Olive Crazy: All About Olives and Olive Oil
Sep 202013

I just read an interesting provisional study by Hady Keita, Eduardo Ramírez-San Juan, Norma Paniagua-Castro, Leticia Garduño-Siciliano and Lucía Quevedo published in the DMS Journal (Diabetology & Metabolic Syndrome). The study is about rats that were fed high doses of extra virgin olive oil.

Yes, they gained a lot of weight. Yes, their insulin resistance increased. BUT their cholesterol levels were reduced and the interior walls of their vascular and lymph systems remained healthy. Here is a link to the entire study.

Below is the provisional abstract.

It has been hypothesized that fatty acids derived from a diet high in saturated fat may negatively affect endothelial function more significantly than a diet high in unsaturated fat; nevertheless, the effects of the long-term ingestion of monounsaturated fatty acids on endothelial function have been poorly studied.

To examine the chronic effects of monounsaturated (e.g., extra virgin olive oil (EVOO)) or saturated (e.g., margarine (M)) fatty acid-rich diets on the development of insulin resistance and endothelial dysfunction in rats, three groups of rats were fed control, high-EVOO or high-M diets for 20 weeks. Body weight, energy consumption, insulin resistance, lipid peroxidation and in vitro vascular reactivity with and without metformin were assessed during the study period.

Both high-fat diets produced obesity and insulin resistance. EVOO-fed rats showed smaller increases in total cholesterol and arterial lipid peroxidation when compared with M-fed rats. Vascular reactivity to phenylephrine and sodium nitroprusside was not modified, but the vasodilating effect of carbachol was especially reduced in the M-fed rats compared with the EVOO-fed or control groups. Metformin addition to the incubation media decreased the vascular response to phenylephrine; decrease that was lower in rats fed with both high fat diets, and increased the carbachol and nitroprusside effects, but the metformin-enhanced response to carbachol was lower in the M group.

Our results suggest that feeding rats with high quantities of EVOO, despite producing obesity and insulin resistance, produces low levels of circulating cholesterol and arterial lipoperoxidation compared to M fed rats and shows a preserved endothelial response to carbachol, effect that is significantly enhanced by metformin only in rats fed with control and EVOO diets.”

Interesting. Right?

May the sun shine through your branches.


  4 Responses to “EVOO Study on Rats”

Comments (4)
  1. Hello Richard,

    Any note or indication on the chemical composition of the “EVOO” used in the control group? As you are well aware, the vast differences encompassed inside the overly broad category known as EVOO are significant.

    Hope you are well.


  2. Hello Richard,
    Any indication of the chemical composition of the “EVOO” used in the control group? Some studies pay little or no attention to the chemical composition of the EVOO when they do these experiments. Obviously, given the wide range of olive oils that legally qualify as “EVOO” one would hope that this is given some consideration. I sent an earlier comment but am not sure if it was sent.

    Hope all is well with you.


    • Hello Michael,

      Richard forwarded my tweet which is why I think you were led to post here. This is Mary Squires, but to answer your question, I too wondered the same and would like to know. I read the entire study and there was no identification of the brand of extra virgin or any indication that the olive oil was checked to make sure it was indeed extra virgin.

      Try Richard on Twitter.


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