Lindsey Harding, ND
May 31, 2025
What Oils are ACTUALLY Healthy to Cook With?
Smoke point advertised on labels is used as a reference to indicate at what temperature the oil will start continuously smoking. This is NOT the actual limit for when an oil's chemical structure changes and goes from healthy to unhealthy. Using smoke point to determine if an oil is "healthy" vs. "unhealthy" has resulted in an increase of processed and oxidized oils in the American diet.
Let's review:
A simple search of "the healthiest oils for cooking" on Google shows:
An article titled "4 Healhier Cooking Oils (and 4 to Avoid)" by Healthline.com In this article, the 4 "healthier" oils are olive oil (there is no distinction made between extra virgin and its processed counterpart), Avocado oil (again, no distinction between processed and unprocessed is mentioned), sesame oil and safflower oil, both of which are seed oils.
An article by the Cleveland Clinic states the healthiest oils for high heat cooking are Almond oil, Hazelnut oil, sunflower oil, refined olive oil, and avocado oil. Additionally, it lists canola oil, grapeseed oil, and peanut oil as healthy for medium-high heat cooking.
So, there is a lot of variation in suggested oils for healthy cooking.
Allow me to provide some information to set the record straight.
As I go through this information, please be aware that oils are not all made equally. Two bottles of extra virgin olive oil can contain different amounts antioxidants and ratio of fats I will describe below. This is especially true when comparing brands based on their sources and manufacturing processes. This will change the chemical nature and oxidative stability of the oil.
WHAT IS OXIDATIVE STABILITY?
Oxidative stability is defined as the ability to resist oxidation. During oxidation, oil reacts with oxygen producing harmful compounds and toxic by-products including aldehydes and lipid peroxidases. These toxic by-products can damage your DNA. This is a major cause of disease. These chemical changes also cause the oil to lose nutritional value. You may have heard the term "rancid" when describing an oil that has gone bad. Rancid is another way to described an oxidized oil. Most fats become oxidized during the cooking process, but how long and at what temperature varies. Smoke point does NOT equal the temperature at which the oil will oxidize. Oxidative stability is more important than smoke point for your health.
How resistant oil is to oxidative stress can be challenging to find out. There is less research on this than on smoke points. There are 3 major factors that determine an oils stability to resist oxidation:
Concentration of antioxidants. Antioxidants protect against oxidation. Any oil that has been refined has had the antioxidants removed, which will increase its smoke point, but decease its ability to withstand oxidation.
READ THAT AGAIN. A refined oil has a HIGHER smoke point, but a LOWER threshold for oxidation.
Ratio of fats. Fat is more resistant to heat if it contains fewer double bonds. Double bonds break down and oxidize more quickly.
Saturated fats do not contain any double bonds, making them stable at high temperatures. This includes oils and fats that are solid at room temperature, such as coconut oil and butter.
Monounsaturated fats contain only 1 double bond. This makes them stable for high heat cooking as well. This category includes: macadamia nut oil, olive oil, and avocado oil.
Polyunsaturated fats have 2 or more double bonds, making them more prone to oxidation with any amount of heat. Oils rich in polyunsaturated fats include canola oil, sesame oil, sunflower oil. (Dear Healthline.com, your healthy oils article is flawed.)
Omega's are a group of mono and polyunsaturated fats known for their health benefits. Omega-3 and omega-6 are polyunsaturated fatty acids (PUFA). Omega-7 and omega-9 are both monounsaturated fatty acids (MUFA). Omega-7 and omega-9 are non-essential fatty acids, meaning your body can make them from other fatty acids, so they are not a requirement in a healthy diet. How much of these oils is needed for a healthy diet? Like anything, it's all about moderation and balance.
Omega-3 is the healthiest omega, playing a role as an anti-inflammatory agent in the body, protecting the cardiovascular system, the brain, and the nervous system. Omega-3 sources include wild caught salmon, herring, mackerel, oysters, sardines, anchovies, algae oil, flax seeds, chia seeds, walnuts, and hemp hearts (and oils from all these sources).
Omega-6 is protective for the skin, but is otherwise considered pro-inflammatory. Oils high in omega-6 include avocado oil, sunflower oil, safflower oil, corn oil, soybean oil, and canola oil.
Omega-7 improves skin elasticity, insulin sensitivity, eye health, and cardiovascular health. Omega-7 is not found in large amounts in cooking oils, but can be found in small amounts in macadamia nut oil, avocado oil, and olive oil.
Omega-9 may help to lower LDL cholesterol, improving cardiovascular health. Omega-9s such as oleic acid, is found in high amounts in olive oil, and in lower amounts in avocado oil, rapeseed/canola oil, macadamia nuts, and peanut oil.
Natural vs. Refined (aka. Has the oil been processed?) You've likely seen oils advertised as "cold pressed," typically combined with "extra virgin" or "unrefined" on a label. These oils have undergone little to no heat and pressure and no chemical bleaching. As a result, these oils retain nutrients from their original sources and are much more resistant to oxidation. However, these oils typically have a lower smoke point. Refined processing includes heat, high pressure, bleach, and other chemicals to neutralize the oil with the general goal of making it more palatable - less odor and less flavor. The process of refining an oil strips nearly all the nutrients from the oil, which reduces its ability to withstand oxidation. You guessed it! This process INCREASES smoke point.
In short, AVOID refined oils and oils high in polyunsaturated fats (canola oil, sesame oil, sunflower oil, refined olive oil, refined avocado oil)
USE oils that say "Virgin," "Raw," or "Unrefined" on the label.
LET'S TALK ABOUT OILS FOR COOKING
AVOCADO OIL has a smoke point of 500-520 degrees. It is made from the pulp of the avocado, not the seed. Avocado oil is mostly unsaturated fats, approximately 2-18% polyunsaturated fatty acids (depending on the quality of the product). It mostly contains omega-6s, and to a lesser extent omega-3s. Like extra virgin olive oil (EVOO), virgin avocado oil contains a high amount of monounsaturated fatty acids, about 70%, which are protective for the cardiovascular system. The rest is saturated fat.
A healthy ratio of omega-6 to omega-3 for the human body is considered to be a 5:1 ratio or lower.
Avocado oil has a ratio of omega-6:omega-3 of about 13.5:1. This is much higher than the recommended ratio for cardiovascular and general health.
OLIVE OIL, specifically extra virgin olive oil (EVOO) contains mostly monounsaturated fats. The remaining fats are polyunsaturated fats, which are present in a 10:1 ratio of omega-6 to omega-3. (Approximately 10% is linoleic acid, an omega-6, and < 1% is linolenic acid, an omega-3). While EVOO is praised for its health benefits, especially in the Mediterranean diet, it is still not an ideal oil for daily use due to its 10:1 ratio of omegas. In this aspect, EVOO is less than favorable, but still better than avocado oil. However, EVOO may be one of the best oils for high heat cooking because it is highly resistant to oxidative damage due to its high polyphenol content. Polyphenols are antioxidants. This means it retains health value even after being cooked at high heat. In a study by Casal, et. al. EVOO was able to withstand up to 27 continuous hours of deep-frying without oxidizing (6).
COCONUT OIL only has a smoke point of about 250 degrees, but it is highly stable at high temperatures. Coconut oil is mostly saturated fats, and contains minimal polyunsaturated fats (< 2%). Coconut oil does not contain any omega-3. Since coconut oil is low in omega-6 linoleic acid, it is still considered to be low on the inflammatory scale, despite its absence of omega-3. Unrefined coconut oil does contain antioxidants. Coconut oil contains no cholesterol, but it is known to increase LDL ("bad cholesterol"). However, some studies link it to increased HDL ("good cholesterol"), so it is possible that it has a balancing effect on the ratio of good to bad cholesterol.
MCT stands for medium chain triglycerides. It is an oil composed of a type of saturated fat that is quickly absorbed and converted into fuel for cells. It is typically derived from coconut oil, and the packaging may use the term "liquid coconut oil" instead of MCT oil. MCT oil contains only 1% polyunsaturated linoleic acid (that pesky pro-inflammatory omega-6), 5% oleic acid, and a small amount of omega-9. MCT oil, like coconut oil, does not contain omega-3. Within coconut oil's 90% saturated fat content, there are long chain triglycerides and medium chain triglycerides. Long chain triglycerides tend to be stored as fat, and thus, are removed to make MCT oil. While both are stable for moderate-high heat cooking, they do not provide many of the health benefits obtained from omega-3, 6, 7, and 9.
Why is the omega content of oil so important?
The excessive amount of omega-6 and saturated fats in oils (and the human diet in general) are key factors that drive the high rate of cardiovascular disease, inflammatory diseases, autoimmunity, and even cancer in the United States as well as in other countries that have adopted an Americanized diet. For this reason, the ratio of omega-6 : omega-3 is extremely important.
"A ratio of 2.5:1 reduced rectal cell proliferation in patients with colorectal cancer, whereas a ratio of 4:1 with the same amount of omega-3 had no effect. The lower omega-6:omega-3 ratio in women with breast cancer was associated with decreased risk. A ratio of 2-3:1 suppressed inflammation in patients with rheumatoid arthritis, and a ratio of 5:1 had a beneficial effect on patients with asthma, whereas a ratio of 10:1 had adverse consequences (1)."
THE HEALTHIEST COOKING OIL IS...
MACADAMIA NUT OIL has the highest amount of monounsaturated fatty acid (MUFA) content of all oils, at 79%. Most of the MUFA content is from oleic acid (51.3%). Oleic acid improves the GLP-1 response, helping the metabolic system. It is the richest source of palmitoleic acid, an omega-7. This omega-7 reduces inflammation, improves insulin sensitivity, and promotes satiety. Macadamia nut oil has been shown to reduce the size of fat cells. It is also low in pro-inflammatory omega-6 linoleic acid (only containing 1-3%) with a total PUFA content around 5%. Macadamia oil is also low in saturated fats. It is very stable against oxidation, higher than avocado oil, making it more stable to cook with, despite avocado oil's claim to a higher smoke point. Macadamia oil has a smoke point around 430 degrees. And finally, macadamia nut oil is very high in antioxidants and contains a significant amount of vitamin E.
UNHEALTHY OILS
These oils have high Omega-3 content, but are still problematic for your health.
CANOLA OIL comes from rapeseed. It is mostly monounsaturated fatty acids, in a 2:1 ratio of omega-6 to omega-3 (11). It contains almost no vitamins or antioxidants. The problem with canola oil is not the rapeseed (which was genetically engineered in Canada in the 1960's and 1970's to no longer contain Euric acid), but it is the chemical extraction process. Most canola is extracted using a solvent called hexane (12). Even very low levels of hexane are toxic, and while the FDA says "there is no risk" to ingesting small amounts, the small amounts found per serving in this oil quickly add up, especially if you use this oil and other refined vegetables oils frequently (12). The chemical extraction destroys the omega-3 content, immediately making this oil rancid and unhealthy. Canola oil also undergoes "deodorization" (like most vegetable oils) and this process results in the formation of trans-fats, the most unhealthy type of fat. "Cold pressed" canola oil is not processed with hexane, and yes, it does exist! But it is difficult to find and definitely is not used by any processed food company using these cheap oils, because it significantly cuts into their profit margin.
SAFFLOWER OIL may be one of the most unhealthy oils there is. While it does contain omega-6 and a tiny amount of omega-3, the ratio of omegas is 77:1, according to DiNicolantonio, et. al. Do you have a bag of chips in your cupboard? Go take a look at the nutrition label - the majority of chips are processed with safflower oil because it is cheap and has a high smoke point. Is it healthy? Definitely NOT.
SESAME OIL in its pure virgin form is healthy and rich in omega-3 with less than a 2:1 ratio of omega-6:omega-3 (14). Unfortunately, that is not how it is generally found in stores. Often mixed with cheaper oils, sesame oil content varies greatly. Roasting sesame oil is an important part of processing this seed for oil. Roasting can cause up to a 10% change in the oils chemical make up (10). Unsaturated fatty acid content (a combination of both MUFA and PUFA) can range from approximately 27% - 55% and saturated fat content can vary from 0%-10%. Sesame oil does contain a high profile of vitamins, but its' variability in quality presents a major problem when choosing it as a primary cooking oil. It could already be oxidized. It's impossible to know without testing the product.
HEALTHY OILS YOU SHOULD NOT COOK WITH
WALNUT OIL contains the highest amount of omega-3 as alpha-linolenic acid of all the oils generally considered to be "cooking oils." The omega-3 content is nearly 5x as high as the equivalent 100g of sardines, but cod liver oil still surpasses walnut oil in omega-3 content by more than double. However, walnut oil also contains a high amount of linoleic acid, an inflammatory omega-6. The ratio of omega-6:omega-3 is 5:1. This is still superior to EVOO and avocado oil, though not as beneficial as macadamia nut oil. However, the total content of omega-3 is higher per tablespoon than macadamia nut oil. The problem with walnut oil is simply that is it mostly omega-3, a polyunsaturated fatty acid, which means it contains multiple double bonds, making it unstable to cook with.
FISH OIL ALGAE OIL, FLAXSEED OIL. These oils are the highest in omega-3 content, making them the healthiest among the oils. Omega-3s are not stable when exposed to heat, oxygen, or light. Keep these oils in a cool dark, airtight container. Purchase oil that comes in amber glass or aluminum, and do not heat these oils - ever!
HEMP SEED OIL is about 55% omega-6 as linoleic acid and about 20% omega-3 as alpha-linolenic acid (9). It contains significantly less saturated fat than olive oil. Hemp seed oil contains high amounts of tocopherols and tocotrienols (forms of vitamin E). It has an omega ratio of 3:1. Hemp seed oil may be safe to cook with over low heat, but product recommendations vary greatly, so if you decide to use hemp seed oil or walnut seed, which is similar in omega content, with heat, use extreme caution.
Resources
Simopoulos AP. The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomed Pharmacother. 2002 Oct;56(8):365-79. doi: 10.1016/s0753-3322(02)00253-6. PMID: 12442909.
Ako H, Okuda D, Gray D. Healthful new oil from macadamia nuts. Nutrition. 1995 May-Jun;11(3):286-8. PMID: 8541698. https://pubmed.ncbi.nlm.nih.gov/8541698/
Stewart, Alan. Essential Fatty Acids. 2025. http://www.stewartnutrition.co.uk/treating_nutritional_deficiencies/essential_fatty_acids.html
https://olivewellnessinstitute.org/article/showdown-what-is-the-best-oil-for-cooking/
Casal S, Malheiro R, Sendas A, Oliveira BP, Pereira JA. Olive oil stability under deep-frying conditions. Food Chem Toxicol. 2010 Oct;48(10):2972-9. doi: 10.1016/j.fct.2010.07.036. Epub 2010 Aug 3. PMID: 20678538.
Rengl, A., Perez, E., Piombo, G., Ricci, J., Servent, A., Tapia, M., Gibert, O., Montet., D. Lipid Profile and Antioxidant Activity of Macadamia Nuts (Macadamia integrifolia) Cultivated in Venezuela. Natural Science; vol. 7 No. 12, Nov. 2015. https://www.scirp.org/journal/paperinformation?paperid=61429
Manitoba Canola Growers. Dietary Fat Chart. https://canolagrowers.com/resource/dietary-fat-chart/
Mikulcová V, Kašpárková V, Humpolíček P, Buňková L. Formulation, Characterization and Properties of Hemp Seed Oil and Its Emulsions. Molecules. 2017 Apr 27;22(5):700. doi: 10.3390/molecules22050700. PMID: 28448475; PMCID: PMC6154611.
El-Beltagi HS, Maraei RW, El-Ansary AE, Rezk AA, Mansour AT, Aly AA. Characterizing the Bioactive Ingredients in Sesame Oil Affected by Multiple Roasting Methods. Foods. 2022 Jul 28;11(15):2261. doi: 10.3390/foods11152261. PMID: 35954028; PMCID: PMC9368678.
Lehman, Shereen, MS. Canola Oil Nutrition Facts. Verywellfit.com 03 Dec 2020.
Crosby, Guy. “Ask the Expert: Concerns about canola oil.” The Nutrition Source. https://nutritionsource.hsph.harvard.edu/2015/04/13/ask-the-expert-concerns-about-canola-oil/
DiNicolantonio JJ, O'Keefe J. The Importance of Maintaining a Low Omega-6/Omega-3 Ratio for Reducing the Risk of Autoimmune Diseases, Asthma, and Allergies. Mo Med. 2021 Sep-Oct;118(5):453-459. PMID: 34658440; PMCID: PMC8504498.
Oboulbiga EB, Douamba Z, Compaoré-Sérémé D, Semporé JN, Dabo R, Semde Z, Tapsoba FW, Hama-Ba F, Songré-Ouattara LT, Parkouda C, Dicko MH. Physicochemical, potential nutritional, antioxidant and health properties of sesame seed oil: a review. Front Nutr. 2023 Jun 1;10:1127926. doi: 10.3389/fnut.2023.1127926. PMID: 37377483; PMCID: PMC10292629.