Healthy oil for cooking
Updated: May 27, 2020
Ever wondered which oil is the best for cooking? Searched online and heard mixed opinions about the best cooking oil? Which one has the highest smoke point? There are a few criteria to consider to look for your perfect oil - this blogpost is all you need!
1. Fatty Acid Composition
Cooking oils are liquid fat derived from plants, nuts or seeds. All oils have a similar energy content (roughly 3500kJ per 100ml, or about 700kJ per tablespoon), but the types and the ratio of fatty acids they each contain. This includes length of the chain and saturation of Hydrogen atoms.
There are 3 main types of fatty acids:
1. Saturated Fatty Acids (SFA): Those with a saturated number of hydrogen atoms in the chain. High melting point (i.e. likely solid at room temperature)
Oils rich in SFAs: Palm oil, coconut oil, butter
2. Monounsaturated Fatty Acids (MUFA): Those with ONE double bond in the chain, meaning the number of hydrogen atoms is not at its max. Low melting point (i.e. likely liquid at room temperature or lower)
Oils rich in MUFAs: Extra Virgin Olive Oil, Refined Olive Oil, Avocado Oil, Rice Bran Oil, Canola Oil, Peanut Oil, Macadamia Oil
3. Polyunsaturated Fatty Acids (PUFA): Those with MULTIPLE double bonds in the chain. Very low melting point (i.e. likely liquid at room temperature or lower)
Oils rich in PUFAs: Flaxseed oil, Rice Bran Oil
High SFA intake is linked to raised levels of LDL ('bad') cholesterol, which is then linked to an increased risk of heart diseases, heart attacks and stroke. On the other hand, PUFA and MUFA are often referred to as ‘heart healthy’ because they lower total and LDL (‘bad’) cholesterol. Monounsaturated fats also increase HDL (‘good’) cholesterol.
General rule of thumb is: if it's solid at room temperature, the oil is highly likely bad. Most nutritional panels of cooking oils would have a breakdown of the amount of each fatty acid it contains.
2. Smoke point
It's commonly thought that the smoke point where oil integrity starts to degrade and hence becomes cancerous. Studies have shown this is not true!
Besides, smoke points are surprisingly high in most common cooking oils. Day-to-day cooking doesn't typically surpass 180 degrees Celsius, which is the max recommended temperature for deep frying. Check this graph below from De Alzaa F, Guillaume C and Ravetti L's paper for different smoke points of common cooking oils.
3. What's indicative then?
New studies say that what's more indicative of temperature stability is a factor called oxidative stability. It's a measurement of oxidation activity (the higher the activity, the worse for our body) and was measured when heating oil at different temperatures. The paper I mentioned above also measured this in different cooking oils.
Extra Virgin Olive Oil (EVOO) showed remarkable stability when heated at high temperatures. Peanut oil showed a similar behaviour than EVOO. Seed oils, such as canola, grapeseed, sunflower and rice bran oils showed lower oxidation stability.
These results are related to oils’ fatty acid composition with higher PUFAs content and lower levels of natural antioxidants (i.e. the higher PUFA and the lower antioxidant content, the lower the oxidation stability when heated).
4. Other nutrients to consider
These include Polyphenols and vitamin E.
Polyphenols are nutrients found from certain plant-based foods. They're packed with antioxidants that can potentially bring us health benefits, such as digestion issues, weight management difficulties, cancer, diabetes, neurodegenerative disease, and cardiovascular diseases.
This graph below is from a webinar I listened to regarding healthy fats and oils, presented by Dr. Joanna McMillan:
NOTE: alpha-tocopherol is vitamin E.
The bottom Line
Extra Virgin Olive oil and Peanut oil seems to have won me over here, with very high smoke points, MUFA content, as well as vitamin E. However, be mindful that the evidence that I've presented are all sponsored by Olive Oil companies. This doesn't turn their evidence unreliable, but it's best to consider its conflict of interest.
How much should I use each meal then? I've actually listerned to a webinar about its latest evidence recently, and can talk about this in future episodes. Stay tuned!