OBJECTIVES: To delineate the influences of the Mediterranean diet (MD) on human mortality and age-related morbid conditions, principally the metabolic syndrome, hypertension, cardiovascular disease, excess body weight, cancer, poor bone mineralization and rheumatoid arthritis, and neurodegenerative disorders. METHOD: Citations were selected from a PubMed search according to their clinical and experimental relevance. RESULTS AND CONCLUSIONS: Individuals who adhere to the principles of the traditional MD tend to have a longer life-span. Both men and women who report eating foods closest to the MD are about 10-20% less likely to die over the course of a study of heart disease, cancer or any other cause. The longevity of Mediterranean people has been related to olive oil, and its several microcomponents of antioxidant potential, present in all MD variants. The prevalence of the metabolic syndrome may be reduced by a MD. The MD is significantly inversely associated with both systolic and diastolic blood pressure. It also has benefits in relation to the prevention of cardiovascular events, reduces the risk of mortality after myocardial infarction, and reduces peripheral arterial disease. The risk of obesity decreases with increasing adherence to the traditional MD. The MD also has a preventive effect on cancer, through its antiproliferative and pro-apoptotic effects, mostly due to the components of virgin olive oil and vegetables. There is some evidence of the benefits of the MD in relation to bone metabolism, rheumatoid arthritis, and neurodegenerative age-related diseases (cognitive deficit, Alzheimer's disease, Parkinson's disease).