PREDIMED, The Oft-Cited Mediterranean Diet Study, Shows No Benefit For Heart Attack

In the Mediterranean diet that gets promoted today, people are advised to consume lots of olive oil and nuts. Here’s an excerpt from a table in the big Mediterranean diet study that often gets cited to defend this way of eating. The study is nicknamed PREDIMED,

Original study:
Primary Prevention of Cardiovascular Disease with a Mediterranean Diet, New England Journal Of Medicine, April 2013


There were 3 groups, about 2500 people in each group. One group (Mediterranean Diet with EVOO) was to consume a liter of extra-virgin olive oil a week, another group (Mediterranean Diet with Nuts) was to eat 30 grams of nuts a day, the last group was a control. The study ran for about 4.8 years.

When I look at the last two columns of numbers (starting with 0.31 and 0.25) I see that neither of the interventions (olive oil or nuts) reached a level of significance compared to control … for any of those three conditions: myocardial infarction or heart attack, death from cardiovascular causes, death from any cause. Any differences fall into the realm of chance. So, for instance, people eating olive oil or nuts had fewer heart attacks than the control group (37 and 31 vs. 38)? Or had more deaths from any cause than the control group (118 and 116 vs. 114)? No, that was all by chance. The P values would have to be below 0.05 for significance, preferably below 0.01.

There were also 179 people assigned to eat the Mediterranean diet (96 in oil group, 83 in nut group) who experienced a “major cardiovascular event” during the study. According to the authors, all 179 had “no cardiovascular disease at enrollment.”

It doesn’t appear, at least from this study, that eating a lot of olive oil or nuts will prevent a heart attack.

I often say this …
Imagine having no cardiovascular disease, being put on a special diet designed specifically to prevent heart attack, and experiencing a “major cardiovascular event” less than 4.8 years later? In contrast, Dr. Esselstyn took people with advanced coronary artery disease, put them on a low-fat, plant-based diet, and 12 years later they had no more cardiac events! Why isn’t a low-fat, plant-based diet the preferred diet? It won’t make Big Food any money.

4 thoughts on “PREDIMED, The Oft-Cited Mediterranean Diet Study, Shows No Benefit For Heart Attack

    1. Bix Post author

      Yes, it was the NEJM. But biased research seems to be everywhere. I think industry sees getting published in a journal just another form of advertising. It’s insidious!


  1. Eddie

    It’s all but impossible to know what heart/medical information is good or bad or relevant. So many “studies” contradict each other or are written in a bias way. I read a study that said statins are only 0.1% effective in men 70 older. I’ve read other studies that say they are 5% to 25% effective in preventing a heart attack. Some studies claim high blood pressure recommendations are too high and that millions of people do not really have high blood pressure at all because the CDC keeps moving the goalpost and lowering the recommend levels. I don’t know what the hell to believe.



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