KNOW THIS: Cooking with some oils can make them carcinogenic.

WHY? When any oil is heated to the point where it smokes, it breaks down, forming free radicals that damage cells.

WHAT CAN I DO ABOUT IT? Make sure you always cook with a healthy oil that has a high smoke point.

Is your oil cooking up a toxic treat?

This is a topic that most people aren’t aware of, yet it’s so important if you want to reduce your risk of cancer.

Most people cook with virgin olive oil because they think it’s a healthy oil, and while it is when drizzled on salads or cooking on a low heat, it becomes toxic at high temperatures.

When any oil is heated to the point where it smokes (its smoke point), it breaks down, and the antioxidants in the oil are replaced by free radicals that are carcinogenic and damage cells. Different oils reach their smoke points at different temperatures, so some should be used for high heat cooking, while others shouldn’t.

When researching topics for Know This, it doesn’t take too long for me to start getting to the bottom of what’s good and what’s bad, but with cooking oils it was a minefield! I’ve been dazzled by the wealth of information out there on which are the best oils to use for cooking with – everyone seemed to have a different opinion.

The one thing that is clear is that cold pressed, unrefined oils should never be used for cooking as they have a low smoke point – with the exception of avocado oil, which because of this and it’s health benefits is the outright winner. But it’s not readily available, so I wanted to give more options – and that’s when things got complicated.

Finding oils that compare with avocado oil isn’t easy. When considering the calories, omega 3 and 6 balance and a high smoke point, some are good in one but not so good in others.

Our western diet is generally too high in omega-6 compared to omega-3, and it’s important to get the balance right. Omega-3 fatty acid is a type of polyunsaturated fat that is especially healthy. It helps to reduce the risk of heart disease, lower blood pressure, guard against plaque build-up in the arteries, and aid in brain development. Omega-6s have arachidonic acid, which causes inflammation. Over time, an excess of arachidonic acid can lead to problems such as blood clots, arthritis, and heart disease and may even increase your risk of cancer. The typical western diet has an omega-6 to omega-3 ratio of about 15:1, but experts recommend a ratio of 4:1 or even 2:1 which is similar to the Mediterranean diet.

Here’s a list of the highest and lowest smoke points of popular cooking oils, plus omega-6 to 3 ratio (where relevant), remembering that western diets should keep omega-6 low.

*note the difference in refined and unrefined oils*

Highest:

480-520 F, 12:1 Avocado oil (not virgin). High in heart-healthy monounsaturated fat (70 per cent).

490 F, 21:1: Rice Bran Oil

485 F, 676:1: Grapeseed Oil

468 F, 13:1: Extra Light Olive Oil (not to be confused with extra virgin which is unrefined)

450 F, 137:1: Sesame Oil, Semi-Refined

450 F: Coconut oil, refined. Full of healthy fats, lauric acid, and medium-chain fatty acids

440 F, 39:1: Sunflower Oil, refined

438 F, 13:1: Olive Oil- refined

438 F, 2:1: Rapeseed Oil, refined

Lowest:

225 F, 39:1: Sunflower Oil, Unrefined

225 F, 1:4 Flaxseed Oil, unrefined250F Butter

320 F, 5:1: Walnut Oil, Unrefined

350 F, 7:1: Butter

350 F: Coconut oil, virgin

375 F 73% monounsaturated, high in Omega 9. Extra virgin olive Oil, Unrefined

Summary: Never use unrefined (cold pressed) oils for high heat cooking. Refined oils have been processed to remove impurities, making them more stable, especially for higher-temperature cooking. However, the process of refining also filters out much of the flavor and nutrients. So use refined oils for high heat cooking and unrefined oils for salads and low heat cooking.

Many people recommend coconut oil for medium heat cooking and baking due to its health benefits, but it’s not recommended for very high heat cooking due to its relatively low smoke point.

For high heat cooking, if you can’t find avocado oil, I recommend using rice bran oil. It’s a rich source of antioxidants and vitamin E, has an almost balanced fatty acid composition, and lowers cholesterol. The viscosity of rice bran oil means that food only absorbs about 20% of the oil, making it a healthy choice. However it is high in calories, so consume in moderation!