OLIVE OIL
Olive oil is made by crushing and pressing the olives that naturally contain a lot of oil (they belong to the Olea genus of trees). The oil can be extra virgin (first pressing), virgin, and further down the scale according to the degree of processing. You usually hear a lot about extra virgin olive oil being the best, and it really is the best - both in terms of flavor and health benefits. And even though it costs more than the less good olive oils, it is worth its price. Olive oil has been made on this planet for over 5,000 years and is one of the earliest foods consumed by the civilized world. It is still a basic ingredient in the diet of the world where it once came from - the Mediterranean. It is also common to hear about the Mediterranean "health diet", based on olive oil that normally constitutes about one-third of the total calorie intake of an average person in these countries. And these people have lower incidences of cardiovascular diseases.
Why is olive oil so healthy? It contains molecules called polyphenols and monounsaturated fats. Polyphenols are very effective in fighting oxidative damages on your blood vessels, the ones that give rise to cardiovascular diseases. They also are good anti-inflammatory agents, meaning that the inflammations building up in the blood vessels are hampered. Monounsaturated fats are good fats that don't actually make you fat but can in fact make you lose your body weight. However, the consumption of the bad animal fat has to be reduced in order to see the effects of olive oil. This is not just a phony talk, this is hard facts backed by scientific research on humans. One thing is important though - to achieve the beneficial effects of olive oil you need to get the best quality oil - extra virgin oil - that contains most of the beneficial health substances. You also need to store the oil properly.
When you buy olive oil, and the price is not that sticking, go for the first grade extra virgin olive oil. This is the most flavorful and healthy oil on the market, it is unrefined, and is perfect to put on almost anything. If possible, buy the oils in dark bottles (protection from light oxidation of the healthy molecules) and also the oil that is sealed with an airtight capsule. Needless to say, the oil should be stored in the dark and tightly sealed, and also in a relatively cold place. These measures of safety are crucial for having the healthiest possible olive oil at home.
You can use olive oil with your salads, soups, and a lot of other ingredients. The less you heat it the better. The heat, as we implied, is deteriorating for the heat-sensitive health molecules in the oil, which is why you should try to use the oil mostly as a seasoning agent after the dish has been cooked.
These requirements of storage and handling of olive oil are not just something to wave away. Scientific studies have shown that the amount of e.g. vitamin E drops by 100% after a year of storage even in the proper conditions. It gets much worse in the worse conditions of course. Light exposure for a few months turns extra virgin olive oil quality into the lesser graded oil (molecularly speaking). Naturally, even if you are careful about storing the oil correctly, you cannot tell how the shop has handled the oil. Try to do the best you can by picking out the bottles that have been hided from the light as much as possible, possibly at the back of the shelf.