by Marilyn Harding


by Marilyn Harding







This post is inspired by Gregory Pappas of Pappas Post who asked a lot of really good questions about high phenolic extra virgin olive oil.

Care of High Phenolic EVOO

As this new category of high phenolic olive oil grows along with the research into its health benefits, facts need to supplant opinion. We at Aristoleo believe that science is unbiased and that health conscious individuals deserve to know the facts.

Nature Has the Final Word

The past harvest year, the general level of phenolic compounds was lower than previous years across the Mediterranean countries under study by the EU Funded ARISTOIL Interreg MED Programme.* The five countries are Greece, Cyprus, Croatia, Italy and Spain.

This could simply be Nature taking her course, but climate change cannot be ruled out as we see the desertification** (becoming desert due to lack of precipitation) of large tracks of the Mediterranean and surrounding areas.

There are cycles within cycles and since phenolic content is the by-product of the life function (photosynthesis) of a plant, weather patterns override the best of man’s interventions.

Nature is ultimately in charge and the phenolic content in olive oil is definitely one of Nature’s many gifts for health when we understand and work within her laws.

What does that mean to you, the buyer?

Athan checking out imported olive oils at Selfridges, London.
Searching for high phenolic EVOO?

How to use high phenolic EVOO? It really depends on your objectives; to use it for everyday culinary use, to meet your overall health and wellness objectives or for specific medical conditions or all of these.

The European Union Health Claim Labelling Regulation 432-2012 states that olive oils with polyphenols of 250 mg/kg or more can claim:

Olive oil polyphenols contribute to the protection of blood lipids from oxidative stress. In order to bear the claim, information shall be given to the consumer that the beneficial effect is obtained with a daily intake of 20 g of olive oil.

Research has shown that the benefits of taking high phenolic olive oil is dose dependent. The higher the concentration of phenolic compounds, the greater the potential health benefit. The upper limit has not been established in research, so it is up to the individual to monitor the body responses to high phenolic olive oil. And, if under medical treatment, to tell the doctor that you are adding this to your daily regimen. There have been cases where prescribed medication has been reduced but this should be done under the doctor’s care. High phenolic olive oil is a known blood thinner and doctors recommend it is not consumed ten days prior to and post-surgery. See disclaimer at the end of this article.

Most human research trials showing the effectiveness of high phenolic EVOO on such illnesses as Alzheimer’s and Leukemia have used olive oils of around 800 mg/kg with the highest ratio of phenolic compounds being oleocanthal and oleacein. Research also indicates that high phenolic EVOO may be a very effective natural blood thinner like ibuprofen, but without the nasty side effects. See disclaimer at the end of this article.

Considering this, Aristoleo Awards submission requirement is a minimum of 500 mg/kg of phenolic content to ensure that the oil will meet the EU Health Claim after eighteen months if sealed and stored properly. This standard also holds true on the Aristoleo Agora Marketplace which showcases high phenolic olive oil brands.



Producers test their olive oil by NMR at time of harvest, usually in the early fall. When we conduct our Aristoleo Awards the following March, the oil is tested again for eligibility (500 mg/kg) so there is a current analysis and to gauge how well it was stored.

As mentioned above, oils over 800 mg/kg have shown beneficial affect on various illnesses in human trials.

Nutritional and Health Benefits of Olive Oil

The nutritional long-term benefit that all olive oil has – even plain olive oil that has been chemically treated – is as a monounsaturated fat. This offers a long term benefit when replacing all animal fats such as butter or or vegetable based margarine with olive oil. Olive oil can aid in weight loss, make simple fare more delicious and nutritious and is a fat that can literally save your life. Read More.



The health benefits of olive oil with high phenolic content have been shown in research to have an immediate effect. This is why we recommend consulting your doctor if you are under medical care as phenolic compounds are anti-inflammatory and antioxidant and also have a blood thinning effect. Doctors recommend cessation of taking high phenolic olive oil ten days prior to and post-surgery. Also in some cases, prescription medication was lowered after introducing high phenolic olive oil to the daily diet. See disclaimer at the end of this article


“The health benefits of olive oil are 99 percent related to the

presence of the phenolic compounds, not the oil itself.”

Nasir Malik, research plant physiologist at the U.S. Agriculture Department.


Understanding High Phenolic EVOO

What are phenolic compounds?

For clarity, the term phenolic compound has become interchangeable with the term polyphenol based on the wording of the EU Health Claim Labelling Regulation 432/2012.

These are the organic compounds that are the by-products of plant synthesis and are known as phytochemicals. Polyphenols are regarded for their health promoting properties and occur in fruits, vegetables, whole grains, nuts, seeds and legumes, beverages (coffee, tea and wine), fats (olive oil) as well as spices and seasonings

However, there are phenolic compounds unique to olive oil that only occur during the malaxation process (crushing olives to release juice). There are 36 known phenolic compounds in olive oil. The two most widely researched for their health protective benefits are oleocanthal and oleacein.

Phenolic compounds are found in significant concentrations in certain olive varieties when harvested at a very specific time of the year. These olive oils are also sometimes referred to as early harvest. Agricultural methods, weather patterns, soil, drainage, harvest time and milling process, storage, and bottling methods affect the phenolic content.

Phenolic compounds, in particular oleocanthal, and oleacein are known for their anti-inflammatory and antioxidant properties. In vitro trials and an increasing number of human trials are studying the potential benefits of high phenolic olive oil in alleviating symptoms and potential therapeutic effect for Alzheimer’s, Rheumatoid Arthritis, Type II Diabetes, Leukemia and many cancers as well as other autoimmune and neurodegenerative diseases that are prevalent in today’s culture. Learn More.

The presence of oleocanthal is indicated by the peppery effect on the back of the throat sometimes causing a cough reflex. Oleacein is known by the bitterness on the tongue. For people accustomed to purchasing olive oils awarded for flavour and aromatic character or a mellow olive oil, these characteristics of pepperiness and bitterness are often mistaken as a flaw in the olive oil. Learn More

Depending on the individual’s palate, this affect varies making it a subjective assessment of a “good” olive oil. That is why we promote the NMR (Nuclear Magnetic Resonance) method of complete analysis from the University of Athens for the full phenolic profile to assure buyers that they are getting what they are paying for.

The proliferation of olive oil taste awards focuses on the gastronomic values of an olive oil – food pairings and taste modelled after wine – which is valid as far as it goes. These competitions are subjective and by virtue of their focus on subjective flavour profile and aromatics disqualify many high phenolic olive oils that would garner our highest awards.

We at Aristoleo are interested in pairing high phenolic EVOOs with personal wellness objectives based on the concentration of specific phenolic compounds, such as oleocanthal and oleacein. There are no official health claims that high phenolic EVOO will have an effect beyond the EU 432/2012 regulation, but many people have reported very positive results. We need more clinical studies to determine why it is more effective on some people and not others.

Our interest in high phenolic olive oils is predominantly for its many health benefits. Taste and chemical analysis matter, of course, and that is why the Aristoleo Awards includes organoleptic and chemical analysis along with the NMR certificate all of which are available from the producer to the buyer on request.

Science is unbiased and when we have the means to evaluate such an important commodity for our health, we want to use a scientific basis to assess and to make better olive oil and to protect health conscious individuals looking for natural foods they can trust. This is the only way to successfully defeat fraud, adulteration and deception in the olive oil industry; transparency

What Affects the Phenolic Content in Olive Oil?

Natural Factors:

Photo Courtesy Laconian Estate

Phenolics vary according to olive variety, time of harvest, soil condition and weather patterns. For example, bio-diversity within the grove adds to the richness of the soil and the nutrition available to the olive fruit.

Rains, drought or winds have greater or lesser impact on phenolic content and amount of olive oil produced depending on when they occur during olive fruit maturation.

Environmental Factors:

For the Producer:

Photo Courtesy Elaion Bio-Green Organic Olive Oil

Considering that olive oil is, in fact, a juice makes the volatility of the phenolic compounds more understandable. It is for this reason that the ARISTOIL Interreg MED Programme includes storage and transportation as key factors in the optimum integrity of high phenolic olive oil.

It has been found that the phenolic content tends to have a preservative affect and drops very little in the space of a year if the olive oil has been properly stored in tanks, sealed (usually with nitrogen) and kept below 16 degrees Celsius prior to bottling.

NMR tests of thousands of olive oils at the University of Athens over the past five years indicate that an expected attrition of phenolic content under correct conditions is expected to be between 5 – 20% over a year.

Olive Oil properly stored in temperature controlled stainless steel tanks topped with nitrogen to eliminate contact with oxygen.

It is incumbent upon the producer, as part of quality control to properly store the olive oil, to test the olive oil at time of bottling and provide that information on request – or on the label where allowed by federal agency.

The Best Before Date can be as long as 18 months after bottling and bottling may be as long as a year after harvest. Again, once shipped to a distributor or retail outlet, the storage must be temperature controlled to preserve the integrity of the olive oil.

LINK to PDF quality control guide for our producers.

For the Purchaser:

If you are purchasing high phenolic olive oil for its health benefits, then you are taking a daily portion as well as using it liberally in your cooking and food preparation. In this case the oil is being used up quickly, well before the Best Before Date. However, your care of the olive oil after it is opened is critical to minimize the loss of the phenolic content and preserve the integrity of its health benefit.

Light, heat and air are the enemies of any olive oil. Storing olive oil in a cool dark place will prolong its qualities of extra virginity (acidity) and high phenolic content.

That means store it in small dark bottles 250-1000ml out of the light in a cool/cold place, replace the cap right away after use and don’t leave it by the stove while cooking!

Phenolic compounds will simply evaporate from an open bottle within a short period. If you purchase a large quantity, it is advisable to either store the container in the refrigerator and dispense to serve, or decant from the large container into smaller bottles and store in the refrigerator with the fruit and vegetables .

Why Does High Phenolic EVOO Cost So Much?

High phenolic olive oil is more labour intensive to produce and offers a lower yield than traditionally produced olive oils which affects the price. The higher cost of temperature controlled tanks and lower yields combine to raise the cost.

It can also be expected that the higher the phenolic content, the higher the price. In higher concentrated phenolic olive oil, less olive oil is consumed to gain the health benefit as set out by the EU Health Labelling Regulation 432-2012.

To evaluate cost vs. value, one must compare high phenolic olive oil to other health supportive foods and products rather than to olive oil on the market shelf. The daily inclusion of high phenolic EVOO in the diet is much less than many supplements and certainly less costly both in price and side effects of pharmaceuticals. In addition, high phenolic olive oil is much more versatile and easier to add to the diet in different ways. Budget will dictate the range of olive oils used on a daily basis – one for cooking, one for fresh and raw foods and one as a part of a daily wellness regimen.

There are now many high phenolic olive oils on the market and more will come as the ARISTOIL Interreg MED Programme supports the education, production and marketing methods of more and more producers.

Athan tasting EVOO at sial paris 2018
Athan tasting EVOO at Sial Paris 2018 International Food Expo

This new category of high phenolic olive oil is barely six years old. The olive growers who produce it are visionaries. They have taken risks to do things differently, to go against centuries old traditions to make something of superior quality; an olive oil measurably different. They all have a story and they are proud to share it.

Every producer has a website and email. Discover the devotion that goes into the product you purchase. Ask questions.

As an informed purchaser, you are in control of the products you buy and through your choices enforce the transparency that is required to assure that production quality of high phenolic EVOO and its distribution go hand in hand with buyer expectation and trust.

We count on you as much as you count on us. We are here to answer your questions and welcome your comments and inquiries. Contact Athan at

To a joyful and healthful 2023!


*Aristoleo Ltd. is a key partner in the ARISTOIL Interreg MED Programme and provides testing of over 3000 high phenolic olive oils during production using the patented Aristoleo Test Kit and Aristometro Spectometer to measure oleocanthal and oleacein in olive oil.

**Desertification is due to many factors including over grazing, unsustainable agriculture including tilling, insecticide and pesticide use and dissolution of biodiversity. Learn more.


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