Olive Oil Science


By Diane Gold

Olive Oil ScienceOlive oil science is much more elusive than discussions about how great olive oil is. There is lots of vague discussion about how it is bad for us when it smokes. Much like treated wood when it burns, the olive oil spits out toxins which produce free radicals, nasty suckers that cruise the body for a place to move in and couple. My goal in writing his article was to find the science behind all the generic verbiage about what happens to olive oil at smoke point.


We learned from someone’s grandma that sauteing garlic in olive oil is great for us to activate flavor and activate enzymes. True enough. But, there may be concern about the heat required to do this. And the browning of the garlic may not tell us we have smoked the oil. And what about lovely olive oil when baking vegetables in an oven higher than 350 degrees Fahrenheit?


Free radicals cause chronic disease, decay, damage, cancer as they change our DNA. So we have a duty to know about the cooking/heating process and what can happen to us, our friends, our wards, our customers and our families when we heat food. We have to be thoughtful to bake veggies at no more than 350 degrees and consider using other oil for stir fry veggies, grilling veggies, sauteing and roasting over the maximum temperature which is around 375 degrees Fahrenheit.


Olive Oil - Verifiable, Scientific ReferenceDuring my olive oil science search, I read about many TV chefs who use extra virgin olive oil for sauteing, roasting and grilling and lots of consumer opins about how, if the TV chef says it, it must be right.

This led to my personal search for whether or not I should I have soaked flax seeds, ground them, grind after soaking for flax milk. I came across this quote about verifiable, scientific reference,

“Nutrition mavens tend to recommend […]but never give any valid, verifiable, scientific reference(s) for their preference. If I can’t find independent research that supports their claims, why should I trust them?

“If you can enlighten me – especially if you can give me references to solid articles in peer-reviewed journals that I can access on the web – I’d love to hear from you (subfuscpersona, a member of the fresh loaf blog put out by the Federated Media Publishing Food channel).”

And there it is!


I found a 2007 online entry where someone from a university answered a query about olive oil smoke point. I would have much preferred it if, as business director of his university’s nutrition division, he had acknowledged that he is knowledgeable by training even though he raises money now since guessing is rampant.

Mary Flynn, PH.D., RD, Associate Professor, Clinical Medicine, Browns U., says that high quality extra virgin olive oil can be heated to 420 degrees F before it reaches its smoke point. If this is true, roasting at 400 degrees would be safe.

Canadian Center For Science & Education, article 21763-14350 says olive oil is

“resistant to oxidation because of its low content of polyunsaturated fatty acids and the presence of natural antioxidants.” That gives a piece to the puzzle.

Mark Sisson, a pop blogger with a BS in Biology, says that oil, when it’s overheated, literally deteriorates chemically. The rate of the breakdown (and total formation of toxic compounds) is dependent on the type of oil and temperature. To this, I say that so many unsubstantiated, vague comments are out there. (Please keep reading for the reference Mark has brought us.)


Olive Oil - Oxidation Process Causes Free RadicalsHappily for all of us, Mark goes on to cite an article that explains what is produced and what is toxic about it, for which I thank him. It is from Science Daily’s June 17, 2005 article, sourced from Elhuyar Fundazioa (translated to Language Foundation), from U of the Basque Country Pharmacy Faculty.
Their studies explain that decomposition results in creation of hydroperoxides and, eventually, increasing levels of aldehydes. These structures are marked as toxic compounds because they have oxidized.

The article talks about how the oxidation process causes free radicals, incomplete anatomical structures, which don’t just hunt for chemical balance through theft. That would be bad, but they do more. They cause a chain reaction of “stealing” from previously healthy structures, altering DNA, causing chronic conditions (http://www.sciencedaily.com/releases/2005/06/050617065306.htm).

Possibly the simplest explanation I saw was one by Henrik Hallberg Jensen, Master of Science at an oil filtration company, C.C. Jensen, in Denmark. I caution that he is talking about the oxidation of crude oil, but the process seems to be the same,

“Oxygen is reacting with the free radicals of the hydro-carbons, which, in turn, form hydro-peroxides. Hydro-peroxides are unstable and [are] soon broken down into ketones and water The ketones oxidize further, forming aldehydes or organic carboxylic acids.”

Jensen goes on to say that the acid causes corrosion, the sludge increases the viscosity and blocks valves as well as other system components. Can we compare his mention of blocked valves to clotting in our arteries caused by oxidation?


A study published in the Proceeds of the National Academy of Sciences, Dec. 28, 2004, shows that Vitamin C can create a conjugate substance that will bind to the toxins mentioned in olive oil breakdown and render them benign. This process is, at least, one of the reasons Vitamin C is a great antioxidant.


The search for olive oil science has been educational and, I hope, ends up being informative. From vagaries to credentialed discussions; it has been a fun journey.

Although I do not have the credentials of the following commenter, she refers to credibility in commenting, and offers an unverified opinion,

Olive Oil - Safe Temperature For Cooking“You cannot test oil for its smoking point on your stove. The so-called ‘smoking point’ is actually the point at which the molecules of your oil start falling apart. This happens long before there is any visible smoke above the pan. At the point where you can see the smoke, it is already too late.” (rumtscho at stackexchange.com)

So the conclusion to this article does not conclude olive oil – safe temperature for cooking. It does, happily, describe what happens to olive oil at breakdown. I would love to believe that I can continue to saute garlic for one minute and roast veggies at 400 degrees. But the jury is still out.


I just finished a chapter by Caldwell Esselstyn, MD, who recommends we remove oil from our diet because it interferes with the endothelial cells’ production of nitric oxide without which our blood vessels do not stay dilated and with which our cells get sticky and blood more easily clots. I am considering this science.


1) If you know a dietician, nutritionist, chef, natural doctor; ask about extra virgin olive oil and its smoke point. More than one answer may surface, but it’s always good to do the work.

2) Write back to us and tell us what you find about olive oil science.

3) Look for olive oil that is organic, with a recent harvest date that is cold pressed (that signifies no chemicals used during extraction, done by mechanical means while controlling the temperature.

4) Keep your Vitamin C levels up.

5) Follow a raw vegan diet for a day or a week. Obviously, when no heat is applied to food, the original nutrients and phytonutrients remain. Pick a favorite vegetable and search a free raw vegan recipe including it.

Article inspired by a discussion I had with my friend, Chef Collin Cook.

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Diane Gold, Founder of Warriors of Weight, Turning Habits Into Health, is a mentor in tai chi, kung fu and meditation, a music, fitness and stress expert, dedicated mom, studying plant-based nutrition in certificate course, peaceful conflict resolution and habit replacement.

She is fascinated by our habits with food and is happy to correct mistakes she and others have passed on due to misinformation. She says,

“I’m still not certain about the smoke point of extra virgin olive oil, cold pressed and organic. What I do know is that there is enough information telling me that heating it past a certain point is definitely unhealthy. With this ammunition in hand, I will make better choices when using it.

“Researching this article was fabulous. It took a lot of opinion reading before I actually got to some science for my sake and the health of others.

“Let us all take good care of ourselves, with this information, because we are so worth it!”Border 728c00

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