Mediterranean Diet

It turns out that the healthiest diet is one of the most enjoyable diets.  Lucky for us, one of the most enjoyable ways to eat a more plant-based, animal-reduced diet is to eat as the traditional Greeks--the dietary pattern affectionately known as the "Mediterranean diet".

In the 1960’s Professor Ancel Keys first reported on the health benefits of people who ate the traditional diet in the Greek island of Crete and Southern Italy in the 7 Countries Study.  Professor Keys documented the diets of 13,000 middle-aged men (ages 40-59) living in Southern Italy, Crete, Yugoslavia, Finland, Netherlands, Japan and the US.  Interestingly, the Cretan diet was one of the highest fat diets in the study (40% fat), but it was low in saturated fat and high in monounsaturated fat, and the Cretan Greeks eating it came out with some of the lowest rates of coronary heart disease and all-cause mortality and had the longest life expectancy in the world at that time. The population of Finland ate the most saturated fat (mostly from cow’s milk products) and had the highest levels of blood cholesterol and the most heart disease.  Even though the population from Finland had a similar intake of fat to that of the Cretans, the population of Finland had 30 times higher the rate of heart disease!  

The Cretan diet was also relatively low in carbohydrates (45% energy) with most of the carbohydrates consumed being of low glycemic index.  However, this is not a “low carbohydrate diet” as has been popularized to Americans in the recent high-protein diet craze (those diets are usually based on a dangerously low carbohydrate intake of about 30-40%).  Unlike the popular “low-carbohydrate diets” of America, the Cretan diet was based on a large volume of plant foods and consisted of a high intake of vegetables (2-3 cups/day, especially green leafy types including purslane), high intakes of legumes (30g/day), nuts (30g/day, especially walnuts), fruit (2-3 fruits/day) and wholegrain cereals (equivalent to 8 slices of bread/day).  They also had moderate intakes of fish (40g/day), alcohol (20g/day with meals, i.e. 2 standard drinks/day) and low intakes of red/white meat (35g/day) and fermented sheep/goats milk products (cheese/yogurt consumed weekly). This is the equivalent of a 5 oz. serving of fish 2x/week, a 4-5 ounce serving of chicken/pork once a week, a 4-5 ounce serving of lamb once a week or less, and bean/lentil soups or casseroles about 2-3 times a week.

The Cretan diet was also low in animal and saturated fat (8% energy), but high in total fat (40% energy) and monounsaturated fat (25% energy).  The major source of fat was olive oil (about 4 tablespoons/day), which was nearly always consumed as 'extra virgin' or the first pressing of the olive and nearly always consumed with plant food.  The combination of vegetables with olive oil in the Mediterranean cuisine may be an important component responsible for its protective effect.  For example, the antioxidant lycopene in tomatoes is better absorbed in the intestine if the tomatoes are cooked, and absorption is even better if cooked with oil, which makes sense since these pigments are fat soluble.  

Countless studies have consistently verified the health benefits of the Mediterranean diet. The Mediterranean Diet pyramid was developed by Professor Walter Willet and colleagues at Harvard University. 

Further evidence in support of the health benefits of the Mediterranean diet emerged in the 1980’s and 1990’s from the Lyon Diet Heart Study in France.  Six-hundred middle aged Frenchmen who had survived a heart attack were placed in two different groups--one group ate a prudent diet recommended by the American Heart Association while the other group ate a Mediterranean diet.  The group on the Mediterranean diet had a 70% reduction in all cause mortality, including heart attack and angina, compared with people on the prudent diet.  Although the study was supposed to last for 5 years, it was stopped after 2 years because of significant differences in the rates of death, heart attacks and angina between the two groups--it just wasn't ethical to keep the group on the prudent diet off of the Mediterranean diet!  After 4 years, overall death rates were 56% lower and cancer deaths were 61% lower among patients eating the Mediterranean diet.  The protective effect of the Mediterranean diet was shown after 2 years and then 4 years, suggesting it is not only effective but robust.  The chances of dying from a heart attack (and cancer) were more than halved in those who had received only one-hour’s instruction on the benefits of eating a Mediterranean diet!  Positive health benefits were achieved with relatively little dietary education--just learning about the diet seemed to be enough to lead to major lifestyle changes.

According to Professor Frank Sacks of Harvard University, both low fat and high fat diets, low in saturates, can reduce LDL cholesterol by 17%.  However, low fat high carbohydrate diets reduce the “good” blood cholesterol (HDL) by 18% as compared to the Mediterranean diet, therefore, a low fat diet would predict a 16% or more increase in coronary incidence.  Additionally, in the short-term at least, low fat diets also increase serum triglycerides about 25%.  This would predict an increase in coronary incidence of 16% in women and 6% in men.  On the low fat diet the benefits of the decrease in LDL are nearly completely offset by the negative impact of reduced HDL and increased triglycerides, and this actually predicts an increase in coronary incidence.

There is no doubt that the Mediterranean diet is the optimal diet to shoot for, and our American research and dietary recommendations have been conforming to that model more and more completely every year.  What has always been an optimal diet, still is an optimal diet, and will continue to be.  An optimal diet has not changed, only our increasingly better understanding of it has. 

Enjoy!

Diane Preves, M.S., R.D.

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