Choosing the Best Cooking Oil: Anti-Inflammatory Diet Essentials

Four factors to consider when choosing the best cooking oil include how the oil was processed, its flavor, nutritional value, and smoke point. These can vary for various cooking methods. Let’s delve into cooking oils, exploring some options and which oils are best suited for your recipe. We get into smoke points, refined oils vs cold and expeller pressed extraction methods, and offer a couple of handy tables about oils and their smoke points as well as how extraction methods impact flavor and nutrition. So read on.

Oil being poured into a wok. Different oils lend themselves to different cooking applications due to their smoke point.
Different oils lend themselves to different cooking applications based on their smoke point, flavor, and even nutritional profile.

Understanding Smoke Points

An anti-inflammatory diet will minimize the amount of oxidized fat and harmful compounds that can form while cooking with oil. Understanding oils and their smoke points is one way to minimize this from happening. Once an oil starts smoking, it’s a red flag that bad compounds are being made, trans fats could be forming, and fatty acids are oxidizing. This will make the fat less healthy and also less tasty.

The smoke point of an oil refers to the temperature at which it begins to break down and produce visible smoke. Beyond this point, the oil can impart an unpleasant flavor to your food and potentially release harmful compounds. Cooking at temperatures above an oil’s smoke point can lead to the degradation of its nutritional content and the formation of harmful free radicals.

Avoiding Oxidation

Oxidation occurs when oil reacts with oxygen, leading to the formation of free radicals and harmful compounds. This process can be accelerated by exposure to heat, light, and air. Consuming oxidized oils contributes to inflammation, oxidative stress, and an increased risk of chronic diseases.

How hot is the stove top, anyway?

All of this may have you asking, ‘how do I know how hot my stove top is?’ There are so many factors to consider, it’s not easy to answer. The size and material of the pan you are cooking in and the food or liquid you are heating impact the temperature during cooking. As an experienced cook in the fine restaurant industry turned much loved home cook for friends and family, my husband has a tip:

Have everything chopped and prepped to go into the pan when you are ready before heating the pan.Letting the pan sit for too long while you chop, chop can lead to overheating of the pan. A red flag for this is if you add oil to a hot pan and it starts to smoke. That would be the most obvious way to know you are working beyond the smoke point and the pan is too hot.

Minimizing Trans Fat Formation When You Cook With Oil

Heating oils beyond their smoking point is discouraged, as it can adversely affect the quality of fats, leading to the generation of trans fatty acids and potentially increasing the levels of carcinogenic compounds. Therefore, cooking at temperatures significantly lower than their smoke point is crucial to prevent the formation of such harmful compounds, in addition to trans fat.

Significant formation of trans fats can occur with temperatures >200 °C or 392°F. 325 to 375oF is a typical frying temperature. Higher temperatures of 375 to 400oF also are used. However, the real trouble is when the oil is hot for extended periods of time. Since it is more likely that oil would be hot for a longer period of time in a restaurant, it is most likely that trans fats from oils would most likely come from fried food in restaurants, not so much at home.

This is not to encourage frying food too often at home, as fried foods have more oxidized fat, creating inflammation. But it is good to know the worse culprit is fried food from dining out. For more information about trans fats, scroll down or read to the bottom of this post, ‘How Do Trans Fats Factor In Here?’

Cooking Oil Options

  1. Avocado Oil: With a high smoke point of around 520°F (270°C), avocado oil is suitable for high-temperature cooking methods like frying and searing. It also contains monounsaturated fats, which are heart-healthy and resistant to oxidation.
  2. Peanut Oil: Peanut oil, with its nutty and robust flavor, has a relatively high smoke point of 450°F (232°C), making it suitable for frying and high-heat cooking methods like stir-frying. It’s also rich in monounsaturated fats, vitamin E, and resveratrol, offering potential health benefits along with its culinary versatility.
  3. Sunflower Oil (High-Oleic): High-oleic sunflower oil has a smoke point of approximately 440°F (227°C) and is rich in monounsaturated fats. It’s suitable for frying and baking, but be mindful of its omega-6 fatty acid content, which may contribute to inflammation if consumed excessively.
  4. Rice Bran Oil: Rice bran oil, with its mild and nutty flavor, has a high smoke point of 450°F (232°C), making it suitable for frying, stir-frying, and other high-heat cooking methods. It is rich in monounsaturated fats and contains vitamin E, offering potential health benefits along with its culinary versatility.
  5. Safflower Oil: The smoke point of safflower oil is typically around 450°F (232°C). Due to its high smoke point, safflower oil is suitable for high-heat cooking methods such as grilling, frying, stir-frying, and roasting.
  6. Canola Oil: Canola oil, known for its mild and neutral flavor, has a smoke point of 400°F (204°C), making it suitable for various cooking methods such as sautéing, baking, and frying. It’s rich in monounsaturated fats and omega-3 fatty acids, contributing to its heart-healthy profile and versatility in the kitchen.
  7. Grapeseed Oil: Grapeseed oil has a high smoke point of around 420°F (216°C) and a neutral flavor profile, making it versatile for various cooking methods. It contains polyunsaturated fats, which are susceptible to oxidation, so it’s best used in moderation and not for prolonged high-heat cooking.
  8. Sesame Oil (Unrefined): With a smoke point of around 350°F (177°C), unrefined sesame oil is best used for low to medium-heat cooking, such as stir-frying and dressings. It adds a distinctive nutty flavor to dishes and contains antioxidants like sesamol.
  9. Coconut Oil: Despite its saturated fat content, coconut oil has a smoke point of approximately 350°F (177°C). It’s ideal for medium-heat cooking and imparts a distinctive flavor to dishes. However, moderation is key due to its saturated fat profile.
  10. Olive Oil (Extra Virgin): Extra virgin olive oil is last but not least. The best olive oil is extra virgin olive oil, and its smoke point is relatively lower compared to other oils. However, the smoke point can vary with processing methods and some evidence suggests that beneficial phenolic compounds in olive oil can decrease the production of unhealthy acrylamides that form during high heat cooking. It works well for sautéing and low to medium-heat cooking. It is even better for unheated preparations, such as salad dressing. Rich in antioxidants and monounsaturated fats, it offers numerous health benefits.

Oils, Their Flavor, Nutritional Value, Smoke Point, and Best Cooking Applications

OilFlavorNutritional ValueSmoke Point (°F)Best Cooking Applications
Avocado OilMild, butteryHigh in monounsaturated fats, vitamin E, and lutein520°F (270°C)High-heat cooking, frying
Peanut OilNutty, robustHigh in monounsaturated fats, vitamin E, resveratrol460°F (237°C)Frying, stir-frying
Sunflower Oil (High-Oleic)Mild, neutralHigh in monounsaturated fats, vitamin E460°F (237°C)Frying and roasting
Rice Bran OilMild, nuttyHigh in monounsaturated fats, vitamin E450°F (232°C)Frying, stir-frying, salad dressings
Safflower OilNeutralRich in monounsaturated fats, vitamin E450°F (232°C)Grilling, frying, roasting
Canola OilMild, neutralHigh in monounsaturated fats, omega-3 fatty acids450°F (232°C)Sautéing, baking, frying
Grapeseed OilNeutralHigh in polyunsaturated fats, vitamin E425°F (218°C)Stir-frying, sautéing
Sesame Oil (Unrefined)Nutty, aromaticRich in antioxidants, sesamol350°F (177°C)Stir-frying, dressings
Coconut OilDistinctive, nuttyRich in saturated fats, lauric acid350°F (177°C)Baking, sautéing
Olive Oil (Extra Virgin)Fruity, pepperyRich in monounsaturated fats, antioxidants325°F (162°C)Sautéing, dressings
These oils are ranked from the highest smoke point at the top to the lowest smoke point at the bottom for a quick reference for selecting the appropriate oil based on the desired cooking method and temperature requirements. Smoke points obtained from Spectrum Organic Oils.

Why Aren’t Corn and Soybean Oil On the Table?

Corn and soybean oils are used so much in food in the United States, too much really. Corn and soy are artificially inexpensive due to the government subsidization of corn and soy. So the oils of corn and soy, as well as other derivatives of these foods, are used a lot by the food industry. Because corn and soy are fed to animals used for meat and dairy product production, we also get a disproportionate amount of fatty acids from these oils from these animal products.

All of this leads to the excessive and disproportionate consumption of omega 6 fatty acids, which are high in these oils. You can offset this disproportionate balance of omega 6 oils by choosing more grass fed and pasture raised animal products, which have become increasingly available in many stores. Meat subscription boxes are another option for obtaining these products, and typically come at more competitive prices compared to what is found in stores. For more information about pasture raised animal product subscription boxes, check out the blog post “Pasture Raised vs Grass Fed: Is There a Difference?

You can also choose different oils.

What Are Seed Oils and Why Are People Avoiding Them?

Corn oil and soybean oil are not the only higher omega 6 oils. Canola, safflower, grapeseed, and sunflower oil, are common used seed oils found in many kitchens. But the others are a bit different, as canola oil, for example, actually has more omega 3 compared to other options.

Omega 3, 6, and 9

Seed oils contribute a disproportionate amount of omega 6 in the total food supply. Being a bit more selective in what oils you use can have an impact on your fatty acid balance and is one of the secrets to an effective anti-inflammatory diet.

In the image below you can see the blue on the right represents the proportion of the more pro-inflammatory omega 6 in the type of oil (on the left). The orange in the middle is the omega 3, harder to come by among these oils for sure. Omega 9, the yellow, also has anti-inflammatory properties.

Canola oil does not bother me in this regard compared to other seed oils. It has more omega 3 than many other oil options. It also can be purchased cold pressed, though this is not the most common version found at the store. We will get into cold processed, expeller pressed, etc in this post shortly.

Safflower, canola, and sunflowers. Seeds from these beautiful flowers are used to make seed oils.

The animal fats on the chart raise questions for me, as research has also shown an animal’s diet has an impact on what fatty acids are found in their resulting animal products. But the focus of this post is on plant oils, so if you are interested in animal fats, you can find more information about omegas and animal products in this post about omega fatty acids, or this one about pasture raised animal products.

Refined Oils

There are also concerns about the refining process of oils. Oils undergo chemical and physical refining to give them a longer shelf life and remove pollutants. But some nutrients can be lost and some undesirable compounds generated in the process. Tocopherols (vitamin E), phospholipids, squalene, polyphenols, and phytosterols may be lost with the refining process.

Hexane

Hexane is a solvent commonly used in the extraction of oils from seeds and nuts. It is likely used because it can extract oil from crushed nuts or seeds quickly, inexpensively, and without much labor. After the hexane application, the oil and solvent mixture is heated to remove the solvent.

While it’s ‘generally regarded as safe’ (GRAS) for use in food processing when used according to regulations and with appropriate safety measures, exposure to high levels of hexane vapor or liquid can cause irritation to the eyes, skin, and respiratory system. Prolonged or repeated exposure to hexane may also lead to neurological symptoms such as headaches, dizziness, and numbness in the extremities. In severe cases, chronic exposure to hexane can cause peripheral neuropathy, a condition characterized by damage to the peripheral nerves.

The use of hexane in food processing has raised concerns about residual levels of the solvent in the final products. While regulatory agencies establish maximum allowable levels of hexane residues in food, you can avoid it by:

  • Choosing oils that are produced using mechanical extraction methods, such as expeller-pressing or cold-pressing. These methods do not involve the use of solvents.  
    • Expeller pressed oils have been mechanically extracted using heat
    • Cold pressed oils are mechanically extracted, but temperatures are kept low to preserve nutrients. So if you intend to use your oil for salad dressing or other non-heated applications, you will get the best nutrition from a cold pressed oil.
  • Selecting organic oils, as organic standards typically prohibit the use of synthetic solvents in food production.

Cold Pressed, Expeller Pressed, First Press and Extra Virgin Oils, Oh My

Cold-pressed oils, expeller-pressed oils, first press oils, and extra virgin oils are all terms used to describe different methods of oil extraction that do not involve the use of chemical solvements. Yay for that.

A couple of oils in my kitchen. Extra Virgin, Cold Pressed or Processed, Expeller Pressed, and Unrefined all have meanings that are not obvious, so let’s define them.

Cold-Pressed Oils: Cold-pressed oils can be extracted from seeds, nuts, or fruits (olives and avocados are considered fruits from a biological standpoint). This is a mechanical means of extraction that uses pressing without adding heat. The process involves cooling to counteract heat produced in the process and generally aims to keep things under 120ºF. The natural flavor, aroma, and nutritional properties of the oil are best preserved with this method. Cold-pressed oils are often preferred for their fresh taste and higher levels of antioxidants, beneficial plant compounds, and nutrients compared to oils extracted with heat or chemical solvents.

Expeller-Pressed Oils: Expeller-pressed oils are also extracted using mechanical pressure, typically with the aid of a screw press or expeller (and expeller is a pressing machine). While heat is generated during the process due to friction, it’s kept to a minimum compared to traditional refining methods. Heating temps generally do not surpass 210ºF. Expeller-pressed oils retain much of the flavor and nutritional value of the source material and are considered healthier alternatives to refined oils.

Let’s lay out cold pressed and expeller pressed in a table to compare these two methods and the impact it has on nutrient retention, flavor, and antioxidant content of olive oil:

CharacteristicCold-Pressed Olive OilExpeller-Pressed Olive Oil
Extraction MethodCrushing olives at room temperature, followed by pressingMechanical pressure extraction with minimal heat
Nutrient RetentionRetains more antioxidants, vitamins, and phytonutrientsSlightly lower retention of heat-sensitive nutrients
Flavor ProfileTypically more robust with fruity and peppery notesGenerally milder flavor profile
Antioxidant ContentHigher due to gentler extraction processSlightly lower compared to cold-pressed oil
Heat ExposureMinimal, no significant heat generation during extractionSome heat generated due to mechanical pressure

First Press Oils and Extra Virgin Oil: First press oils are the same as extra virgin oil, and refer to oils extracted from the first pressing of the seeds or fruits. This initial pressing yields the highest quality oil, with the most robust flavor and nutritional content. Subsequent pressings may produce lower-quality oil with a milder flavor and fewer nutrients.

Extra Virgin Oils: Extra virgin oils, such as extra virgin olive oil, are the highest grade of oil, prized for their superior quality, flavor, and health benefits. They are first press oils and don’t use of heat or chemical solvents.

Malaxing

Malaxing isn’t just fun to say, it is an extremely important phase in both avocado oil and olive oil extraction. It is kinda mesmerizing to watch if you’d like to check it out with the link: https://www.facebook.com/watch/?v=594448501384074

Aside from olive oil, you can find unrefined (no chemical refinement) canola, walnut, pumpkin seed, sesame, hazelnut, and other oils. Olive oil has so many beneficial compounds and attributes, I would defer to it. But avocado oil does tolerate higher heat cooking, has a more neutral flavor, and is a monounsaturated fat, similar to olive oil.

Canola oil can be found that has not undergone the hexane refining that has been under scrutiny. You would choose an organic one that is labeled cold pressed or expeller pressed to be sure.

While I don’t recommend using cold pressed walnut, pumpkin seed, sesame seed, or hazelnut oil as frequently as unrefined extra virgin olive oil because they are higher in omega-6 fatty acids, they can add distinctive flavor and variety to meals.

Coconut Oil: Is It Healthy Or Just Hype?

In a study ranking the nutritional quality of oils and giving them a score, olive oil ranked #1 while coconut oil got a zero! But let’s see why this was rather than just accepting it at face value.

Among 32 edible oils that were evaluated, virgin olive oil scored #1 with 100 out of a possible 100. All plant oils, with the exception of coconut oil, scored greater than 50 out of a possible 100. The study quantified various fatty acids, tocopherols (vitamin E), EPA and DHA (mostly just in animals and fish but also found in algae), hydroxytyrosol (found in olives, so other oils couldn’t compete), and phytosterols (compounds found in plants). Coconut oil ended up scoring so low due to its high saturated fat content.

While many point out that the saturated fat in coconut oil is different than that of meat products due to its shorter fatty acid chain and ability to be liquid rather than solid at warmer temperatures, other research confirms that similarly to other saturated fats, it raises lipid levels similarly to other saturated fats and can allow inflammatory bacteria to cross the barrier more easily. This is a topic for another post, but for this reason, and because the focus of this blog is anti-inflammatory nutrition, coconut oil probably is not going to be a great anti-inflammatory choice for a cooking oil.

How Do Trans Fats Factor In Here?

Trans fats come from 3 possible sources:

  • Some occur naturally, coming from ruminants (such as cows and sheep), and are found in meat and dairy foods. Science is kinda mixed on if these are equally harmful as industrially produced trans fat.
  • The most notorious trans fat is industrially produced, being formed by partial hydrogenation of vegetable oils (check your peanut butter as it is still commonly found in most peanut butters). A ban is in effect but not all that effective due to long time frame requirements for implementation.
  • Heating oils at high temperatures, especially for prolonged periods of time, can also create trans fatty acids. Deep frying, pan frying, and stir-frying all fall into this category.

Chemical structure wise, trans fatty acids are fatty acids with at least one unsaturated, non-conjugated double bond in the trans configuration. Consumption of trans fatty acids is pretty clearly very bad for you, being associated with cardiovascular disease risk factors including increased low-density lipoprotein cholesterol (LDL), triglycerides, and lipoprotein (a) levels, decreased HDL cholesterol, and increased insulin resistance, adiposity (fat), and endothelial dysfunction (blood vessels). Furthermore, increased trans fatty acid consumption is associated with greater incidence of diabetes and coronary heart disease.

I can tell you that as an inpatient Registered Dietitian working with cardiac surgery patients, there have been some relatively younger ones that used Crisco on the regular. Now, in 2022, Crisco changed its formulation due to the ban of industrially produced trans fats. But the substitution of industrially made, partially hydrogenated oil with palm oil and soy oil is not much, if any, better.

Some research has even attributed a diet high in trans fatty acids with approximately 645,000 annual deaths globally. The World Health Organisation, along with other food and health advisory organisations, recommends that trans fatty acid intake make up no more than 1% of total calorie intake, as even this much has been linked to said health risks. Trans fatty acid consumption remains high at around 6.5% of calorie intake in many parts of the world.

Does an oil’s container matter?

Yes! Turns out the light exposure through a clear bottle or plastic jug leads to antioxidant loss. Research on this topic found tin canisters or dark glass to be the best at preserving antioxidant levels of olive oil.

Tips for Safe and Healthy Cooking with Oils

  • Choose the Right Oil for the Job: Select oils with smoke points appropriate for your cooking method to minimize the risk of overheating and oxidation.
    • See the chart in this post for reference information about smoke points of oils and most ideal cooking preparation applications.
  • Store Oils Properly: Keep oils in a cool, dark place away from heat and light to prevent oxidation. Use them within their recommended shelf life for optimal freshness.
    • According to the USDA, you can keep unopened cooking oils in the pantry for 4 months.
  • Avoid Reusing Oils: Reusing cooking oil can accelerate oxidation and the formation of harmful compounds (trans fats and carcinogenic compounds).
    • Dispose of used oil responsibly or consider recycling it for other purposes. Don’t ever pour oil down the sink (or you will be calling Rotorouter). Very small amounts of oils can either be wiped away with paper towels or if plant based, added to your compost.
  • Balance Your Fat Intake: While certain oils offer health benefits, it’s essential to consume them in moderation as part of a balanced diet rich in whole foods.
    • Just because olive oil is a healthier choice, for example, does not mean you want to ladle it onto your food.
  • Avoid Extreme High Heat: Heating oils to very high temperatures and for prolonged periods of time should be avoided due to the formation of trans fats and carcinogenic compounds (I know, this is maybe the third time this has been stated. Hear me, hear me).
    • An overheated pan is going to lead to smoking oil. Have your ingredients chopped, prepped, and ready to go before you start heating your pan or add any oil.

In conclusion, choosing the right cooking oil involves considering factors like how the oil was made, its smoke point and susceptibility to oxidation, flavors, and of course, nutritional profile. By selecting oils with higher smoke points when needed and healthier fat profiles, you can enjoy delicious meals while minimizing the risk of harmful chemical reactions. Remember to store oils properly and practice moderation for optimal health and culinary satisfaction.

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Anne Marie Berggren RDN, MS, CDN, CNSC is a Registered Dietitian with a Master's Degree in Nutrition, training in integrative and functional nutrition, nutrition for mental health, obesity and weight management, is a board certified nutrition support clinician, and an adjunct professor for the Stony Brook Graduate Nutrition Program teaching advanced clinical nutrition.

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