Polyphenols and oxidative stress

Polyphenols in olive oil are interesting for their flavor, quality, and documentation. They are also linked to one of the EU's few approved health claims for olive oil: the protection of blood lipids from oxidative stress.

This is a precise formulation. It's not about olive oil treating diseases, but about an approved nutrition and health claim that can be used when the oil meets clear conditions.

What is oxidative stress?

Oxidative stress occurs when reactive molecules, often called free radicals, are formed faster than the body's own defense systems can neutralize them. This process is a normal part of metabolism, but an excess can contribute to the oxidation of cell structures, proteins, and lipids.

In EFSA's approved claim, blood lipids are the focus. Blood lipids are susceptible to oxidation, and it is in relation to these lipids that olive oil polyphenols have been evaluated.

EFSA's approved health claim

Within EU Regulation 432/2012, the following health claim is approved for olive oil polyphenols: olive oil polyphenols contribute to the protection of blood lipids from oxidative stress.

This is an Article 13.1 claim. This means it is based on a scientific assessment of a relationship between a food or substance and a physiological effect. The claim is also specific: it applies to olive oil polyphenols and the protection of blood lipids from oxidative stress, not general health or a specific disease.

Conditions for using the claim

For an olive oil to be able to use the approved claim, it must provide at least 5 mg of hydroxytyrosol and its derivatives, such as oleuropein complex and tyrosol, per 20 g of olive oil.

The consumer information must also state that the beneficial effect is achieved with a daily intake of 20 g of olive oil. This is a regulatory information requirement linked to the claim. It is not a medical recommendation from Vala Selection.

This is why documented analysis is important. It is not enough for an oil to be marketed as "rich in polyphenols"; the content needs to be traceable to batch, method, and laboratory results.

What 1,004 mg/kg means

Vala Selection's reference batch 2025-VL-MIR-001 has been analyzed to have a total polyphenol content of 1,004 mg/kg by HPLC at the University of Split. This is a high value in relation to the level required for the approved health claim to be relevant.

Nevertheless, the figure should be understood correctly. It applies to the current batch, not future harvests. Polyphenol content is affected by olive variety, harvest time, weather, pressing, storage, and time since production. Therefore, each batch should be analyzed separately.

Read more about the basics here: polyphenols in olive oil.

Hydroxytyrosol, oleuropein, and oleocanthal

EFSA's conditions mention hydroxytyrosol and derivatives, including oleuropein complex and tyrosol. In practice, this refers to a broader phenolic profile where several compounds and derivatives contribute to the oil's analytical value.

Oleuropein is closely associated with bitterness and the olive's green, phenolic character. Oleocanthal is more linked to the peppery sensation in the throat. Together, they provide a more complete picture of why a high-polyphenolic oil can feel more intense than a mild standard oil.

Vala Selection communicates total polyphenol content at batch level because it is the most robust and customer-understandable value. Individual molecular values can be interesting, but without methodological and sample context, they can easily be misinterpreted.

What the claim does not mean

The approved claim does not mean that olive oil is a medicine, a treatment, or a guarantee of a specific health outcome. Food products may not be marketed as remedies, treatments, or preventive measures against disease.

Nor does it mean that more is always better. Olive oil belongs in a balanced diet, and the regulatory wording is deliberately narrow: blood lipids, polyphenols, and oxidative stress.

For Vala Selection, the important point is transparency. If a health claim is used, the customer should be able to see which batch it applies to, how the analysis was done, and why the oil meets the conditions.

Why handling and storage matter

Polyphenols begin to degrade after harvest, and the process is affected by time, temperature, oxygen, and light. Rapid pressing, careful handling, and dark bottling help preserve the oil's phenolic profile.

After purchase, storage also plays a role. Store the oil in a cool, dark, and well-sealed place. This not only preserves the taste but also helps protect the compounds that make the oil analytically interesting.

More information

About the method behind the analysis: HPLC analysis of olive oil.

About polyphenols as a group: polyphenols in olive oil.

About bitterness and oleuropein: oleuropein in olive oil.

About pungency and oleocanthal: oleocanthal in olive oil.

Sources: EU Regulation 432/2012 on approved health claims. EFSA Journal 2011;9(4):2033. HPLC analysis performed at the University of Split. Batch 2025-VL-MIR-001.