🧪 Olive and olive oil composition and health

Olive and olive oil composition and health is the section about what olives and olive oil contain and which claims about their benefits have official backing. The fruit holds little sugar (2.6–6%) and a lot of oil, 12–30% depending on the cultivar and ripeness.

The main fatty acid in olive oil is Oleic acid: under IOC and EU standards it makes up 55–85% of the fatty acids, and the USDA table gives 71.3 g per 100 g. Those 100 g supply 884 kcal and 14.35 mg of vitamin E, roughly 120% of the EU reference value.

Fresh olives owe their bitterness to Oleuropein, the main olive phenol: young fruit can contain up to 140 mg per gram of dry matter, and the amount falls as the fruit ripens. Lye treatment and fermentation turn it into hydroxytyrosol. Polyphenols in extra virgin oil vary widely, from 43 to 1,386 mg/kg in competition samples from 2023–2024, while refined oil has none detectable.

The EU allows one claim about olive oil polyphenols: they contribute to the protection of blood lipids from oxidative stress. It may be used only when 20 g of oil contain at least 5 mg of hydroxytyrosol and its derivatives, that is 250 mg/kg, with the effect obtained from 20 g of oil a day. In 2025, however, EFSA found no established link between olive oil phenols and HDL cholesterol, lower LDL or blood pressure.

Table olives are fairly salty: USDA lists 1,560 mg of sodium per 100 g for canned green olives and 735 mg for black ones. WHO advises adults to keep below 2,000 mg of sodium a day, so 10 green olives supply roughly a fifth of that limit.