Olive oil is extremely healthy.
It’s not only loaded with beneficial fatty acids and powerful antioxidants but also a dietary staple for some of the world’s healthiest populations.
However, many people believe that it’s unsuitable for cooking due to its unsaturated fat content. Others claim that it’s an excellent choice for cooking — even for high-heat methods like frying.
This article explains whether you should cook with olive oil.
Why are some people concerned?
When fats and oils are exposed to high heat, they can become damaged.
This is particularly true of oils that are high in polyunsaturated fats, including most vegetable oils like soybean and canola.
When overheated, they can form various harmful compounds, including lipid peroxides and aldehydes, which can contribute to cancer.
When cooked, these oils release some carcinogenic compounds that may contribute to lung cancer when inhaled. Simply standing in a kitchen as these oils are used can cause harm.
If you want to minimize your exposure to potentially harmful and carcinogenic compounds, you should only cook with fats that are stable at high heat.
Two properties of cooking oils matter most:
- Smoke point: The temperature at which the fats begin to break down and turn into smoke.
- Oxidative stability: How resistant the fats are to reacting with oxygen.
Olive oil performs well in both categories.
Summary: It is important to choose cooking fats that are stable when heated, as some oils can form carcinogenic compounds during cooking.
Olive oil is high in heat-stable monounsaturated fats
Fatty acids can be either saturated, monounsaturated, or polyunsaturated.
While saturated fats like coconut oil are very resistant to heat, most vegetable oils contain polyunsaturated fats. Olive oil, on the other hand, contains mostly monounsaturated fats.
Only polyunsaturated fatty acids — like those in soybean and canola oils — are sensitive to high heat.
Keep in mind that oils are usually composed of different types of fatty acids. For example, olive oil is 73% monounsaturated, 11% polyunsaturated and 14% saturated.
In other words, the heat-resistant monounsaturated and saturated fats make up 87% of olive oil.
Summary: Olive oil contains mostly monounsaturated fatty acids, which are largely resistant to heat.
Olive oil is high in antioxidants and vitamin E
Extra virgin olive oil is derived from the first pressing of the olives and offers numerous bioactive substances, including powerful antioxidants and vitamin E.
Vitamin E’s main purpose is as an antioxidant. It helps fight free radicals that can damage your cells and lead to disease.
Because olive oil is high in antioxidants and vitamin E, it provides significant natural protection from oxidative damage.
Summary: Olive oil contains Vitamin E and many powerful antioxidants, which give numerous health benefits.
Olive oil is resistant to oxidative damage
When oil oxidizes, it reacts with oxygen and forms various harmful compounds.
This can happen at room temperature and is one of the ways oils go rancid — but this process is greatly accelerated when oils are heated.
However, olive oil holds up well during heating due to its high antioxidant and low polyunsaturated fat content.
In one study that used several types of olive oil for deep frying, extra virgin olive oil proved particularly resistant to oxidation.
Other studies note that olive oil does not oxidize much when used for cooking, while vegetable oils like sunflower oil oxidize.
Suggested read: Why extra virgin olive oil is the healthiest fat on earth
That said, one study showed that a meal with heated olive oil increased oxidative markers in the blood compared to a meal with unheated olive oil.
However, this olive oil was not an extra virgin olive oil and was cooked for eight hours — so the conditions of this study may be unrealistic.
It is also a myth that heating olive oil leads to the formation of trans fats. In one study, frying olive oil eight times in a row only increased the trans fat content from 0.045% to 0.082% — still a negligible amount.
Olive oil is very stable overall, even under extreme conditions like deep frying.
Summary: Many studies have exposed olive oil to high heat for long periods. Even under such extreme conditions, olive oil does not form significant amounts of harmful compounds.
Olive oil has a moderately high smoke point
The smoke point of an oil is the temperature at which it starts to degrade and produce visible smoke.
When this happens, fat molecules break apart and turn into various harmful compounds.
But the oil’s other trace nutrients, such as vitamins and antioxidants, can also start to burn and give off smoke — sometimes at lower temperatures than the oil itself.
Usually, a portion of the fatty acids in the oil are free fatty acids. The more free fatty acids there are in oil, the lower its smoke point.
Because refined oils are lower in trace nutrients and free fatty acids, they usually have a higher smoke point.
What’s more, heating causes more free fatty acids to form — so the smoke point goes down the longer you cook it.
While it’s difficult to determine an oil’s exact smoke point, a range can provide a good estimate.
Some sources put the smoke point of olive oil somewhere around 374–405°F (190–207°C).
This makes it a safe choice for most cooking methods, including most pan frying.
Suggested read: Olive oil vs. vegetable oil: Which to pick?
Summary: Extra virgin olive oil’s smoke point is somewhere around 374–405°F (190–207°C). This makes it a good choice for most cooking methods.
Cooking olive oil may destroy some of its antioxidants
Normal cooking use is unlikely to oxidize or significantly damage olive oil.
However, it may degrade some of the antioxidants and vitamin E, which are sensitive to heat.
In one study, heating olive oil at 356°F (180°C) for 36 hours led to a decrease in antioxidants and vitamin E, but most of the trace compounds were intact.
One of the main active compounds in extra virgin olive oil is oleocanthal. This substance is responsible for olive oil’s anti-inflammatory effects.
Heating olive oil at 464°F (240°C) for 90 minutes reduced the amount of oleocanthal by 19% according to a chemical test and 31% according to a taste test.
In another study, simulated frying for 24 hours reduced some beneficial compounds, but 10 minutes in a microwave or boiling in the water had only minor effects.
The trace compounds in olive oil are also responsible for some of its flavor. Therefore, overheating olive oil can remove some of its taste.
Keep in mind that these studies use rather extreme conditions.
Summary: While studies indicate that high heat and prolonged cooking may destroy some of the olive oil’s beneficial compounds, these studies are applying extreme methods.
Summary
Quality extra virgin olive oil is an especially healthy fat that retains its beneficial qualities during cooking.
The main downside is that overheating can adversely impact its flavor.
However, olive oil is quite resistant to heat and doesn’t oxidize or go rancid during cooking.
Not only is it an excellent cooking oil, but it is also one of the healthiest.
