A Mediterranean diet helps control blood pressure

This trial studied the effect of a traditional Mediterranean diet on blood pressure control.

Hypertension (high blood pressure) is a leading risk factor for strokes and heart disease (collectively referred to as cardiovascular diseases), as well as early mortality (death). Adopting a healthy diet is important in the control and treatment of high blood pressure. The traditional Mediterranean diet has been identified as a high-quality diet in the management of cardiovascular risk. A Mediterranean diet is one rich in fruits, vegetables, nuts, fish, dairy products and wine, and only small amounts of meat and poultry. Extra virgin olive oil and nuts are the main sources of fats in the typical Mediterranean diet. While many recent trials have demonstrated the benefits of a Mediterranean diet on blood pressure values or cholesterol levels, this controlled trial is the first large study to report the long-term effect of a Mediterranean diet after 4 years.

This trial included 7,158 men and women at a high risk of developing cardiovascular disease (due to factors such as hypertension, smoking, obesity or family history). Participants were randomly placed in one of three groups. Group 1 received education on following a Mediterranean diet and free supplemented extra-virgin olive oil. Group 2 received education on following a Mediterranean diet and free supplemented mixed nuts. Group 3 received education on following a low-fat diet and acted as a control group.

All three groups showed a significant reduction in blood pressure values after 4 years. Systolic blood pressure (the pressure in the arteries during contraction of the heart muscle) was not significantly different between the three groups. A significantly greater reduction in diastolic blood pressure (the pressure in the arteries while the heart muscle is relaxed, between heart beats) was found in the Mediterranean diet groups compared to the control group. The greatest reduction in diastolic blood pressure was found to be in the Mediterranean diet group supplemented with extra-virgin olive oil.

This study concluded that following a traditional Mediterranean diet, supplemented with high amounts of extra virgin olive oil or nuts, provides a long term benefit over blood pressure control.

The good quality of the low-fat diet prescribed to participants in the control group may have impaired this study’s ability to find larger differences between the three groups.  In addition, no information was provided regarding the adherence of participants to their assigned diet plan.