Updated: Oct 9, 2018
There are many different types of cooking oils, and many can be detrimental to your health if used poorly! Selecting the right oil should come down to more than just flavor. The right fat can totally change the way your meal affects your health. Erroneous dietary guidelines have given poor advice around the safety of saturated fats, and as a result many of us are left confused about which fats and oils are safe to use.
When it comes to selecting your cooking oil, you need to be mindful of how you will cook it, how hot it’s going to get, and the chemical makeup of the cooking oil. There are 3 main types of fats, and each fat has different chain lengths, and sits on a spectrum of how prone to damage or oxidisation it is. The type of fat dictates how resistant it is to damage, and the chain length determines how anti-inflammatory the fat is. In order to understand how and why certain oils are more resistant to oxidisation, we need to look at each of the three main fatty acid types.
Saturated Fats (SFA)
All of the binding spaces are filled or ‘saturated’ so that free radicals can’t attach and oxidise the fat. Saturated fats are the most stable. Examples: Coconut oil, palm oil, butter, meat, ghee, full fat dairy, MCT oil. Looking at the below structure of saturated fats, you can see that the maximum possible number of hydrogen atoms (H) are attached to every carbon atom (C), meaning that the carbon atoms are saturated, and less prone to free radical damage. (It's a little geeky but it helps show how fats can get oxidised!)
H H H H
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H - C - C - C - C - H
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H H H H
Monounsaturated Fats (MUFA)
Monounsaturated fats are relatively stable, as there is only one space for a free radical to enter. Less stable fats are not necessarily bad for you, they just need to be handled with care (ie don’t heat them or grind them up) Sources: olives, olive oil, peanut oil, canola oil, sesame oil, sunflower oil, nuts, seeds (pumpkin, flax, sesame, sunflower), cheese, avocado
H H H
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H - C - C - C - C - H
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H H H H
Polyunsaturated Fats (PUFA)
Polyunsaturated fats are the least stable fats as there are many spaces for free radicals to bind, making them more prone to being oxidised. Omega 3’s and 6’s essential fatty acids are two of the most important polysaturated fats. Our bodies can’t make these, we need to eat them. Omega 3 and 6’s exist in a ratio in our bodies, the standard diet is too dominant in omega 6’s which are more inflammatory than omega 3 fatty acids.
Omega 3 fats are an integral part of your cell membranes through your whole body, and are important in hormone, heart and genetic function. Studies continually link omega 3’s with preventing heart disease, stroke, arthritis, brain disease and mood disorders like depression. There are 3 types of Omega 3, EPA and DHA from animal sources, and ALA from plant sources. Humans convert ALA poorly to DHA so animal sources are more ideal. DHA is proven to help with inflammation, mood, insulin sensitivity, muscle growth, sleep quality and nervous system function. Omega 3 sources: black beans, algae, canola oil, soybean, salmon, sardines, trout, herring, walnuts, pasture raise meat,
Omega 6 fats help with brain function, hormone production, muscle growth and more, but also cause inflammation and compete with omega 3 fats. Omega 6 oils are cheap to produce and are used in processed foods, and are often hydrogenised to increase their shelf life. Omega 6 sources: avocado, cashews, coconut, eggs, canola oil, flax, pumpkin seeds, poultry, hemp oil, nuts, whole grain breads, walnuts
C - C - C - C - H
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H H H
Hydrogenated and Transfats
Hydrogenation seeks to make vegetable oils more stable by adding hydrogen atoms in the heating process which increases shelf life and profits. Remember above how saturated fats were stable because all of the carbon atoms were bound to hydrogen? Hydrogenising leads to dangerous chemical changes to the structure of the fat and the creation of transfats.
Industrial seed and vegetable oils are cheap to produce and are prolific in processed food and restuarants. In addition, most vegetable oils that are hydrogenised are GMO, and use solvents in processing, degrade the fascial system and increase soft tissue injuries, increase heart disease risk factors, damage the brain and more. If every cell in our body is made from a lipid fat layer, eating the wrong kinds of damaged fats can have widespread affects throughout the body.
This is why transfats are no longer Generally Regarded as Safe (GRAS) by the World Health Organisation, and are banned in most countries.
Oils to avoid
These oils are high in Omega 6 oxidise when exposed to high temperatures, and produce a variety of toxic chemicals when heated and form transfats. Safflower, Soybean, Ricebean, Vegetable oil, Canola Oil, sunflower, margarine, Corn oil
Preventing damage to your fats
Baking or frying fats can damage oils if the temperature is above it's smoke point. If you are adding oils for baking, barbecue or frying, then it's worth being mindful of the temperatures you are cooking at, and how that might affect the oil. Heating oils above their smoke point is a fire risk, but also it destroys essential phytonutrients and increases the risk of free radical damage. Saturated fats are more stable for cooking than monounsaturated fats, and monounsaturated fats are more stable than polyunsaturated fats.
Fatty acids are damaged by heat, light, and oxygen and so it's important to make sure your oil is sealed and stored in a dark glass bottle, away from light and heat in order to prevent it from oxidising. Another thing to watch out for when buying a good oil, is to make sure that it actually is what you are buying. Many companies label their oil as being 100% olive oil, but will 'cut' the oil with cheaper and dangerous canola oil to save money.
Grass fed Ghee and coconut oil are best choice for cooking due to their high saturated fat composition. Ghee is more stable than butter because of the extra processing which removes sugars and protein. Olive oil is mostly monounsaturated fat and was previously thought to oxidise at high temperatures but newer research shows that because it contains polyphenols and tocopherols, it actually is more resistant to oxidisation.
Medium heat in a fry pan tends to be around 160 degrees centigrade, and high heat around 200 degrees. Cooking at lower temperatures doesn't just protect your oils, it also protects the quality of your food. High temperatures denature the protein in meats, and can destroy vital nutrients and vitamins found in your food.
Ghee Smoke point: 251c
Butter Smoke Point: 177c
Coconut Oil smoke point: 177 c
Olive Oil smoke point 162-190 c
A bad fat can make you age faster, suffer nervous system issues, gain weight, and increase your risk of disease. A good fat can do wonders for your physical and mental health, waistline and energy. Hope that inspires you to understand your oils and fats better, and make some healthier choices with a more informed opinion.