Is olive oil the reason why the Mediterranean diet is so healthy?

When researchers studied the Mediterranean diet, they assumed olive oil played a key role in its health benefits.

However, contrary to the hypothesis, they discovered that olive oil actually impairs artery function after eating! (1)

Saturated fats (even from olive oil) stiffen the walls of arteries and make them less responsive to nitric oxide, which dilates the vessels and increases blood flow to organs. (2)

No difference was found in the acute adverse effect of the ingestion of different vegetable oils on the endothelial function. All the vegetable oils (including EVOO), fresh and deep-fried, produced an increase in the triglyceride plasma levels in healthy subjects. (3)

Are vegetable oils better alternatives to butter and other animal fats?

Vegetable oils have a slightly lower effect on raising LDL cholesterol than butter and animal fats; that’s why they are promoted as *better* (clever marketing), but they still raise LDL cholesterol. (4)

And since impaired artery function and high LDL cholesterol are the biggest risk factors for heart disease—the #1 cause of death—it makes sense not to contribute to it.

So why is the Mediterranean diet so healthy?

Dietary fruits, vegetables, and their products appear to provide some protection against the direct impairment in endothelial function produced by high-fat foods, including olive oil.

It appears the Mediterranean diet is healthy *despite* the olive oil, probably because of the high fruit and vegetable content.

Sources

(1) Journal of the American College of Cardiology Volume 36, Issue 5, 1 November 2000, Pages 1455-146: The postprandial effect of components of the Mediterranean diet on endothelial function; Robert A Vogel MD, FACC, Mary C Corretti MD, FACC, Gary D Plotnick MD, FACC.

(2) Dr. Klaper – Olive Oil Is Not Healthy (YouTube video explaining the study)

(3) Olive, soybean, and palm oil intake have a similar acute detrimental effect over the endothelial function in healthy young subjects
Rueda-Clausen, Christian F. et al. Nutrition, Metabolism and Cardiovascular Diseases, Volume 17, Issue 1, 50 – 57

(4) Human Nutrition and Metabolism Butter Differs from Olive Oil and Sunflower Oil in Its Effects on Postprandial Lipemia and Triacylglycerol-Rich Lipoproteins after Single Mixed Meals in Healthy Young Men1 Nadia Mekki,* Monique Charbonnier,* Patrick Borel,† Jeannie Leonardi,* Christine Juhel,* Henri Portugal** and Denis Lairon*2