The Healthiest Cooking Oil

The Low Down on Vegetable Oils

What are Vegetable Oils?

Vegetable oils are oils that have been extracted from various seeds such as rapeseed (canola oil), soybean, corn, sunflower, sesame, peanut, etc. Unlike coconut oil or olive oil that can be extracted by pressing, these oils are extracted in very unnatural ways. We examine the healthiest cooking oil by analysing each type and exposing its best and worst uses.

Have We Been Misled?

For many years, the general perception was that vegetable oils such as sunflower or corn oil were healthier when used for cooking, than saturated animal fats such as butter and lard. However, a recent study in the UK by Professor Martin Grootfeld of the De Montfort University Leicester (DMU) has uncovered that maybe we have been misled by smart marketing campaigns over the past 50 years. Note that this is only one study thus far, but the results are conclusive.

Test volunteers were asked to cook everyday meals in their homes using sunflower, cold-pressed rapeseed, corn and olive oil as well as butter, goose fat and lard (pig fat) and then to send the remaining oils to the lab to be analysed by the team of scientists. After the researchers had completed their analysis, they found that sunflower and corn oil in particular when heated at or close to 180 degrees C produced aldehydes (chemical compounds linked to an increased risk of heart disease and cancer) at levels 20 times higher than recommended by the World Health Organisation. The study results also showed that the longer these oils such as sunflower and corn are heated, the more aldehydes they produced.

An example of the study showed that a typical meal like fish and chips, fried in vegetable oil, contained as much as 100 to 200 times more toxic aldehydes than the safe daily limit set by the World Health Organisation. Olive oil, rapeseed oil, butter and goose fat, on the other hand, produced far fewer aldehydes. The reason for this is that these fats (including lard) are more abundant in monounsaturated and saturated fats and are more stable when heated. Sunflower and other polyunsaturated oils were found to generate higher levels of damaging aldehydes.

Which Oil Should I Use?

We have put together a guide to the various cooking oils and the pros and cons of their usage:

Extra Virgin Olive Oil

Made from the extracted juice of crushed olives. It is one of the only cooking oils made without the use of chemicals and industrial refining. There are specific standards that oil must meet to receive the label “extra-virgin”. Because of the way extra-virgin olive oil is made, it retains truer olive taste and has a lower level of oleic acid than other olive oil varieties. It also contains more of the natural vitamins and minerals found in olives.

– Best for: dressing salads, drizzling over pasta, baking.
– Worst for: frying at high temperatures, because of its low smoke point.

Olive Oil

Made from the oil extracted from pressed whole olives. This oil is typically a blend of virgin olive oil and refined olive oil (which refers to oil where heat and chemicals are used in the process of extracting oil and removing flaws from the fruit). Pure olive oil is a lower-quality oil than extra-virgin or virgin olive oil, with a lighter colour, more neutral flavour, and oleic acid measuring between 3-4%. This type of olive oil is all-purpose cooking oil.

– Best for: light frying and salad dressing, baking, dressings.
– Worst for high-temperature frying.

Canola Oil (Rapeseed Oil)

Made from oil extracted from rapeseed. In the last few years, there’s been a surge in artisanal, British, “cold-pressed” rapeseed oils, which are marketed much like single-estate olive oils. Unlike olive oil, rapeseed doesn’t go toxic at high heat, while the smoke point is higher than that of olive oil it makes it marginally more suitable for frying.

– Best for roasting potatoes, frying.
– Worst for: it has a very subtle flavour, so it’s not to everyone’s taste for drizzling.


It’s made of the fatty deposits from pigs.

– Best for: baking, high-temperature frying.
– Worst for: anything that doesn’t involve high temperatures.


Made from boiled butter, churned with cream with the liquid residue removed.

– Best for high-temperature frying.
– Worst for anything that doesn’t involve high temperatures.

Sunflower Oil

Made from oil extracted from sunflower seeds.

– Best for the latest advice says we should avoid altogether – if we use sunflower oil, use it unheated in salad dressings.
– Worst for cooking or frying at high temperatures – e.g. Frying batter in sunflower oil. (Avoid sunflower oil at high temperatures).

Vegetable Oil

Made from the oils extracted from seeds like soybean, corn, sunflower, and safflower.

– Best for the latest advice says we should avoid altogether.
– Worst for high-temperature frying.

Coconut oil

Most coconut oils are made from smoke drying, sun drying, or kiln drying the dried meat of the coconut called ‘copra’.

– Best for high-temperature frying, baking.
– Worst for drizzling over food, although it can be combined with other ingredients to make a dressing.


The healthiest cooking oil is not any particular type, but the one that is correctly used such that it doesn’t pose a health risk to you and your family.