Hydroxytyrosol (HT) is arguably the most effective natural antioxidant from the olive — the foundation of many health benefits of the Mediterranean diet.
Hydroxytyrosol — HT for short — is a natural polyphenol (a phenylethanoid) from the olive. It is found in olive leaves, olives and olive oil, and is regarded as the most potent known natural antioxidant of plant origin.
The key to its action is its catechol structure: it can donate hydrogen atoms, directly neutralise free radicals and interrupt the chain reaction of lipid oxidation. HT also chelates metal ions such as Fe²⁺ and Cu²⁺ that catalyse oxidation.
This makes HT both an effective food preservative and a bioactive compound with health benefits.
µmol TE/g — comparison of common antioxidants
Schematic representation based on ORAC comparison data.
The effects have been studied in lab, animal and early clinical studies. A selection with references.
Scavenges free radicals and protects cells from oxidative stress. In cell studies (HEK-293), HT lowered elevated ROS and restored glutathione levels.
In a 12-week placebo-controlled trial (92 adults, 30 mg HT/day), LDL cholesterol fell in the HT group while rising in the placebo group.
HT inhibits the inflammatory enzymes COX-2 and iNOS. In a small clinical study it improved pain and function in early knee osteoarthritis.
As a food additive, HT extends shelf life: it prevents fats from going rancid, protects nutrients and preserves colour and flavour.
HT can defend cells against oxidative damage — a mechanism linked in research to neuroprotection and healthy ageing.
HT has a long history of consumption via the Mediterranean diet and is approved in the EU as a "novel food" and in the US (FDA GRAS).
Hydroxytyrosol is naturally present in olive leaves, olives and olive oil. In virgin olive oil it occurs mostly in bound form (e.g. as oleuropein), from which free HT is released in the body.
Within the oil matrix, HT is well absorbed and reaches plasma quickly. Phenol-rich extra virgin olive oils deliver HT together with companion compounds that complement its action — the most natural way to consume it.
The key active compound thus sits in a tiny but precious fraction. [1]
"Olive oil polyphenols contribute to the protection of blood lipids from oxidative stress."
Authorised EU health claim — Regulation (EU) No 432/2012, based on the EFSA scientific opinion (EFSA Journal 2011;9(4):2033).
The effect is obtained with a daily intake of 5 mg of HT and its derivatives. [8][9]