The Diet Myth: The Real Science Behind What We Eat

by Tim Spector

Olive oil comes in three main types: expensive high-quality extra virgin olive oil, which has less than 0.8 per cent acidity, indicating its freshness and quality, plus a strong, sometimes slightly bitter taste. This comes from the rapid first pressing of the olive – which is performed at cold temperatures and marketed as ‘cold-pressed’. Virgin olive oil is a grade lower, possessing higher acidity and still some taste; then finally there’s regular olive oil. This last is made industrially by refining the leftovers and is cheap and normally tasteless, but may be given some flavour by mixing with a small amount of extra virgin oil. We now know there are huge differences between the health properties of the types, and most of the Italian and Greek oil produced now is extra virgin. Good-quality extra virgin olive oil contains the greatest amounts of the chemicals known as polyphenols, which have special properties and probably account for much of its health benefits.