Florence, Italy - Sticking with any diet is difficult, but the incentives of adhering to the traditional Mediterranean diet are particularly beneficial, a new meta-analysis has shown [1]. Strictly following the Mediterranean diet reduced the risk of dying from cancer and cardiovascular disease as well as the risk of developing Parkinson's and Alzheimer's disease, and investigators say that greater adherence can be a relatively simple tool to reduce the risk of premature death in the general population.

"The practical implication is that we are able to talk to our patients and show them that sticking to this diet, the specific characteristics of the diet, improves their overall health and quality of life," lead investigator Dr Francesco Sofi (University of Florence, Italy) told heartwire. "This is good information to give, especially if we're able to tell them something as simple as eating more fruits and vegetables."

The meta-analysis, published online September 12, 2008 in BMJ, included primary-prevention studies that assessed how well individuals stuck to the traditional Mediterranean diet and whether this translated into health benefits. In each of the 12 trials included in the meta-analysis, which included more than 1.5 million patients followed from three to 18 years, a numerical score, known as the adherence score, was used to assess how closely individuals were following the diet. A score of zero indicated low adherence to the diet, while a score of 7 to 9 points indicated high adherence to the Mediterranean diet.

Individuals who stuck strictly to a Mediterranean diet—defined as a two-point increase in the adherence score—had significant improvements in their overall health, including a 9% reduction in all-cause mortality, a 9% reduction in mortality from cardiovascular disease, and 6% reduction in cancer mortality. Although only three trials examined the association between adhering to the diet and the risk of Parkinson's and Alzheimer's disease, there was a reduced risk of these diseases when individuals closely followed the Mediterranean diet.

"The results overall showed that increasing two points on the adherence score results in a significant protective effect in terms of chronic diseases," said Sofi. "The study supports the current guidelines and recommendations of all the current scientific organizations that encourage the Mediterranean diet. It does say more, however, in terms of adherence, meaning it is important to actually stick with the diet."

In terms of applying the findings to the real world, Sofi said creating an adherence score based on "a theoretically defined Mediterranean diet" could be used as preventive tool for reducing the risk of mortality and morbidity in the general population. However, he added, it is important to define the diet properly.

"The problem with the literature is that a lot of papers suggest eating in a Mediterranean way, but what is the Mediterranean way? That's the problem. If you ask two subjects, you're going to get two different answers. We need to attempt to develop the characteristics of the Mediterranean diet and create the adherence score based on that."