The Buzz about the Mediterranean Diet and Cardiovascular Disease

You may have been hearing the recent buzz about a new study released this week in the New England Journal of Medicine touting the health benefits of the Mediterranean diet. So what are we supposed to make of it? Should we all start dousing our food in olive oil? Or start eating a handful of nuts a day? Well, maybe, but the study isn’t as clear-cut as all the articles have made it out to be. Don’t get me wrong, I am a huge proponent of eating a healthy diet, and that ‘healthy diet’ may even look a lot like the Mediterranean diet described in this study, but you have to take the study with a grain of salt. Here’s my take.

First, here are the nerdy researcher’s details on the trial.

The population studied:
  • 7447 adults (men aged 55-80 and women aged 60-80)
  • They had no known cardiovascular disease (CVD) but had to be at ‘high risk’ which meant that had to have diabetes or had to have 3 of the following CVD risk factors: smoking, hypertension, high LDL, low HDL, overweight or obesity, family history of early heart disease
The intervention:

There were 3 dietary intervention groups:

  • Mediterranean diet supplemented with extra-virgin olive oil 
  • Mediterranean diet supplemented with nuts (walnuts, hazelnuts, and almonds)
  • Control diet (supposed to be a low fat diet, but it ended up being a modern diet because no one really stuck to the low fat part)

The Mediterranean diet basically consisted of a diet with lots of vegetables, fruits, beans, fish, white meat and avoidance of typical bad stuff (processed foods, sugary beverages, red meat, desserts, cream, butter). The folks on the Mediterranean diet were also recommended to eat at least 2 meals sitting down. All good stuff.

There was no calorie goal – they could eat as much as they wanted. And no physical activity recommendations.

Here are the study’s take-home points, though some stretch the truth a bit.

1. Mediterranean diet is better than a low-fat diet

Not quite. The truth is that the people on Mediterranean diet did better than the people on the other diet, which as it turns out, wasn’t exactly a low-fat diet. It was a modern diet, the one we basically recommend against, with processed foods and sugary beverages and lots of carbohydrates and red meat. The statement would be better rephrased as “Mediterranean diet is better than a modern diet.” Which, as it happens, is still a good thing.

2. Mediterranean diet lowers the risk of heart disease

Not quite. In the study, the Mediterranean diet lowered the risk of  the main outcome (a combination of heart disease, stroke, and death from a cardiovascular cause) by a whopping 30%. This is a number comparable to the effect of statins, powerful cholesterol lowering drugs.  If you dive a bit deeper, it looks like the main benefit was in lowering the risk of stroke, as opposed to heart disease or cardiovascular death. There really wasn’t so much of a benefit to heart disease or to overall death. So a better statement might be “Mediterranean diet lowers risk of stroke.” Which, I suppose, is also still a good thing.

Here are my take-home points:

1. Eat a healthy diet like the Mediterranean diet. It’s better than the diet you are probably eating right now… Here’s what I recommend to my patients with and without heart disease as elements of a healthy diet:

  • Lots of fruits, vegetables, beans, and nuts
  • Stay away from processed foods which tend to be high in carbohydrates (translation: Eat REAL food, before anyone else has gotten their hands on it.)
  • Avoid or limit intake of refined carbs, potatoes, rice, bread, and sugary beverages. I mean, did you really need to drink the vente caramel mocha Frappuchino from Starbucks today?
  • Limit fat. No further explanation required.

2. Sit down and eat. It’s so easy to get bad food that’s transportable. It’s pretty hard to eat salad in your car. Sit down at a table, preferably with family or friends and enjoy your meal. The corollary: cook your own food.

3. Don’t forget all the other stuff important for heart health – exercise, don’t smoke, watch your blood pressure, cholesterol, and diabetes. When in doubt, talk to your doctor.

The study isn’t perfect but it’s the best diet and nutrition study we’ve seen in a long time. And one of the few to use ‘hard’ endpoints of heart disease, stroke, and death to assess the effect of diet.

Turns out, diet really does matter.  But you already knew that.  Now, change yours and get healthy.

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