Olive oil is a vegetable oil extracted from crushing and pressing of olives (fruit of the olive tree). Based on the type of processing, olive oil is commonly graded into: virgin or extra virgin oil, refined and pure. Virgin or extra virgin oil are varieties extracted through the first pressing of olives. No chemicals are used to obtain these unrefined oils. Virgin is considered to have a higher acidity level, less phytonutrients and a less delicate taste than extra virgin oil. Virgin contains upto 2 percent of free oleic acid, while extra virgin contains only 0.8 percent of free oleic acid.
Refined olive oil is obtained after chemical treatment which neutralizes the strong taste as well as the acidic content. However, virgin oil is considered superior to refined oil. Another variety, commonly known as pure olive oil, is a blend of refined and virgin olive oil, containing 1.5 percent acidity. It usually lacks a strong flavor. Pure and virgin are used only in salads, sautéing and stir frying; however, extra virgin can be used for cooking too.
The beneficial effects of olive oil are mainly due to its concentrated source of mono-unsaturated fatty acids, vitamin E and antioxidants. Olive oil decreases the risk of cardiovascular diseases. Mono-unsaturated fats and polyphenols (natural antioxidants) present in olive oil have been found to lower total cholesterol, triglycerides and LDL (bad cholesterol) and to increase good cholesterol levels i.e. HDL. It also prevents the formation of blood clots and platelet aggregation. It helps in avoiding excessive blood coagulation. Olive oil is also known to regulate blood pressure and is found to be beneficial for hypertensives.
Interestingly, vitamin E, a natural antioxidant in olive, is found to protect the skin from ultraviolet light, prevent cell damage from free radicals, and delay the aging process. Vitamin E is also known to have a protective effect against cancer. It has the ability to reduce the conversion of host cells into cancer cells. Other Specific compounds found in olive oil, mainly lignans and secoiridoids, have been known to fight breast cancer.
Moreover, olive has been known to maintain metabolism and contribute to the development of the brain and bones in children. Also, it slows down acid overproduction in the digestive system, thereby diminishing the potential for ulcers and other gastrointestinal problems