Oleocanthal, oleuropein, hydroxytyrosol: behind the bitterness and pepperiness of a good extra virgin olive oil lies its real richness. Here's what polyphenols are, what benefits they bring, and how many you really need.
Polyphenols are a large family of natural antioxidant compounds found in plants. In extra virgin olive oil they're the true source of much of its health benefits and of that bold flavour — bitter and peppery — that sets a living oil apart from a flat, anonymous one.
Unlike fats, which provide energy, polyphenols have no caloric value: their job is to protect. In the olive they shield the fruit from environmental stress; in the oil they slow oxidation (that is, rancidity) and, once consumed, exert an antioxidant action inside our body too.
A detail many people miss: polyphenols are present only in extra virgin olive oil obtained mechanically. In refined oils or generic "olive oils" they are largely destroyed by chemical and thermal treatments. It's one of the reasons it pays to understand how to choose a good EVOO rather than settling for the lowest price.
"Polyphenols" is an umbrella term. In extra virgin olive oil the most important — and the most studied — are three.
Hydroxytyrosol deserves special attention: it's on this molecule (and its derivatives) that the European legislator built the health claim we'll look at shortly. When you read "polyphenols" on a label, it's mostly this one behind the name.
Talking about extra virgin olive oil and its benefits without mentioning polyphenols would be like talking about wine without naming the grapes. They're what makes the nutritional difference, and this is one of the few cases where the European Union has authorised an explicit health claim on a food.
In plain terms: blood lipids are the fats circulating in the blood, and oxidative stress is the "wear" they undergo from free radicals. Thanks to their antioxidant action, polyphenols help protect them. It's a benefit recognised at a regulatory level, not a marketing promise.
Beyond this regulated aspect, polyphenols are at the heart of scientific research for their role within the Mediterranean diet, considered for decades a protective dietary model. It's no coincidence that a good extra virgin olive oil is one of the most representative foods of this regimen.
The best part is that you don't need lab equipment to get a first clue: your palate is already a good sensor. Polyphenols and the benefits of olive oil go hand in hand with two distinct sensations.
A slight bitterness mid-palate is the sign of oleuropein. An oil that's entirely "sweet" and neutral is often low in antioxidants.
The sting in the throat — the one that sometimes makes you cough — is oleocanthal. The sharper it is, the richer the oil is in polyphenols.
An intense green can indicate early-harvested olives, richer in polyphenols. On its own, though, colour isn't enough: it's just a clue.
The only absolute certainty is the value stated by the producer in mg/kg. A serious company communicates it without hesitation.
The key question is: what's the threshold above which an oil can truly be called "polyphenol-rich"? European regulation sets the starting point, but oils of excellence go far beyond it.
The polyphenol value depends not only on the olive variety, but above all on the moment of harvest (earlier = more polyphenols) and on cold processing. Storage also counts: even the best oil loses polyphenols if exposed to light and heat. That's why we've dedicated a separate guide to how to store extra virgin olive oil and protect its properties over time.
QuBi is 100% Italian extra virgin olive oil, single-origin and blend-free, cold extracted below 27°C so the heat doesn't degrade the polyphenols. The result is an oil with acidity below 0.2% and polyphenols above 350 mg/kg: comfortably over the minimum threshold required by EU Regulation 432/2012.
But having a polyphenol-rich oil isn't enough: you also have to store it well down to the last drop. And this is where the squeeze bottle comes in. Every time you open a traditional bottle, air gets in and triggers the oxidation that consumes those very polyphenols. QuBi's squeeze system reduces contact with air and lets you dose only what you need, with no drips. If you want to dig into the difference between the two systems, read the comparison between squeeze oil and a glass bottle.
To use the health claim under EU Reg. 432/2012 you need at least 250 mg/kg of polyphenols (5 mg of hydroxytyrosol and derivatives per 20 g of oil). Higher-quality oils go further: QuBi exceeds 350 mg/kg.
By the bitterness and the pepperiness in the throat (oleocanthal). They aren't defects but signals of antioxidants. The absolute certainty, however, remains the value in mg/kg stated by the producer.
It's one of the most powerful and studied polyphenols in extra virgin olive oil. Together with its derivatives, it's the parameter the European claim for protecting blood lipids from oxidative stress is based on.
Yes: light, heat and oxygen degrade them. Store the oil in a cool, dark place, in opaque, well-sealed containers, and use it within 12-18 months of pressing.
QuBi Olio: 100% Italian, cold extracted, acidity <0.2% and polyphenols >350 mg/kg, in the squeeze bottle that doses with precision and slows oxidation.