The traditional diet of Greece and other Mediterranean countries is linked to lower mortality rates, according to a recent study conducted by researchers at the Harvard School of Public Health (SPH).
The study is unique in determining the association between a precisely defined dietary pattern and overall survival, said Dr. Dimitrios Trichopoulos, who directed the study.
"There have really been thousands of studies on particular components of diets," said Trichopoulos. "But there has been very little attention on what the whole diet can do to overall health, as reflected on overall survival."
The study examined the survival rates of some 200 elderly residents of rural villages in Greece for six years. A cross-cultural study undertaken by the International Union of Nutritional Services provided data on the residents' dietary habits.
"A problem that faces many studies which begin following adults is that they must wait a long time in order to determine whether mortality is associated with overall diet," Trichopoulos said.
Trichopoulos said his research team was able to obtain statistically valid mortality rates over a period of just six years, since the subjects chosen were all over age 70.
Subjects were given a classification from one to eight, depending on how closely they followed the eight defined components of a traditional Mediterranean diet.
Dietary components included high consumption levels of legumes, fruits, other vegetables, and cereals; low consumption levels of dairy products and meat products; a high proportion of monounsaturated fat intake (such as olive oil) relative to saturated fat; and moderate alcohol consumption (see graphic).
Subjects who followed this traditional diet closely and had a high score were then compared to subjects who followed it loosely and had a low score. Other factors were taken into account in these comparisons, such as differences in exercise levels, smoking status, gender and exact age.
With the assistance of Loren Lipworth, a third-year doctoral student in the School of Public Health Epidemiology Department, Trichopoulos used statistical modeling and multivariate analysis to determine that an increase of one point in traditional dietary adherence corresponded to an average 17 percent decrease in mortality rate.
Those with scores of six or higher had an eight percent mortality rate over 5.5 years, while those with scores of two or lower had a 38 percent mortality rate.
Overall, subjects adhering to six of the eight traditional dietary components tended to have half the rate of dying as subjects who followed only two.
For Students, Too
While the findings are based on the elderly, they could also apply to other age groups.
"Our view is that our results, which were very clear among older persons, reflect what may well be happening among younger people as well," said Trichopoulos.