Monday, October 12, 2009

Which Oils and Fats Are Best for Cooking?

Avocado oil has the highest smoking point.
Avocado oil has the highest smoking point. (Photo by Muffet)

If you've wondered which oils and fats are the best choices for cooking your meals, this post is for you.

The first question we need to ask is what makes an oil good or bad for cooking? Putting the cholesterol issue aside for a moment, we can say that perhaps the most important thing is how well the oil tolerates heat. We are using it for cooking, after all.

Two factors that affect heat tolerance are smoking point and oxidation. Smoking point is, as you might have guessed, the temperature at which the oil begins to smoke. It's also the point the oil starts to break down chemically. This is something you generally want to avoid, so it's usually recommended that you don't heat the oil to its smoking point. This, of course, rules out using oils with a low smoking point for cooking at high temperatures.

The second factor, oxidation, is related to smoking point in the sense that both are affected by temperature. However, oxidation also happens at lower temperatures than are needed for the oil to start smoking. Oxidation is problematic because the lipid peroxidation end-products (ALEs) it creates can wreak havoc inside the body. These products have been shown to accumulate with aging and cause problems such as liver spots on the skin.

So which oils are most susceptible to oxidation? If you've read this blog before then you already know the answer: polyunsaturated fats. In fact, polyunsaturated fatty acids (or PUFAs) tolerate heat very poorly. Not only do they oxidize when you heat them on a frying pan, they do so inside the body as well. On the other hand, monounsaturated fats are much more resistant to oxidation than polyunsaturated fats. Saturated fats are the most resistant.

This gives us a good rule of thumb when looking for fats to use in cooking: avoid oils high in polyunsaturated fatty acids. Because of their potential to undergo lipid peroxidation inside the body, I tend to restrict their consumption altogether, but even if you are a fan of vegetable oils and omega-3, using them for cooking is not a very good idea.


Fatty acid composition of cooking oils
The table above shows the relative percentages of saturated (SA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA) in various cooking oils and fats (data from US and Finnish food databases). They are in a decreasing order of PUFA content, meaning that the oils moist suitable for cooking are on the left and the least suitable oils are on the right.

As you can see, coconut oil has the highest SA content and the lowest PUFA content of all oils, making it very resistant to oxidation. Ghee and butter also have very little PUFA and lots of saturated fat. Based on this, butter is actually one of the best choices for cooking, although the high AGE content of butter and its tendency to brown quickly suggest to me that perhaps ghee is a better option. The reason might be that butter also contains some protein and a small amount of carbohydrate.

Palm oil and lard are somewhat lower in saturated fat than the first three, but since their MUFA content is quite high, they still make good choices for cooking. The rest to the right of these five are less than optimal. Corn oil, sesame oil, rapeseed oil, peanut oil, and canola oil are all high in polyunsaturates, making them prone to lipid peroxidation. And unless you buy them cold-pressed, they will have been heated during refining anyway, so some oxidation has probably happened before you even use them.

What about olive oil then? Even though everyone seems to love olive oil in general, there's something of a debate going on over whether it should be used for cooking purposes. My opinion is that, like the graph suggests, it's not the worst choice but it's not the best either. The smoking point of extra virgin olive oil seems to vary from 160 to 190 °C, depending on the free fatty acid content. Virgin olive oil, however, has some properties that make it more heat-tolerant than most other oils (link).

In general, the less refined the oil, the lower the smoke point. Unrefined oils high in PUFAs have the lowest smoking points (link), but high saturated fatty acid content does not necessarily guarantee a high smoking point. Coconut oil, for example, has a fairly low smoking point (177 °C, about the same as butter and lard) compared to peanut oil (227 °C). Refined avocado oil, which is mostly monounsaturated fat, appears to have one of the highest smoking points at 255-270 °C (link). Ghee is another oil with a very high smoking point (252 °C).

So which oils should you use for cooking? For sautéing and cooking at light to medium temperatures, my choice would be the ones on the left of the graph: coconut oil, ghee, butter, palm oil, and lard. If you stay below 170 °C, you're in pretty safe waters in terms of oxidation regardless of which one of them you choose. Virgin olive oil seems like a viable choice, too; just make sure the particular olive oil you're using it doesn't start smoking.

For searing, browning and other methods of cooking requiring higher temperatures, ghee and avocado oil seem like the best choices. When it comes to resistance to oxidation, ghee might take the cake, but avocado oil appears to have the highest smoking point of all oils, even though it does have 13.5% PUFAs. Still, keep in mind that when cooking at very high temperatures, some advanced glycation end-products (AGEs) are bound to be generated.

For more information on fats and health, see these posts:

Coconut Lowers LDL, VLDL and Triglycerides, Raises HDL
My Current Health Regimen
Blood Test Analysis: The Cholesterol and Saturated Fat Issue Revisited
Should Saturated Fat Be Avoided in Low-Carb Diets?



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17 kommenttia:

Kismet October 13, 2009 at 5:24 PM  

No comment about sat. fat? Your paleo bias is showing :P

I think you should do a post on sat. fat if you haven't in the past (I know others have).

I love your recent articles, though.

JLL October 13, 2009 at 8:46 PM  

@Kismet,

What kind of comment are you looking for specifically -- that saturated fats increase cholesterol? I discussed this a while ago, and linked to that post in the beginning of this one. If that's what you're referring to, based on what I've read, I don't see high cholesterol levels as a bad thing (as long as HDL/LDL ratio is good), and not all saturated fat increases cholesterol. I've actually done several posts on saturated fats, but the cholesterol issue has been sort of done to death in other blogs (wholehealthsource and hyperlipid come to mind), probably in more depth than I could do.

I try to be un-biased, but as I've openly stated before, I do eat a diet that is mainly paleolithic. I don't hide it. That said, I very much disapprove of the naturalistic fallacy, and am willing to change my diet into any direction that suggests longevity benefits (except for CR, which at least for the moment has too many disadvantages for my taste).

Whether or not high-fat or high-carb is the way to is subject to debate, but if one does follow a high-fat like I do, then saturated fats seem like a much healthier choice than polyunsaturated fats. I guess you could argue that MUFAs > SAs > PUFAs, but what is the evidence for such a claim?

Thanks for the comment.

- JLL

Aaron October 14, 2009 at 12:44 AM  

MUFA >SFA> PUFA

i guess you could argue for ratios similar to what would be maintained in tissue-- with the exception that you want to keep polys low because an increase in dietary polys increases polys in tissues.

Kismet October 15, 2009 at 3:10 PM  

Oh, I almost thought you did post about sat. fat. I was just too lazy to check.
If one is to accept a linear relationship between LDL and cardiovascular or all-cause mortality, one could argue that MUFA > Sat.

Hmm, I need to review the sat. fat-cholesterol-mortality association for myself.

Anonymous October 23, 2009 at 11:54 PM  

I'm not sure where I stand on the SFA issue. Please post more on it. Love your blog and the way you tackle issues.

More food for thought:
http://www.skepdic.com/refuge/bunk28.html

rwac February 20, 2010 at 7:25 AM  

No mention of High Oleic Sunflower oil ? It has <10% of PUFA.

I need to get a more accurate value though.
The label claims
1g PUFA,
12g MUFA,
1g SFA
out of 14g in a serving.

JLL February 20, 2010 at 6:00 PM  

@rwac,

I didn't know sunflower oil came in a high oleic version. Not sure I've ever seen it on sale here, but it does look like it could be used for cooking. Thanks for the comment!

- JLL

Anonymous April 27, 2010 at 6:46 PM  

How about Macadamia nut oil?

It's mostly made up of MUFA's, contains less PUFA's than olive oil, has a better ratio of omega 3 to omega 6 than olive oil and has a very respectable smoke point of 210°C

http://en.wikipedia.org/wiki/Macadamia_oil

Linda Prout December 30, 2010 at 7:24 PM  

I have been ruminating on this question myself for quite a while. A point of confusion for me is if PUFA's are least desirable for cooking and break down easiest, (safflower being the most unsaturated, or close) why is safflower listed as having one of the highest smoke points of all lipids? This smoke point value is according to your link to cookingforengineers and also on wikipedia/cooking oils.

JLL December 31, 2010 at 10:36 AM  

@Linda Prout,

There are two kinds of safflower oil, one high in PUFAs and one high in MUFAs. Maybe the high smoke point is referring to the latter? Also, the smoke points don't always seem to go hand in hand with the saturation level of the oils. Refined oils have much higher smoke points (unrefined safflower oil has a very low smoke point). But I don't know which chemical changes are responsible for the dramatic change in safflower oil's smoke point during refining. Any chemists here that might know the answer?

- JLL

Florent Berthet February 7, 2012 at 8:47 PM  

What do you think about Chris Masterjohn's different take ont butter's AGEs' content?
Here's the article: http://blog.cholesterol-and-health.com/2010/10/is-butter-high-in-ages.html?showComment=1328637072957#c2476885799859857150

JLL March 10, 2012 at 6:09 PM  

@Florent Berthet,

I think he's right on the money.

- JLL

Anonymous April 13, 2012 at 4:06 AM  

Would love to hear your thoughts on macadamia nut oil!

JLL April 13, 2012 at 11:47 AM  

@Anonymous,

85% MUFAs, high smoke point - seems pretty okay to me. I'd probably use it myself in some cooking if it wasn't so damn expensive here. If you can get it for a reasonable price, I'd say go for it.

- JLL

Sandalsay April 10, 2013 at 6:25 PM  

I happen to be one of those people who believe in moderation of all things, i.e.. SFA, carbs, sugar, etc. I use both butter and olive oil in my cooking, although the whole high heat/smoking point issue is new to me. It makes some sense but I haven't read the literature myself. However, I am a nurse practitioner and have to comment about your statement about cholesterol ratio and SFA. Keep in mind that SFA still have implications in heart disease and the key is to limit all fat, overall, in your diet (not eliminate them, however). The body does need some fat and, people who are trying to diet/lose weight, actually lose more weight when consuming some unsaturated fat in their diet (in addition to the saturated fats that they get in their foods). However, your statement about cholesterol is only true to a point. Ration of HDL/LDL is definitely a consideration, but if your total cholesterol is too high, the ratio becomes less important. There are also many other components to your lipid profile that play a role in overall health, triglycerides being one of these (which are also increased with alcohol consumption). So, total cholesterol level still needs to be considered despite your ration of good to bad cholesterol.

I believe that body mass index is a better indicator of health, as well as whether you are exercising 4+ days/week regardless of what your BMI is. I do not believe in these low carb diets. Our bodies are designed to need carbohydrates. However, the refined and genetically modified ones are consumed in excess and are definitely a contributor to weight gain and obesity in our culture. Also, most people are consuming far too much protein than their bodies require. If you follow that old food pyramid we all learned about in elementary school, your probably doing a good job with your diet, being that you are limiting your saturated fats, limiting your refined/processed carbohydrate intake, and limiting your sugar intake. Keep in mind I am saying limit and not eliminate. Bottom line, if you are eating more calories than you burn off each day, you will gain weight, and any type of excess calories will eventually become stored fat in your body, even simple carbs. Obesity and over eating leads to high fluctuation of hormone levels, such as insulin, which reeks havoc on your system and leads to other problems like weight gain and Type II diabetes, among other things. Being obese puts you at higher risk of heart disease, diabetes, and even cancer. So, there is no simple formula to staying healthy. Again, one of the best diets to follow is that food pyramid from the ADA.

As a nurse practitioner, the only diet program I would recommend is Weight Watchers, which allows people to lose weight slowly and incorporates everything I mention here. Fad diets that allow you to lose more quickly, aren't healthy and will not teach you how to eat properly so you can keep the weight off. Portion control is VERY important and this is something that WW teaches my patients.

Another key to healthy living is consuming enough water. Almost every chemical reaction in our body requires H2O.

john del castillo May 4, 2013 at 10:43 PM  

Canola and raspeseed are both the same stuf, they contain erucid acid wich is DEADLY POISONOUS, DONT USE THEM, there are canola inductry money interest to not inform about to the consumers

john del castillo May 4, 2013 at 10:44 PM  

dont use Rapeseed oil neither Canola oil wich is the fake name of Rapeseed, Deadly Toxic for humans!!

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