We’re often told that olive oil is fantastic for health, but that cooking with olive oil is a bad idea. The oil, especially the extra virgin kind, has a low smoke point, which isn’t desirable.
This is a key reason why coconut oil is recommended for cooking instead.
Yet, the comparison of olive oil vs coconut oil for cooking isn’t as clear-cut as it might seem.
Some recent research has called our assumptions into question, suggesting that olive oil might be a good cooking option after all.
Smoke Point and Health
It’s long been assumed that smoke point is a key indicator of an oil’s stability at high temperatures. This is the point in time during cooking when the oil is consistently producing smoke.
Oils with a high smoke point (like coconut oil and ghee) are considered to be more stable, while oils with a lower smoke point (including extra virgin olive oil) are viewed as less stable.
The idea is important. The changes that oils go through can have direct implications for our health. To get the most benefits, we need to focus on stable oils, ones that don’t produce harmful chemicals. Because extra virgin olive oil has a fairly low smoke point, it’s often considered unsafe for cooking.
Smoke point is a useful tool. But, it doesn’t tell us anything about chemical changes. That’s where this study comes in.
Smoke point is used as a proxy for heat stability, but it doesn’t consider chemical changes
The Research Study
The study in question was published in 2018, in the journal Acta Scientific Nutritional Health. It is an Australian study, conducted by Modern Olives Laboratory Services.
In it, the authors considered the heat stability of 10 commonly used cooking oils.
- Extra virgin olive oil (EVOO)
- Virgin olive oil (VOO)
- Olive oil (OO)
- Canola oil (CO)
- Rice bran oil (RO)
- Grapeseed oil (GO)
- Coconut oil (CoO)
- High oleic acid peanut oil (PO)
- Sunflower oil (SO)
- Avocado oil (AO)
The oils were put through two different heating trials. Each oil sample was then cooled and stored, before undergoing chemical analysis.
Trial One
This trial involved heating a 250 ml sample of oil in a frying pan from 25°C to 240°C (77°F to 464°F). Samples were taken at intervals of 150°C, 180°C, 210°C and 240°C (302°F, 356°F, 410°F and 464°F).
The design serves to replicate the temperatures and processes used with pan frying.
Trial Two
In this trial, 3 liters of each oil was heated to 180°C (365°F) in a deep fryer for 6 hours. Samples were collected at 30, 60, 180 and 360 minutes.
The design mimics outcomes for deep frying and 180°C is also the maximum recommended deep frying temperature.
The study conducted chemical analysis on 10 different types of oil. Each oil went through two distinct heating trials
The Results of Analysis
The authors considered multiple parameters in their study and the results were fascinating.
Polar Compounds
Polar compounds are produced during heating and may be damaging to the body. This is a key reason why we consider smoke point, but smoke point isn’t an accurate estimation.
Trial 1 (click/tap to see a larger version)
Trial 2 (click/tap to see a larger version)
Across the two trials, extra virgin olive oil and coconut oil were the clear winners.
Polar compounds before and after heating (averaged across the two trials)
The seed oils performed badly. Canola and grapeseed oil were particularly concerning for regular frying, while sunflower oil and grapeseed oil were problematic for deep frying.
Coconut oil and olive oil produced the fewest potentially dangerous polar compounds
Oxidative Stability
This term refers to how an oil reacts with oxygen as it is heating. A higher level of oxidative stability means the oil is more resistant to oxidation. This is a critical outcome for health and we want to be consuming oils that have been through minimal oxidation.
Coconut oil was the best performer here, with high oxidative stability. Extra virgin olive oil was relatively high as well, as was peanut oil.
Interestingly, avocado oil and regular olive oil both had low oxidative stability. This makes them much less appealing as oils to cook with.
Coconut oil had the best oxidative stability, followed by peanut oil and then extra virgin olive oil
Antioxidants
In a previous study, the authors looked at the antioxidant content of the oils. Olive oil outperformed all other types here, with extra virgin olive oil offering the most antioxidants (1).
The outcome isn’t especially surprising, as most of the other types of oils are refined. Seeds are also a poor source of antioxidants in general.
Avocado oil is relatively low in antioxidants mostly because avocados themselves are not high in antioxidants. The same is true for coconut oil. Coconuts do not have high levels of many antioxidant compounds.
The antioxidant content is interesting but is only partially relevant when you’re choosing the best oil for cooking. After all, there are plenty of other ways to increase your antioxidant intake.
The highest antioxidant options were the olive oils, with extra virgin being the best performer
Outcomes vs Smoke Points
The authors also considered the smoke points of the various oils.
Comparing these to the polar compounds produces some interesting results.
The graph is almost the opposite of what we commonly assume. The oils that produced fewer polar compounds tended to have a lower smoke point.
The best performing oils tended to have low smoke points, while ones that performed poorly often had higher ones
Conclusion and Implications
This study highlights some interesting things about cooking oils.
First, it shows that the smoke point doesn’t mean what we expect. Instead of being unhealthy, some of the oils with low smoke points produced fewer polar compounds. This is the opposite of what we commonly assume.
Second, the study highlights the importance of olive oil – particularly extra virgin olive oil. The oil produced few polar compounds, is a powerful antioxidant and has decent oxidative stability.
Not only is extra virgin olive oil safe for cooking, it’s also good for you.
The study also shows that coconut oil is a good cooking choice. It doesn’t have the same levels of antioxidants that you find in olive oil. But, coconut oil was the most oxidatively stable choice and produced few polar compounds.
Third, there are some oils that you should avoid entirely when cooking.
- Canola oil, as it produces a large number of polar compounds, especially during frying.
- Grapeseed oil, for the same reason. Canola oil does produce more polar compounds, but they’re both poor choices.
- Rice bran oil. This oil isn’t as bad as canola and grapeseed oil, but it still performed poorly.
- Sunflower oil. This oil performed poorly for deep frying, while it was fine for pan frying.
Avocado oil also deserves a mention. This does have many health benefits and is a good source of oleic acid. However, it has poor oxidative stability and released more polar compounds than many other options.
As such, it is a good addition to salads and similar recipes, but shouldn’t be your first choice for cooking.
Potential Conflict of Interest
The group behind the study was Modern Olives Laboratory Services. This does introduce the potential for bias. Nevertheless, there are some key factors in favor of the research.
First, there have been other studies in this field with similar conclusions. For example, authors have found that the olive oil doesn’t oxidize at high temperatures (2,3).
The company also has a solid history, including some government-funded research. Their studies (including this one) go through the peer review process, so they're reliable.
Finally, industry funding is sometimes needed. Studies that compare different types of cooking oil aren’t likely to attract government funding, despite the knowledge gap. As a result, companies do sometimes need to fund the research themselves.
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Read this
https://www.oliveoiltimes.com/olive-oil-business/major-spanish-cooperative-under-fire-for-importing-and-exporting-practices/63778
Thank you for the article Victor. The olive oil industry and marketplace is a complex one. The consumer is in search of real quality olive oil , while certain producers are after marketshare. There are luckily some high quality EVOO out there. I have an article here on the site about that.