Tuesday, 23 August 2016

Dangers of cooking oils

 Our daily meal often contains some form of fried food. Many of us are aware that fried food has high fat content but it is very difficult for us to get rid of. Will using different cooking oil makes fried food less harmful? 

Before going into the details of cooking oils, here is a brief overview on types of fats which are the main components of oil. There are three main types of fats; monounsaturated(MUFA), Polyunsaturated (PUFA), Trans fat saturated fatty acid. 

Scientists have found that using monounsaturated fat in our cooking reduces triglycerides in our blood while improving the level of HDL aka “good cholesterols”. 

Does that mean we can be healthier by using oil rich in monounsaturated fatty acids? We looked at 3 commonly used cooking oil focusing on the benefits and harms of each. 

Olive oil

Olive oil is obtained from the olive seeds and used heavily in Mediterranean diet. Apart from containing Vitamin E and K, it has 73% monounsaturated fatty acid. It is commonly used for cooking as well as salad dressing. 

One important thing to remember is that, when we heat the oil beyond its smoking point, harmful substances such as aldehydes will form. Aldehydes are known to cause cancer and is normally produced by vegetable oil when it reaches its smoking point.

Fortunately, olive oil has a moderately high smoking point, around 216 Celsius. For high temperature cooking, such as frying olive oil will reach its smoking point but since it contains mostly monounsaturated fatty acid, aldehydes production is minimal. 

Pro: Healthy, contains monounsaturated fatty acid, produces minimal aldehydes
Cons: Expensive

Sunflower oil

There are three types of sunflower oil in the market currently. All three have different processing methods and have different nutrient content. The standard sunflower oil is rich in polyunsaturated fat, while the high oleic version contains 82% monounsaturated fatty acid making it comparable with olive oil. 

Sunflower oil has approximately the same smoking point, around 227 degree Celsius, but since it contains mainly polyunsaturated fat (in the standard version), it is very unstable and produces aldehyde quickly and in higher percentage compared to olive oil. 

Sunflower oil also contains higher Omega 6 (a type of polyunsaturated fat) level, compared to Omega 3. While Omega 3 is known to reduce inflammation in body and helping in reducing heart attacks, omega 6 is pro-inflammatory. Omega 6 has the potential to increase heart diseases, and other inflammatory problems such as rheumatoid arthritis. The ratio of Omega 6: Omega 3 in sunflower oil is 40:1 which is not healthy. 

Even though theoretically this should increase inflammatory conditions, till date there is no enough evidence to prove that. 

Pro: Has omega 3, cheap
Cons: Mostly polyunsaturated fat, and Omega 6. High aldehyde production on cooking. Possibly pro-inflammatory.

Palm Oil

Palm oil is the mostly used cooking oil, especially in the Asian households. Palm oil has been linked with health risks as well as environmental risks. 


There are some strong evidences suggesting palm oil increases the risk of heart problems. For example in a research done in Costa Rica, scientists found that people consuming palm oil are more likely to develop heart attack compared to those consuming other types of oil. Another group of scientists from Singapore concluded that palm oil increases LDL cholesterol by 0.24mmol/l after looking at various researches done on this matter.

This bad effect of palm oil can be explained by presence of almost 50% of saturated fat which is proven to be harmful for our health. 

Palm oil consumption is also said to be harmful to the environment. According to a group of activists, over 300,000 different animals are found in Borneo, and Sumatra and many of them are injured, killed or displaced because of deforestation. Deforestation is done to clear the forest for palm oil plantations. According to the World Wildlife Fund, an area the equivalent size of 300 football fields of rainforest is cleared each hour to make way for palm oil production. Read more on this from here. 

Pro: Cheap, widely available

Cons : Increases risk of heart attack, leads to deforestation 


Among the available cooking oil, olive oil seems to be the best. Choose refined olive oil for deep frying as it has higher smoking point compared to extra virgin olive oil which is more suitable for shallow frying or salad dressing. 

For further reading:

Palm Oil& Environment : http://www.saynotopalmoil.com/Whats_the_issue.php

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