A Radical Guide To Polyphenols
Polyphenols are not a buzzword. They are the chemical response a plant builds to survive. We press that response out of the olive and put it to work in the body.
What they are
Polyphenols are a family of micronutrients plants produce under stress — drought, heat, UV, pressure. The harder the olive tree strains to live, the more polyphenols its fruit carries. In the human body they function as antioxidants and anti-inflammatories, but the interesting part is where they act: directly on the vagus nerve and the gut–brain axis.
How they're measured
A bottle of olive oil is measured in milligrams of polyphenols per kilogram — mg/kg. Supermarket oil often sits below 100 mg/kg. The number is not a guess and not a marketing figure: it is the output of a laboratory instrument.
mg/kg
Milligrams of total polyphenols per kilogram of oil. One number that bundles every phenolic compound the laboratory can identify and quantify. The higher the count, the more active compound per drop.
HPLC
High-performance liquid chromatography — the international standard. The oil's phenolic fraction is separated on a column, and each compound is identified and counted against calibrated standards. Certificates of analysis are produced by machines, not by taste.
Tyrosol & hydroxytyrosol derivatives
Almost everything in the count belongs to one of two families — tyrosol derivatives and hydroxytyrosol derivatives. On the De Sierra certificate: 632 mg/kg tyrosol derivatives and 730 mg/kg hydroxytyrosol derivatives. Together they make up the total.
Oleocanthal + oleacein
The two dialdehydic secoiridoids, measured together. These are the throat-sting compounds. De Sierra: 59 + 59 = 118. Tropicual EVERYDAY: 46 + 52 = 98. The sting is not an accident — it is the compounds announcing themselves.
250 mg/kg · 5 mg/20 g
Two numbers to know. 250 mg/kg — the widely used floor for a 'high polyphenol' oil. And under EU Regulation 432/2012, 5 mg of hydroxytyrosol derivatives per 20 g of oil — the level at which the only authorised health claim applies: protection of blood lipids from oxidative stress.
Independent certificates
We do not estimate polyphenols. We publish them. Every figure on the oils ledger comes from an independent certificate of analysis — the World Olive Center for Health in Athens, or the producer's own HPLC — and the certificate travels with the tin.
Across the current ledger that range runs from 651 to 1,711 mg/kg — lab-verified, not marketing-rounded. The higher the count, the more of the active compound reaches the nervous system per drop.
The Compounds
Oleocanthal
The compound that makes quality oil sting the throat. Oleocanthal activates TRPV1 receptors on the vagus nerve, suppressing systemic inflammation through the vagal–adrenal axis. It is ibuprofen's distant, bitter cousin — plant-made.
Oleacein
Closely related to oleocanthal and a potent protector of the cardiovascular system. Oleacein scavenges free radicals and supports the arterial wall, linking the drop that reaches the vagus nerve to the one that reaches the heart.
Hydroxytyrosol
Among the most powerful antioxidants in the olive. Hydroxytyrosol is absorbed rapidly and is the EFSA-approved basis of the olive oil polyphenol health claim — protecting blood lipids from oxidative damage.
Tyrosol
Hydroxytyrosol's quieter partner. Tyrosol accumulates in tissues and extends antioxidant protection long after ingestion, supporting cardiometabolic markers — blood pressure, insulin, lipid profile.
Oleuropein
The parent compound — the source from which oleocanthal, oleacein, and hydroxytyrosol are made as the olive ripens and the oil is pressed. Oleuropein is the tree's master compound, carried into the bottle.
Why they matter
Three reasons, in descending order of how formally they are established.
The one the law concedes. The European Food Safety Authority's only authorised health claim for olive oil polyphenols is protection of blood lipids from oxidative stress. That is the cardiovascular floor — the regulated, defensible minimum.
The one the throat announces. Oleocanthal activates TRPV1 receptors on the vagus nerve — the sting of a quality oil is a signal travelling up the vagal–adrenal axis to dampen systemic inflammation. These compounds are not antioxidants first. They are nervous system compounds first.
The one the gut translates. Roughly 95% of ingested polyphenols pass through the small intestine unabsorbed and feed the microbiota — which feeds the brain in return. That is the microbiota–gut–brain axis, detailed below.
The evidence, reference by reference, lives on the research page.
The Gut Microbiota
Roughly 95% of ingested polyphenols are never absorbed in the small intestine. They reach the colon intact, where bacterial enzymes cleave the secoiridoids into smaller phenolic acids — hydroxytyrosol among them — which are absorbed more readily than the parent compounds. Two people can drink the same oil and receive a different dose, because they carry a different microbiota.
The traffic runs both ways. Olive polyphenols act as a prebiotic, favouring Lactobacillus and Bifidobacterium and raising output of short-chain fatty acids: acetate, propionate, butyrate. Butyrate feeds the colonocyte, tightens the gut barrier, and keeps bacterial endotoxin out of circulation — the difference between a quiet immune system and a body running a permanent low fever it cannot name.
Those metabolites then stimulate vagal afferents and modulate microglia in the brain. This is the microbiota–gut–brain axis, and it is the reason a fat pressed from a fruit can change how a nervous system behaves.
Not Food
High-polyphenol olive oil lowers cortisol, and supports emotional regulation. This is why it is not just food. It is a biotechnic tool. It interacts with the body at the level of receptors, enzymes, genes, and neural pathways.
The Pathway in Summary
You inhale the aroma. The brain prepares. You swallow. Oleocanthal hits the TRPV1 receptors at the back of your throat. The vagus nerve fires. The parasympathetic system activates. Oleocanthal enters the bloodstream and inhibits COX enzymes. Secoiridoids feed the gut microbiome. Nrf2 and NF‑κB are modulated at the cellular level. The brain receives signals of safety, satiety, and calm.
All of this happens in the time it takes to taste a single bottle, or a single drop.
This is what you are selling. Not oil. A relationship with the nervous system. A way of reclaiming sovereign biology. A daily tool for resistance, resilience, and recovery.
They do not cure anything. They create the conditions for recovery. That is what we do.
The Radical Apothecary.