Smokin’ Hot or Unsafe? Is cooking with grape seed oil a good idea?
I (Margaret) get asked all the time about whether grape seed oil is safe for cooking. There’s lots of confusion and mis-information on the topic of fats generally, and cooking is no exception. Grape seed oil is advertised as appropriate for high heat because of it’s high smoke point. But is it? Caroline Barringer NTP CHFS FES, owner of Immunitrition and lead instructor for the Nutritional Therapy Association gives a thoughtful answer here. This is an excerpt from her article “Cooking with Grape Seed Oil or Rice Bran Oil: Is it safe?”, which you can read in full on her website here (scroll down to the “articles” section on that page)
A professional chef recently contacted me at Immunitrition with a question about the smoke points of oils, as well as the safety of cooking with rice bran oil and grape seed oils in particular. She explained to me that the smoke point of an oil or fat is considered important to culinary professionals because they want to be able to cook certain foods quickly at high temperatures without the food burning or having an “off” flavor, which is a strong indication that the oil has gone rancid. Oils with higher smoke points may be important to a modern chef, but what they fail to understand is that the smoke point of an oil or fat has nothing to do with its health benefits or its safety for cooking at higher temperatures. Fats and oils are made up of all fatty acid types (mono-unsaturated, poly-unsaturated, and saturated), so we must first investigate to see what the predominant type of fatty acid a specific oil or fat contains to determine whether or not it should be exposed to heat, oxygen, light, or moisture.
As a rule of thumb, if the predominant classification of an oil or fat is polyunsaturated, then we should never cook with it – regardless of its smoke point. Grapeseed oil is predominantly classified as a polyunsaturated fatty acid, and is thus highly reactive. Lipid (per)oxidation and free-radical production quickly takes place when these types of fatty acids are exposed to any degree of heat – even very low heat. This is a big red flag for producing inflammation and irritation within our bodies.
Here are the fatty acid profiles for grape seed oil and rice bran oil.
|Grape Seed Oil||Rice Bran Oil|
|71% POLYunsaturated||36% polyunsaturated|
|17% monounsaturated||48% MONOunsaturated|
|12% saturated||17% saturated|
|(485º smoke point)||(490º smoke point)|
As you can see, grape seed oil is mostly a polyunsaturated fat and should never be exposed to any degree of heat. It should be stored in the refrigerator and used sparingly. Rice bran oil, on the other hand, is predominantly a monounsaturated fatty acid. It is a bit more stable than grape seed oil, and can be used for very low-heat applications, but rice bran oil still has a hefty polyunsaturated content (36%), so it’s best to store it in the fridge and use in moderate amounts. Rice bran oil’s 17% saturated fatty acid content protects the delicate polyunsaturated fatty acids when exposed to low-heat cooking. Rice bran oil shares a similar profile to sesame oil (43 poly, 42 mono, and 15 sat), so it’s best to follow the same rules for cooking with both rice bran and sesame oils, although sesame oil has a higher antioxidant profile for added protection. I always add a bit of a saturated fat to any monounsaturated fat I use for cooking a light stir-fry or low-simmer dish to protect the polyunsaturated content that particular fat may have.
For comparison, let’s take a look at the fatty acid profiles of other commonly used monounsaturated oils: avocado, macadamia nut, and olive oils.
|10% polyunsaturated||10% polyunsaturated||12% polyunsaturated|
|70% monounsaturated||78% monounsaturated||75% monounsaturated|
|20% saturated||12% saturated||13% saturated|
|(485º smoke point)||(490º smoke point)|
As you can clearly see, avocado and macadamia nut oils have a very similar profile with a substantial mono-unsaturated fatty acid content and a fairly low poly-unsaturated fatty acid content (especially macadamia oil), along with a fair amount of saturated fatty acid content to help protect the more delicate poly and mono fats when exposed to heat. Olive oil has the highest poly-unsaturated fatty acid content of this group, so it may be wise to store it in the refrigerator then allow it to melt at room temperature for pouring over foods after cooking, or to use with a very low heat setting for a short period of time. Peanut oil is another type of monounsaturated dominant oil, but it also has 34% poly fats in its profile, so very limited use, especially where heat exposure is involved, is advised.
Corn, safflower, sunflower, flax (linseed), walnut, hazelnut, hemp, pine nut, pumpkin, and wheat germ oils should only be used raw and in small amounts. Never cook with these nut and seed oils as they are polyusaturated dominant. They are delicate and easily damaged by heat, light, oxygen, and moisture, so refrigeration in a tightly sealed, opaque bottle is a must. Look for cold-pressed, unrefined versions only.
Additionally, accessory oils such as cod liver, fish liver, borage, black currant oil, and evening primrose should NEVER be used for cooking. These therapeutic fatty acids are mostly found in nutritional supplements, but there are some free-flowing versions now available. If you plan on using a free-flowing version, keep it cold at all times, stored in an opaque bottle, and take it as a supplement – right off the spoon – as directed by your health care practitioner.
Cottonseed oil, canola oil, and any hydrogenated oils should always be avoided. These fats are anti-nutritive, denatured, highly processed, pesticide and solvent laden, rancid, and refined. Of course, we all now know about the dangers of trans fats so avoid all fats that have hydrogenation listed on the label. NO AMOUNT OF TRANS FATS is safe to consume.
For more on cooking with vegetable oils, check out these articles:
The Complete Guide to Fats and Oils – What to Cook With (or not), What to Avoid and Why
5 cooking oils you think are healthy, but aren’t
Why vegetable oil is NOT healthy
The real dangers of vegetable oils
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