If you have ever heard that "extra virgin olive oil is good for you", there is a specific substance behind this phrase: polyphenols. These are the compounds that make EVO oil not just a condiment, but a true functional food. Here's why, and why they're not found in all oils.
What are polyphenols
Polyphenols are plant compounds with high antioxidant power, naturally present in olives. They are partly transferred to the oil during cold mechanical extraction. They are mainly responsible for the healthy properties of extra virgin olive oil.
The three main ones in EVO oil are:
- Oleocanthal: responsible for the tingling in the throat. It has natural anti-inflammatory effects similar to ibuprofen in small doses (Beauchamp et al., Nature 2005).
- Oleuropein: responsible for bitterness. Strong antioxidant, cardiovascular protective.
- Hydroxytyrosol, tyrosol: among the most powerful plant antioxidants known.
What EFSA says
The European Food Safety Authority (EFSA), in EU Regulation 432/2012, recognized this claim for olive oils:
The polyphenols in olive oil contribute to the protection of blood lipids from oxidative stress.
To display this claim on the label, an oil must contain at least 5 mg of hydroxytyrosol and derivatives per 20 g of oil (i.e. 250 mg/kg). A dosage achievable only from high quality and fresh extra virgin oils.
How many polyphenols does an extra virgin olive oil have?
Indicative values:
- Industrial oils, «non-extra virgin» olive oil: 0-50 mg/kg (refining destroys most of the polyphenols)
- Basic commercial EVO oil: 100-200 mg/kg
- Quality artisanal EVO oil: 200-400 mg/kg
- High content monovarietals phenolic (Ortice, Coratina, Picual): 400-800 mg/kg
Our oils, analyzed every year, typically contain between 350 and 500 mg/kg of total polyphenols. A value that can only be achieved with care of the supply chain from the olive grove to bottling.
What influences the polyphenol content
- Cultivar: some varieties are naturally richer (Ortice, Coratina, Frantoio, Picual)
- Ripeness stage: olives harvested early (green-turned) have more polyphenols than olives harvested late
- Water stress: olive trees that have had a dry summer produce oils richer in polyphenols
- Altitude and climate: hills better than plains, high temperature range better than constant low temperatures
- Harvest-milling time: with every hour that passes, some polyphenols degrade
- Extraction temperature: above 27°C the more delicate polyphenols are lost
How to recognize an oil rich in polyphenols
Polyphenols are perceived as bitter and spicy in taste. Practical indicators:
- The oil "stings" in the throat, gives a slight cough
- Perceptible, balanced bitter flavor
- Green scent: cut grass, olive leaf, almond
- Bright green color (chlorophyll pigments often accompany polyphenols, but the color is not enough on its own)
Polyphenols decrease with time: a one-year-old oil will have fewer polyphenols than an oil from the new harvest. This is why fresh oils (within 12 months) have the most intense flavour.
How much to consume per day for real benefits
The guidelines on the Mediterranean diet recommend 2-4 tablespoons (30-50 ml) per day of extra virgin olive oil, preferably raw. With an oil rich in polyphenols (300+ mg/kg) you can reach the therapeutic dosage recognized by the EFSA with a handful of spoons.
They are not "medicines" - they are food. But they are one of the few foods for which the effect on health has been scientifically demonstrated in clinical studies (e.g. PREDIMED study).
Frequently asked questions
Are polyphenols found in all olive oils?
No. In refined oils and generic "olive oil" they are almost absent (refining destroys them). They are found in significant quantities only in extra virgin oils obtained by cold mechanical pressing.
Do polyphenols resist cooking?
They degrade with prolonged heat. To fully benefit from their properties, extra virgin olive oil should be consumed raw (salads, finishing dishes). For short and moderate cooking (sautéed, light sautéing), the loss is limited.
How do I know how many polyphenols my oil has?
Serious producers have their oil analyzed annually in accredited laboratories. Ask for the analyses: a transparent manufacturer willingly shares them. Be wary of those who refuse them.
Why does a very stinging oil make me cough?
Oleocanthal stimulates TRPA1 receptors in the throat, the same ones activated by irritating compounds. It is the sign of a fresh oil rich in antioxidants. For those who are not used to it, it may seem "too much", but it is a marker of quality.
Do polyphenols last over time?
They gradually decrease over the months. A freshly bottled oil has more polyphenols than one aged 12 months, and much more than one aged 18 months. For this reason it is important to consume the oil within 18-24 months of bottling and keep it away from light and heat.