Michael Greger M.D. FACLM February 25th, 2015 Volume 23
“The Mediterranean Diet is an “in” topic nowadays in both the medical literature and the lay media”: 450 papers published in the medical literature over just the last year alone–more than one a day. “Uncritical laudatory coverage” is common, but specifics are hard to come by. What is it? Where did it come from? Why is it good? “Merits are rarely detailed; possible downsides are never mentioned.” So, let’s dig in.
After World War II, the government of Greece asked the Rockefeller Foundation to come in and assess the situation. Impressed by the low rates of heart disease in the region, nutrition scientist Ancel Keys, after whom K-rations were named, initiated his famous Seven Countries Study, in which he found the rate of fatal heart disease on the Greek isle of Crete was 20 times lower than in the United States. They also had the lowest cancer rates and fewest deaths overall. What were they eating? Their diets were more than 90% plant-based, which may explain why coronary heart disease was such a rarity. A rarity, that is, except for a “small class of rich people whose diet differed from that of the general population: they ate meat every day instead of every week or two.”
So, the heart of the Mediterranean diet is mainly vegetarian, much lower in meat and dairy–which Keys considered the major villains in the diet because of their saturated fat content.
Unfortunately, no one is really eating the traditional Mediterranean diet anymore–even in the Mediterranean. The prevalence of coronary heart disease skyrocketed by an order of magnitude within a few decades in Crete, blamed on the increased consumption of meat and cheese at the expense of plant foods.
Everyone is talking about the Mediterranean diet, but few are those who do it properly. People think pizza or spaghetti with meat sauce, but while “Italian restaurants brag about the healthy Mediterranean diet, they serve a travesty of it.”
So, if no one’s really eating this way anymore, how do you study it? Researchers came up with a variety of Mediterranean diet adherence scoring systems to see if people who are eating more Mediterranean-ish do better. You get maximum points the more plant foods you eat, but effectively get points deducted eating just a single serving of meat or dairy a day. So, no surprise that those who eat relatively higher on the scale have a lower risk of heart disease, lower risk of cancer, and lower risk of death overall. After all, “the Mediterranean diet can be considered to be a near-vegetarian diet. As such, it should be expected to produce the well-established health benefits of vegetarian diets.” So, less heart disease, cancer, and death and less inflammation, improved arterial function, a lower risk of developing type 2 diabetes, and it reduced risk for stroke, depression, and cognitive impairment.
How might it work? I’ve talked about the elegant studies showing that those who eat plant-based diets have more plant-based compounds, like aspirin, circulating within their systems. Polyphenol phytonutrients in plant foods are associated with a significantly lower risk of dying. Magnesium consumption, also associated with a significantly lower risk of dying, is found in dark green leafy vegetables, as well as fruits, beans, nuts, soy, and whole grains.
Heme iron, on the other hand–the iron found in blood and muscle–acts as a pro-oxidant and appears to increase the risk of diabetes, whereas plant-based, non-heme iron appeared safe. Same thing with heart disease: animal-based iron was found to significantly increase the risk of coronary heart disease, our #1 killer, but not plant-based iron. The Mediterranean diet is protective compared to the Standard American Diet—no question. But any diet rich in whole plant foods and low in animal fat consumption could be expected to confer protection against many of our leading killers.
