Is Extra-Virgin Olive Oil Healthy? New Data on the Great Debate
After 44 years on a plant only (vegan) diet, I have lectured, written, and taught countless individuals on the health advantages of a diet from the produce department, farmer’s market, and garden. In my preventive cardiology clinic, I get to listen to and counsel thousands of patients, many on a plant diet, from around the world. Routinely, if it is not the first question asked, it is in the top three: the query ”what about oil,” especially oils thought to be healthy, like olive oil?
So, is extra virgin olive oil healthy or not?
A few years back I wrote a piece supporting the data that a low or no oil plant diet is optimal. Without question, all of the studies focused on reversing disease states as published by Drs. Ornish, Esseltsyn, McDougall, Barnard, and others, have advised avoiding added oils. A new and large study requires discussion and consideration if an oil-free diet is the best recommendation for most on a vegan diet. First, let’s look at two studies supporting the no-oil diet.
In 2000, cardiologist and friend Robert Vogel, MD published a study of 10 healthy subjects studied on several different diets. The end-point was a measurement of artery function called flow-mediated dilation or FMD. It is not good for FMD to drop. The study found FMD dropped significantly with a combination of olive oil and bread. However, when they studied a combination of canola oil and bread, a combination of salmon and cracker, a combination of olive oil with bread and vitamins C and E, and finally, a combination of olive oil, bread, salad, and vinegar, FMD did not demonstrate a significant drop. Olive oil, in this study extra-virgin olive oil or EVOO, appears to affect arteries based on the company it keeps.
Then, in 2007, ten healthy subjects were studied in terms of their response measured by FMD to three soups with either olive oil, soybean oil, or palm oil. All of the soups enriched with oils produced a decline in FMD.
Can you confidently recommend no oil diets to the bulk of people adhering to a plant-based diet on the basis of two studies with a total of 20 patients?
Maybe not.
But a new study with 805 patients has just been published and is worthy of attention. The research was done in Cordoba and Madrid, Spain, as part of a larger study called CORDIOPREV. Two healthy diet patterns were evaluated in a randomized manner: a “low-fat” diet versus a Mediterranean diet enhanced with EVOO. Of the 805 subjects who all had prior evidence of heart disease, half were advised to enhance their diet with around four tablespoons of EVOO daily along with vegetables, fruit, legumes, fish, and nuts and seeds. The other half were advised to minimize oil in cooking, not to eat red meat often, to choose low-fat dairy, to avoid oily fish, to avoid nuts and seeds, and to avoid commercial baked goods. All of the subjects underwent unbelievably sophisticated measurements of endothelial (arterial) function at baseline and again at a year follow-up.
At one year, the subjects on the EVOO enriched diet had a higher HDL (healthy) cholesterol, a lower fasting glucose, and a lower inflammatory marker hs-CRP. There was a more favorable FMD measure of artery function in the EVOO group and the also had other markers (endothelial progenitor cells) that indicated better artery function. Elegant analyses of the production of proteins (proteomics) indicated the EVOO-enhanced diet resulted in the suppression of proteins related to inflammation.
The authors concluded that the Mediterranean diet enhanced with EVOO led to better endothelial function, enhanced endothelial repair, and reduced artery damage. They felt the EVOO enhanced diet was the best dietary strategy to recover endothelial function in patients with heart disease.
Photo by Lisa Fotios from Pexels
What are we to do?
On the one hand, this study is the largest and most elegant evaluation of a higher fat diet with EVOO on artery function, and the results are impressive. The fact that they were done in patients with heart disease is important and would suggest the findings would be the same or even better in those without known heart disease. The only drawbacks are the study was funded by a foundation of EVOO producers as the project was undoubtedly quite expensive. The other drawback is that they did not look at heart attacks and other events but the full CORDIOPREV study of 1,002 subjects is evaluation that and there will be future publications.
But, overall, the great fear that EVOO of high quality is dangerous to arteries must be reevaluated in light of this large study. On a personal note, I use EVOO regularly and advise it as okay for the majority of my heart patients.
Joel Kahn, MD, FACC of Detroit, Michigan, is a practicing cardiologist, and a Clinical Professor of Medicine at Wayne State University School of Medicine. He graduated Summa Cum Laude from the University of Michigan Medical School. Known as “America’s Healthy Heart Doc”, Dr. Kahn has triple board certification in Internal Medicine, Cardiovascular Medicine, and Interventional Cardiology. He owns GreenSpace & Go, a health restaurant in suburban Detroit. Dr. Kahn can be found at www.drjoelkahn.com.
- Is Extra-Virgin Olive Oil Healthy? New Data on the Great Debate - September 24, 2020
Comments (4)
Why would they compare apples to oranges?!?
Had this study kept the first group as described (Mediterranean diet with EVOO) and the second group the same Mediterranean but *without* any EVOO, then the results would have been more meaningful and conclusive! Once you introduce meat and dairy into the second group, I have no confidence in the states results and conclusions.
…I’m sure Drs. Ornish, Esselstyn, and Barnard would agree.
Oh, and the fact that the study was funded by the EVOO industry In Spain speaks volumes!!!
PS: I was born in south Italy and grew up on the Mediterranean diet (including ‘healthy’ doses of olive oil). I had a heart attack 18 months ago and have since flipped the switch to Whole-Food Plant-Based Nutrition without any nuts or oils (as per the Esselstyn gospel). I lost 30 lbs (down from 195 to 165) and feel great!!!
The comment about the quality of the EVOO is absolutely true. I would also add that there are many more nutritious whole plant foods that could be substituted for something that is basically 100%fat. You have a decision to make: oil, or nuts, seeds, avocados or olives to add healthful fat to your salads sandwiches and pastas. Also, there is still no data comparing an optimal low oil whole plant food diet, with a EVOO drenched vegan diet. You can have 300 kcals of oil or 300 kcals of Olives, avocado, nuts/seeds which contain fiber, and protein and carbs and phytonutrients and more antioxidants! Why avoid fiber ever? I admire Dr. Kahn, but I’d choose fiber rich food over plain oil any day.
Excellent article on this very controversial matter, thank you!
The problem with olive oil is that it is laureated to be a pure and healthy oil and maybe it is…BEFORE it reaches all those distributors in many countries where they mix it with cheaper oils and sell them as genuine. Even one I thought really genuine which is made in America: “California Ranch Olive Oil”, have come up with the same name but where they mixed it with oils from Argentina, Chile and I believe Dominican Republic though not sure. I went to their site to get it, but they changed it to: “Globally”. Hmmm, now they’re trying to hide the mixture.
Now I’m back on square one. I’ve been buying some “365 Italian Oil Unfiltered” sold at Whole Foods until I find another one made from only one country and this country is America. Of course I know they can also mix them fraudulently here but at least they may be caught more easily IF government interferes which would be a good thing for retail buyers.
If I may be bold, may I ask what olive oil you use? Thank you very much! 🙂
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