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

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02 January 2013
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Use Any Olive Oil You Like, As Long as it’s Green and Bitter

By Julie Butler
Olive Oil Times Contributor | Reporting from Barcelona

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.

 

Why is it important to reduce oxidative damage to blood lipids?

We know that high cholesterol is dangerous, but the greatest danger is when this cholesterol is oxidized, because it can then readily promote atherosclerosis (build-up of fatty deposits on artery walls). Of course, if you have high cholesterol you have more probability of a large amount of it being oxidized.

 

What are you researching now?

There are two main areas in which we are continuing our work on olive oil. One is to assess if besides promoting an increase in HDL cholesterol, the polyphenols in olive oil also increase the funcionality of this lipoprotein. That’s because the important thing is not only to increase the lipoprotein (HDL) but that this protein be functional. So one thing is measuring the quantity and another is measuring the functionality.

 

Why it is beneficial to increase the functionality of HDL?

The inverse relationship between HDL cholesterol levels and coronary heart disease has stimulated interest in pharmacological agents that elevate plasma HDL. However, recently there has been an unexpected association of a drug that increases plasma HDL-C with increased cardiovascular mortality. One of the consequences of this is consideration of whether the functional quality of HDL is perhaps more important than how much of it is circulating in the blood.

 

What is the other area of your current research?

We are working to increase our knowledge of the mechanism by which the polyphenols in olive oil exert their beneficial effects. Besides the classic role of scavenging free radicals, we think – and have some supporting data – that EVOO has a nutrigenomic effect. In other words, we are investigating the protective factor that EVOO’s high polyphenol content provides in terms of the expression of genes related to atherosclerosis.

 

Is it okay to fry with olive oil?

Yes, because although lipid peroxides – which increase the risk of atherosclerosis, cancer and other chronic degenerative diseases – are formed when olive oil is heated, the polyphenols in it protect against this lipid peroxidation.

However, frying once with EVOO reduces the polyphenols by half and the second time they are reduced to about 18-20% of the original. So it is not advisable to cook with EVOO more than once, or twice at maximum.

 

How should we use EVOO in order to maximize its health benefits?

You need to use EVOO as your main fat, for cooking and other purposes. It’s not advisable to have huge quantities, because it is a fat, but simply to use EVOO as both your raw fat and for cooking. And to combine it with a healthy diet, that means with a lot of vegetables.

Another thing many people don’t know is that olive oil must be kept in a cool, dark place, and ideally it should be used within a year of the production date. Some bottles are clear and that’s wrong. But most EVOO now comes in dark bottles.

Also, people in Mediterranean countries tend to know that EVOO is greener and more bitter but sometimes people in other countries don’t like it to be so bitter. So I say that everyone must find an olive oil that they like. You need to taste several types and get the one you like the most, as long as it is green and bitter. You want it to be bitter because it’s the concentration of polyphenols that contribute to that taste.

You don’t need to take olive oil as a medicine, you must enjoy it. I think it is a very important part for the health benefits, to enjoy it.

Two More Greek Regions Apply for Olive Oil PDOs

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02 January 2013
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Two More Greek Regions Apply for Olive Oil PDOs

By Costas Vasilopoulos
Olive Oil Times Contributor | Reporting from Athens

 

The three “legs” of the Chalkidiki peninsula extend into the northern Aegean Sea.

Two more regions of Greece, Messinia and Chalkidiki, have submitted applications to the European Commission for a ‘Protected Designation of Origin’ (PDO) label for their extra virgin olive oil.

Messinia it southern Greece, aims at putting all the olive oil it produces under the PDO umbrella with the ‘Kalamata’ tag, while Chalkidiki, near Salonika, wants to secure a special type of oil produced when the olives are still green and not fully ripe called ‘Agoureleo Chalkidikis.’

A PDO is a designation which acknowledges that an agricultural product or food originating from a specific area or location bears characteristics almost exclusively attributed to the place of its origin, and more specifically to the environmental conditions, the microclimate and the human factors. Another preposition is that the product is produced or made within the geographical limits of the area.

Both regions had to include in their applications the special characteristics of their olive oil, such as color, aroma, taste, acidity, oleic acid, the olive drupes variety and also the processing methods in great detail.

A PDO process is not an easy task to complete; a variety of facts and figures must be collected to prove that the product under examination differentiates from other similar products from other areas and characterizes the place it originates from. Then the application is published in the Official Journal of the European Union and, if no objections occur within six months, the PDO name tag is registered for exclusive usage.

The aim is to protect and promote high quality products and at the same time signal that these products are worth consumers’ money. So far, according to the Ministry of Agriculture, 16 areas of Greece have been awarded a PDO label for their olive oil.

Researchers Say New Tool Measures Olive Oil ‘Healthfulness’

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02 January 2013
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Researchers Say New Tool Measures Olive Oil ‘Healthfulness’

By Julie Butler
Olive Oil Times Contributor | Reporting from Barcelona

 

How good a specific extra virgin olive oil is for your health could be easier to assess with a new Greek system to measure and rate the content of key olive compounds oleocanthal and oleacein.

Oleocanthal has anti-inflammatory effect similar to Ibuprofen and Oleacein is a powerful antioxidant, but until now they have been difficult to analyze chemically, according to Dr. Prokopios Magiatis, assistant professor of pharmacognosy and natural products chemistry at the University of Athens.

At the recent Terra Creta Olive Oil Conference on Crete, Magiatis said he and his team from the university had developed a method using 1H-NMR, a form of nuclear magnetic resonance, to directly measure oleocanthal and oleacein levels.

“The new method makes it possible to identify differences between extra virgin olive oils and to classify them according to their potential health effects” he said.

 

Inspiration from ancient medics

Ancient Greek doctor Dioscorides piqued the researchers’ interest. “He, and others after him, insisted that the best health effects come from fresh olive oil from unripe olives, or from specific varieties.”

This set them investigating ways to pinpoint what molecules were responsible for health effects and to compare olive oils based on their contents of them.

Five years later, they have developed an NMR test that just takes 50 seconds.

“You can analyze hundreds of samples in a very short time but of course you need a very expensive instrument and we’re happy to have one in our lab in Athens” Magiatis said.

 

New indexes proposed

The team homed in on the key olive polyphenols oleocanthal and oleacein and rates EVOOs according to both the sum of their levels of these molecules, index D1, and to their oleocanthal to oleacein ratio, index D2.

 

Dr. Eleni Melliou

“D is for Davis because this study was done in collaboration with the UC Davis Olive Center” Magiatis said. He and Dr. Eleni Melliou, a co-author of the study, were visiting scientists at UC Davis in 2011. Dan Flynn, the Olive Center’s director, gave them advice and oil samples.

The new system was applied to more than 250 samples from monovarietal olive oils from Greece and California over two years and, according to Magiatis, revealed big differences between oils.

“Among the nineteen varieties studied, the highest concentration was found in Koroneiki olive oil and it’s very good for Greece because more than 70 percent of its olive trees are this variety.” Non-Greek varieties grown in California, like Barouni, Leccino, and Mission, also had high concentrations. Wider studies are needed of other varieties around the world, he said.

 

High heat in mill, less healthy oils

Processing temperature is another factor affecting oleocanthal and oleacein levels.

“When we test the same olive fruit in the same olive mill but using different temperatures you can see a huge difference in the concentration of these compounds, with high temperatures having negative effects” he said.

The trial also revealed a positive link between early harvesting and high levels of both compounds. Some olive varieties, however, deliver low levels regardless of geographic origin, harvest time or if best practices are followed.

Oils with high levels of oleocanthal and oleacein retained most of this content even 18 months after harvest.

 

Olive oil heart-health claim

When last year the European Food Safety Authority approved the claim that consumption of olive oil polyphenols protects LDL particles from oxidative damage, it said this hinged on the daily consumption of “5mg of hydroxytyrosol and its derivatives (e.g. oleuropein complex and tyrosol) in olive oil”.

Magiatis said the new method made it possible to measure all the compounds mentioned by EFSA in one experiment. “And we can provide the necessary data for the health claims.” The latter could help producers of olive oils with high quantities of hydroxytyrosol gain better prices.

 

Why oleocanthal and oleacein?

Oleocanthal and oleacein were of most interest to the team as they are the two most abundant forms of conjugated hydroxytyrosol and tyrosol in the olive oils they studied.

Oleacein is a derivative of oleuropein and the most powerful antioxidant constituent of olive oil” Magiatis said.

Oleocanthal is said to have potential to inhibit tumor growth, to offer protection against Alzheimer’s disease and to be a COX-1 and COX-2 inhibitor.

It is responsible for the pungency that comes from unripe olives in fresh olive oil and that irritates the throat.

“Chronic exposure to low doses of anti-inflammatory agents like oleocanthal offers protection against cardiovascular diseases and aging” he said.

 

Applications: extra virgin olive oil as a new drug?

As for potential applications of his research, Magiatis said one use could be to target specific olive oils at people with heart disease.

However, consumers will need education to accept and value the taste of oils with very high levels of potential health effects because they are usually more pungent and bitter.

“It will be difficult for producers to achieve a balance between taste and high concentration of specific polyphenolsMagiatis said.

At the same time, the new index can help correlate the organoleptic properties of an olive oil, predicting what pungency and bitterness should be expected.

“What we have provided is a powerful new tool for the evaluation of olive oil quality” Magiatis said.

“Not all extra virgin olive oils are the same. Some present great potential as health protecting or therapeutic agents and we have provided the scientific community with a new index offering an estimate of these health related properties.”

footnote: Magiatis and his research colleagues recently published a paper relating to their research in the Journal of Agricultural Food Chemistry.

Titled “Direct Measurement of Oleocanthal and Oleacein Levels in Olive Oil by Quantitative 1H-NMR. Establishment of a New Index for the Characterization of Extra Virgin Olive Oils”, it is available here: http://pubs.acs.org/doi/abs/10.1021/jf3032765

The researchers are: Evangelia Karkoula , Angeliki Skantzari , Eleni Melliou , and Prokopios Magiatis.