The oils are usually extracted from the fruit of a plant or their seeds (such as the case of the most used oil nowadays, the sunflower oil), but, although less frequently, they can be extracted from the leaves, steam or the root of a plant. In the last mentioned cases, those oils are extracted from certain herbs, and they are called the essential oils, mostly because they are very strong and only a little bit of them should be used, and that is usually in the medicinal and cosmetic purposes. Naturally, same as the vegetables themselves, the oils extracted from them are beneficial for health on many levels as well.
The truth about the vegetable oils
The most important thing that we, as the consumers must be aware of, is the fact that not all the oils are equally healthy. Also, one of the most important things, that we should be keep in mind when deciding which one to buy, is that the least processed oils are the healthiest. However, it is not necessary to mention over and over again the health benefits of the vegetable oils, in the comparison to the animal fat, of course, when used for culinary purposes. And that is because the saturated fats have been very unpopular lately.
Concerning the misconception that every vegetable oil is good for health, we reach the most important point of this issue. The explanation is simple, the health benefit of an oil depends on the way it is processed. That is, the oils that are processed with heath lose almost all the beneficial nutrients which the original vegetable was rich in. The reason for such a processing is the enormous demand for the oils for cookery on the market.
Nevertheless, maybe even more dangerous way of the processing of a vegetable oil, is the technique called hydrogenation, which is, basically, the process of turning the fluid form of oil into the solid form, so that even more products based on vegetable oils could be made. The good example is margarine, the product of the everyday use, which is very tasteful and indispensable for making sandwiches, but very harmful for health.
As opposed to that, the best example for really beneficial oil is the coldly pressed olive oil, which is, in that case, called the extra virgin oil. If possible, one should introduce this oil in the everyday consumption, but it is not good to be heated at all, so there are the other olive oils designed for cooking on the market.