Can a Mediterranean diet improve mortality risk?

The authors assessed the association between a Mediterranean diet and mortality in patients with a history of cardiovascular disease.

The Mediterranean diet includes a high consumption of fruit and vegetables, a substantial intake of protein from plant sources (legumes and nuts) and a high intake of fats (mostly monounsaturated fats). There is also a moderate to high consumption of fish and subsequently, a low consumption of meat and meat products. Alcohol intake is moderate, olive oil is the predominant fat used for cooking and dressing salads while sautéing and stir-frying are the main cooking methods.

There is substantial evidence for the benefit of the Mediterranean diet on long term health. However, its effect in people with previous cardiovascular disease is not well established. Thus, the objective of this study was to assess the long-term association between a Mediterranean-style diet score and all-cause, cardiovascular and cancer mortality in men and women with cardiovascular disease.

The study included 6,137 men and 11,278 women with nonfatal cardiovascular disorders. The events considered were myocardial infarction (heart attack), stroke, angina pectoris (chest pain due to lack of oxygen reaching the chest muscle), coronary bypass (to reduce risk of death from coronary artery disease) and coronary angioplasty (a procedure to open narrow blood vessels during coronary artery disease). After the initial diet assessment, diets were assessed with a food-frequency questionnaire every 2-4 years following. The average follow-up for men was 7.7 years and for women was 5.8 years.

The Alternate Mediterranean Diet score was calculated by rewarding 1 point if dietary intake was above the group-specific average for vegetables, legumes, fruit, nuts, whole-grain cereals, fish, and monounsaturated fats, and 1 point for intake below the group-specific average for red and processed meats. In addition, alcohol intake of 5 to 15 g/day for women and 10 to 15 g/day for men received 1 point. Thus, a higher score represented a higher adherence to the Mediterranean diet, with a score range between 0 and 9.

Patients with lower scores were more likely to be smokers, to have less physical activity and drink less alcohol than those with higher scores. During the follow up, 1,142 male and 666 female deaths were attributed to cardiovascular disease, and 344 male and 197 female deaths were attributed to cancer.

Compared to those with the lowest scores, those with the highest scores has a 19% reduced risk of overall mortality (death) during the study period. In addition, a 2 point increase on the Alternate Mediterranean Diet score was associated with a 7% decrease in the risk of mortality. For men, compared to those with the lowest scores, those with the highest scores had a 23% reduced risk of mortality from cardiovascular disease. This association, however, was not seen for women. For women, compared to those with the lowest scores, those with the highest scores had a 25% reduced risk of mortality from diseases other than cardiovascular disease or cancer (including diabetes, Alzheimers disease, Parkinson's disease and liver cirrhosis).

The authors suggested that adherence to a Mediterranean-style dietary pattern was associated with lower all-cause mortality in individuals with cardiovascular disease.