Clinical Question: Is a Mediterranean diet associated with lower mortality?

Setting: Population-based

Study Design: Cohort (prospective)

Synopsis: Numerous ecologic studies have suggested that a Mediterranean diet high in vegetables, legumes, fruits, nuts, cereals, olive oil, fish, and alcohol; moderate in cheese and yogurt; and low in saturated lipids, meat, and poultry is associated with greater longevity. This is the largest prospective study to date of this hypothesis.

Investigators identified 25,917 community-dwelling Greek persons to participate in the study, 3,874 of whom were excluded because they had coronary heart disease, diabetes mellitus, or cancer at enrollment. Investigators conducted a detailed assessment of the participants' diet and lifestyle, and rated their adherence to the Mediterranean diet on a scale from zero (not at all) to 9 (perfect adherence). The median follow-up was 3.7 years. This was not a randomized trial, so the outcomes were adjusted for age, gender, smoking status, body mass index, and energy expenditure. The mean body mass index was 28.1 for men and 28.8 for women; 60 percent were women, and more than one half of all participants had never smoked.

Other than the ratio of monounsaturated lipids to saturated lipids, individual dietary factors were not associated with mortality. However, every 2-point increase in the Mediterranean diet score was associated with a 25 percent reduction in the risk of death from any cause, a 33 percent reduction in the risk of death from coronary heart disease, and a 24 percent reduction in the risk of death from cancer. The benefit was greater in women, persons older than 55 years, never-smokers, overweight persons, and sedentary persons.

Bottom Line: This excellent study lends further strength to the association between a Mediterranean diet and a reduction in all-cause mortality. (Level of Evidence: 2b)