Millions of words have been written over the past several years extolling the virtues of the "Mediterranean diet," because of research indicating that populations living in the region and following a traditional diet have lower rates of heart disease and death. But diets vary from one country to another, and time has brought change to some areas too. So what can be said with certainty about the Mediterranean diet as currently consumed? A recent study of a population in Greece does, in fact, show that adherence to a traditional Mediterranean diet is associated with lower rates of mortality. The results have been published in the New England Journal of Medicine.

Studying a "traditional" diet in Greece

Researchers studied more than 22,000 residents of Greece (ages 20 to 86) to determine if adherence to a traditional Mediterranean diet was associated with lower mortality from cardiovascular disease or from cancer. The traditional diet is high in vegetables, fruits, legumes, nuts, and grains (particularly whole grains), and olive oil. It's low in saturated fat, meat, and poultry, but moderate in yogurt and cheese. Fish intake is generally "moderately high, depending on the proximity of the sea," and alcohol intake is moderate (generally in the form of wine taken with meals).

At the beginning of the study, the participants completed detailed questionnaires about their diet and other lifestyle habits. They were followed for an average of 44 months, during which time there were 275 deaths.

Diet associated with lower risk of mortality

The researchers adjusted for other factors that could have influenced mortality risk, such as age, gender, body mass index, smoking status, and physical activity level.

They found that the more strongly people adhered to the traditional diet, the less likely they were to die from cardiovascular disease or cancer; the protective effect of the traditional diet appeared stronger for cardiovascular disease than for cancer. Interestingly, individual components (food groups) of the diet did not, on their own, impart significant protection.

No "magic" foods

Exactly how the traditional Mediterranean diet may affect life expectancy is unknown. But the data from this study indicate that it is the overall dietary pattern - not merely eating some particular foods - that promotes longevity. The point is: You can't just start adding lots of olive oil to an unhealthful diet and expect to reap benefits.

Can Americans see the same benefits?

It's also important to note that these results were observed in people living in Greece, where day-to-day life may be markedly different than in other countries. It may be that something about their entire lifestyle - including factors not measured in this study - contributes to longevity. Whether or not Americans can adopt such a diet without changing their overall lifestyles and still see health benefits remains to be seen.

Still, this adds to existing evidence that health-conscious consumers could benefit by increasing their intake of fruits, vegetables, whole grains, and legumes and by decreasing their intake of saturated fat.