Ask anyone about the "Mediterranean diet" and the ingredient that instantly comes to mind is... olive oil!

Olive oil is made by pressing tree-ripened olives to extract a flavorful, heart-healthy monounsaturated oil that is prized throughout the world. While some olive oils come from California, many are imported from France, Greece, Italy and Spain.

The flavor, color and fragrance of olive oils can vary depending on distinctions such as growing region and the crop’s condition - much like wines.

Extra virgin olive oil, the cold-pressed result of the first pressing of the olives, is only 1 percent acid. It is considered the finest and fruitiest of the olive oils and is therefore also the most expensive. It can range from a champagne color to greenish-golden to bright green. In general, the deeper the color, the more intense the olive flavor, and more phytonutrients present.

In addition to monounsaturated fatty acids, olive oil also contains polyphenols, flavonoids, vitamin E, beta-carotene, and squalene.

When choosing and using olive oil, it's important to take note of a few things. First, you get what you pay for. The more flavorful  (and expensive) olive oils have a higher concentration of phytonutrients. And next, use olive oil cold - for drizzling. You will notice at medium to medium high heat, olive oil begins to smoke or hit its flash point. Going beyond the flash point creates harmful lipid oxidation products (LOPs) that damage cells. If you see smoke, throw it out and start over.

Olive oil should be stored in a cool, dark place for up to 6 months. It can be refrigerated, in which case it will last up to a year.