Oxidation. Excessive oxidation increases the risk of heart disease, cancer, and general aging. Oxidation is encouraged with the main type of fat found in vegetable oils (polyunsaturated fat). Extra virgin olive oil is rich in monounsaturated fat, which does not oxidize. Extra virgin olive oil also contains a number of phenols that are antioxidants, which lower oxidation. Extra virgin olive oil with a high phenolic content has been shown to decrease LDL oxidation (1), which lowers the risk of heart disease. Oxidation of DNA can initiate cancers and extra virgin olive oil with a high phenolic content will decrease DNA oxidation (2).
Blood levels of fasting insulin and glucose. Higher blood levels of both insulin and glucose have been related to an increased risk of heart disease and several cancers. Two tablespoons of extra virgin olive oil a day was shown to decrease blood levels of glucose and insulin (3). Besides decreasing your risk of heart disease and cancer, extra virgin olive oil would also improve blood glucose control for diabetics.
Blood pressure. Two to 3 tablespoons of extra virgin olive oil a day has been shown to lower blood pressure (4). Extra virgin olive oil with a higher phenol content lower systolic blood pressure in men compared to a lower phenol content oil (5).
Inflammation. High levels of inflammation (measured in the blood) that occur with a disease, like heart disease or cancer, have been related to a less favorable outcome. Oleocanthal, found in some extra virgin olive oil and is responsible for the “burning” sensation when swallowed, is a natural anti-inflammatory agent (6). It works like ibuprofen does to limit the production of inflammatory compounds in the body.
Blood coagulation. blood that is too clotty will increase your risk of heart disease and cerebral vascular accidents (strokes). Extra virgin olive oil is high in phenols has been shown to decrease blood from clotting (7).
Body weight. I have found that people express concern that “olive oil is a fat”, when I recommend that they use more extra virgin olive oil. However, patients who use extra virgin olive oil as part of a weight loss program lose weight better than on a low-fat diet (8). Studies have shown that people who use extra virgin olive oil as their main diet fat also tend to have a lower body weight (9) and gain less weight over time (10). A meal that contains fat leads to satiety, meaning you are satisfied from eating the meal so you stop eating; it also means that it will take longer for you to get hungry for your next meal.
The health benefits of extra virgin olive oil start at about 2 tablespoons a day and many studies show that the benefits increase with higher intakes. I recommend that extra virgin olive oil is used mainly to prepare vegetables using 1 tablespoon of extra virgin olive oil per cup of vegetables.