Cooking Oil: What To Look For And Avoid
Cooking oil is an essential kitchen ingredient. The oil is subject to high temperatures, which allows heat to be quickly transferred to the food and speeds up the cooking process.
Choosing the right cooking oil matters a great deal because it can have a detrimental effect on your health. Many people have now been awakened to the hidden dangers of trans fats as research showed that these fats raise your bad (LDL) cholesterol and lower your good (HDL) cholesterol levels. Eating trans fats raises your risk of developing heart disease, stroke, and type 2 diabetes.
There are many different types of cooking oil on the market. How do you choose the appropriate one for your cooking? What do you look for in a cooking oil and what do you want to avoid? The following will provide the answers.
What To Avoid In A Cooking Oil
Partially Hydrogenated Oils
- Any time you spot "partially hydrogenated oils" on the ingredient list, you know that they are trans fats. Trans fats can be found in many foods, including fried foods like doughnuts, French fries, fried chicken, battered fish, baked goods such as cakes, pie crusts, biscuits, cookies, crackers, frozen pizza, spreads like vegetable shortening and margarine, and some microwavable popcorn.
- Hydrogenated oils are manufactured by forcing hydrogen into the ingredients to increase their shelf life. As a result, the structure of the fat molecules are transformed into an opposite direction compared to natural fat molecules.
- Examples of cooking oil that may be partially hydrogenated are soybean oil, corn oil, cottonseed oil, canola oil, and vegetable oils (blend of soybean, corn, and/or canola oils).
GMOs And Pesticides
Consuming oils derived from genetically modified plants may lead to adverse health effects in the long-term. Unless specified that it is non-GMO or organic, most soybean oil, corn oil, cottonseed oil, and canola oil are mostly genetically modified.
Herbicide-tolerant GM crops enable farmers to use certain herbicides that will kill weeds without harming their crops. The prime example is Roundup-resistant GMOs (e.g. Roundup Ready Soybeans) which are designed to tolerate the herbicide glyphosate, an ingredient in the weed killer Roundup. Glyphosate is the most widely used herbicide in the world by volume. The World Health Organization has classified it as a carcinogen and many studies have shown its link to cancer.
For this reason, it is wise to avoid all cooking oils that come from GMO crops, in particular, soybean, corn, cottonseed, and canola. Additionally, be very cautious with peanut oil as this plant is often heavily sprayed with pesticides. It can also be contaminated with a mycotoxin called aflatoxin during pre-harvest, storage, or processing.
High Levels Of Omega-6 Fats
Eating foods with too much omega-6 leads to chronic inflammation in the body. Omega-3, in contrast, reduces inflammation. A healthy balance of omega-6 to omega-3 in the diet is about 1 to 1. Many oils derived from nuts and seeds are especially high in omega-6 with little or no omega-3 in the fats. Hence, they should not be used as your staple cooking oil.
Fatty Acid Composition Of Cooking Oils With High Omega-6
(Omega-6 & Omega-3 Fats As A % Of Total Fats)
Safflower_________(75%, 0%)
Grape seed________(71%, 0%)
Sunflower_________(65%, 0%)
Hemp____________(60%, 20%)
Corn_____________(59%, 0%)
Pumpkin seed______(55%, 0%)
Cottonseed________(52%, 0%)
Soybean__________(51%, 8%)
Walnut___________(51%, 5%)
Sesame___________(45%, 0%)
Rice bran__________(35%, 1%)
Peanut____________(35%, 0%)
Canola (rape seed)__(30%, 9%)
Highly Refined Oils
In general, oils extracted from nuts and seeds do not hold up to high heat. The reason is because they are high in omega-6 and/or omega-3 fats. Both omega-6 and omega-3 are polyunsaturated fats, which are liquid at room temperature and unstable by nature. When heated, they are easily susceptible to oxidative rancidity, resulting in harmful compounds.
Therefore, the only way to transform these oils into cooking oils is to "refine" them. It involves an extremely intensive mechanical and chemical process. High heat, chemicals, and solvents are used to extract the oil from plant seeds. Then the oil goes through further refining including degumming, neutralization, bleaching, and deodorization, resulting in a highly refined oil that can withstand very high temperatures.
In general, the more refined the oil is, the higher is the smoke point. A smoke point refers to the amount of heat an oil can withstand before it begins to break down and burn. Highly refined oils are used in the fast food industry because the oils have a long shelf life and they do not absorb the flavors of the foods cooked in them. Restaurants can cook multiple items in the same batch of oil without the foods picking up each other's flavors.
Chemically refined oils are highly processed foods. Stay away from using these oils, namely safflower oil, grape seed oil, sunflower oil, corn oil, soybean oil, refined peanut oil, canola oil, vegetable oil, and margarine.
What To Look For In A Cooking Oil
Stability And Smoke Points
Different oils have different smoke points. You should never heat the oil until it smokes. That means the temperature is too high and the molecular structure of the oil has been altered and damaged. Discard the oil, clean the pan, and start over at a lower temperature.
Natural oils and fats contain varying ratios of three types of fats and they differ in their degree of stability.
- Polyunsaturated fats (omega 3s and 6s) - liquid at room temperature and very heat sensitive and unstable. Oils high in these fats should never be used for cooking.
- Monounsaturated fats - liquid at room temperature and fairly resistant to heating.
- Saturated fats - solid at room temperature and most resistant to heating.
Fatty Acid Composition Of Good Cooking Oils
(Polyunsaturated, Monounsaturated, & Saturated Fats As A % Of Total Fats)
Coconut oil________(3%, 6%, 91%)
Butter and ghee____(4%, 28%, 68%)
Tallow (beef fat)____(5%, 40%, 55%)
Palm oil___________(10%, 40%, 50%)
Lard & bacon fat____(10%, 50%, 40%)
Duck fat__________(13%, 49%, 33%)
Chicken fat________(21%, 45%, 30%)
Avocado oil________(13% 71%, 16%)
Olive oil___________(11%, 75%, 14%)
Thermal Guide
Sautéing 300 F
Deep-fat frying 325-375 F
Stir-frying 350-400 F
Roasting 400-450 F
Coconut oil is an excellent oil for medium to high heat cooking. It is made of mostly saturated fat and is very stable when heated. Organic, virgin, expeller-pressed coconut oil is the best.
Refined coconut oil that involves chemical refining is not desirable at all. If you are looking for a good refined coconut oil for higher heat cooking, make sure it is steam-refined and uses no chemicals. The color should be slightly yellowish. If it is pure white, it has been chemically bleached.
Smoke point: 350 F for virgin coconut oil and 400 F for refined coconut oil.
Butter is good for low heat cooking only because it contains milk solids which will burn at higher temperatures. An alternative is to use clarified butter or ghee which is pure butterfat, this way it can withstand much higher heat. Always buy butter and ghee from grass-fed cows.
Smoke point: 300 F for butter and 480 F for ghee.
Animal fats like tallow (beef fat), lard (pork fat), duck fat, and chicken fat are excellent for medium to high heat cooking. If the animals are pasture-raised or grass-fed, there will be more saturated and monounsaturated fats in them. If they eat a lot of grains, the fats will contain more polyunsaturated fats. Therefore, always buy animal fats from animals that are pasture-raised. Also, make sure the animals are not given antibiotics and hormones as their residues are stored in the fat.
Smoke point: 400 F for tallow and 375 F for lard, chicken fat, and duck fat.
Palm oil, derived from the fruit of oil palms, is another good choice for high heat cooking. Unrefined, red palm oil is much preferred to the highly refined ones. However, some concerns have been raised about the sustainability of harvesting palm oil. Apparently, growing these palm trees means less environment available for Orangutans, which are an endangered species.
Smoke point: 450 F
Avocado oil and olive oil have very similar fat composition with predominantly monounsaturated fats. Choose avocado and olive oils that are extra virgin, unrefined, and cold-pressed as they are the highest quality and have the best flavor with the most nutrients. These are best for low to moderate heat cooking.
If you buy refined avocado and olive oils, make sure no high temperatures or chemicals are used in the refining process. Instead, they should be expeller-pressed and naturally refined with low heat and no chemicals. Quality refined oils can be used for higher heat cooking. However, they will not have the aroma and flavor of the extra virgin oils.
When you buy avocado and olive oils, make sure they are 100% pure and not a blend of other cheaper oils.
Smoke point: 320 F for high quality, extra virgin olive oil. As high as 470 F for refined, light olive oil.
Smoke point: 375 F for virgin avocado oil and 500 F for refined avocado oil.
Sesame oil, despite its high omega-6 content, has very good oxidative stability due to the presence of sesamin which has anti-tumor and antioxidant properties. When sesame oil is added to other oils for use in cooking, the oxidative properties of the recipient oil are improved. In Asian cooking, a little toasted sesame oil is often used as a flavoring oil, but not the main cooking oil. Look for sesame oil that is expeller pressed and unrefined.
Smoke point: 350 F for unrefined sesame oil.
Nutrients
Coconut oil
- Very rich in lauric acid, which has antimicrobial properties that can kill harmful pathogens like bacteria, viruses, and fungi.
- Most of the fats in coconut oil is medium-chain triglycerides (MCTs), whereas other types of fats are mainly long-chain triglycerides. MCTs go straight to the liver (instead of being broken down and digested in the small intestine) where they can be used as a quick source of energy. The liver produces ketones from MCTs that are beneficial for the brain. Scientists are studying the effects of ketones in treating epilepsy and Alzheimer's disease.
- Increases good (HDL) cholesterol that helps improve heart health.
- Good for skin, hair, and teeth.
Butter & Ghee
- Butterfat from grass-fed cows is rich in vitamins A, D, E, and K.
- Contains fatty acids like conjugated linoleum acid (CLA) and butyrate. CLA has cancer fighting properties while butyrate is particularly beneficial for the integrity of the intestinal lining.
- Rich in antioxidants.
Animal Fats
These days, animal fats have a terrible reputation, but like all the rest of the low-fat myth, it is totally unsubstantiated. Fats from healthy pastured animals are natural, unrefined, unprocessed fats with high amounts of very stable monounsaturated and saturated fats. However, only choose animal fats from pastured animals as you do not want to eat the fats from a conventionally-raised animal that has been administered antibiotics and hormones or GMO feed.
Before using any animal fat to cook with, it has to be rendered. This is a simple process of melting the fat so that any impurities will float to the top. You can buy animal fat raw and render it yourself, or buy it pre-rendered.
- Tallow, also called suet, is the rendered fat from a cow. Tallow is hard and brittle in room temperature because it is high in saturated fat, hence, it is very stable and is an ideal fat for high heat cooking. Tallow had been a popular fat in the US for deep frying potatoes until the mid-1980s. Like butter, tallow is high in CLA. Grass-fed beef fat contains 2-3 times more CLA than grain-fed beef fat.
- Lard is rendered pork fat. It is high in the heart-healthy monounsaturated fats like those found in olive oil. For centuries, lard has been a major food fat in China and parts of Europe. It is a popular fat for pastry and for frying potato chips. Quality of the lard depends on the pig's diet. Pasture-raised pigs eat everything they can find in nature, including mice, worms, and grass. Conventionally-raised pigs eat GMO corn and soybean meal. Do not buy commercial lard, which comes packaged as a solid block. It is often treated with chemicals and hydrogenated fats.
- Duck fat, like lard, is high in monounsaturated fats. Fats from pastured ducks contain CLA, vitamin E and choline. Vitamin E is an antioxidant that helps protect the cells from damage. Choline is important for the liver, brain, muscles, nervous system, and metabolism. Duck fat, both rich and delicious, has been a highly treasured fat in France and Europe.
- Chicken fat is rich in vitamin E and choline, and a good source of antimicrobial fats. It was a popular fat in the US a hundred years ago when it was used as a pastry fat.
Olive Oil
The first pressing of the olive fruit yields a top grade oil called extra virgin olive oil. It is usually darker in color, contains more flavor and nutrients like antioxidants, vitamin E, K, and phytosterols (with cholesterol-lowering effects) than the refined, light olive oil.
Avocado Oil
Avocado oil has the same heart-healthy benefits like olive oil. It is rich in vitamin E and eye-protective antioxidants lutein and zeaxanthin. It also nourishes the skin and the gums.
Conclusion: Best Cooking Oils
High heat cooking
- Refined avocado oil (500 F)
- Ghee (480 F)
- Refined, light olive oil (470 F)
- Refined coconut oil (400 F)
- Tallow (400 F)
Medium heat cooking
- Lard, chicken fat, and duck fat (375 F)
- Virgin avocado oil (375 F)
- Virgin coconut oil (350 F)
- Unrefined toasted sesame oil, for flavoring (350 F)
Low heat cooking
- Butter (300 F)
- Extra virgin olive oil (320 F)
Make sure the oils are pure and not blended with other cheaper oils.
With refined oils, they should be expeller-pressed and naturally refined with low heat and no chemicals.
With animal fats, they should come from animals that are pastured-raised.
Carol Chuang is a Certified Nutrition Specialist. She has a Masters degree in Nutrition and is a Certified Gluten Practitioner. She specializes in Metabolic Typing and Functional Diagnostic Nutrition.
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