts of olive oil, can eas­ily be con­sumed in the con­text of a bal­anced diet. How­ever, the con­cen­tra­tions in some olive oils may be too low to pro­vide a suf­fi­cient amount of polyphe­nols while still main­tain­ing a bal­anced diet.

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