Cooking with olive oil is a controversial subject with some people saying it is fine and others insisting it damages the oil. The truth falls somewhere in between, so if you prefer olive oil in your recipes, use the suggestions below as precautions to preserve nutrients.
Olives are one of the oldest foods known to man and are thought to have originated in Crete or Syria some 6000 years ago. The golden color of the rich oil pressed from tree-ripened olives has been consumed by healthy traditional cultures since as early as 3000 BC.
Olive oil especially the first Fall harvest known as Olio Nuovo is truly one of the crown jewels of fats!
Olive oil is primarily composed of oleic acid, which is monounsaturated fat. Monounsaturates are one of the three main categories of fats. The other two are saturated fats and polyunsaturated oils.
The three types of fats – do you know how to tell the difference?
Saturated fats like coconut oil and tallow, are extremely stable because they pack together tightly courtesy of very straight carbon bonds that are all occupied by hydrogen atoms. Saturated fats are solid or semisolid at room temperature and make ideal cooking fats because of the inherent stability provided by their chemical structure which means that they do not easily go rancid when heated during cooking or form the free radicals that contribute to heart disease and cancer.
Polyunsaturated fats do not pack together as tightly as saturated fats and hence are liquid at room temperature and remain so even if refrigerated. The chemical structure of polyunsaturated oils is such that there are unpaired electrons for every carbon-carbon double bond which are highly reactive if heated or processed in any way. Even simple exposure to the air or light can cause rancidity in fairly short periods of time. Grapeseed oil is a fat that is extremely high in polyunsaturates.
Monounsaturated fats like olive, canola and avocado oil are liquid at room temperature yet become semi-solid if refrigerated. Sesame oil has very similar levels of mono to polyunsaturated fat.
The single carbon-carbon double bonds which make up the chemical structure of monounsaturated fats do not pack together as tightly as saturated fats but are more tightly bound than those of polyunsaturated oils.
Monounsaturated fats do not go rancid as easily as polyunsaturated oils but are more delicate than saturated fats due to a slight molecular bend which is not as straight in shape as the carbon bonds in a fully saturated molecule.
Now that we understand the basic structure of the 3 types of fats, it is easy to identify the type of fat that primarily composes an oil as this can be ascertained by simply observing its form at either room temperature or when refrigerated.
If a natural fat is solid or semisolid at room temperature, then it is primarily saturated. If it is fully liquid at room temperature but goes solid in the refrigerator, it is primarily monounsaturated, and if it is liquid when either refrigerated or at room temperature, it is mostly polyunsaturated.
With proper identification of the kinds of fats now complete, let’s turn our attention to the proper cooking oils.
Cooking with what fats – when?
It is clear that fats that are primarily saturated like tallow, coconut or palm oils are wonderful for cooking as the heat from cooking does not easily damage them or form free radicals.
On the other hand, polyunsaturated oils like sunflower, corn, grapeseed, soy or safflower should be strictly avoided for cooking as they are too easily damaged as those free electrons react too easily with heat or oxygen.
But what about monounsaturated fats, in particular, olive oil? This is where the issue gets a bit murky.
It is absolutely true that cooking with olive oil will not form trans fats. Even higher heat cooking with olive oil will not cause much free-radical creation although I would venture to say that there are certainly some free radicals formed when high heat cooking with monounsaturates due to the slightly less stable structure as compared with saturated fats.
I personally choose to avoid cooking with olive oil, especially extra virgin olive oil (EVOO). For one thing, good quality EVOO is quite expensive and should be properly packaged in dark-colored glass to protect the delicate nutrients. Studies have shown that light quickly degrades the quality of extra virgin olive oil. Research published in New Scientist magazine showed only two months’ exposure to light caused free radical increases in extra virgin olive oil to such a level that it could no longer be classified as extra virgin!
With light so easily damaging to extra virgin olive oil, it seems obvious that heat and cooking would damage it as well and studies bear this out. Heat as low as 350F (180C) can significantly damage the beneficial phenols in olive oil. Phenolic substances are highly anti-inflammatory in nature and likely an important reason why studies of the Mediterranean Diet which is high in olive oil have indicated a decrease in heart disease risk.
As a result, it seems prudent that even though cooking with olive oil does not produce any transfats or much free radical damage, it does reduce much of the beneficial aspect of consuming this healthy traditional oil in the first place.
Light saute cooking with olive oil at temperatures no higher than 200-250F seem to be safe and minimally damaging, but oven baking or higher heat cooking on the stovetop with olive oil is not wise given that there are much hardier and less expensive fats to choose from like expeller-pressed coconut oil or palm oil!
By far, the best use of good quality, nutrient-loaded extra virgin olive oil is as a salad dressing. Combining one part vinegar or lemon juice with between 3-5 parts oil along with a drizzle of walnut oil and flavoring herbs of choice will provide a truly healthy topping for any salad or vegetable mix.
A Word of Caution for Olive Oil Lovers
While numerous studies have shown the beneficial effect of olive oil in the diet likely due to the anti-inflammatory nature of the phenols, it is advisable to go easy on this traditional fat if weight loss is your goal.
In 1994, the journal The Lancet published a study which noted that fat tissue is primarily composed of monounsaturated fat. Could this be a contributing reason for middle-age weight gain that is so common in Mediterranean countries (Eat Fat Lose Fat, p.70)?
The chemical structure of monounsaturated oils could be part of the problem. Monounsaturates like those found in olive oil are composed of longer chain fatty acids unlike the short and medium-chain fatty acids found in coconut oil, palm oil, butter, and other animal fats. Short and medium-chain fatty acids are absorbed quickly and directly by the body for immediate energy whereas the longer chain fatty acids must be acted upon by bile salts to be digested. For this reason, longer chain fatty acids are more likely to contribute to weight gain.
Where to Find Quality Extra Virgin Olive Oil
It is important to realize that much of the conventional olive oil on the market isn’t even olive oil at all, according to Tim Mueller, an investigative journalist who has written a book on the subject called Extra Virginity: The Sublime and Scandalous World of Olive Oil. If you suspect your olive oil is fake, put it in the refrigerator to see if it properly solidifies. Another test is to see if your extra virgin olive oil can keep a wick burning. Refined oils masquerading as extra virgin olive oil cannot hold a flame.
Unfortunately, neither of these tests can completely guarantee authenticity. To be sure of the quality of your extra virgin olive oil, click here for a list of vetted sources that I trust and buy from myself coming directly from the olive oil farms themselves.
More Information
Extra Virgin Olive Oil Like You’ve Never Seen or Tasted Before
Traditional and Unusual Uses for Olive Oil
Liver and Gall Bladder Cleanse Using Olive Oil
Selecting a Healthy Cooking Oil and Reusing it Safely
The Truth About Pumpkin Seed Oil
Is Rice Bran Oil a Healthy Fat?
Caution When Using Chicken Fat for Cooking
How Vegetable Oils Make Us Fat
How Argan Oil Benefits Health
Red Palm Oil Benefits Rival Coconut Oil
Walnut Oil: Healthy Sub for Flax Oil
Picture Credit
Sarah, the Fats & Oils link on your Resources page doesn’t seem to work.
Very Informative! Thank you!
No, or only use low temp heat.
http://www.spain-in-iowa.com/2012/01/how-to-cook-with-extra-virgin-olive-oil-the-right-way-including-an-experimental-video/
The best Olive Oil I have found is sold by Chaffin Family Orchards, by internet. I have visited the farm and I am certain that this is 100 percent olive oil, organic, with the additional benefit of being grown on rich land that has never been sprayed with chemicals, which makes it truly nutrient dense.
Aside from this, I am not sure if other brands are adulterated with cheap omega 6 oils or not, except that I would trust every oil personally vetted by Sarah.
Thank you so much for the refrigerator test, Sarah, I am going to use it to test some suspect olive oil from Spain.
I’ll seccond Chaffin Family Orchards! I was buying organic “EVOO” from Costco and one solidified in the fridge and the other did not at all. I saw an article about this farm and decided to give it a try (about $60/gallon). I never knew olive oil could be so tasty. It almost had a tiny hint of citrus.. Ironically, I just moved accross the street from Queen Creek Olive Mill and just paid $72 for a gallon of their EVOO. It’s very good too. I’ve decided due to price and flavor it’s just better to enjoy it on salads and such anyways. That way I can rationalize the “special purchase” to my husband 🙂
I agree with Stanley, Chaffin Family Orchard’s olive oil is bar none, the best olive oil I have ever tasted, and I’m sure its quality is superior to most on the market. Whenever I can, I keep their olive oil in my cupboard. When I’m not using that, I often buy Napa Valley Naturals extra virgin organic olive oil. I do cook with olive oil sometimes because it is perfect for steak and I also use it for making sauces such as my home-made enchilada sauce with chicken broth. But I don’t use high heat temperatures, and I do use it raw regularly in our home-made salad dressings and mayo.
Although I only use tallow, lard, ghee, coconut oil for cooking, I just heard about Rice Bran Oil. The claim is that it can take higher heat that olive oil thus avoiding the dangers. I would love to know your take on this oil. I got some mostly for my mayo as I don’t care for the taste of all olive oil and really don’t like to use the safflower that much. I am thinking that I have a healthier oil for my mayo than Safflower and would love to hear what you say. 🙂
Thanks for yet another great article.
I make mayo with half olive oil and half coconut oil. I sometimes add lemon juice and grated lemon rind, or a roasted red pepper. I like the fact that it refrigerates to a more solid state than commercial mayo. And you can’t find ANY on the shelves without soybean oil ;-(
I’ll seccond that too! The olive/ coconut oil combo works for my picky family 🙂
i would not go near a “bran” oil – the bran part of a grain seed is where a host of nutrients are located…. all locked up with anti-nutrients, phytic acid etc for the benefit of the seed when it sprouts. One of the biggest mistakes made in plant-nutrient sourcing is assuming that the good vitamins and minerals present in seeds and seed oils are available to us via digestion – they are not. This is why sprouting, soaking and fermenting are necessary before consuming ANYTHING from seeds – the seed itself or the oil pressed from them.
Easiest is to simply avoid any oil pressed from the seeds of a plant, olive oil and coconut oil are pressed from the flesh in/around the “seed” – the soft tissues meant to fertilize the environment that the seed finds itself in when it drops to the ground.
I stopped buying palm oil when I learned that it comes from places where the native populations are killing oranutans in order to clear more land and plant more palm oil trees. There are other good fats, like coconut and butter (as I’ve learned here) but there are only a limited supply of these magical creatures.
Adipose tissue is composed of mostly monounsaturated fats, especially oleic acid because they are structural/functional fats. Funnily, or not, oelic acid is the major fat in our myelin sheath.
More than likely the middle age, spread associated with modern Mediterraneans, is likely due to insulin resistance of their adipose cells; related to their love of refined carbs.
Please read, “The Art and Science of Low Carbohydrate Living”, by Volek and Phinney.
Adipose tissue is composed of mostly monounsaturated fats, especially oleic acid, because they are structural/functional fats. Funnily, or not, oelic acid is the major fat of our myelin sheath.
More than likely, the middle age spread associated with modern Mediterraneans, is due to insulin resistance of adipose cells; related to their love of refined carbs.
Please read, “The Art and Science of Low Carbohydrate Living”, by Volek and Phinney.