Olive trees are thought to have originated in Greece or Syria but over the last millennia and more their cultivation has spread across the Mediterranean region, making olives and olive oil a staple of the local diets. The biggest European producers are Spain, Italy and Greece.
Olive oil can become rancid from exposure to light and heat so it’s best to look for olive oils that are sold in darker tinted bottles and are not displayed in bright sunshine or near a heat source.
There are many varieties, which reflect how the oil has been extracted and processed. Extra virgin olive oil is cold-pressed from olives and has the most delicate flavour and strongest overall health benefits. Virgin olive oil is made the same way but from slightly riper olives and it has a lighter flavour but still retains all the nutrients.
Virgin olive oils also differ in their content of free oleic acid, depending upon the extent to which fat has broken down into fatty acids. Extra virgin olive oil can have up to 0.8 per cent, virgin olive oil up to two per cent.
Extra virgin and virgin olive oils are always unrefined – have not been treated with heat or chemicals – and thus retain many beneficial phytonutrients. They are best used cold for dipping, salad dressings or drizzling on top of dishes because heat destroys a good amount of those beneficial components.
|Nutrients in olive oil||In one tablespoon (14g)|
|Calories||119 kCal (498 kJ)|
|Total fat||13.5 g|
|Saturated fat||1.9 g|
|Monounsaturated fat||9.8 g|
|Polyunsaturated fat||1.4 g|
|Vitamin E||1.9 mg|
If the label simply says ‘olive oil’ or ‘pure olive oil’, it means it’s a mixture of virgin and refined olive oil, which has been treated with heat or chemicals. These oils have much less olive aroma, flavour or colour and lack many of the beneficial phytonutrients. On the other hand, they are more temperature stable and are good for cooking and baking – their smoking point (when the oils start breaking down) is around 230° as opposed to 160° for extra virgin olive oils. That’s higher than butter or coconut oil! ‘Light’ olive oil is not lower in fat, the name simply refers to its colour and fairly neutral flavour.
Olive oil is unique for its high percentage of monounsaturated fat. Between 70 to 85 per cent of olive oil is monounsaturated oleic acid – omega-9 fat. This is not an essential fat but is thought to have cholesterol and blood pressure lowering properties. It’s certainly much healthier than saturated fats. This, together with the fact that olive oil contains phytosterols – another group of compounds helping to lower cholesterol – contributes to olive oil’s heart-protective properties.
All olive oils have very similar fat composition so the main difference between them is their phytonutrient content – in particular polyphenols. These antioxidant, anti-inflammatory, natural compounds can help protect your blood vessels and other tissues from damage. Only virgin olive oils contain significant amounts of polyphenols and there’s no need to consume huge amounts – one tablespoon a day is more than enough.