Oils are in everyday meals, and they represent one of the best sources of the fats macronutrient in your diet. There are many oils of different characteristics as regards their taste, potential health effect, and temperature resistance. Thus, which oils should you use for frying? Which one is better to flavor a salad or baking a cake? And last but not least, which one is better to avoid? Let’s find out!
The first thing to know is that every oil is a dense liquid consisting almost totally by fat, so they are among the most caloric food you can have in this world. We can divide these fats into several categories by their chemical structure. The right balance of the following fatty acids is one of the bases for a good health and the right amount of energy.
SATURATED FATTY ACIDS
They are divided into other categories based on their molecule lenght. The bigger they are the harder is for the body to handle burning them for prompt energy. Moreover, this seems to increase “bad” cholesterol LDL with the related cardiovascular disease. They are not totally to avoid since the human body uses them as a source of energy and in the synthesis of several hormones like testosterone, so you just have to control their assumption by limiting mostly the animal sources of these fats.
POLYUNSATURATED FATTY ACIDS
They are not as bad as the saturated ones, as once in the body they in general lead to an increase of HDL cholesterol (the “good” one). This doesn’t mean you can eat them as much as you want because their amount should be balanced. The well-known omega 3 and omega-6 series belong to this category. The important and hard thing is to have the correct ratio between omega-6 and -3, as the first ones are very common in many foods, while omega-3 are usually rare, found in low quantity and easily degradable. Moreover, they are called “essential” since the body is unable to produce them by itself. It’s notable that some vegetable oils are rich in omega-3 and thus also used as a supplement, even if it’s not clear to the scientific community whether vegetable or animal sources are better.
MONOUNSATURATED FATTY ACIDS
These fats are present both in animal food and vegetables and they are the main components of olive oil. What you have to know is that they exist in the trans- and cis- form. Cis ones are ok, but the trans fatty acids have been recently labeled as dangerous by the scientific community because the body can’t dismantle them easily, thus leading to a general mild inflammation. They are not so common in natural vegetable products, but some industrial transformation can lead to this undesirable product.
The smoke point of an oil or fat is the temperature at which they begin to produce a continuous bluish smoke with an acrid smell. This happens when the heat dismantles and re-combines some molecules of the product, leading to several toxic and carcinogenic substances. This temperature mostly depends on the acidity of the oil (the amount of fatty acids freed from glycerol) and the ratio between monounsaturated and polyunsaturated fatty acids. So if you forget your oil or butter on the cooker and found it smoking, let it cool down and throw it away!
Well, let’s analyze the most common oils as regard these characteristics.
Widely used oil both for its low price, neutral taste and the high smoke temperature in the refined versions. It contains 10% of saturated fatty acids (with only 5% the “bad” palmitic acid) with the rest made of monounsaturated oleic acid (30%) and omega-6 linoleic acid (59%). The unrefined oil has only 107°C smoke temperature, while the refined one can handle temperature around 230° (even it’s better to stay way lower), making it one of the best oils for frying. The raw version is rich in antioxidants (vitamin E) which makes it more stable, suggesting the use as a food preservative. You can also use it as butter alternative in either salty or sweet preparations or adding it to salads.
It’s the real king of oils, well known everywhere but especially used in Europe, being an irreplaceable ingredient of the Mediterranean diet. Its fame is due to both its unique taste and excellent nutritional values, enriched with the presence of several kinds of antioxidants such as flavonoids, lignans, vitamin E, and others. The presence of these antioxidants gives the olive oil a good stability and health benefit, helping to fight free radicals (a major cause of aging). The main fatty acid in olive oil is oleic acid (around 73%), a monounsaturated fat which is very important for the stability at high temperature, pushing the smoke point above 200°C for the extra-virgin quality with low acidity. The only limit for the use as a frying medium is its cost. However, considering its health benefits and good taste, if you occasionally want a super cheat meal with something fried, you should definitely give a try.
It’s the most controversial oil and you can find it in many industrial packaged foods. I won’t discuss the environmental sustainability of this product, but only its health and nutrition aspects. Let’s begin saying that two kinds of palm oil exist, one made from the palm seed and the other from the fruit. Both are not as healthy as the other edible oils because they contain more than 40% of saturated fatty acids, mostly palmitic acid. Since probably you already have your source of fatty acids through other food like meat, cheese, eggs etc. it’s not a bad idea to avoid the additional use of palm oil in your diet. Nevertheless, it still has some interesting aspects: the red colored raw palm oil (which is not refined) is rich in carotenes, co-enzyme q-10, vitamin E and other interesting micronutrients for your health, while the refined oil has one of the highest smoke points among all edible oils.
This is another very common oil among South East Asia, but also used everywhere in sweet preparations and beauty products. It’s almost totally made of saturated fatty acids, reaching 87g on 100g of pure product. You could think this is really bad, but we are actually talking about lauric acid, a medium chain saturated fatty acid which has a way smaller impact to the LDL cholesterol than longer chain fatty acids like palmitic. Not just this, coconut oil has been investigated for its benefits on losing weight in obese patients (https://www.ncbi.nlm.nih.gov/pubmed/19437058), even if many of its miracles and benefits claimed on the internet are not based on robust researches. It’s also very stable as regard as conservation due to its low concentration of unsaturated fats, so it’s possible to keep it for months at room temperature. You can use it to give an exotic taste to your recipes, but not for frying as it has one of the lower smoke points among all oils.
An interesting oil as regard as nutritional aspects in the raw version, since it contains from 4% to 11% of omega-3, 70% of unsaturated fats and 14% saturated fats. The presence of a good amount of omega-3 makes the raw soybean oil unsuitable for frying. It’s also quite unstable by having a low amount of vitamin E, so to prevent the oxidation of the precious omega-3 you should keep it in a cold and dark place and for not much time. You can use it to flavor salads and ethnic food, given its particular taste. The refined version is obtained by partial hydrogenation of the raw oil, thus removing the omega-3 content and giving it more stability. However, the refining process leads to the formation of a small quantity of trans- fatty acids, which are not a good deal for your health.
It’s well known for the high content of omega-3 fatty acids, around 53%, thus way more than soybean oil. The remaining fraction is composed of omega-6 monounsaturated fatty acids (oleic and mostly linoleic) and only 10% of saturated fats (just 5% palmitic). Like soybean, you can’t fry with this oil, with the same recommendations about storage. Its particular flavor makes it suitable as a condiment for European cheese, grilled fish, chickpeas hummus and everything fits its faint walnuts taste.