High Phenolic Olive Oils: A Powerful Superfood

Olive oils

Extra virgin olive oil is a staple in many kitchens and is typically used to add flavor to and enhance a variety of dishes, from salads to desserts. But this precious liquid Hippocrates called “the great healer” is much more than a simple condiment, it’s also a health food. Rich in polyphenols, extra virgin olive oil has powerful medicinal properties. Regular consumption can provide a health boost and help fight disease. Consumer interest in olive oils with high phenolic content is increasing, and many olive oil makers are now marketing their high-quality extra virgin olive oil as a medicinal superfood. Read more about the health benefits of olive oil.

The Power of Polyphenols

Olive oil contains over a dozen polyphenols – these are natural micronutrients with strong antioxidant and anti-inflammatory properties. Studies and clinical trials have revealed that the polyphenols in olive oil trap disease-causing free radicals and protect cells from damage. These magical micronutrients are what make extra virgin olive oil a health-boosting elixir even though they represent only about 2% of the total mass.

The numerous health benefits of high phenolic olive oil have been scientifically validated. These include reducing inflammation, lowering blood pressure and cholesterol levels, protecting against cancer and heart disease, improving brain health and cognitive function, and promoting optimal health overall.

How Oleocanthal Fights Cancer

Dr. Goren in lab

Dr. Limor Goren, a molecular biologist and cancer researcher, has extensively studied the effects of oleocanthal, a polyphenol found only in olive oil because it’s created during the malaxation phase of the extraction process. Another thing that makes oleocanthal unique is the fact that it’s the only polyphenol with anti-inflammatory qualities.

“I think oleocanthal is the most important or the most special polyphenol because it has an anti-inflammatory effect that others just don’t have. Other polyphenols are strictly antioxidants,” she says. Those with antioxidant qualities found naturally in olive oil include tyrosol, hydroxytyrosol, oleacein, and oleuropein aglycone.

Goren discovered that oleocanthal is particularly powerful because it’s toxic to cancer cells. “What we showed in our lab is that oleocanthal damages an organelle inside cancer cells called lysosome,” she explains. “Lysosomes exist in every cell in our body but cancer cells are more reliant on them. They often have increased lysosome fraction inside the cells because they use it to support their growth and division and generation of necessary biomaterials for the cell. Sometimes it also happens, especially in people going through cancer treatment, that cancer cells have increased lysosomes because they help exclude the poisons, the chemotherapy, from the cell. So in a way cancer cells can sometimes protect themselves from chemotherapy and they do that by using the lysosomes. That’s why lysosomes are more important for cancer cells than regular cells. What we found out was that oleocanthal causes the lysosomes to be defective, to be leaky, so they leak material and are no longer functional and also turn the cellular environment toxic, causing cancer cell death. This happens with much much higher affinity than non-cancerous cells.”

The EU Health Claim

The medicinal value of high phenolic olive oil thanks to its high concentration of health-boosting polyphenols has been validated by the European Food Safety Agency (EFSA). It recognizes the validity of the following health claim: “The polyphenols in olive oil contribute to the protection of blood lipids from oxidative stress”. 

According to a 2012 European Union (EU) regulation, a bottle of extra virgin olive oil can be labeled with this health claim if it contains “at least 5mg of hydroxytyrosol and its derivatives per 20g of olive oil”. Furthermore, it defines a high phenolic olive oil as one containing at least 250mg of polyphenols per kilogram of olive oil. The regulation also suggests that consumers should be informed that a daily dose of 20g (a little less than two tablespoons) of extra virgin olive oil is recommended in order to enjoy its beneficial effects.

As a result of this health claim, more and more producers have been doing lab analyses of their olive oils to get a picture of their polyphenol content and marketing their high phenolic olive oils as an elixir. Also, “health claim” is a recent award category introduced at international olive oil competitions that reflects increasing interest and appreciation for high phenolic olive oil. 

Olive oils entered into competitions under this category are typically evaluated based on a chemical analysis of their polyphenol levels, in particular oleocanthal, oleacein, oleuropein aglycon, and ligstroside aglycon. This lab test accounts for a majority of the total final grade granted, in addition to an analysis of organoleptic or sensory qualities which are determined by a panel made up of expert olive oil tasters.

Olio nuovo

“I’ve seen producers get polyphenol levels well into the thousands, up to 3000 (ml/kg),” reveals Goren. “The EU claim gives extra validation to what science has been showing for years. But the number (250mg/kg) is a little bit too low for two reasons. It’s really a very low minimum that I believe is not so medically beneficial at those levels based on data from the lab. But also the bigger problem is that polyphenols are measured at the time of harvest and if the oil is not stored properly, or even if it is, the polyphenol level drops throughout the year. So an olive oil with 250mg/kg at time of harvest may only have 150mg/kg by the time it gets to the consumer. Experiments show that some varieties lose up to 50% of polyphenols in the first year. So there is some talk in academia and within the industry to try to redefine the threshold of 250mg/kg.”

Dr. Goren pouring oil

Identifying High Phenolic Olive Oil

How do you know the bottle of olive oil in your kitchen pantry is high in polyphenols? Look for a certification on the bottle’s label indicating that it has been tested for polyphenol levels and contains a minimum of 250mg/kg. Just as important is the harvest date mentioned on the bottle: this should be as recent as possible and not more than 18 months.

Your tongue can also help determine whether an olive oil is rich in polyphenols. High phenolic olive oils are robust with a noted bitter taste that causes a peppery burn in your throat. It’s not uncommon to cough when tasting a high phenolic olive oil. If this happens, it’s a sure sign it’s high in oleocanthal in particular, which triggers the burning sensation in your throat. Meanwhile, the bitterness is the work of oleuropein and tyrosol.

But how palatable is a high phenolic but bitter olive oil that burns the throat? While the bitterness of extra virgin olive oil is certainly a desired attribute, this must be balanced with other notes to make it appetizing. “Olive oils with polyphenol levels over 2000mg/kg usually don’t taste great and have mostly a bitter taste,” points out Goren. “That’s okay if you’re taking it for medicinal purposes, medicines often don’t taste good! But if you’re using it for culinary purposes, then it’s not very palatable at those levels. You can make an olive oil with levels of 1000-1500mg/kg that taste fantastic. I would say that above 2000mg/kg, you start to lose that balance.”

High Phenolic Cultivars

lianolia and koroneiki oil from Kyoord

When it comes to polyphenol content, not all olive cultivars are created equal. Some of the varieties especially high in polyphenols include the coratina, maurino, and moraiolo cultivars from Italy, and picual and conicabra from Spain. The aglandau variety from France is also high in polyphenols, as is the Istrska Belica/Istarska Bjelica cultivar from Istria, a region shared by Slovenia and Croatia. Other high phenolic varieties include chetoui from Tunisia, the athinolia, kalamon, koroneiki and lianolia cultivars from Greece, and mission from California.

Of these high phenolic olive cultivars, not all are high in anti-inflammatory oleocanthal. “The Mission variety is high phenolic but extremely low in oleocanthal, so that’s one good example of this,” shares Goren. “The one that’s highest in oleocanthal that’s been identified so far is kalamon, followed by lianolia, both Greek varieties.”

Other Conditions Influencing Phenolics

Hand harvesting olives photo credit Olio Piro

While certain olive cultivars are especially high in polyphenols, there are several other factors that influence the phenol content of olive oil. These include soil conditions in the olive grove, the year of production, harvest time, the production methods used, and storage conditions. Climate is another factor. Moderate Mediterranean climates enjoying sunny days and cool nights are ideal, while mild water stress can also result in increased phenolic levels.

An early harvest is ideal, while the olives are still green and unripe and polyphenol levels are high. Care must be taken not to damage olives during harvest and they should be pressed immediately to preserve the concentration of polyphenols.

Finally, freshly pressed olive oil has the highest polyphenol levels. Olive oil quickly loses polyphenol compounds when exposed to light, heat, and air, causing oxidation. This is why proper storage is key and the reason why a bottle of olive oil should be consumed as quickly as possible after opening.

How Much Olive Oil is Beneficial?

Olive oil spoon

Following interest expressed by friends and family in the powerful high phenolic olive oil she was experimenting with in her cancer research, Goren launched Kyoord (pronounced “cured”) to make high phenolic oils available to consumers. “We get reports from people seeing positive effects on their blood pressure, and arthritis,” shares Goren. “Also people who went through cancer treatment report that their cancer’s in remission. I also have clients who take it for long Covid and they say their symptoms have improved.”

Finally, just how much of this powerful olive oil should be taken a day to feel its superpower effects? “In studies we see good effects with as little as 20ml per day, which is a little over a tablespoon,” says Goren. “But some studies mention 40ml or 50ml a day – something more like two or three tablespoons. So I would recommend between one and three tablespoons.”