This has to do with the molecular arrangement of oils. Saturated fats contain no double bonds so are not sensitive to heat, light or oxygen, unlike unsaturated fats. Unsaturated fats (vegetable oils) have double bonds, making them very sensitive to heat, light and oxygen. In addition, heating these kinds of oils can change their molecular structure, destroying a handful of the healthy properties.
Monounsaturated Fats In Olive Oil Are Not Heat Stable
Olive Oil is made up of about 70-80% monounsaturated fat, in the form of ellagic acid. As a consequence, this oleic acid is what provides Olive Oil a handful of its incredible health benefits such as improved insulin resistance, cancer-fighting properties, and improved heart health.
It is also these monounsaturated fats that provide Olive Oil a low smoking point, making it unsuitable for temperatures above 250'F (121'C).
Heart Healthy Polyphenols In Olive Oil Are Seamlessly Damaged By Heat
Olive Oil has phenolic chemicals, mainly hydroxytyrosol and oleuropein, that are rich in antioxidant properties. These phenols, which work as antioxidants to preserve heart health, start to degrade at high heats.
Heating Olive Oil Helps Destroy Omega Fatty Acids
Olive Oil contains the Omega 3 and Omega 6 Fatty Acids. According to Dr. Mercola, omega-3 fats are"significant structural parts of the cell membranes of tissues throughout the body and are especially rich in the retina, brain, and sperm, where docosahexaenoic acid (DHA) constitutes 36.4% of total fatty acids".
These fatty acids are sensitive to heat and are easily ruined when Olive Oil is heated.
Low Smoke Point = Breathing In Toxic Smoke
If an oil is heated beyond its smoke point, it gives off poisonous smoke. Because Olive Oil has a low smoking point, generally, cooking together with Olive Oil runs the risk of creating smoke that contains compounds that are harmful to human health.
Many Olive Oils Are Not Real
A handful of brands cut their Olive Oil with inexpensive oils such as soybean oil, canola oil, hazelnut oil and low grade olive oils.
A study by UC Davis in 2011 discovered that 73 percent of the 5 best selling imported brands of Olive Oil did not fulfill the international sensory standards for Extra Virgin Olive Oil set by European regulators.
This usually meaning that they could be adulterated or combined with other vegetable oils such as soy, corn, cottonseed, hazelnut, or canola oil.
What Is One To Do ?
Olive Oil is a healthy and delicious oil. It is amazing in salad dressings and dips and can be drizzled over already cooked vegetables.